Barrier Analysis of Flexibilization of Cooling Supply Systems

Abstract

The present study examines the barriers that prevent cooling system flexibility from being optimized. In the context of an increasing reliance on renewable energy sources, the necessity for flexible energy utilization is becoming increasingly apparent. A survey and discussion groups were conducted with various stakeholders within the cooling value chain to obtain their experiences and insights regarding barriers to flexibilization. The findings point out that economic, technological, and regulatory barriers are the primary factors impeding the implementation of flexible solutions. In particular, high investment costs, complex technical implementation, a lack of information, and a complicated legal framework were identified as significant impediments. To enhance the flexibility of cooling systems, coordinated efforts are necessary to address these barriers. Practical examples, training, and the standardization and digitalization of processes could facilitate the widespread implementation of flexible cooling systems.

1. Introduction

The German government has set a target of achieving greenhouse gas neutrality by 2045 [1]. A central goal of the energy transition is for renewable energies (RE) to account for at least 80% of gross electricity consumption by 2030 [2]. In 2023, the share of renewable energy in gross electricity consumption was 51.8% [3], indicating that a significant increase in power generation from RE is necessary. This share rose to 55.2% in 2024 [4].

Given the limited number of controllable geothermal power plants in Germany and the fact that its hydropower potential is largely tapped, the expansion of renewable energy capacity will primarily come from wind and photovoltaic (PV) installations. Both wind and PV energy are classified as variable renewable energies, as their output cannot be directly controlled and fluctuates throughout the day and year. Without appropriate energy storage systems, the gap between the minimum and maximum power generated by photovoltaic and wind sources will increase as the number of these facilities expands. This growing disparity highlights the critical necessity for flexibility within the energy system [5].

To ensure this flexibility, it is essential to introduce flexibility in consumption across different application areas. One important area is the cooling of various products and processes. In 2017, electricity consumption for cooling systems in Germany was 73 $\mathrm{T}$$\mathrm{W}$$\mathrm{h}$, representing 14% of total electricity consumption [6]. This demand is distributed across a variety of sectors with different consumption profiles and operational characteristics. For example, air conditioning in buildings and vehicles consumed around $11.0$ $\mathrm{T}$$\mathrm{W}$$\mathrm{h}$. Industrial cooling processes (excluding food production) represented another significant share with $11.9$ $\mathrm{T}$$\mathrm{W}$$\mathrm{h}$, and supermarket refrigeration consumed $8.5$ $\mathrm{T}$$\mathrm{W}$$\mathrm{h}$. These examples highlight the diversity of cooling applications and underline the importance of considering sector-specific requirements and barriers when discussing flexibilization potentials. This substantial demand for electrical energy presents a significant opportunity for load management within the power grid. Cooling systems are integral to the supply infrastructure, allowing them to dynamically adjust both their cooling capacity and energy consumption, thereby contributing to grid stability. Additionally, by storing surplus renewable electricity as heat or cold during high generation periods, these systems support the integration of renewable energy from wind and photovoltaic sources and help mitigate generation peaks [7].

The importance of cooling systems in the context of load management is increasingly acknowledged. The cooling sector’s significant contribution to Germany’s total electricity demand makes industrial cooling supply systems a promising option for scalable flexibility solutions. Their capacity to manage loads and optimize energy consumption makes cooling systems a valuable tool for the implementation of demand-side management strategies [7].

In the past, several research projects have addressed the flexibilization of cooling supply systems, ranging from Night Wind [8] (2006–2008) and eTelligence [9] (2008–2012) to more recent initiatives such as FlexKaelte (2019–2022) [10], FlexKälte (2020–2023) [11], and BlueMilk (2018–2022) [12]. All of these projects concluded that flexibility within cooling supply systems exists and that it presents opportunities for greenhouse gas reduction. Therefore, the ongoing research project FlexBlue (grant number 03EN6035A), within which this paper was developed, aims to further explore this topic and derive actionable recommendations that will encourage widespread implementation and mobilize the potential. As part of the project, an attempt was made to identify implementation examples, which proved to be highly challenging, with only a few cases found. Due to this discrepancy between potential and lack of implementation, it is crucial to examine the existing barriers. A key research objective is to understand what limits the implementation of flexibility and what solutions could help overcome these challenges. To achieve this, a survey will be conducted to obtain relevant feedback from a wide range of stakeholders within the value chain, as shown in Figure 1. The aim of this approach is to identify the barriers specific to each stakeholder and to provide a comprehensive overview of the problems encountered, ultimately serving as the basis for formulating actionable recommendations.

2. State of the Art

2.1. Definition of Flexibility

The scientific literature offers a variety of definitions of flexibility in energy systems. However, flexibility can be generally understood as the ability to respond to changes in demand. This is evident in the works of various authors [7,13,14,15,16,17], all of which highlight the importance of responsiveness to demand fluctuations. Further definitions of flexibility of different authors are summarized in [18]. These discrepancies illustrate the complexity and multifaceted nature of the subject matter, as the concept of flexibility is interpreted in diverse applications and under disparate conditions. A precise definition is essential for an accurate understanding of the role of flexibility in energy generation and utilization.

In this paper, flexibility is understood according to the definition in [18]:

“Flexibility is the capability of an energy system to undergo temporary, reversible, and expectable changes to fulfil a specific goal over a certain period in reaction to an external signal.” Specifically applied to cooling supply systems, this means that the operation of the chiller—which uses electricity to generate cooling—deviates from normal operation for a certain period of time in response to an external signal. In normal operation, the chiller would generate exactly as much cooling as is demanded at any given time. In contrast, the flexible operating mode follows a signal, which can be the electricity price or CO₂ emissions of the electricity supply, for example. Flexibility serves, for example, as an instrument to generate monetary benefits in companies, to reduce CO₂ emissions associated with the electricity purchased for cooling or, if necessary, can also be used as an opportunity to reduce grid constraints resulting from the volatile feed-in of renewable energies. This can also provide monetary benefits to companies by reducing network costs.

Flexibilization refers to the adaptation of a system or facility to enable it to provide flexibility. In the context of cooling supply systems, flexibilization means modifying the system in such a way that it can temporarily adjust its electricity consumption in response to external signals (e.g., price or CO₂ intensity), without compromising overall cooling requirements. This may involve, for example, the integration of thermal storage, adjustments to control strategies, or changes in operational planning.

If there is a high supply of electricity from renewable energies, this results in low electricity purchase prices on the electricity exchange and is generally accompanied by low CO₂ emissions. At these times, the chiller should operate at the highest possible output, while the cooling not utilized by the cooling application is stored. A cold storage unit is used for this purpose, or the storage capacity for the refrigerated goods to be stored is utilized. In the case of high prices on the electricity exchange with a low supply from renewable energy sources, the chiller is reduced or ideally switched off. In these phases, the cooling demand is covered by the implemented cold storage system so that the cooling that is required for the cooling application is always reliably available.

2.2. Flexibilization Strategies of Cooling Systems

Given the challenges associated with decoupling cooling demand and generation, the implementation of innovative technologies and strategies is essential. The integration of thermal storage is one of the most promising methods to achieve this decoupling. Thermal storage allows cooling to be generated when energy costs are low, and then the stored cooling can be used when needed, as described in the previous subsection.

Sensible and latent cold storage systems can be used for cold storage. In sensitive cold storage systems, water or a water/glycol mixture is used as a refrigerant and storage medium. The supply and extraction of thermal energy is noticeably felt in sensitive storage systems through a change in temperature. Latent cold storage utilizes the phase change of the storage medium. This means that during a phase transition, heat is added to or extracted from a storage medium without a noticeable change in temperature. Ice storage represents a form of latent cold storage system. Another possibility is the use of macro-encapsulated phase-change materials.

An alternative option is taking advantage of the inherent storage capacity of certain commodities or conditioned spaces, such as deep-freeze warehouses for food items. By utilizing temperature changes, energy can be stored and released in these materials, allowing for a flexible supply of refrigeration. This study focuses on the flexibilization of electrically operated cooling systems. However, it should also be mentioned that there are thermally driven systems for cold generation as well. Whether these can be used for flexibility in the sense described here depends on which heat source they use. If waste heat is used as a heat source for refrigeration production, this would represent a very environmentally friendly way of generating cooling, but due to the lack of coupling to the electrical energy system, no flexibility can be provided for this. When using a combined heat and power (CHP) plant for combined heat and power generation, the CHP plant can be used as a flexible facility [10].

The following section describes several studies about the flexibilization of cooling supply systems and cooling applications. This is not an exhaustive list, as more studies exist. Cooling applications can be categorized into the following areas: process cooling, product storage, and air-conditioning [19].

In the study by Stöckl et al. [20], the authors investigate the flexibility potential of a cold storage warehouse for dairy products as a case study of flexibility in product storage. The cooling capacity of the storage facility is adjusted by modulating the air temperature. The stored products respond to these adjustments by undergoing temperature changes within a predefined temperature range, effectively serving as an inherent thermal cold storage. The flexibility of the cold storage facility must be evaluated in the context of the overall cold chain to ensure compliance with quality and safety standards.

The study presented by Howard et al. [21] serves as an example of flexibility in process cooling. In this study, production and cooling processes for canned meat are analyzed using a custom-developed multi-method simulation. Another example of process cooling in the food industry was examined by von Hayn et al. [22]. Here, the flexibility of various cooling processes in beer production is investigated. Beer production is particularly well-suited for flexibility measures, as it inherently incorporates multiple energy storage systems, with beer itself also functioning as an inherent thermal buffer. Repke et al. [23] explore the use of products as thermal storage in cold storage warehouses to minimize electricity costs. The air temperature is adjusted based on electricity price forecasts, allowing only minor fluctuations. The highest savings are achieved when the temperature is set to the upper permissible limit, though this may affect the stored products. Similarly, Svane et al. [24] examine the use of frozen meat as thermal storage. Their results also indicate significant cost savings, especially with longer forecasting periods. However, they highlight that while warehouse operators aim for flexibility, they often lack the necessary data and expertise.

In the study by Khorsandnejad et al. [15], the variation of electricity consumption by the cooling system in a cold storage warehouse is analyzed with the objectives of reducing electricity costs, lowering greenhouse gas emissions, and mitigating peak loads. The reduction in electricity costs and greenhouse gas emissions is based on the dynamic nature of electricity prices in the market and the specific emissions associated with electricity procurement from the public grid, which fluctuate due to the variability of renewable energy generation. Unlike the approach by Stöckl et al. [20], a dedicated thermal energy storage system is utilized instead of leveraging the stored products as inherent thermal storage.

Laband et al. [7] focus on the inherent thermal flexibility of cooling systems for air-conditioning. Their research is focused on investigating the impacts of diverse cooling demand profiles on flexibility, with the objective of demonstrating how these systems can contribute to the stability of the power grid. The study aims to quantify and classify the flexibility of cooling systems by analyzing a range of characteristics, including cooling demand profiles and storage sizing. From a methodological perspective, their research entails an examination of various cooling demand profiles and their impact on flexibility.

In the German energy market, there are market mechanisms available both to reduce costs and to increase profits. Cost reduction can, for example, be achieved by optimizing electricity procurement in the day-ahead and intraday markets or by minimizing grid charges. Examples of profit-increasing mechanisms include providing system services, such as offering positive or negative balancing power [25].

2.3. Literature Overview of Existing Barriers

In order to gain insight into the barriers faced by stakeholders in the flexibilization value chain as part of the ongoing transformation toward greater flexibility, a comprehensive literature review has been conducted. Existing literature includes studies and reports [26,27] that provide broad overviews of flexibility in general and of common barriers as well as literature that primarily focuses on barriers in industrial companies, the manufacturing sector, and the trade, commerce, and services sector [28,29,30]. Additionally, some studies specifically examine cooling applications [31] or include the barriers and perspectives of transmission system operators (TSO) and distribution system operators (DSO) [32]. The identified barriers are primarily associated with operators of cooling systems and cooling applications in the context of the flexibility definition used, i.e., barriers from the literature that do not apply to the relevance of cooling systems, their flexibilization, or to the definition used are not included. However, it is important to note that there are additional stakeholders within the value chain, which are illustrated in Figure 1. Flexibilization value chain in the context of electrical consumers and producers refers to the coordinated effort of multiple stakeholders across the entire value chain to enable flexible energy consumption and generation. The aim is to optimize energy usage, integrate renewable sources more effectively, and provide flexibility for the energy system. Besides operators of cooling systems and cooling applications, the value chain includes other stakeholders such as planning offices, virtual power plant operators, manufacturers of refrigeration machines, and thermal storage. The stakeholders referenced in existing literature are depicted in orange. The stakeholders that have been additionally identified—and for which no barrier analysis has yet been conducted—are shown in blue. Furthermore, a single barrier may be attributed to multiple stakeholders, which has been taken into account in the subsequent stages of the investigation.

It became evident that a significant number of stakeholders are not considered at all in the existing literature regarding their barriers. This gap in the literature highlights the necessity for further research and leads to the decision to conduct a survey in order to reach additional stakeholders in this area to identify reservations regarding the implementation of flexibilization measures. The barriers identified in the literature are illustrated in the subsequent

Table 1. Barriers in the Economic category.

Barrier	Literature
Share of power cost too small within total production costs	[28]
Greater economic appeal of alternative measures to optimize power costs	[28]
Lack of revenues through demand response	[28,29,30]
(Power) cost savings through demand response are low	[28,30,33]
Price-spreads on spot markets too small	[28]
(Potentially) decreasing profitability in ancillary service markets	[28]
Costly flexibilization investments necessary	[28,29,34]
High IT investments necessary	[28]
Lack of access to external and internal capital	[28]
Additional operating costs due to demand response measures	[28,30]
Cost savings too far in the future	[28]
Potential risk on production target values	[28]
Necessary hedging against non-availability of contractually reserved load for demand response	[28,29]
Uncertainty of revenue	[29]
Uncertainty of system value of demand response	[29]
Competing motivations for market participants	[29]
Demand response programs or energy management are often not part of the core business	[30]
Energy efficiency may decrease at the cost of providing demand response	[30]
Hidden production costs, e.g., production interruptions for equipment installation	[35]
Transaction costs, e.g., negotiating and managing contracts	[35]
Activation costs, i.e., costs of starting processes	[35]
Tedious activation tests	[29]

,

Table 2. Barriers in the Regulatory category.

Barrier	Literature
Complex regulatory framework	[28,30]
Restrictive regulatory framework	[28,30,32]
Lack of access to time-variable electricity prices	[28]
High costs and effort for pre-qualification	[28]
Flexibility product design may limit the potential of demand response	[28]
Contradictory legal incentive	[28]
Distortion of the market signal by levies or fixed prices	[28]
Conflicts with grid fee regulations	[28]
Prioritization of energy efficiency measures	[28,34]
Conflicts with energy efficiency	[28]
Penalties for not providing reserved flexibility	[28]
Demand response not covered by legal framework for privacy and data security issues	[28]
Lack of harmonization in the regulatory framework	[28]
Globally heterogeneous legislation	[28]
Lack of sufficient financial public funding	[28]
Aggregators are necessary due to the low capacity of individual systems	[34]

,

Table 3. Barriers in the Technological category.

Barrier	Literature
Technical risk of disruption of production process	[28,29]
Technically infeasible to reduce peak load	[28]
Risk of lower product quality	[28,30,34]
High requirements of IT	[28]
High effort and complexity within IT system	[28]
Lack of computational capacity	[28,29]
IT security and data security	[28,29]
Lack of IT prerequisites in the company	[28]
Non-availability of appropriate technology to control the demand response measures	[28]
Lack of standardization of IT systems	[28,29]
Lack of interoperability of IT systems	[28,29]
Lack of sensing and metering infrastructure	[29,32]
Complexity and effort to implement and respond to time varying signals	[29]
Fear of equipment wear due to more up/down ramping of production processes	[30]
Linked up-/downstream processes may hinder demand response due to technical requirements	[30]
Aggregator role is not sufficiently developed to utilize demand response from smaller grid-users	[32]
Lack of information about actual capacity in the grid	[32]
Cold chain must not be disrupted	[34]
Load peaks may be generated, which may lead to higher grid fees	[33]
Reluctant to implement demand response, as existing optimization has established a high level of quality	[33]
No sufficiently high-resolution power measurement available	[36]
Potential exposure to hacking from third-party control	[29]

,

Table 4. Barriers in the Organizational category.

Barrier	Literature
Overall missing acceptance of demand response	[30,34]
Additional workload/general restrictions with respect to employees	[28]
Internal guidelines regarding the duration of projects	[28]
Lack of importance of sustainability	[28]
Low priority of energy management and corresponding investments at top management	[28,29]
Power procurement policy of company	[28]
Relevant decision-maker does not have enough power within the organization	[28,29]
Multiple decision-makers involved in decision process of projects	[28,29,32]
Necessity/dependence on external service providers	[28]
Lack of communication and cooperation between different parts of the DSO organization and between DSO and TSO	[32]
Lack of competence and tools to estimate predictability and security margins of flexibility in long term grid planning	[32]

,

Table 5. Barriers in the Behavioral category.

Barrier	Literature
Lack of acceptance among employees	[28]
Skepticism toward fully automated interfaces	[28]
Perceived inconvenience of demand response provision	[28]
Acceptance of third-party control	[29,30,34]
Lack of credibility, familiarity, and trust between parties	[29]
Electricity consumers value comfort over financial reward and unpredictability of response	[29]
Perceived risk of change with pricing and inertia to change the status quo	[29,37]
Bounded rationality for consumer decision making	[29]
User behavior can be counterproductive	[34]
Demand response negatively impacts user comfort	[34]

,

Table 6. Barriers in the Informational category.

Barrier	Literature
Lack of transparency and asymmetry of information	[28,29]
Uncertainty regarding financial implications	[28,29]
Risks and uncertainties regarding price forecast	[28]
Uncertainty about future regulations and legislative developments	[28]
Unclear interpretation of legislation	[28]
Uncertainty regarding allocation, roles, and responsibilities	[28]
Lack of standardized baseline calculation for demand response market	[28,29]
Technological measures for implementing demand response unknown	[28,29]
Costly and uncertain demand response project analysis	[28]
Consumer lack of awareness about demand response	[29,32]
Form of Information and contract complexity	[29]
Regulatory and tariff structures hide the cost of electricity for consumers	[29]
Lack of understanding of cost and benefits related to flexibility	[32]

and

Table 7. Barriers in the Competence category.

Barrier	Literature
Lack of (internal) resources	[28]
Employees lack needed skills	[28,37]
Lack of knowledge about the production process and existing flexibility potential	[28]
Lack of knowledge about energy markets and the potentials of demand response	[28]

.

In some cases, barriers have been assigned to new categories that the authors consider relevant and may not necessarily reflect the categorizations found in the original sources. Barriers are classified into the following categories: economic, regulatory, technological, organizational, behavioral, informational, and competence [28], which are explained in more detail below using selected but not exhaustive examples.

Economic barriers encompass factors related to the financial aspects of flexibilization, e.g., high investment costs and inadequate profitability. These barriers can prevent companies from investing in flexible systems, as the economic benefits are often not clearly evident.

Regulatory barriers pertain to the legal framework, which may be restrictive or complex in nature. This includes the lack of access to variable electricity prices and the high costs associated with pre-qualification, which present significant challenges to the implementation of flexibility solutions.

Technological barriers are technical challenges that impede the implementation of flexible systems. Such risks include those related to the technical aspects of production, the potential for a reduction in product quality, and the high demands placed on information technology (IT) infrastructure.

In the category of organizational barriers, internal barriers within companies are explored, highlighting challenges in adopting flexibilization measures. Significant factors include insufficient acceptance among staff and a failure to adequately prioritize energy efficiency efforts.

When considering behavioral barriers, the emphasis shifts to how human attitudes and behaviors obstruct the implementation of flexibilization measures. Psychological, social, and habitual factors play a critical role in shaping resistance to change and innovation within both individuals and groups.

For informational barriers, the primary concern is the lack of sufficient knowledge or clarity that prevents progress toward flexibility. Uncertainty surrounding future market trends, such as regulatory updates, price dynamics, and financial outcomes, creates barriers to effective planning and decision-making.

In addition, competence barriers include the lack of expertise or knowledge, e.g., about the production processes or technical aspects, and resources within the organization, and are therefore unable to identify and capitalize on the potential for flexibility inherent in their systems.

The literature review demonstrates that a comprehensive array of barriers has been documented. However, as illustrated in Figure 2, the existing studies primarily focus on the manufacturing sector and the trade, commerce, and services sector, with minor attention to grid operators, while all other stakeholder groups have been neglected. To fully capture the range of barriers, a targeted survey encompassing all stakeholder groups will be conducted.

3. Materials and Methods

To identify barriers and experiences in the flexibilization of cooling supply systems along the value chain, a survey was conducted, and multiple discussion groups were held.

3.1. Design and Realization of the Survey

In addition to the literature review, which only focuses on specific stakeholders, the questionnaire aims to provide a comprehensive barrier analysis covering all stakeholders involved in the flexibilization value chain. The approach involves designing a single questionnaire applicable to all stakeholders, structured as follows:

• General Information;
• Experience with Flexibilization;
• Motivation and External Pressure to Act;
• Impact Strength;
• Barrier Analysis;
• Recommendations for Action.

General Information: The questionnaire starts with 5 general questions, focusing primarily on participants’ self-identification as one or more stakeholders in the flexibilization value chain.

Therefore, the barriers faced by these different stakeholders need to be considered in order to ensure a comprehensive and effective implementation of flexibilization measures. The industry sector is inquired in the questionnaire; as barriers and incentives for cooling system flexibilization can vary between sectors. Additionally, participants are asked about their company size and department.

Experience with Flexibilization: Participants are asked whether they have experience with the flexibilization of cooling supply systems. Based on a simple distinction (yes/no), follow-up questions are tailored accordingly. Such inquiries encompass an examination of the underlying factors that contribute to positive experiences, as well as an investigation into the circumstances that lead to the absence of such experiences in individuals who have not yet had the opportunity to experience them. Additionally, participants are asked about any challenges encountered and what could have improved the outcome. This approach helps differentiate between those with practical experience and those who have only considered flexibilization without implementation, or whose previous implementations were discontinued. Subsequently, the results may be subjected to further analysis with a view to identifying common problems or exemplars of best practice. The reasons for why flexibilization has not been implemented, or the issues that led to the discontinuation of efforts, are also explored.

Motivation and External Pressure to Act: Subsequently, participants are queried regarding their motivation for pursuing flexibilization, e.g., cost reduction, regulatory compliance, operational reliability, and the external pressures that have influenced the implementation of such measures, e.g., government policies, market competition, and stakeholder expectations. This allows for an evaluation of the external pressures on participants and an estimation of the relative importance of the barriers identified.

Impact Strength: Furthermore, participants are requested to evaluate their impact strength. In this context, the term “stakeholder impact strength” is used to describe the degree of influence a particular stakeholder has in implementing flexibilization, in comparison to the influence of other stakeholders. This assessment allows for the weighing and categorization of the identified barriers, affording greater weight to those faced by stakeholders with a higher level of influence while still considering all barriers.

Barrier Analysis: Participants are requested to select from a list of predefined answer options and to provide an open-ended response indicating their primary barrier.

Recommendations for Action: Furthermore, participants are requested to offer practical recommendations for action that would facilitate the implementation of flexibility solutions. This facilitates the identification of necessary improvements and areas in which additional assistance is required.

3.2. Data Analysis

In the course of the investigation, the relevance of the conducted survey was initially evaluated to ensure that the collected data would yield meaningful and valuable insights, thus justifying the research project as a whole. Subsequently, a canonicalization procedure was conducted to ensure a uniform representation of the responses. This approach transformed the data into a standardized, uniform format, creating a foundation that enables consistent comparisons and insightful analyses. This stage was of great importance in enhancing the quality of the data and preventing bias in the subsequent analysis.

Following the canonicalization process, the collected responses were subjected to a systematic review and categorization in accordance with the established methodology. Thematic categorization is employed to organize related terms under broader categories. To illustrate, terms such as “low savings potential,” “uncertainty about returns,” and “lack of flexible electricity tariffs” are grouped under the category of economic viability. The categorization process allowed for the identification of patterns within the dataset, thereby enabling a differentiated analysis of the results. The categorization of responses also facilitated an understanding of the diverse perspectives of the respondents, which in turn enabled a more detailed and nuanced evaluation.

In the final stage of the process, a statistical analysis was conducted on the categorized responses. This analysis entailed the collation of frequencies pertaining to individual results, in addition to the calculation of percentage shares in relation to the population. By employing this methodological approach, a robust interpretation of the results was achieved, which can serve as a foundation for further discourse and conclusions.

It is important to note that the composition of the respondent base may vary across questions due to the implementation of branching logic. Additionally, some open-ended questions were optional and therefore not answered by all participants. Consequently, the scales of the axes differ accordingly.

3.3. Discussion Groups

Discussion groups were utilized to identify and thoroughly examine the key barriers to the implementation of cooling flexibilization measures. The groups comprised a diverse array of stakeholders, each contributing unique perspectives and expertise to the discourse. In addition to the researchers leading the discussion groups, the following stakeholders were involved:

• Manufacturers of refrigeration machines;
• Planning and Design of cooling supply systems;
• Manufacturers of cold thermal energy storage;
• Planning and Execution of Maintenance;
• Data center operators representing cooling applications;
• Cooling system operators;
• Distribution network operators;
• Electricity suppliers;
• Metering point operators;
• Representatives of associations;
• Virtual power plants.

The discussions addressed several key topics, including the involvement of additional stakeholders in the flexibilization value chain and the barriers associated with each of these stakeholders. The objective of these discussions was to gain a more comprehensive understanding of the value chain and to identify the specific challenges that can be attributed to each stakeholder.

4. Results

4.1. Survey

The following section presents the results of the online survey. The survey was aimed at all companies operating in the field of cooling system flexibilization, serving as stakeholders along the corresponding value chain. A total of 52 companies participated. The results are described thematically.

4.1.1. General Information

The companies assigned themselves to one or more stakeholder roles, as shown in Figure 2.

Additional stakeholder roles (represented as “Other” in Figure 2) include research institutions, associations, other manufacturers, and entities involved in energy inspection. There were certain stakeholder roles for which there were no responses (e.g., Transmission System Operators) or only very few responses (e.g., Experts / Consults). A considerable number of companies are involved in some aspect of planning, even if it is not their core business, which accounts for the high number of mentions in this area. It is important to consider that the survey primarily reached companies that serve customers, rather than the customer base itself, when analyzing the survey results. In this case, customers are mainly cooling system operators.

4.1.2. Experience with Flexibilization

Figure 3 shows the survey results on whether the companies have some experience with the flexibilization of cooling supply systems.

A total of 35% of the surveyed companies have experience with flexible cooling supply systems, while 37% are currently exploring the possibility of implementing such systems. Approximately 19% of the respondents indicated that they did not pursue this option or decided to exclude it from further consideration.

The questionnaire is now divided into two sections: one for those who have experience with the subject matter (18 participants, representing 34.6% of the total number of respondents) and one for those who have not (29 participants, representing 55.7% of the total number of respondents).

Existing Experience with Flexible Cooling Supply Systems: Those with experience were asked if their experience with the flexibilization of cooling supply systems had been positive (closed-ended question, $N=18$):

• “Yes, predominantly positive”: 12 companies, 66.7%.
• “Yes, but with limitations”: 6 companies, 33.3%.
• “No, no positive experiences”: 0 companies, 0%.

All companies surveyed indicated that their experience was overall positive, with no company stating that every experience was negative. The majority of companies that have had experience have reported a predominantly positive experience.

Additionally, respondents were queried as to the principal factors that contributed to their positive experiences. The most frequently cited factors were as follows (open-ended question, $N=13$):

• Decreasing energy costs: 8 mentions.
• Improved efficiency: 3 mentions.
• Energy savings: 2 mentions.
• Functioning systems: 2 mentions.
• Measurement data volume creates additional benefits: 2 mentions.

Furthermore, the following factors were mentioned once: payback time, positive impact on control behavior, price advantages, and the feasibility of solutions through customized approaches. The reduction of energy costs was identified as the primary factor influencing the economic situation of the companies, while efficiency improvements and energy savings also contributed to this outcome.

The challenges associated with the implementation of flexible cooling systems were classified. Figure 4 illustrates these challenges, which include the following aspects:

• Economic challenges: High investment costs and time-consuming planning.
• Technological challenges: Product quality and technical constraints.
• Lack of knowledge and information: Lack of understanding of complex systems.
• Lack of Willingness to Implement: Lack of willingness to realize flexibilization measures.

The survey results indicate that companies encounter a number of barriers when it comes to the flexibilization of their cooling systems. These challenges can be classified into several categories, which will be elaborated upon in the following sections.

First, there are the economic challenges. These include the following:

• High investment costs: The initial cost of implementing flexible systems can be significant.
• Time-consuming and consulting-intensive planning: Planning and consulting often require significant time and resources.
• Inaccurate payback calculations: Inaccurate calculations can cause companies to avoid investing.

In addition to the economic issues, there are also technological challenges to consider. Companies reported the following issues:

• Product quality: Product quality must be ensured.
• Quality assurance: Measures are needed to ensure quality during implementation.
• Technical constraints: Certain technical conditions may restrict flexibilization.
• Tight temperature limits: Temperature limits must be strictly adhered to in order to guarantee the quality of the product.

A further significant issue is the lack of knowledge and information. Many companies find themselves in a position where they are unable to cope with the following difficulties:

• Understanding systems in complex plants: A deep understanding of systems is essential for flexibilization.
• Few examples of successful implementation: There is a lack of inspiring examples that can serve as references.
• Lack of knowledge about power markets: Lack of knowledge can hinder decision making.

A lack of willingness to implement was also mentioned. The following factors play a role:

• Persuading decision-makers: Decision-makers often need to be convinced of the benefits of flexible systems.

Some companies also mentioned other challenges such as the following:

• External intervention in the control of the cooling system: These can affect the effectiveness of the systems.
• Adjustment of user behavior: Changes in user behavior are necessary to use the systems effectively.
• Availability of qualified staff: The lack of sufficient qualified personnel can lead to difficulties in implementation.

Additionally, participants were queried as to what factors could have enhanced their experience with flexibilization. Frequently evinced suggestions included the following: (open-ended question, $N=13$):

• Digitization of the system: This could increase efficiency.
• Standardized interfaces: A single standard would make integration easier.
• Reduced development effort: Reduced effort would speed implementation.
• Increased flexibility within constraints through quality assurance: This could improve usability.
• Greater user involvement: Greater user involvement could promote success.
• Demonstrate benefits to decision-makers: Clear benefits must be communicated.
• Sound technical planning and realistic costing: These are critical to success.
• Regulatory framework for assessing the suitability of energy systems (see ISO 50001 [38]): A clear framework would facilitate decision making.
• Reform of the network tariff system: This could provide incentives for investment.

No existing experience with flexible cooling supply systems: A particular emphasis was placed on the reasons why some companies have not yet had the opportunity to gain experience with flexibility. The most frequently occurring reasons were as follows (semi-open question, $N=29$):

• No customer mandate: Many companies are waiting for a push from customers.
• “Never change an existing system”: The attitude that existing systems should not be changed is widespread.
• Lack of qualified personnel: A lack of qualified personnel can complicate implementation.
• Lack of flexible electricity tariffs: The availability of such tariffs is of paramount importance.
• Lack of information about flexible electricity tariffs: A lack of information can have a deterrent effect.
• Return on investment (ROI) too high: Many companies are wary of high investment risks.

Among the various reasons proffered, the absence of a customer mandate was identified as the most frequently cited.

4.1.3. Motivation and External Pressure to Act

The participants in the survey were invited to evaluate their own levels of motivation and pressure to act, each on a scale of low, medium, or high. This yields a total of 9 potential combinations within the matrix.

The results of the survey (depicted as red circles in Figure 5) indicate that companies are strongly motivated to enhance the flexibility of their cooling systems. In fact, more than half of the participating companies (29 out of 52) reported high motivation in this regard. Overall, 88% of respondents indicated either medium or high motivation. Nearly half of the companies reported experiencing a medium or high level of pressure to act. Interestingly, even among those who reported no pressure to act, a significant number (20 out of 24) still expressed motivation to improve flexibility. This suggests that motivation is not solely driven by external pressure, but may also stem from internal strategic considerations or perceived long-term benefits.

After the self-assessment based on motivation and external pressure to act, respondents were asked about the reasons for their evaluation. For both motivation and external pressure to act, the categories “medium” and “high” were combined. As a result, the categories A, B, C, and D were derived, as shown in Figure 5.

• Category A represents a low external pressure to act. It comprises a total of 24 companies, representing a range of levels of motivation. Of these, 13 companies report high motivation, 7 report medium motivation, and 4 report low motivation. These companies demonstrate a notable willingness to increase flexibility, but require external incentives to act.
• Category B shows companies that experience both medium and high external pressure to act. A total of 28 companies are included in this category, comprising 12 companies with medium pressure and 16 companies with high pressure. Of these, 2 companies exhibit low motivation, 10 demonstrate medium motivation, and 16 are characterized by high motivation. These companies demonstrate motivation, yet their actions are contingent upon external factors such as customer demands and regulatory requirements.
• Category C encompasses organizations that exhibit a spectrum of medium to high motivation level, alongside a corresponding variation in external pressure to act. A total of 46 companies are included in this category, comprising 29 with high motivation and 17 with medium motivation. These companies are subjected to a total of 15 instances of high pressure, 11 of medium pressure, and 20 instances of low pressure. These entities are subject to a multitude of internal and external influences that collectively inform their decision-making processes and facilitate an increase in flexibility.
• Category D includes companies with low motivation. A total of six companies are included in this category, with four exhibiting low pressure and one demonstrating medium and high pressure. Such companies may encounter difficulties in initiating change, due to a combination of low motivation and an absence of sufficient external pressure.

In addition, the reasons for perceived pressure to act are summarized in

Table A1. Classification of reasons for motivation and external pressure to act.

Category	Reasons
A	Dependence on decision-makers (3)
	Lack of incentives for decision-makers (3)
	No variable electricity tariffs (2)
	Environmental reasons not a priority
	Use of green energy
	Lack of awareness
	No external pressure to act, only internal
	Customer requirements
	No legal requirements
B	High or rising energy costs (20)
	Compliance with sustainability requirements (12)
	Laws and regulatory requirements (10)
	Customer requirements (10)
	Grid stability (8)
	Internal energy management (8)
	Society (3)
C	Economic reasons (38)
	Environmental reasons (30)
	Other (8)
	Innovation, technology, and industry leadership (2)
	Ensuring better planning capability for energy providers as a consumer
	Enthusiasm for the transformation of electricity consumption
D	Limited network congestion at the city level
	Not economical due to additional effort for trade businesses
	Difficult to implement in production

.

The most common reasons in each category are as follows:

• Category A: Reasons are characterized by dependencies and a lack of incentives for decision-makers, such as the lack of variable electricity tariffs and environmental issues that are not prioritized.
• Category B: This category is dominated by economic considerations, including high or rising energy costs and compliance with sustainability requirements, which put significant pressure on companies.
• Category C: This category is driven by economic and environmental reasons, with companies seeking to position themselves as innovation leaders and improve their planning capabilities.
• Category D: Companies in this category are faced with challenges related to limited grid capacity and difficulties in implementation in production.

4.1.4. Impact Strength

The participants were requested to categorize their influence as “no impact,” “low impact,” “medium impact,” or “high impact” in order to assess their own influence as part of the flexibilization value chain in terms of their impact strength on flexibility potential (closed-ended question, $N=51$).

The majority of respondents, 51% (26 companies), indicated that they perceive their influence to be of a medium degree. This indicates that companies are conscious of their potential influence but may also acknowledge the difficulty of optimizing their influence in this context.

In addition, 23.5% (12 companies) indicated that their influence was perceived to be minimal. On the one hand, these responses reflect self-assessments of their impact strength, especially from companies that already have experience with flexibility measures. On the other hand, a large part of the group has only rudimentary experience with such measures and may therefore be unable to accurately assess their impact strength.

This assessment may indicate that these companies are experiencing difficulties in identifying or realizing their impact on the flexibility potential within the value chain.

A smaller proportion of respondents, representing 21.6% percent of the total, 11 companies rated their influence as “high.” These companies appear to have a clear understanding of their role in the value chain and may be willing to contribute to increasing flexibility potential in an active manner.

Finally, 3.9% (2 companies) stated that they have “no influence” on flexibility potential. This assessment may indicate a perceived isolation or lack of influence within the value chain.

The results indicate that, while a significant portion of companies perceive a medium level of influence, there is room for strengthening their position and influence within the flexibilization value chain. The differentiation in influence highlights the variety of perspectives and challenges that companies face with respect to flexibility potential.

4.1.5. Barrier Analysis

Figure 6 illustrates the different categories of barriers that companies face when implementing cooling system flexibilization measures.

The category “Regulations and laws” is of particular note, with the highest number of mentions (26), indicating that the legal framework has a significant impact on the ability to implement flexibilization measures. This is closely followed by the “Lack of knowledge and information” category with 24 mentions. This indicates that a considerable number of companies encounter difficulties in acquiring the information required to make well-informed decisions. The “Economic” category also received 21 mentions, indicating that economic factors such as high investment costs and insufficient profitability are perceived as relevant barriers. Similarly, the category “Lack of willingness to implement” received 21 mentions, indicating that there are barriers in this area that prevent companies from taking action. The “Technological” category has 17 mentions, indicating that technical limitations are regarded as a significant obstacle to implementation. In addition, the “Other” category is represented with 8 mentions, which may indicate specific barriers or challenges that are not captured in the previously defined categories. Finally, the category “No barriers are present” has 2 mentions, indicating that some companies do not perceive any significant barriers to implementing flexibilization measures.

The Figure 6 provides insight into the variety of barriers faced by enterprises, highlighting the economic and informational challenges that can impede the implementation of flexibilization measures. The data are based on respondents’ self-assignment of barriers to predefined categories, with multiple answers possible. As such, the figure reflects perceived groupings rather than an exhaustive or exclusive classification of all identified barriers.

The barriers described above are further specified in Figure 7, which illustrates the primary barriers identified by the companies. The most frequently reported barriers to the implementation of flexibilization measures in cooling systems are presented.

“Economic viability” has the highest frequency with 14 mentions, indicating that economic viability plays a pivotal role in the decision-making processes of companies. This is followed by “Knowledge and information” with 14 mentions, confirming the hypothesis that a considerable number of companies experience difficulties in obtaining the information they require to make well-informed decisions. “Investment costs”, with 12 mentions, indicates that high initial investment is perceived as a significant barrier. The category “Operational reliability” has 10 mentions, underscoring that operational reliability is another relevant barrier. With seven mentions, “Staffing” suggests that the required staffing is a factor that prevents companies from implementing flexibilization measures. The category “System compatibility and implementation” also received seven mentions, suggesting that technical considerations and system implementation represent significant challenges. The concept of “Corporate culture”, which encompasses the cultural aspects of organizations, was referenced on six occasions. Furthermore, “Technology” also received six mentions, while “Space requirements” received four mentions, suggesting that spatial conditions are also a challenge. Finally, “Regulations and laws” and “None” each received one mention, indicating that some companies do not perceive significant barriers to implementing flexibilization measures. Figure 7 illustrates the various barriers encountered by enterprises and elucidates the economic and informational impediments that can impede the implementation of flexibilization measures.

Table A2. Classification of barriers to flexibilization (supplementary to Figure 7).

Category	Examples
Economic Viability	Economic viability
	Low savings potential
	Uncertainty about returns
	Low proportion of energy costs in total costs
	Demonstrable ROI
	Lack of flexible electricity tariffs
	Lack of economic incentives for load shedding
Knowledge and Information	Low density of information and transparency regarding solutions
	Lack of examples of successful implementation
	Lack of data on economic viability
	Future cost development
Investment Costs	High (investment) costs
	High effort
	Lack of capital
	Lack of monetary support
Operational Reliability	(Lack of) operational reliability
	Process supply security
	Process reliability
	Product quality
	Temperature compliance
Staffing Effort	Staffing effort
	Lack of personnel
	Lack of availability of specialists for programming
	Limited time resources
	Unpaid additional services
	Collaboration with overloaded service providers
	Poor load forecasting
System Compatibility and Implementation	Complex operational management
	Complex systems/implementation
	Implementation in existing setups
	Incompatible systems
	Lack of standardization
Corporate Culture	Lack of willingness to implement
	Priority setting
	Willingness to invest
	Lack of willingness in state properties and ministries
	No turnkey systems
Technology	Limited cooling system design
	Lack of storage technologies
	Refrigerant selection
Space requirements	Space requirements
Regulations and laws	Grid fee system

provides a comprehensive enumeration of the barriers mentioned in the survey and illustrates the manner in which they were classified in accordance with the categories depicted in the accompanying Figure 7. This overview permits a detailed examination of the particular barriers encountered by companies when implementing cooling system flexibilization measures.

4.1.6. Recommendations for Action

Figure 8 depicts the survey participants’ perceptions of the most effective strategies for addressing the challenges associated with the implementation of flexibility. It can be seen that the participants in the survey consider most of the proposed options to be helpful. The “Examples of successful implementation” option received the most responses.

Of the various recommendations put for consideration, the proposal to provide illustrative “Examples of successful implementations” was the most frequently mentioned, with 34 references. This suggests that the provision of practical application examples is an effective means of establishing trust in new systems or processes. Moreover, the provision of “Information events” with 27 mentions and “Guidelines as support” with 26 mentions was identified as a significant factor that can contribute to the reduction of barriers.

The provision of “Training for practical implementation” was also identified as a relevant measure, with 19 mentions. This underscores the imperative for the implementation of practical training programs that can effectively translate theoretical knowledge into practical applications. In terms of financial considerations, the provision of “Monetary support” was regarded as a significant factor, with 17 mentions. “Offer of turnkey systems” received the lowest number of mentions, with only 11 mentions.

It is noteworthy that four respondents indicated that “None of the mentioned options” were helpful. Three of those four respondents gave alternative suggestions. These are included in the evaluation of Figure 9.

In conclusion, the findings of the survey demonstrate a compelling necessity for intervention. The provision of practical examples, training, and information events may prove instrumental in overcoming existing barriers and promoting the implementation of new approaches.

In response to the query regarding the existence of any notable solutions to overcome the identified barriers, the survey participants proffered a range of responses, as illustrated in Figure 9.

The results show that the “Political and regulatory framework” is the most frequently cited solution, mentioned by eight respondents, corresponding to 34.8%.

“Standardization” was identified as a key factor, with six mentions. This response indicates that the establishment of a uniform standard for processes and technologies is considered a fundamental element in the reduction of uncertainties and the enhancement of efficiency.

Furthermore, the implementation of “Subsidy programs” was identified as a pivotal strategy for establishing financial incentives to encourage investments in new systems, with six references. The provision of support from “Consulting and service providers” was identified on four occasions, indicating that external expertise is regarded as a valuable resource for the optimization of implementation strategies.

“Economic conditions” were referenced on three occasions, while “Electricity tariffs” were mentioned on two occasions as factors that could potentially influence implementation. Ultimately, one respondent indicated that “no further incentives” are necessary, suggesting that some participants believe the existing options are sufficient.

In conclusion, the survey results indicate that a range of factors are perceived as potential solutions to mitigate barriers. In particular, further investigation into the political framework and standardization is recommended in order to facilitate the implementation of new approaches.

Table A3. Barrier reduction solutions mentioned (supplementary to Figure 9).

Category	Solutions Mentioned by the Participants
Political and Regulatory Framework	Implementation of flexibility measures into ISO 50001
	Participation in the spot market
	Simplification of approval procedures and subsidy programs
	Anchoring transformation requirements in laws
Standardization	Standardized interfaces
	Minimizing development effort through standardization
	Opening and standardizing digital platforms
	Databases for economic feasibility calculations
	Ready-made concepts must be available
Subsidy Programs	Setting up subsidy programs
	Simplifying subsidy applications
	Uncomplicated subsidy programs
Consulting and Service Providers	Assistance with potential analysis
	Consultation of the federal government by experts
	Training sessions
	Service providers for implementation

presents potential solutions, as identified by participating companies.

As illustrated in

Table 8. Opportunities identified for significant optimization potential (open-ended question, $N=23$).

Category	Identified Opportunities
Political and Regulatory Framework (16)	Grid fee structure
	Tax relief
	Legal framework
	Reforming the electricity market for grid congestion management
	Regulatory framework
	Implementation of RED II
	Political framework
	Stricter obligations for public institutions
	Simplifying legal requirements for implementation
	Highlighting financial incentives for flexibilization in the electricity market
	Obligation of electricity providers to offer flexible tariffs
	Creating incentive models
	Simplifying participation in the spot market
	Regional time-based electricity pricing
Technical Solutions (9)	Requirements for system efficiency
	Integration of cooling supply and renewable energy generation into a local energy management system
	Cost-effective storage technologies
	Technical solutions for direct evaporators
	Predictability of cooling demand
	Load forecasting
	Technical solutions to improve economic viability
	Technical prerequisites
Economic Viability (7)	Economic Viability
Grid and Infrastructure (6)	Registration of cooling systems with grid operators
	Implementation of energy communities
	Fast expansion of power grids
	Unified design of interfaces with grid operators
	Development of energy communities
	Expansion of cooling networks
Standardization (5)	System standardization
	Turnkey systems
	Standardization of digital interfaces
	Opening of digital platforms
	Standardization of digital platforms
User Behavior and Training (3)	User behavior
	Training of personnel
Communication and Collaboration (3)	Collaboration between plant engineering and energy economics
	Coordination between plant operators, energy providers, and service providers
	Communication and collaboration among stakeholders
Planning (3)	Realistic planning
	Planning must align economically and technically
	Incorporating cooling supply into heat supply planning
Implementation Examples (3)	Publishing examples of successful implementation
Knowledge and Information (3)	Detailed analysis of economic viability
	Reliability presentation
	Methods for assessing economic feasibility
Subsidy Programs (2)	Subsidy programs
	Monetary support for smaller systems
Business Models (2)	Easily applicable business models

, the survey results offer insights into the identified optimization potentials from the perspective of the participating companies. This question specifically invited respondents to highlight fundamental areas where significant improvements could be made to facilitate the flexibilization of cooling supply systems. Participants were asked to point out structural barriers and propose optimization potentials, such as regulatory frameworks, technical conditions, economic viability, and business models. The objective was to gather perspectives on systemic weaknesses and strategic levers that, if addressed, could create more favorable conditions for flexible and sustainable cooling solutions.

The distinction when comparing Table 8 with Figure 8 and Figure 9 is that these earlier questions focused on practical, short-term measures to directly overcome existing barriers. Participants were asked to select or suggest concrete support actions, such as training programs, informational events, guidelines, examples of successful implementations, and financial assistance.

As shown in Table 8, it becomes evident that the political and regulatory framework has been identified as the primary category with the widest scope for optimization opportunities. The surveyed companies identified the necessity for reforming the structure of grid fees, creating tax incentives, and simplifying the legal framework as means of promoting the integration of flexible systems. The implementation of a reformed electricity market that addresses the challenges of grid overload, as well as the implementation of RED II (European directive for the promotion of the use of energy from renewable sources), are crucial factors that can influence companies’ commitment to flexibilization measures.

Furthermore, technical solutions are of paramount importance. The integration of cooling supply and renewable energies into local energy management systems, as well as the development of cost-effective storage technologies, are fundamental prerequisites for enhancing system efficiency and improving economic viability. Furthermore, companies have indicated a necessity for enhanced predictability of cooling requirements and more precise load projections in order to optimize flexibility planning.

An additional crucial element is economic viability. The intention behind publishing examples of successful implementations is firstly to provide a template for best practices and secondly to encourage other companies to adopt similar measures. The formation of energy communities and enhancements to infrastructure are of paramount importance in facilitating engagement in flexible energy markets. Furthermore, the importance of standardization, user behavior, communication, and collaboration was underscored. The establishment of a uniform standardization of systems and digital interfaces can facilitate the reduction of complexity and the integration of flexibility solutions. It is similarly vital to implement training measures for personnel in order to guarantee a comprehensive understanding of new technologies and their applications.

In conclusion, a comprehensive optimization of the political, technical, and economic framework conditions is essential to induce the necessary incentives for flexibilization. As illustrated in Table 8, the responses of the participating companies demonstrate the complex challenges that must be overcome in order to successfully advance flexibility in the energy sector.

4.2. Discussion Groups

The identified barriers and considerations highlighted in the discussion groups have been systematically captured and summarized in

Table A4. Barriers and considerations identified for the discussion groups.

Statements from the Group Discussions	Derived Barriers
Lack of awareness regarding specialists.	Lack of expertise regarding contact persons and implementation
Uncertainty regarding the implementation.
Lack of clarity on the benefits of implementing flexibilization measures.	Lack of expertise regarding the benefits and costs of flexibility measures
Questions about the economic efficiency and value of flexibilization measures.
Oversizing chillers for flexible operation leads to higher investment, which is seen as an economic barrier.	Economic factor
Lack of implementation of flexibilization measures if they are not documented in official guidelines or directories, despite available expertise.	Guidelines and directories
Increased planning effort compared to previous approaches.	Planning effort
Machine operating limitations that can affect warranty and operational safety.	Machine operating limitations
Reduced efficiency at certain operating points of cooling systems.	Machine efficiency
Negative impact on forecasted power requirements and power purchase volume due to flexibility measures.	Impact on power purchase forecast
Space requirements for required equipment technology.	Space requirements
Difficulties in making existing projects more flexible.	Existing projects
Limited adoption of flexible billing models for end users; preference for fixed amounts.	Flexible billing models
Increased effort is required if each end user manages a virtual power plant individually. Instead, centralized coordination is considered useful and should be taken into account during the planning phase (cf. heat contracting)	Service provider coordination
Synergy potentials should be considered in the planning phase.	Spatial separation of synergy potentials
The need for cooperation among the stakeholders of the plant operators, as they pursue similar interests.	Cooperation between stakeholders
The challenge of bringing together the diverse interests of stakeholders in the cold chain (production, storage, transportation).	Uniting different interests
The complexity of operating cooling systems may increase.	Complexity of operating cooling systems
The additional costs and efforts associated with flexibilization measures.	Additional cost and effort
The need for an appropriate economic evaluation methodology to assess additional costs.	Evaluation of additional costs
Difficulties in the technical implementation of cold supply regulations.	Technical feasibility of regulations
Insufficient availability of network condition data required for flexibility.	Grid condition data
Lack of availability for the implementation of flexible tariffs.	Technical requirements for flexible tariffs
The need for virtual power plants to comply with the requirements of the grid operator and to be taken into account in the management of the systems.	Rules for virtual power plants to follow system operators requirements
The complexity of contractual relationships between virtual power plants and network operators.	Contractual complexity
The lack of foundations to provide flexibility in the area of cooling by virtual power plants.	Lack of foundation for flexibility
High effort required to account for local energy generation units and to integrate them into energy management.	High effort
Costs for external service providers.	Costs for service providers
System capacity is insufficient for balancing the energy market.	Insufficient system capacity
Problems identifying the optimal schedule without a service provider.	Scheduling problems
Surrender of control and sovereignty to external service providers.	Control and sovereignty
Fear of hacker attacks due to external control.	Cybersecurity concerns
High investment requirement for integration in site energy system optimization and virtual power plant.	High investment requirement
Lack of trust in cooling quality when controlled by service providers.	Lack of trust in cooling quality
Required service providers, e.g., for creating optimized schedules, are not familiar with the production processes.	Service providers are not familiar with the production processes
Slow processes and lack of personnel capacity in traditional municipal utilities	Slow processes with electricity suppliers

. The discussions, conducted in five groups across two thematic areas, yielded a broad and differentiated collection of perspectives on the implementation of flexible cooling systems.

A central barrier frequently emphasized—both by participants and in the literature—is the lack of expertise. This includes insufficient knowledge about flexibilization in cooling systems, uncertainty regarding responsible contact persons, and implementation challenges. From the end-user perspective, it is particularly important to incorporate consumer needs early in the planning process—especially in the case of cost-intensive retrofitting.

The discussions also revealed significant economic barriers, most notably the high investment costs associated with oversizing chillers for flexible operation. Moreover, participants pointed to the lack of official guidelines and directories, which limits the dissemination of best practices and undermines the practical implementation of flexibility measures.

In addition, the group discussions identified multiple technical and operational constraints, including increased planning effort, reduced efficiency at partial load, equipment space requirements, and machine operating limitations that may compromise warranty or safety.

Further challenges emerged on the organizational and regulatory levels. These include the complexity of coordinating service providers, the difficulty of aligning stakeholder interests, and a lack of foundational frameworks for virtual power plants. Participants also expressed concerns about cybersecurity, loss of control, sovereignty, and slow processes in traditional utilities.

These findings underscore the multifaceted nature of the barriers to flexibilization in the cooling sector. A comprehensive overview of all challenges raised during the discussions is provided in Table A4 in the appendix.

Newly Identified Barriers from Survey and Discussion Groups

The following

Table 9. Newly identified barriers from survey and discussion groups.

Category	Newly Identified Barriers
Economic	High effort when focusing on flexible systems
	Unrealistic planning
	The market for energy storage is a niche and often does not meet specific customer requirements
	The current product range is not affected, reducing the incentive for flexibilization
	High development effort due to lack of standardization
	Lack of incentives for decision-makers reduces motivation
	Lack of customer commissioning for implementation
	Lack of monetary support
	Profitability of retrofitting is questionable
	Consulting-intensive and time-consuming planning
	Incorrect amortization calculations
	For craft businesses, implementation is not economically viable as the extra effort remains unpaid
	High labor costs
	Unclear or unsuitable profitability methods
	Lack of demonstrable ROI
	Costs for service providers
	High investment requirements for integration in site energy system optimization and virtual power plants
	Impact on power purchase forecast
Regulatory	Lack of legal regulations for energy system suitability
	Lack of regional and time-dependent electricity prices
	Lack of tax relief
	Lack of obligation for electricity suppliers to offer flexible electricity tariffs
	Inadequate and opaque funding programs
	Lack of bureaucracy reduction in approval processes and funding programs
	Complex legal requirements for implementation
	Lack of legal mandates for transformation
	Lack of integration of flexibility into ISO 50001
	Complexity of funding applications
	Network operators as a limiting factor
	Lack of documentation of flexibility measures in guidelines and directories
	Contractual complexity between virtual power plants and network operators
	Difficulties in the technical implementation of cooling supply regulations
	Rules for virtual power plants to follow system operators requirements
Technological	Coordination and knowledge of local conditions are necessary
	Difficult implementation with existing systems instead of new builds
	Process cooling is often technically non-flexible
	Implementation is often too tailored to specific customer needs
	Lack of storage technologies
	Lack of turnkey systems
	Inadequate expansion of cooling networks
	Delays in the expansion of electricity networks
	Flexibilization measures are difficult to implement in production
	Complex operations
	The priority of supply security leads to less favorable operating methods
	The availability of cooling systems for the production process limits flexibility measures
	Hygiene requirements in the area of cooling towers
	Refrigerant selection
	Complicated implementation
	Space requirements for system technology
	Insufficient consideration of synergy potentials
	Complexity of operating cooling systems
Organizational	No contact with cooling system operators
	Necessary coordination of multiple trades
	Limited time resources for technical operating personnel
	Lack of skilled workers
	Lack of a business model
	Company size often too small for implementing measures
	Project priorities are frequently directed toward other areas
	Increased effort for coordinating service providers
	Slow processes with electricity suppliers
Behavioral	The effort seems too great
	Never change a running system mentality
	Difficulties in convincing decision-makers of benefits
	Low engagement of users
	Too many stakeholders with insufficient interest
	Limited acceptance of flexible billing models
	Lack of collaboration between stakeholders
	Challenge of reconciling different interests in the cooling chain
	Lack of trust in cooling quality when managed by a service provider
Informational	Lack of guidelines as support
	Lack of a network for better exchange
	Inadequate tender documents
	Poor predictability of cooling demand and insufficient load forecasts
	Lack of examples for successful implementation diminishes trust
	No training for service providers
	Lack of data complicates the indication of the measure’s profitability
	Uncertainty regarding future energy cost developments
	Lack of expertise regarding contact persons for implementation
Competence	Lack of support in the potential analysis
	Existing expertise is not utilized toward flexibility
	Lack of system understanding in complex systems
	Low information density among decision-makers
	Incomplete knowledge of service providers
	Lack of easily applicable business models
	Local technical conditions are often not sufficiently considered
	Inadequate technical planning
	Complex grid fee structure
	Increased planning effort compared to previous approaches
	Problems identifying the optimal roadmap without a service provider

presents a summary of the newly identified barriers that emerged from the conducted survey and discussion groups. These barriers were subjected to systematic analysis and comparison with existing findings from the literature.

5. Discussion and Conclusions

The present study highlights significant interest from companies across the entire process chain in increasing the flexibility of cooling supply systems. This interest stems from the potential benefits, including reductions in energy costs, increased efficiency, and enhanced transparency through improved access to system data. However, achieving these benefits on a broader scale requires overcoming numerous challenges and barriers.

Figure 10 shows the new barriers identified in this study, broken down by survey and discussion groups, compared to the barriers from the literature for the seven categories. Barriers that were already present in the literature are counted as literature, even if the barrier was also mentioned in this study. Ninety-eight barriers were taken from the literature. This study provided 128 barriers, 39 of which were already present in the literature, i.e., 89 barriers were identified as new. In total, there is a list of 187 barriers that are relevant for the flexibilization of cooling supply systems.

The results show that the focus on refrigeration supply systems and the extension of the stakeholders to the flexibilization value chain provided new insights.

These new 89 barriers can be categorized as follows: 18 instances are of a technological nature (20%), 18 are economic (20%), 15 are regulatory (17%), 11 relate to competences (12%), 9 are behavioral (10%), 9 are informational (10%), and 9 pertain to organizational aspects (10%).

The present findings raise the following key aspects:

• Economic barriers: For a cost–benefit analysis, both the effort and the benefits must be quantified. However, for some companies, this can be challenging, as both factors are highly dependent on individual circumstances. In particular, there is a lack of studies and generalizable data on investment costs, making it difficult to assess the required effort.
• Technological challenges: The high complexity of integrating flexible systems into existing infrastructures shows that there is a lack of standardized solutions. Companies need clear technical guidelines and support to reduce uncertainty.
• Regulatory uncertainties: The complexity of the legal framework and access to flexible electricity pricing models must be simplified. It is critical that policymakers create clear and consistent guidelines to facilitate implementation by companies.

To ensure broader implementation of flexible cooling systems, an integrated approach is essential. The following actions are recommended:

• Showcase successful implementations by utilizing examples such as living labs, role models, and practical experiences to convince decision-makers of the feasibility and benefits of flexible systems. Highlight supply and process security to increase confidence in adoption.
• Provide verifiable economic calculations to demonstrate cost-effectiveness, particularly for projects commissioned by customers. Establish financial assistance programs for essential investments, ensuring that costs and benefits are transparent and comprehensible.
• Simplify implementation through standardization, digitalization, and turnkey concepts to minimize personnel and cost efforts.
• Ensure easily accessible information, such as guidance on flexible electricity tariffs, to improve understanding and encourage adoption.
• Address regulatory barriers, such as the complexity of existing frameworks and limited access to time-variable electricity pricing. Integrate flexibility measures into standards like ISO 50001 to complement efficiency initiatives.
• Promote acceptance among employees and decision-makers by emphasizing the tangible benefits of flexible systems. Provide targeted technical training to build competence and support the adoption of novel technologies.

Addressing the identified barriers requires collaboration between policymakers, businesses, and research institutions. Policymakers must focus on regulatory reform to streamline implementation and enable access to flexible energy solutions. At the same time, businesses and researchers must work together to develop and demonstrate practical, cost-effective solutions that can serve as benchmarks for success.

Further investigation into stakeholder-specific barriers is crucial for developing tailored recommendations. A deeper understanding of the unique challenges faced by various stakeholders will enable the formulation of bespoke strategies to overcome these barriers effectively.

The findings of this study illustrate the necessity for an integrated approach to successfully promote the flexibilization of cooling systems. By addressing technological, economic, regulatory, and behavioral barriers in a coordinated manner, the potential benefits of flexible cooling systems—such as reduced energy costs, greater efficiency, and improved transparency—can be realized. Collaboration among key stakeholders will be pivotal in overcoming these challenges and fostering the acceptance and widespread implementation of flexible cooling solutions.

The results are based on a relatively small sample of 52 companies and can therefore only be generalized to a limited extent. In addition, it should be noted that certain stakeholder groups, such as energy service providers (e.g., electricity suppliers or traders), are underrepresented or not represented at all (e.g., regulatory authorities). This is due to the nature of the data collection: the study was based on an online survey in which every valid response was included. Given the relatively small number of responses, no selection process was applied. As a result, the dataset reflects only those stakeholders who actively chose to participate, and some key groups did not respond. This limitation should be addressed in future research through targeted outreach or stratified sampling. To strengthen the findings, individual interviews with key actors should be conducted, as they allow for follow-up questions and enable a more nuanced interpretation of the results. Furthermore, the group discussions should ideally be repeated with a larger and more diverse set of participants, for example, through a public event or open forum, to capture a broader spectrum of perspectives and increase the robustness of the conclusions.

Furthermore, part of the analysis is based on open-ended responses and self-assessments by participants, which implies a certain degree of subjectivity and room for interpretation. Future work should complement this with quantitative, representative analyses and more in-depth case studies. While the survey results indicate a strong motivation among participating companies to enhance the flexibility of their cooling systems (see Figure 5), this finding should be interpreted with caution. It is likely that companies with little or no motivation in this area were also less inclined to take part in the survey. This could lead to a response bias, where the reported level of motivation is higher than what would be observed in a fully representative industry-wide assessment.

A more comprehensive study covering a broader sample of companies, including those that may not actively seek improvements in cooling flexibility, would help to validate these findings and provide a more balanced perspective on the overall industry sentiment.

The focus group and the online survey were not intended to validate or replicate each other but rather to complement one another by capturing different stakeholder perspectives. As barriers to flexibilization are inherently subjective and context-specific, differences between the two methods are to be expected and are not necessarily contradictory. Each method contributed distinct insights: the focus group allowed for in-depth discussion and exploration of interdependencies, while the survey enabled broader coverage across the cooling value chain. Although full triangulation of findings was not conducted, the combination of methods provides a more comprehensive picture. Future research could build on this foundation by applying structured cross-validation techniques to systematically explore potential overlaps and contradictions.

While this study focused on identifying and categorizing a broad range of barriers across the flexibilization value chain, the degree of influence of each barrier was not quantified. Future research should aim to assess the relative impact and prioritize the identified barriers, for example, by applying methods such as the Analytic Hierarchy Process (AHP) or MaxDiff scaling. This would support a more targeted development of measures to overcome the most critical barriers.

Additionally, a comparison between Germany and other countries could provide valuable insights into how similar barriers are addressed in different policy and energy system contexts. Learning from international approaches may help identify strategies to overcome certain barriers more effectively.