Renewable Energy Sources and Improved Energy Management as a Path to Energy Transformation: A Case Study of a Vodka Distillery in Poland

Abstract

The increasing awareness of the need for sustainable solutions to secure future energy supplies has spurred the search for innovative approaches. Energo-Efekt Sp. z o.o. has prepared a project for the green transformation of the energy system at a producer of spirits through the rectification of raw alcohol. An installation was conceptualised to develop the system to convert energy from biomass fuels into electricity and heat. The innovation of the installation is the use of an expander—a Heliex system which is the twin-screw turbine generator converting energy in the form of wet steam into electrical power integrated with pressure-reducing valve. This system captures all or part of the available steam flow and reduces the steam pressure, not only delivering steam at the same, lower pressure but also generating rotary energy that can be used to produce electricity with the power output range of 160 to 600 kWe. Currently, the company utilises natural gas as a fuel source and acquires electricity from the external grid. Implementing the system could reduce the carbon footprint associated with the production of vodka at the plant by 97%, to 102 t CO₂ annually. This reduction would account for approximately 21% of the total carbon footprint of the entire alcohol production process. The system could also be applied to other low-power systems that produce < 250 kW, making it a viable option for use in distributed energy networks, and can be used as a model solution for other distillery plants. The transformation project dedicated to Polmos Żyrardów involves a comprehensive change in both the energy source and its management. The fossil fuels used until now are being replaced with a renewable energy source in the form of biomass. The steam and electricity cogeneration system meets the rectification process’s energy demand and can supply the central heating node. Heat recovery exchangers recuperate heat from the boiler room exhaust gases and the rectification cooling process. Potentially, all of these changes lead to the company’s energy self-sufficiency and reduce its overall environmental impact with almost zero CO₂ emissions.

1. Introduction

In the late 1990s, international efforts were initiated by the UN Framework Convention on Climate Change to prevent dangerous human-induced climate change [1]. Soon afterwards, the European Union (EU) adopted the goal of limiting global warming to within 2 °C above preindustrial levels as a target to guide global mitigation and reduction efforts [2]. The steady increases in global greenhouse gas (GHG) emissions have spurred further international action on climate change, including the announcement by the European Union (EU) of ambitious plans to achieve net-zero GHG emissions by 2050 [3]. On 31 October 2023, Directive (EU) 2023/2413 was published, amending Directive (EU) 2018/2001 relating to the promotion of renewable energy and the repeal of Directive (EU) 2015/652 (Renewable Energy Directive III-REDIII) [4]. In regard to renewable energy, the directive establishes an ambitious objective to supply 42.5% of the EU’s total energy consumption using renewable energy by 2030, with the possibility of reaching 45%. Over the last few years, there has been swift technological progress and an increase in the use of all renewable energy sources, including solar, hydroelectric, wind, geothermal, and biomass (biomass, biofuels, and biogas). As a result, there has been a general negative trend in the production of primary energy from solid fossil fuels, oil, and natural gas, as well as nuclear energy. For the first time, a negative annual growth rate (−3.3%) was recorded in 2020 for total world natural gas production, and a decline of 6.9% was recorded for world oil production [5]. The production of renewable energy showed a clear positive trend over the same period. Primary production of renewable energy has been on a long-term upward trend, with an overall increase of 184% between 1990 and 2015 and an average annual growth rate of 4.3% [6].

Poland’s energy economy is still based mainly on burning fossil fuels, although there has been a steady increase in the share of other sources. In 2023, the proportion of electricity generated from coal declined to 60.5%, representing a 10% reduction compared to the previous year and reaching its lowest historical level [7]. Concurrently, energy production from natural gas increased by over 40%, largely due to price fluctuations. For the first time, energy production from RES (renewable energy sources) constituted 27% of the total. The majority of the increase in capacity from renewable sources in 2023 (5.6 GW) was attributable to solar power (4.8 GW), with consumer photovoltaic installations accounting for 1.9 GW. Wind installations contributed an additional 0.8 GW to the total capacity [7]. Waste can also be utilised as an alternative energy source. Co-combustion of alternative fuels is practised in Polish cement plants, utilising waste materials including tyres, plastics, wood, rubber, textiles, non-recyclable paper, meat and bone meal, dried sewage sludge, and many other substances [8,9]. There is a pressing need to hasten the integration of RES in Poland’s energy mix, in line with the goal of decarbonising EU economies [10].

Between 2016 and 2023, energy production in Poland from small renewable energy installations increased from 176.6 GWh to 4058.9 GWh [11]. This was associated with an increase of 1313% in the number of small RES installations, from 428 at the end of 2016 to 5630 at the end of 2023. A small installation is an installation with a total installed electrical capacity of more than 50 kW and not more than 1 MW, connected to the electricity grid with a voltage rating lower than 110 kV or with a cogenerated heat output of more than 150 kW and less than 3 MW, where the total installed electrical capacity is more than 50 kW and no more than 1 MW [12]. As of 31 December 2023, the majority of small installations used solar radiation energy (4411; 78.5%). These installations accounted for 87.5% of the total installed capacity in that year. The number of small-scale biomass installations has not changed since 2022, although the capacity of those eight plants has increased slightly from 4.607 MW to 4.763 MW. The individual installed capacity of RES installations in Poland ranged from 0.2 to 0.995–4.763 MW. Recently, due to the annual production of large quantities of agrobiomass with high calorific value, agricultural lignocellulosic waste biomass has attracted interest as a feedstock for biofuel production [13,14]. Lignocellulosic plant biomass is abundantly available worldwide [15].

Polmos Żyrardów is a Polish distillery that produces vodkas, employing over 250 people. In recognition of the need to adapt its production process to meet the demands and expectations placed on contemporary companies, Polmos Żyrardów has initiated the development of an in-house energy production system utilising renewable energy sources. This is of particular significance given that the production of alcohol is among the most energy-intensive industrial processes. Preliminary findings indicated that biomass was the most accessible and obvious potential source of energy, primarily due to its high availability. In the context of a distillery, biomass can be employed in two distinct ways: either through direct combustion or via prior carbonisation [16,17,18,19]. This study focuses on the viability of utilising post-production waste and biomass (wood chips) as a source of energy to power the Polmos distillery. The proposed model incorporates a technological change component, and the modernisation model is presented alongside the initial outcomes, which include a reduction in CO₂ emissions. The implemented technology could support the decarbonisation of the industry.

2. Materials and Methods

This article outlines the concept behind modifications made to the energy production and management system that was designed for a vodka distillery. The purpose of the transformation process was to establish an autonomous energy generation system and the recovery of energy from operational production processes. The level of detail in which the technological improvements are described respects the limits imposed by intellectual property protection. The main components of the designed installation are presented in Figure 1. Pillar 1 presents the part of the installation where the biochar is produced. Pillar 2 shows the recuperation of waste heat. Pillar 3 illustrates the process of producing steam and electric current.

The effectiveness, significance, and validity of the proposed technological solution were evaluated through the following steps: (1) installation of the biomass-based energy generation system; (2) analysis of potential energy efficiency results; (3) analysis of environmental impact based on carbon dioxide emissions. The design of the installation and environmental impact based on carbon dioxide emissions were elaborated by Energo-Efekt Sp. z o. o., Poznań, Poland.

3. Results

3.1. Installation for Biomass-Based Energy Production

The availability of biomass for energy production within the region formed the foundation upon which a model for the modernisation of the energy system at the distillery was selected. In the Mazowieckie Voivodeship, where Polmos is located, renewable energy development encompasses solar, wind, and geothermal sources. However, the region’s renewable energy landscape is dominated by biomass and wind energy [20]. The “Draft Assumptions for the Heat, Electricity, and Gas Fuel Supply Plan for the City of Żyrardów for the Years 2012–2027” provides estimates of the city’s biomass energy potential. According to these estimates, waste wood from roads holds the highest potential, accounting for 40%, followed by wood resources from energy crops (20%) and biomass from forests (20%). This characterisation of the distribution of biomass potential is a result of the specificity of the area, which is mainly urbanised land with marginal forests, orchards, and meadows, as well as a relatively large number and length of tree-lined roads. The biomass energy potential was estimated as 3273.96 GJ/year in total (straw, hay, biomass from forests, orchards, waste wood, and wood from energy crops), including 1306.12 GJ/year from waste wood. Organic waste from the numerous companies in the region, including fruit and vegetable processing (fruit pomace), milk (fats, whey, waste from on-site effluent treatment plants) and meat production (slaughterhouse waste), also has high energy potential. Other important local fuel sources that could be utilised by the company include distillery decoction in the form of liquid biomass (approximately 20% dry weight) derived from spirit production in partnering companies that supply raw materials to the distillery.

During the selection process, it was decided that woodchips would be the main source of biomass for energy production due to their relatively stable availability regardless of the season. The second, seasonal source was to be liquid biomass (about 20% of the dry weight). This was to be mainly derived from distillery decoction, which is a waste from the production of spirits. Due to the high hydration of the decoction distillery biomass, the technological system was intended to perform both drying and carbonisation of organic fractions. The drying and carbonisation chamber has been designed to allow two processes to occur simultaneously. The carbonisation process operates continuously in automatic mode. Technology used for the production of biochar has also been developed but is not presented in detail here as it is pending patenting. The general idea behind the proposed system was to allow for flexible changing of biomass sources and the possibility of using biomass from streams of different origin with varying dry matter content.

The starting point for the development of the energy system was data obtained from laboratory-scale tests presented in our previously published work [18]. In that research, thermal carbonisation (pyrolysis) was studied in a CZYLOK reactor (Jastrzebie-Zdrój, Poland; model FCF 2R), which was modified in the laboratory to enable the collection of pyrolysis gas. The biomass conversion process was studied under oxygen-limited conditions. The temperature in the reactor was gradually increased during the first 30 min to reach 850 °C. Pyrolysis was then continued for another 60 min. The biochar was obtained from waste biomasses from agricultural production, such as residues from the production of flavoured alcohols (lime, grapefruit, and lemon pulp), beetroot pulp, apple pomace, brewer’s spent grain, bark, and municipal solid waste (sawdust, prunings, and wood), with the biochar yield ranging from 25.89% to 40.85% and carbon content in the mass increasing up to 80.18% [18]. The physico-chemical properties of the biochar obtained from thermochemical decomposition of this biomass showed a calorific value of between 27 and 32 MJ/kg, which is comparable to or even higher than the calorific value of good-quality coal (24–26 MJ/kg).

A very interesting part of the overall technological solution for energy production and recovery is the use of an expander to produce electricity using steam from the boiler (presented in Pillar 3 (Figure 1)). This power supply system is a commercial product manufactured by Heliex Power Ltd., a company that is licenced to use technology covered by a patent held by City University of London. The expander is intended for use in small-scale power generation, with a capacity below 200 kW. Saturated steam is utilised directly from the boiler, obviating the necessity for overheating, which significantly reduces installation costs. The steam produced in the boiler is directed with a pressure of about 18 bar and in the amount of about 4.5 tons/h initially, with a maximum steam inlet temperature of 224 °C (saturated steam), to generate electricity [21]. Then, when the pressure is reduced to about 3.5 bar, the steam is reused to feed the rectification process. Additionally, the steam from the expander can feed the central heating node. Due to the small amount of steam used and low power generated, this cogeneration system is an innovative process.

Another very important benefit of the technological solution designed for Polmos is reduction in energy losses. The project enables the recuperation of the heat of the exhaust gases from the boiler room and heat from the rectification cooling process (Figure 2). Consequently, the temperature of the exhaust fumes can be reduced to below 50 °C. The utilisation of heat recovery exchangers from the flue gas facilitates the recovery of approximately 1000 kW of heat, thereby achieving a 20% reduction in primary energy consumption relative to fuel.

The utilisation of waste heat in the boiler plant will primarily be achieved through the process of exhaust gas heat recovery. The presence of dust or other impurities in the flue gases has a negative impact on the efficiency and technical condition of the exchangers due to the rapid fouling of their heat transfer surfaces. This problem can be overcome by employing a diaphragm exchanger.

The installation of heat recovery exchangers and heat pumps at the distillery makes it possible to increase the efficiency of power generation to ≥120%, compared to the above-mentioned value that would have been possible with the assumed biomass and combustion process parameters. This parameter is understood as the ratio of the useful electrical and thermal energy to the energy in the fuel in relation to its calorific value (using biomass with a relative humidity of 50%).

Energy generation efficiency η [%] was determined as the ratio of useful energy (ΣQ) to energy delivered as fuel (7.9 MJ/kg, relative to LHV (Lower Heating Value) (J/g)).

$$\eta ={\displaystyle \frac{\sum Q(useful heat)}{\mathsf{\Sigma }\mathrm{Q} fuel \left(\mathrm{LHV}\right)}}\times 100\%={\displaystyle \frac{4798 \left[\mathrm{kW}\right]}{3996 \left[\mathrm{kW}\right]}}\times 100\%=120\%.$$

To evaluate the generation efficiency, the indirect method of efficiency assessment (according to energy loss analysis) is not employed. Accordingly, the generation efficiency of the system may exceed 100%, provided that a proportion of the energy from the analysed system is recovered through the use of energy from the condensation of water vapour in the flue gas. This entails the recovery of the latent heat from the vaporisation of water resulting from the drying and combustion of the biomass, which contains hydrogen. If the system is able to utilise the energy present in the flue gases to achieve an outlet temperature of approximately 50 °C, then a system efficiency of h = 120% can be obtained (

Table 1. Technical specifications of the designed system. Energy generation is calculated using wood chips as a reference biomass (energy delivered from fuel: 7.9 MJ/kg lower heating value; moisture content: 50%; fuel flow: 1.82 t/h). Own needs are not included in the SQ calculations (* values).

Instrument and Technological Parameter		Energy Flow [kW]	Exhaust Gas Outlet Temperature [°C]	Energy Share [%]
1. Energy in fuel (biomass); Qfuel		3996		100
2. Useful heat; Q		4798
2.1.	Boiler (saturated steam boiler 5.3 t/h, 18.5 bar)	3350	220	83.83
2.2.	Economiser (Exhaust gases/feed water 100/140 °C)	254	145.7	6.36
2.3.	Exchanger (for heating condensate 68/95 °C)	161	96	4.03
	Exchanger (for heating air 20/70 °C, 2.476 kg/s)	124 *	60.6	own needs
2.4.	Exchanger (for heating water 40/55 °C)	528	45	13.21
2.5.	Heat pump (COP = 6; heating water: 55/69 °C)	505		12.64
	Generated electricity (expander) to power heat pump	84 *		own needs
	Heat recovery from the refrigeration system of the rectification process (421 kW, water 55/45 °C)
Energy generation efficiency (η = ΣQ/ΣQfuel)				120%

). To achieve such a significant use of low-temperature heat, after research on materials for the construction of recuperators for heat recovery, bromo-silicon glass and special steel alloys were selected. The increase in energy efficiency is achieved by reducing energy consumption.

The energy efficiency (EE [%]) for energy generation was determined as the energy savings that would be achieved compared to a reference system, assuming a reference temperature of 0 °C, biomass moisture content W equal to 50%, and oxygen content in the flue gas of 8%.

-

biomass energy generation efficiency for the reference system: η_ref = 87%,

-

biomass energy generation efficiency of the analysed system: η = 120%,

Therefore:

$$EE=\left(1-{\displaystyle \frac{{\eta }_{\mathrm{ref}}}{\eta }}\right)\times 100\%=\left(1-{\displaystyle \frac{87\%}{120\%}}\right)\times 100\%=27.5\%$$

Comparing the system presented with the reference, we can see that 27.5% of the fuel is saved.

3.2. Environmental Effect of the Modernisation

Renewable energy is seen as a gradual and strategic replacement for fossil fuels. It can replace rapidly depleting fossil fuel reserves, reduce environmental damage by managing GHG emissions, and mitigate environmental problems associated with pollution. The overall environmental impact of producing bioenergy can be approximated quantitatively using Life Cycle Assessment (LCA). The analysis identifies the main environmental aspects of the product from production to disposal and indicates ways of preventing or minimising those effects. Standards provide guidance on how to conduct this complex analysis correctly. Proper LCA requires the use of ISO 14000 standards (in particular 14040 [22] to 14049 [23]). In general, the research methodology consists of four phases: goal and scope definition; life cycle inventory analysis (LCI); life cycle impact assessment (LCIA); and life cycle interpretation (LCI) [24].

An LCA can be employed to identify groups of tasks within the operations of a distillery. The main steps involved are illustrated in Figure 3.

The objective of the analysis is to ascertain the dependence of the environment on all analysed inputs and outputs from and to the reference frame. The predominant categories employed for impact analysis encompass human health, ecosystem quality, and natural resource utilisation. Within these broad categories, the following specific issues can be identified: global warming, ozone layer depletion, air pollution, land use, ecotoxicity and eutrophication. When analysing the rye production process, it is necessary to consider the following components: fuel needs, water usage, fertiliser and pesticide requirements, and post-production by-products such as straw left on fields. In the context of a distillery, the emissions of greenhouse gases (GHG) are attributable to the cultivation, harvesting and transport of substrates, as well as the production of raw spirit and its distillation, followed by the bottling of the product [25,26,27,28].

An analysis of spirits production at the Polmos distillery conducted in 2020 based on the data from 2019 by implementation of the Greenhouse Gas Protocol (Ecoact, which uses databases such as ADEME, DEFRA, Agrifootprint, and EcoInvent) revealed that the stage with the highest carbon footprint was the production of raw spirit. This stage accounted for 43.3% of the total GHG emissions, equivalent to 7316 tonnes of CO₂ per year (Figure 4).

The environmental impact of rye cultivation (4332 t of CO₂ per year) and distillation of vodka (3483 t of CO₂ per year) was determined at a similar level. In the balance carried out in 2018, distillation of vodka accounted for 20.6% of the CO₂ produced. Polmos has been unable to reduce the environmental impact across all stages of vodka production, primarily due to its involvement in only some of these stages. However, it was possible to introduce changes to reduce the emission of GHG during the distillation process. The final stage of vodka production is carried out entirely by the distillery, and the company is solely responsible for decisions regarding potential changes. An additional factor in the decision was the potential reduction in production costs as a result of reducing the energy required. In 2018, the distillation of vodka relied on the combustion of fossil fuels, which generated the equivalent of 3483 t CO₂ per year. After changing the energy source from natural gas to biomass, regarded as being CO₂-neutral, and the system as a whole to the presented solution, the carbon footprint responsible for the distillation of vodka to obtain spirits could be decreased by about 97% to 102 t CO₂ per year in the 2019 base year comparison for scope I and II alcohol production at the distillery (Scope I: direct emissions, i.e., reductions resulting from energy efficiency, the transition to renewable energy sources (RES) and vehicle fleet modernisation; Scope II: indirect emissions, i.e., reductions resulting from the purchase of energy, e.g., green energy). At the company scale, this will reduce the carbon footprint of the entire alcohol production process by about 21% (Figure 3). The fundamental principle underlying the reduction of CO₂ emissions is energy efficiency. This is comprehended as a reduction in energy consumption by the system under modernisation, achieved through the reduction in energy consumption, transmission, transformation and generation. The existing literature indicates the potential for such modifications to have a substantial impact on the value of CO₂ equivalent. Numjuncharoen and co-workers [29] report that the production of steam in ethanol production generates the equivalent of 0.872 kg CO₂/L using carbon, but using biomass for this purpose the equivalent was 0.029 CO₂/L, which gives a reduction of 96%. Switching from coal to biomass in the production of steam reduces the carbon footprint of cassava ethanol production by more than 50% [29].

The requirements for emissions of gases were also taken into account in the design of the installation. The installation must comply with the emission standards set out in the Regulation of the Minister of Climate from 24 September 2020 on emission standards for certain types of installations, sources of fuel combustion, and waste combustion or co-incineration installations (Dz.U. 2020/1860) and in the Directive (EU) 2015/2193 of the European Parliament and of the Council of 25 November 2015 on the limitation of emissions of certain pollutants into the air from medium combustion plants [30,31]. Emission volumes are limited to the following levels: SO₂ ≤ 200 mg/Nm³; NO_x ≤ 300 mg/Nm³; dust emissions ≤ 20 mg/Nm³, with a normalised O₂ content of 6% for facilities using solid fuels.

In all EU countries, the energy sector is in the process of transformation in order to meet the requirements and challenges of the green transition [3] and to achieve the required energy mix. The analysis of energy transition policies demonstrates a dynamic landscape of evolving approaches, with nations pursuing a spectrum of strategies to facilitate a shift towards renewable sources [32]. The transition in Polish energy production is progressing, and 2023 was a year of records; for the first time ever, the share of coal in electricity generation fell to 60.5%, which is as much as 9.9% lower than the previous year [7,33]. Energy market data shows that 27% of electricity generated in 2023 came from renewable sources, rising from around 20% in 2022. Onshore wind provided 14% of the total generation, photovoltaics provided 6.8%, and biomass provided 2.9% [34].

The green transition represents a significant challenge for humanity, with potential benefits including a reduction in environmental pressures, greater independence from fossil fuel supplies, enhanced security through distributed electricity generation, and autonomy from external influences, including those of a global and regional political and military nature [35,36]. From the perspective of a company, the implementation of renewable energy sources represents a strategy for reducing reliance on external energy supplies and prices, while simultaneously cultivating a favourable public image.

Nevertheless, several obstacles impede a green transformation. The construction of a plant necessarily entails an initial investment, which is generally long-term, with the expected technological lifecycle, as reflected in the LCOE (Levelised Cost of Energy) calculation, spanning a period of 10 to 20 years. In this rapidly evolving market, uncertainty regarding the return on investments is one of the main barriers affecting investors’ decision-making [37]. Consequently, investment is frequently made with the objective of maintaining a competitive position [38].

In contrast to other alternative energy sources, such as photovoltaics or wind, biomass and hydropower plants are capable of supplying continuous electricity regardless of weather conditions and are typically regarded as forms of secure energy storage. Biomass is seen as a suitable option for buildings with high annual electricity consumption [39]. Nevertheless, the utilisation of biomass is not without disadvantages. The direct application of biomass for the production of heat and power is constrained by a number of factors, including its high moisture content, low energy density, inconsistent composition, and hydrophilic nature, which collectively present considerable challenges [40]. In order to overcome the identified limitations and enhance the utility of biomass in RES sectors, it is necessary to implement a pretreatment process to produce biochar [18,41,42,43]. The efficiency of the process, as well as the quality of the final product, is dependent on a number of factors. The type of product obtained following the torrefaction process is largely determined by the process parameters and the composition of the biomass; the yield of biochar is derived from the lignocellulosic properties, while the calorific value and ash content are influenced by the physical and chemical properties of the biomass in question [44,45]. The practical viability of biomass-based energy systems is dependent on the extensive availability of the feedstock and the technical ability to generate both heat and power. A disadvantage of biomass fuel is the presence of particulate matter as a significant component of the flue gas emissions. The nature of coarse particles (≥10 µm) is twofold: firstly, unburned organic particles, and secondly, inorganic particles such as sand or soil derived from the fuel. Particles with a diameter of less than 1 µm consist of inorganic compounds or elements themselves, including K, Na, Ca, Zn, Cl, S, Mn, Mg, P and Pb, among others [46]. In addition, heavy metals such as Cu, Pb and Cr and low concentrations of Cd may be emitted from the fuel through accumulation in plants. The presence of ash deposits and slag on the heat transfer surfaces of combustion equipment has been shown to result in a deterioration in heat transfer and a consequent reduction in the efficiency of the equipment [47]. The deposition of sediment is commonly accompanied by the process of corrosion. Biomass fuel is characterised by the presence of significant quantities of alkali metal elements and chlorine elements. During the process of combustion, these elements have been observed to readily form alkali metal chlorides, including potassium chloride, sodium chloride, hydrochloric acid and chlorine dioxide [48]. The KCl has been identified as a potential catalyst for high-temperature corrosion [49]. The gases HCl and Cl₂ accumulate in and penetrate the defective oxide film on the metal surface, which reacts with the metal, causing severe oxidation and corrosion [50].

The presented system was developed by Energo-Efekt Sp. z o. o., Poznań, Poland, for a distillery. Its implementation was the subject of a doctoral dissertation [51]. There are numerous examples in the literature of other distilleries where modifications have been implemented and energy is derived from RES. The biogas plant at the Glendullan Distillery in Speyside, Scotland, which is owned by the Scotch whisky producer Diageo, has been operational since 2015. After a period of one year, the plant was capable of converting 1000 m³ of malt whisky distillation by-products per day into 16 MW hours of renewable heat [52]. The plant reduced its use of fossil fuel energy by 25%. A combined system comprising biomass combustion and anaerobic digestion was demonstrated by Diageo Roseisle Distillers in Scotland as a means of recovering energy. The system was shown to produce a power output of 8.6 MW, which represents 84% of the total steam load required at the plant. Ref. [53] Cameronbridge Distillery (Diageo), located in Fife, has constructed a bioenergy plant that employs anaerobic digestion, biomass combustion, and water recovery for the production of energy. The plant is capable of generating in excess of 30 megawatts (MW) of energy, thereby fulfilling 95% of the plant’s energy requirements through the recycling of natural distillation by-products [54].

The Scotch Whisky Association in 2021 stated that a 53% reduction in greenhouse gases had been achieved in whisky distilleries from 2008 and 20% renewable energy achieved [55]. This indicates that about 40% of the GHG reduction came from the use of biomass and 60% from process thermal efficiency improvements.

4. Conclusions

As the pursuit of climate neutrality and zero net emissions is a shared objective amongst various industries, including but not limited to the distilling industry, it is imperative to gain a comprehensive understanding of the technological solutions currently available, as well as those that are projected to be available in the future, to facilitate the decarbonisation process.

In this study, we have presented an innovative solution conceptualised and implemented by Energo-Efekt Sp. z o. o., Poznań, Poland, at Polmos Żyrardów to modify its system of energy generation, circulation, and management. Polmos Żyrardów has implemented a comprehensive modernisation initiative, including the integration of eco-friendly solutions, through a systematic, multi-faceted approach to energy management. Throughout the design process technological solutions were selected to meet the specific requirements of the company. These requirements encompassed both the dynamics of technological processes and the demand for electricity and heat. The design process was based on initial data from monitoring technological processes within the company, energy balances, and an energy strategy assuming emission-neutral fuels and highly efficient processes. A key assumption of the transformation was replacing the existing main energy source, natural gas, with biomass. The selection of a renewable energy source was determined by an analysis of local conditions and the availability of alternative energy sources. The expander, which had been designed for the purpose of small-scale power generation, was utilised to generate energy, with electricity being produced using steam from the boiler. Concurrently, technological solutions were implemented, facilitating the utilisation of waste heat and thereby substantially mitigating energy losses. The company’s pro-ecological stance is exemplified by the preference for green energy. The implementation of these strategies has yielded substantial and readily observable outcomes, as evidenced by metrics such as the company’s carbon footprint. Energy is now generated in-house at the plant, making the distillery almost independent of external energy suppliers. Energy generation in this innovative system can be achieved using direct combustion, using lignin-cellulosic biomass (wood chips), or via biochar production. The boiler can be fuelled with either lignin-cellulosic biomass (wood chips) or wet biomass. In the first case, direct combustion will be feasible. The second source will necessitate pre-treatment to produce biochar, using a drying and carbonisation chamber. Biomass that cannot be used directly for energy purposes due to its too-high moisture content (e.g., pomace) can be converted in a specially designed part of the system to biochar.

The modernisation of the entire system has brought positive economic and environmental benefits. Economically, the advantages include reduced consumption of purchased energy, enhanced energy efficiency, and lower production costs. The positive environmental impact stems from replacing fossil fuel-based energy with renewable sources, leading to a more than 90% reduction in CO₂ emissions. The applied innovative technological solution can serve as a model for similar low-power systems. The actions taken by Polmos align with energy transition strategies designed to facilitate the emergence and growth of regional decentralised energy systems. This concept is especially relevant at the present moment, when centralised sources of energy production and supply are becoming the target of physical and cyber attacks.

To reduce emissions and achieve carbon neutrality, distilleries globally are adopting various measures. These include the utilisation of renewable energy sources, upgrading heating systems, and afforesting land. An extensive analysis of the potential for decarburisation of whisky production using bio-waste was performed by Andres et al. [56], which demonstrates that distillery waste alone is inadequate as an energy source and that alternative bio-waste sources must be utilised to achieve full decarburisation targets. Bio-wastes from the whisky industry, such as malt-house bio-waste, farm barley straw and maturation bio-char, would enhance the decarburisation of the distillery industry to 89%. In order to achieve the full decarburisation goals and address the current inadequate supply of distillery-specific bio-waste, the industry must also utilise other energy sources. The recommended solution involves the gasification of wet draff and straw to produce biomass gasification gas. When supplemented with hydrogen, this offers a low-emission heat source for distilleries.

The Absolut vodka distillery in Åhus, Sweden, is now fossil-free and has achieved carbon neutrality through a 100% renewable electricity contract (primarily hydropower) and highly energy-efficient systems [57]. In 2024, their carbon efficiency for distillation and bottling reached a remarkable 1 g CO₂/L of vodka, a 17-fold reduction from 2023 levels. Any remaining emissions are offset by strategic tree planting.

In 2022, Irish Distillers committed to investing in Midleton Distillery with the objective of achieving carbon neutrality by the end of 2026, thereby converting it into Ireland’s first and largest carbon-neutral distillery [58]. The production capacity of the facility is reported to exceed 70 million L of pure alcohol per annum, making it a significant contributor to the global supply of Irish whisky. Midleton Distillery has announced its intention to cease the use of fossil fuels. The objective of the transformation is to reduce energy consumption by enhancing efficiency, recycling waste heat, and utilising renewable energy sources. The implementation of highly efficient boilers and innovative mechanical vapour recompression technology represents a development in the field of energy management. It is estimated that these modernisations will result in a 70% reduction in emissions. In order to achieve all the objectives, Midleton Distillery will be utilising renewable energy sources, such as green hydrogen and biogas, while discontinuing the use of natural gas.

LEBANON, KY, utilised a number of other solutions. In September 2021, the company opened Diageo’s Lebanon Distillery in Kentucky, specifically designed to be the company’s first carbon-neutral distillery in North America [59]. The facility possesses the capacity to produce up to 10 million proof gallons per year and has initiated the distillation of Bulleit Bourbon using electrode boilers that are powered by 100% renewable electricity throughout the cooking, distillation, and dry house processes. Diageo has already succeeded in halving the carbon emissions associated with its operations since 2008. The organisation is now working to reach net-zero carbon across its direct operations by 2030, a target which it aims to achieve by harnessing 100% renewable energy. Furthermore, the company is working to achieve net-zero carbon across the entire supply chain by 2050. Diageo has entered into a partnership with Inter-County Energy and East Kentucky Power Cooperative (EKPC) for the purpose of sourcing a combination of wind and solar energy. It is estimated that the implementation of these technologies at the Diageo Lebanon Distillery will result in the avoidance of approximately 117,000 metric tons of carbon emissions on an annual basis.

In the ongoing efforts to reduce emissions and achieve carbon neutrality, distilleries worldwide are implementing a range of strategies and frequently combinations of these.