Search Results (4)

The volatility of renewable energy outputs is a well-known obstacle that has hindered the integration of more renewables in the UK’s energy mix, as the current network was not designed to handle such swings. Microgrids (MGs) may function as an effective means of integrating more renewables, particularly if they can effectively control the volatility of renewables at a smaller scale (the MG level) through a collaborative operational strategy. This paper focuses on the management of renewable energy fluctuations in MGs, proposing a pre-contract order update (COU) strategy based on the lean balancing (Heijunka) concept. The study compares the performance of collaborative and selfish MGs in terms of levelized cost of electricity (LCOE), order volatility, and carbon emissions. Two simulations models for the collaborative and selfish MGs were implemented, while considering two distinct backup generation scenarios within the MG system. The findings indicate a two-dimensional trade-off between the collaborative MG models, which are 61% more sustainable and reduce order volatility to the utility grid by 55%, and the selfish MGs, which incur lower energy consumption costs reduced by only 19%. These findings highlight the potential of collaborative MGs in enhancing grid stability and supporting broader renewable energy integration goals. Full article

This paper explores the integration of microgrids within utility networks and distinguishes selfish from collaborative microgrids. Research has shown that selfish microgrids tend to increase volatility of order updates to power generators, whereas collaborative microgrids decrease that volatility, resulting in smoother, more controllable operations of networks. This paper proposes an analytical formula linking power volatility to power quality, i.e., to issues such as voltage dips, surges, and transients. These are known risks for disrupting the operation of utility grids, causing instability and jeopardising efficiency and reliability. As collaborative microgrids reduce volatility, they improve power quality. That argument is extended to propose that collaborative microgrids can act as quality improvements agents within wider networks. Full article

The United Kingdom seeks to achieve net-zero emissions by 2050, mostly via the shift to an electrical system exclusively powered by zero-carbon sources. Microgrids (MGs) can be seen as an effective system for integrating renewables into the energy portfolio. Nonetheless, MGs face the acknowledged obstacle of backup power generation due to the intermittent nature of renewable energy sources, necessitating the establishment of backup power generation capacity. This paper contrasts selfish power generation, where the MG pursues complete energy autonomy, with an alternative influenced by lean principles (Heijunka production), which seeks to stabilise power transactions within the national electricity supply chain, reduce emissions, and tackle the backup generation challenge. This study proposes a pre-contractual order update (COU) strategy for the operation of hybrid collaborative MG where a forward order update to the utility grid is placed, in contrast to selfish MG, which uses a spot order update strategy. The COU strategy was defined, and two simulation models (for selfish and collaborative MG) were developed, each incorporating four backup generation scenarios to illustrate the method’s efficacy by assessing the system’s critical performance metrics. It has been found that the collaborative MG model reduced the carbon emissions by 62% and the volatility of unplanned orders to the grid by 61% compared to the selfish model in the first scenario (grid-dependent MG). Furthermore, the MG achieved zero volatility and a 33% reduction in carbon content in the collaborative MG when using the H₂ burner as backup generation compared to the first scenario. Indicating that sustainability encompasses not only the use of renewable resources but also the stability of their outputs through the implementation of collaborative MGs. Full article

Due to the context of market competitiveness and the economic and financial crisis, companies need to optimize their production systems, tracking the raw material from the suppliers until the final product arrives to the consumer. The Lean philosophy assumes a relevant role for today’s industries through its concepts and tools, enabling optimization, increasing revenues, and having the principle of not expropriating the environment. This article aims to analyse the level of maturity reached by industries in Luanda regarding the practices and tools of the Lean philosophy. A Lean graphic model was built, measured by the Lean Enterprise Self-Assessment Tool (LESAT) maturity model through qualitative and quantitative research focusing on the statistics of 87 circumscribed industries at Viana Industrial Development Pole in the Economic Special Zone of Luanda region, Angola. Initially was conducted an analysis to see whether Lean practices and tools were used: 5S, OKJust-In-Time, Kanban, Bottleneck Analysis, Jidoka, Kaizen, Poka-Yoke, SMED, Gemba, Heijunka, Value Stream Mapping, Hoshin Kanri, and Andon. The next steps were to analyse the following: customer value analysis; value chain analysis; analysis of the use of the pulled production system; and analysis of the use of the continuous production flow analysis of continuous improvement. The result shows these industries using the Lean philosophy at a very low level of maturity. Only the 5S tool was known and used. The JIT, Kanban, and Bottleneck Analysis were moderately used. Only 50% of Lean practices were used. Full article