Participation of Energy Communities in Electricity Markets and Ancillary Services: An Overview of Successful Strategies

Abstract

Energy communities are a transformative force in the electricity markets and ancillary services, reshaping the energy landscape through collective action. This paper explores the successful strategies adopted by these communities, highlighting real-world cases where they have participated directly in the market, or through aggregators, or sold their energy to retailers, which is of paramount importance because it serves as a foundation for those countries that wish to implement these entities as part of their decarbonization plan. It also serves as a model for the development of future citizen initiatives that aim to turn citizens into active users of the electricity system. The paper examines collaborative dynamics within the energy sector, highlighting how these communities optimize resource sharing and contribute to a more resilient and sustainable energy system. The study emphasizes the potential of energy communities in driving innovation and fostering a participatory approach to energy management. The results show that some pilot projects are being developed and several electricity cooperatives, one of the most common forms of energy communities, are participating in energy trading with their members and other entities. More efforts are also needed for energy communities to participate more directly in the market and/or through aggregators.

1. Introduction

Energy Communities (ECs) are communities with energy resources, such as photovoltaic systems, micro-wind, bio-energy, and the consumption of its residents is controlled by its members. These new entities contribute to the energy transition towards a zero-gas emission system and enable people to be active users of the energy system. There are two types of ECs: Renewable Energy Communities (REC) and Citizen Energy Communities (CEC). Both terms have been defined by the European Directives in 2018 and 2019 [1,2].

The primary goal of ECs is to provide social, environmental and economic benefits to members and the community in which they operate. The European Directives allow these legal entities to participate in the electricity markets [1,2]. It is the responsibility of each member state to implement the legal framework effectively and practically so that ECs can participate in the electricity sector without discrimination and fulfill their obligations and rights [3].

ECs are primarily driven by the active participation of citizens, empowering them to take control of both energy generation and consumption within the electricity system. This empowerment is anticipated to foster more engaged and responsible energy use among the population. Consequently, numerous studies have explored the potential social and environmental impacts of ECs on society [4], with some focusing on their role in alleviating energy poverty [5,6]. Given their objectives and characteristics, ECs are also being considered for implementation in various countries, including Egypt [7].

In addition to these impact studies, research has also highlighted the importance of creating inclusive and participatory environments for the successful implementation of ECs. For instance, ref. [8] emphasized the role of energy cooperatives in fostering community engagement, noting that a strong local perception and sense of ownership are critical for these initiatives. Similarly, ref. [9] conducted a comparative analysis of seven pilot EC projects across Europe—including Belgium, Spain, the Netherlands, and Greece—focusing on the design elements that contribute to the success of ECs. Their study, which employed a multi-criteria and multi-stakeholder approach, concluded that such methods are instrumental in helping stakeholders align their objectives.

The study in [10] analyzes best practices for transferring the experience of multi-functional energy gardens from the Netherlands to Germany, serving as a potential model for ECs. These projects emphasize renewable and ecological approaches. The authors conclude that the success of such transfers relies heavily on active participation from local governments and communities, financial support, clear objectives, and strong commitment [11]. Additionally, a favorable regulatory framework for energy sharing significantly aids the development of these initiatives. Other research, such as [12], has focused on replicable strategies and trends, particularly in creating positive energy buildings and smart cities. The analysis of these strategies is not only of great societal interest but also crucial for understanding contextual adaptation.

In [13], the authors provide a descriptive analysis of various ECs funded by European projects, along with case studies on their implementation. The evaluation centers on the primary operational strategies and identifies key European strategic policies. One of the barriers to EC development as highlighted by the authors is the challenging relationship between citizens and institutions. Moreover, technological advancements and national legislation often lag behind the implementation pace proposed by European directives.

The study in [14] analyzes four pilot EC projects in the Netherlands, Belgium, Sweden, and the UK through interviews, focusing on member participation, management, and legal aspects. The findings suggest that further legislative efforts are necessary to ensure the successful operation of these community initiatives. Similarly, ref. [15] identifies the best administrative, technical, and technological practices for developing REC within the Italian regulatory framework, emphasizing the need for strategies to attract stakeholders and underscore the importance of energy issues [16,17].

In [18], the most effective strategies for achieving net-zero and positive ECs are outlined based on the findings of the Zero-Plus project. The case studies analyze cases in New York in the United States, Calgary in Canada, Granarolo dell’Emilia in Italy, and Cairo in Egypt. Among the study’s conclusions, the authors mention that these initiatives have focused more on the generation side than on demand reduction or efficiency improvements to reduce consumption, which requires new and better policies and management tools. In [19], the authors analyze 24 case studies of ECs in different European countries, and identify different design options for ECs. They evaluate the cases using a morphological box, in which they analyze the cases in terms of their role in the value chain, support, geography, financial volume, and application in the sector. Among the conclusions, they underline that the participation schemes should be focused on the demand flexibility services that urban citizens organized in ECs could offer to the Distribution System Operators (DSOs).

Although some of the studies mentioned above present real cases of ECs, there is a gap in the literature to study the interaction of ECs in the energy market. ECs also open the door to the development of new energy technologies. In [20], the authors study the best practices of Termoli REC in the city of Termoli, Italy, in which they highlight the technological design tool Enea. Enea’s strategy is to facilitate a development process starting from RECs considering energy exchange. Enea has created a digital framework to support ECs through the creation of tools and services, taking into account the evolution of the regulatory framework in Italy. Also, in [21], the authors present an Energy Community Platform, a modular system designed for the smart monitoring of local ECs to encourage a more conscious energy use by users, and the Energy Community Tokenization Platform as part of the best practices within ECs. In [22], the authors study the implementation of fifth-generation district heating and cooling and propose best practices for its implementation. In doing so, they refer to three business models of ECs: local energy markets, third-party sponsored communities, and community ESCO (energy service companies). This study focuses on Swedish district heating and cooling but can be applied to other contexts. Also in [23], the implementation of the combination of collective investment and the P2P business model is advised.

Four cases of Dutch and German communities are studied in [24] to identify the factors influencing the formation and development of RECs. The author concludes that he found no significant differences between the two countries, despite their different regulations and backgrounds, nor did he find urban or rural location to be an influential factor. However, he did find that there is a high level of investment in communities where citizens have a good and close relationship of trust, as well as the size of the community. In [25], an analysis is conducted of the strategies some RECs have used to engage their members and enable them to save energy. In [26], a study is made of the factors that facilitate and hinder the implementation of sustainable ECs, based on two case studies, one from Denmark and the other from Ireland. Among the conclusions, the authors mention the need to identify the key person of influence in the project as well as to interact with the community members.

As can be observed, these studies are based on sound practices in the functioning of the EC or the provision of technological tools that facilitate its development. Furthermore, some of the studies also concentrate on the membership practices of the community. Nevertheless, there is a lack of focus on the strategy of participation of the ECs in energy markets.

Unlike previous studies, our study focuses on identifying ECs that participate in energy and ancillary services markets and other energy services. ECs are expected to accelerate the decentralization and decarbonization of the electricity system; therefore, analyzing the current and expected future implementation cases helps predict the impact of these entities on the electricity systems.

Contribution and Organization

This study aims to answer the following questions:

• What is the current participation of ECs in the electricity market?
• What strategies are ECs using to participate in the electricity sector?
• In what services are ECs expected to participate in real projects under development?

This article addresses the regulatory perspective of ECs in different countries, outlining the implementation strategies and lines of action or operation of real cases of ECs. It also presents ECs that aim to provide flexibility services and have been evaluated for this purpose. Furthermore, it presents some community aggregation programs that can serve as references for the aggregation of ECs and participation in flexibility services.

The remainder of the paper is organized as follows: Section 2 describes the methodology we used to analyze the literature. Section 3 provides the definition and gives the context of the ECs studied in this article. Section 4 presents real case studies of ECs that participate in the electricity sector, and Section 5 summarizes the main conclusions of this study.

2. Materials and Methods

This study aims to present real-life case studies of ECs operating in the electricity sector, highlighting the importance of transferring best practices and success stories. Given the diverse nature of ECs (some focused on energy efficiency, self-consumption, or electric mobility), it would be impractical to present all existing examples. Not all ECs are involved in selling energy to the grid or offering ancillary or flexibility services. Therefore, this study concentrates on a selection of relevant case studies from various contexts and countries, ensuring a versatile approach.

The methodology employed involved reviewing real cases of ECs with specific characteristics, such as the following:

• Providing energy to different users, agents, and/or directly to the electricity sector;
• Participation in ancillary or flexibility services.

To gather data on these cases, a wide range of sources were consulted, including national and international publications, public and private databases, and the websites of relevant projects. Additionally, the legal structures that can constitute an Energy Community were also considered.

3. Energy Community Concepts

The European directive introduced two distinct concepts of ECs: Renewable Energy Communities (RECs) [1] and Citizen Energy Communities (CECs) [2]. An REC is a legal entity characterized by several key features. It is based on open and voluntary participation, ensuring autonomy and effective control by partners or members who are located near renewable energy projects that are owned and developed by the entity. These partners or members can include natural persons, small and medium-sized enterprises, or local authorities, such as municipalities. The primary purpose of an REC is to deliver environmental, economic, or social benefits to its partners, members, or the local area in which it operates, rather than seeking financial gain. Furthermore, member states are required to guarantee that RECs have the right to access all relevant energy markets, whether directly or through aggregation, on a non-discriminatory basis.

On the other hand, a CEC is also a legal entity, but it emphasizes voluntary and open participation with effective control exercised by individuals, local authorities (including municipalities), or small businesses. Similar to RECs, the primary objective of CECs is to provide environmental, economic, or social benefits to their partners, members, or the local community, rather than focusing on financial returns. CECs engage in a wide range of activities, including the generation of energy (potentially from renewable sources), distribution, supply, consumption, aggregation, and storage of energy. They may also provide energy efficiency services, electric vehicle charging, or other energy-related services to their members or partners. Member states must ensure that CECs have access to all organized markets, either directly or through aggregation, under non-discriminatory conditions.

Figure 1 illustrates some of the components that can form an EC. This legal entity can consist of energy-consuming buildings or homes, as well as businesses and prosumers, i.e., consumers who also produce energy. It can also include electric mobility, and public charging stations for electric vehicles, which can serve as flexible loads for the community and can be managed. On the generation side, most ECs currently have photovoltaic installations, but they can also include other renewable and even conventional technologies. In contrast to CECs, RECs can only include renewable generation technologies due to the definition of the European Directive.

4. Case Study Analysis

This section presents case studies of real ECs, identified and separated by different activities: ECs that participate in market platforms, ECs that supply energy and heat, ECs that supply energy but also have electromobility services, ECs that participate as electricity suppliers and citizen energy projects that sell their energy to entities such as electric cooperatives, ECs that intend to participate in flexibility services, and finally, community aggregation projects that can be used as a reference to develop models for flexibility services to the electric grid.

4.1. Energy Communities and Market Platforms

Some ECs are operating energy market platforms as shown in Table 1. Some are regulated by law and others with exceptional permits. For example, in the pilot project of Eemnes. This is a pilot project developed by the European Renaissance project and is located in the center of the Netherlands. The objective is to validate a local, blockchain-enabled, peer-to-peer energy market in an operational environment. As part of the operational strategy, they have tested with 100–200 households, local businesses, and farmers for the operation of this marketplace.

This project will operate a peer-to-peer (P2P) trading system strategy. For the optimization model, 250 smart meters, 250 gateways, a battery, and a trading platform will be implemented. Stakeholders in this pilot project include the Energie Cooperative Eemnes, a local non-profit energy association, Energie Van (acting as Energy Service Aggregator on behalf of the Cooperative), Stedin, the Dutch Distribution System Operator (DSO), and Eemnes citizens [27].

The municipality of Eemnes has been granted an exemption from the Dutch Electricity Act by the Ministry of Economic Affairs (2018–2027) [27]. In July 2022, the Netherlands proposed a draft law introducing ECs (CECs and RECs) into the Energy Act. Under this proposal, ECs would be allowed to supply gas and electricity to their members without a permit under certain conditions, e.g., the EC does not provide more electricity or gas for one year than it contributes to the system annually [28]. However, countries such as Germany and the Netherlands have had a large number of ECs since before the European directives issued the law on the inclusion of CECs and RECs in the national laws of the member states. These countries have an orientation towards community energy projects [29].

Another case of a market platform is the Ourpower Die Energy Cooperative in Austria. This has a P2P marketplace platform and has developed several pilot projects for ECs. One of the pilot projects is the Citizen Energy Community OurPower (BEG Ourpower), which sells the surplus energy to the Ourpower marketplace [30], also the Renewable Energy Community Sekem Energy, located in Styria, focuses on consuming assets that can be traded, trading its energy. This community is focused on active consumers who produce and consume energy [31]. The operation of these pilot projects is legal under the Renewable Energy Expansion Act in Austria.

In July 2021, Austria published its Federal Act on the Expansion of Energy from Renewable Sources (Renewable Energy Sources Expansion Act—EAG). The original in German is as follows: Bundesgesetz über den Ausbau von Energie aus erneuerbaren Quellen (Erneuerbaren-Ausbau-Gesetz—EAG). The scope of this law includes the organization and operation of REC and their participation in support schemes. It stipulates that the REC may be formed by two or more members or shareholders and specifies the forms that an energy community may take, indicating that it may be an association, cooperative, partnership, or corporation, or a similar association with a legal personality.

The maximum amount of energy generated within the community (Renewable Energy Community and Citizen Energy Community—§ 16b. WOG 2010) but not consumed may not exceed 50% of the total amount of energy produced [32,33]. This amount can be fed into the public grid and receives a market premium. In addition, they can receive financing in accordance with the provisions of this Act [32], as well as subsidies for new wind power plants of up to 1 MW [34].

Section 16d of the ElWOG also stipulates that the EC must have a licensed grid operator and may entrust the operation and maintenance of its generation facilities to a third party [35].

Another project aimed at creating small ECs is the Green Energy Community (GECO) project [36]. This project is being developed in Bologna in the Pilastro-Roveri district, and citizens are expected to benefit from reduced tariffs; the main aim of this project is to contribute to increasing sustainability and reducing energy poverty.

One example of projects where the University are involved is the Svalin co-housing complex project. This is serving as a living laboratory for the Technical University of Denmark’s (DTU) research project Energy Collective developed in Roskilde, Denmark. In this project, each household consumes its own electricity production, while the surplus is sold to the grid within the current Danish regulatory framework. The objective is to collectively consume 100% renewable and local energy by sharing their renewable energy generation among the community, thus avoiding the traditional intermediary parties. This project is based on the concept of the consumer-centric electricity markets in various forms as community-based or peer-to-peer, to demonstrate the flexibility of a community sharing electric energy [37,38].

In Denmark, ECs exist mainly in the form of citizen wind turbine owners and district heating companies or consumer cooperatives; in Denmark, the law prohibits district heating systems from making a profit, but they remain profitable [39]. Through contracts between the REC or CEC and a trading company, the latter can manage the compensation and distribution of the shared energy and the additional energy needed to meet the community’s needs, although the REC or CEC can also carry out this activity itself while fulfilling all the obligations required of a company involved in energy trading [40].

In Denmark, a grant scheme for local community energy projects was approved. The Order on Subsidies for Local Energy Communities and Local Anchoring of Climate Change was approved in June 2022, which provides for subsidies to finance renewable energy projects developed in local communities. These grants are intended, among other things, for the dissemination of information for the development of renewable energy projects in local communities, the planning, development, and establishment of solutions for energy storage, aggregation, energy efficiency, savings and relief for the collective electricity grid and climate benefits for the community [41].

Table 1. ECs participating in energy market platform.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Eemnes	Pilot project	2018	The Netherlands	Peer-to-peer energy market in an operational environment	Photovoltaic, BESS	[27]
2	Citizen Energy Community OurPower (BEG Ourpower)	CEC	2022	Austria	Peer-to-peer energy market in an operational environment	-	[30]
3	Renewable Energy Community Spörbichl	REC	2022	Austria	Collective self-consumption	Photovoltaic, Wind, Hydro	[42]
4	The Renewable Energy Community Sekem Energy	REC	2022	Austria	Peer-to-peer energy market in an operational environment	Photovoltaic, Hydro	[31]
5	The Renewable Energy Community nahwaerme Reidling	REC	2022	Austria	Collective self-consumption. Electricity and heat supply	Photovoltaic, Biomass/Biogas	[43]
6	Svalin co-housing complex	Energy collective project (Co-housing community)	-	Denmark	P2P, Generation renewable electricity and consumption; Energy services; electro-mobility; energy sharing	Photovoltaic, BESS, Heat pumps	[37,38]

Table 1. ECs participating in energy market platform.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Eemnes	Pilot project	2018	The Netherlands	Peer-to-peer energy market in an operational environment	Photovoltaic, BESS	[27]
2	Citizen Energy Community OurPower (BEG Ourpower)	CEC	2022	Austria	Peer-to-peer energy market in an operational environment	-	[30]
3	Renewable Energy Community Spörbichl	REC	2022	Austria	Collective self-consumption	Photovoltaic, Wind, Hydro	[42]
4	The Renewable Energy Community Sekem Energy	REC	2022	Austria	Peer-to-peer energy market in an operational environment	Photovoltaic, Hydro	[31]
5	The Renewable Energy Community nahwaerme Reidling	REC	2022	Austria	Collective self-consumption. Electricity and heat supply	Photovoltaic, Biomass/Biogas	[43]
6	Svalin co-housing complex	Energy collective project (Co-housing community)	-	Denmark	P2P, Generation renewable electricity and consumption; Energy services; electro-mobility; energy sharing	Photovoltaic, BESS, Heat pumps	[37,38]

4.2. Involving Energy Communities in Commercialization

There are ECs that are active in the commercialization of energy and participate in other energy services. This section presents some examples of ECs grouped by activity.

4.2.1. Electricity and Heat Supplier

As mentioned above, Germany has a long tradition of energy cooperatives. In addition to the supply of electricity, there is also the modality of heat supply, through heat networks, as shown in Table 2. For example, the Elektrizitätswerke (EWS) Schönau eG operates electricity grids and gas and heat networks in Germany. It also offers charging solutions for electric vehicles through different tariffs. The takeover of the electricity grid in Schönau was the key to the success of this cooperative. Regionally, they now operate nine electricity and three gas grids [44]. Another example is the Beauvent cooperative that is a cooperative in Belgium that supplies renewable heat and operates a district heating network; energy efficiency; and third-party financing services. It sells the energy it produces to Ecopower and large customers. It also produces renewable electricity, including the sale of electricity to customers with PV panels on their roofs [45].

Another example of this kind of ECs is the Skawina Energy Cooperative—SES. The purpose of the cooperative is to produce electricity or biogas or heat in renewable energy installations and to balance the electricity demand, exclusively for the needs of the cooperative and its members. It enables the members of the cooperative to obtain income from the sale of electricity produced from renewable energy sources within the cooperative, organizing the supply and collection of electricity produced for them from renewable energy sources within the cooperative between the members of the cooperative [46].

Unlike Germany, Belgium is not one of the countries with a long tradition of electric cooperatives, but there are some energy cooperatives in operation. Due to the Belgian form of government, the administration of the RECs scheme is carried out on a regional basis. The European Directive on RECs and CECs was implemented in the Brussels region in March 2022. A third type of energy community has been created, the Local Energy Community, which is limited to renewable energy production, energy sharing, and storage within the community. Sibelga is the DSO in Brussels and is responsible for facilitating energy sharing and ECs.

In Brussels, Sibelga has applied tariffs for shared consumption since 2022. These tariff adjustments will apply from 1 September 2022 until 31 December 2024. In addition, COOP US in the Brussels region offers financing to cooperatives, including those developing energy solutions as a carbon-free economy for society [47,48,49].

In the Flemish region, the concepts of the Citizen Energy Community and the Renewable Energy Community have been transposed. The legislation has weaknesses in administrative procedures, such as the registration of ECs, which should be improved. Energy sharing is possible in Flanders under certain conditions, with a framework planned for 2023 [50].

In the Walloon Region, the definition of RECs and CEC was implemented in May 2022. ECs must notify the Walloon Energy Commission (CWaPE) if they intend to participate in the electricity markets, and this must be made public to all grid operators. The activity of energy sharing does not require a license, only an initial authorization [51].

Table 2. ECs participating as heat and electricity supplier.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Elektrizitätswerke (EWS) Schönau eG	Cooperative Vertrieb GmbH	2009	Germany	Electricity and gas network operator (operate 9 electricity grid and 3 gas grids). Offers charging solutions for electric vehicles through different tariffs.	Photovoltaic, Wind, Hydro, Biogas	[44]
2	BeauVent	Cooperative Limited Liability Company (CVBA)	2000	Belgium	Cooperative electricity supplier	Photovoltaic, Wind, Biomass/Biogas, Cogeneration	[45]
3	Skawina Energy Cooperative—SES	Energy cooperative		Poland	Organize the supply and collection of electricity generated from renewable energy sources within the Cooperative among the members of the Cooperative	Photovoltaic, Biogas	[46]
4	Albarracín	Association	2022	Spain	To provide the Senda Muerta neighborhood with heating and hot water for sanitary purposes. To offer a cheap heating system to its future clients and the whole of Arrabal de Albarracín. It will provide the houses with an autonomous heating system, with the possibility of replacing the heat source with a biomass heating network. Electrical self-sufficiency	Biomass, Photovoltaic	[52]

Table 2. ECs participating as heat and electricity supplier.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Elektrizitätswerke (EWS) Schönau eG	Cooperative Vertrieb GmbH	2009	Germany	Electricity and gas network operator (operate 9 electricity grid and 3 gas grids). Offers charging solutions for electric vehicles through different tariffs.	Photovoltaic, Wind, Hydro, Biogas	[44]
2	BeauVent	Cooperative Limited Liability Company (CVBA)	2000	Belgium	Cooperative electricity supplier	Photovoltaic, Wind, Biomass/Biogas, Cogeneration	[45]
3	Skawina Energy Cooperative—SES	Energy cooperative		Poland	Organize the supply and collection of electricity generated from renewable energy sources within the Cooperative among the members of the Cooperative	Photovoltaic, Biogas	[46]
4	Albarracín	Association	2022	Spain	To provide the Senda Muerta neighborhood with heating and hot water for sanitary purposes. To offer a cheap heating system to its future clients and the whole of Arrabal de Albarracín. It will provide the houses with an autonomous heating system, with the possibility of replacing the heat source with a biomass heating network. Electrical self-sufficiency	Biomass, Photovoltaic	[52]

4.2.2. Electric Mobility Services

The proliferation of electric mobility solutions and associated services plays a pivotal role in facilitating the energy transition and decarbonizing electricity systems. The increase in supply can lead to a reduction in the cost of services. Some ECs, in addition to the commercialization of energy, are also involved in the provision of electric mobility services as is shown in

Table 3. ECs participating in electric mobility.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Courant d’Air	Cooperative Limited Liability Company (SCRL)	2009	Belgium	Electricity supplier. Offer alternative electric mobility options by renting an electric car. ORES charging station of 22 kW. Support the municipality with energy and financial savings. Support for energy renovation and energy monitoring.	Photovoltaic, Wind, Hydro, Biomass/Biogas	[53]
2	Som Energia	Cooperative	2010	Spain	Producer and trader of green energy (supplier). Supplier of exclusively electric vehicle charging points with public access. Forecast and make agreements to buy and amount of energy needed to market.	Photovoltaic, Wind, Biogas	[54]
3	Cunastera	CEC	-	Spain	Commercialize energy to different CEs. Offer mobility solutions: Electric vehicle charging in public infrastructure.	Renewable Energy	[55]
4	Vacoe	Cooperative society	-	Spain	Collective self-consumption, with surpluses and with compensation. Creation of vehicle charging points.	Photovoltaic	[56]
5	CTM EC	EC	-	Spain	Installation of 3 semi-fast 50 kW electric vehicle charging points for public use. Self-consumption of renewable electric energy	Photovoltaic	[57]
6	Arousa	EC	-	Spain	Collective consumption. Intelligent energy demand management system. Dual charger for electric vehicles.	Photovoltaic	[58]
7	Otzi	Cooperative	-	Germany	support 100% of electromobility with the Ötzi charging station. Trading electricity	Photovoltaic, hydro, wind	[59]

.

Courant d’Air, for example, is a citizens’ renewable energy cooperative in Belgium, recognized as a social economy enterprise operating in the east of the country. Founded in 2009, the cooperative operates renewable energy production projects in the wind, photovoltaic, hydroelectric, and soon biomass sectors. Information and awareness-raising are also part of its objectives as is educational work in schools. Together with nine other Walloon energy cooperatives, Courant d’Air has set up the Comptoir Citoyen des Energies (COCITER), which supplies green electricity produced by its members.

In partnership with the Carpooling Centre “Fahrmit ASBL”, Courant d’Air has been providing electric cars since June 2017. The idea is to offer interested citizens an alternative mobility option by renting a car. The car has a reserved parking lot at the “Büchelturm” in St. Vith, right next to the ORES charging station (22 kW), which allows the car’s battery to be charged to 80% of its capacity in 1 h [53].

Som Energia, in Spain, is a cooperative that manages, buys, and bills the electricity used by partners who have chosen to use it as a marketer of green electricity. This cooperative is responsible for the production and marketing of green energy. Som Energia forecasts the energy they will need on the market. This cooperative also offers exclusive use of electric vehicle charging points with public access. This cooperative also offers the services of representatives of the producers so that they can sell the energy they produce on the electricity market [54].

In the case of Spain, there is still no complete regulation of ECs. In April 2023, the Ministry of Ecological Transition and the Demographic Challenge (MITECO) published a draft law for the regulation of ECs, which has not yet been approved [60]. However, the Institute for Energy Diversification and Saving (IDAE) has subsidized the development of about 74 CE projects through the CE-IMPLEMENTA program, which is currently underway [61]. Several of the ECs that benefited from this aid have as one of their objectives the provision of electric mobility services, with some projects being more advanced than others. Table 3 shows some of the projects and their proposed operations.

4.2.3. Electricity Supplier

European directives have allowed ECs to participate in the energy and electricity markets. Because of their power and energy capacity, they can participate directly by offering energy on the market or by trading their energy with end users. In Table 4 some examples of projects are presented in different countries. In Portugal, there is an example of the renewable energy cooperative Coopérnico that harnesses solar energy to benefit the local community. The cooperative works by renting the roofs of social institutions for its photovoltaic projects, providing these institutions with additional income. At the end of the lease, the cooperative gives the solar equipment to the host institution free of charge. The energy produced by these roofs is fed into the grid and purchased by the distributor at a fixed price [62]. Coopérnico is also active in the retail sector, which means that it can directly sell electricity to its members at a fair price, guaranteeing that the amount of electricity produced by Coopérnico’s projects is more than the one consumed by its members. This is one of the reasons why they have become very successful [62]. Another example is the citizen cooperative for renewable energy Ecopower cvba [63].

In Bulgaria, Izgrei-BG is an REC. This community sells any surplus, generating a small income. The electricity from the 4 kW panels is used for self-consumption, and any surplus is sold back to the grid. There is no fixed price for selling to the grid; instead, the electricity is sold on the open market, and the price varies hourly [46]. In October 2023, the Bulgarian government introduced a legal definition for ECs, but this is very basic, and Izgrei is concerned that national legislation could change again. Izgrei is currently looking for ways to expand the energy community and add more members according to the basic definition.

The management strategy of the ECs in each country is determined by the legislation in that country. The energy cooperative TOER U.A. in the Netherlands provides green energy (wind turbines) to its members. To become a member, you must belong to one of the postcodes defined for the Postcode Rose Scheme. The green energy produced is sold to energy companies. Selling the energy produced to energy suppliers means that this cooperative sells the energy to energy suppliers (companies that sell the energy to other customers) [64]. In Germany, the Heidelberg Energy Cooperative aims to implement projects that contribute to climate protection. These include renewable energy generation, energy efficiency, and energy conservation projects, most of which are carried out by citizens. This cooperative provides renewable energy to citizens [65].

In the case of France, we have Enercoop as an example. Enercoop has 11 cooperatives spread across France and is the electricity supplier. The objective is to supply electricity of 100% renewable origin [66]. Several community projects and ECs in France sell their energy to Enercoop. Some of these projects are presented here [67,68,69,70,71,72,73,74,75,76,77,78,79,80,81]. We have records of more than 100 citizen-based renewable energy projects selling their energy to Enercoop. In the ordinance 2021/236 of March 2021, France introduced the concept of Citizen Energy Communities [82]. Articles 291-1 and 292-1 of the Energy Code define the concepts of REC and CEC, which are faithful to the definition of the European Directive. The legal treatment of ECs is based on the legal rules of self-consumption defined in article 315-2-2 of the Energy Code, where ECs are treated as entities constituting collective self-consumption [83].

Table 4. ECs participating as electricity suppliers.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Energy Cooperative TOER U.A.	Energy cooperative	1994	The Netherlands	Sell the energy production to energy providers	Wind	[64]
2	Energy Cooperative Elektropionir	Energy Cooperative	2022	Serbia	Sell green energy to a company (a supplier company) thought contract	Photovoltaic	[84]
3	Izgrei-BG	REC	2021	Bulgaria	The electricity from 4 kW of panels is used for self-consumption and any excess is sold back to the grid. The electricity is sold on the free market and the price varies every hour.	Photovoltaic	[46]
4	Enercoop	Collective Interest Cooperative Society (SCIC)	2005	France	Green electricity supplier. Energy efficiency	Photovoltaic, Wind, Hydro, Biomass/Biogas	[66]
5	Heidelberg Energy Cooperative	Energy cooperative	2010	Germany	Supplier of green energy to citizens	Photovoltaic, Wind, Hydro	[65]
6	Coopérnico	Energy Cooperative	2013	Portugal	Rents the roofs of socially-orientated institutions for its PV projects. Sell the energy produced on the rooftops to a distributor at a fixed price. Participate in active in the retail sector selling electricity to their members at a fair price.	Photovoltaic, Biogas	[46]
7	Plaine Sud Energies	SCIC/SARL	2012	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[67]
8	Bégawatts	SAS	2014	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[68]
9	Energy Ethics 04	SAS	2013	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[69]
10	Les Ailes des Crêtes	SAS	2016	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[70]
11	Combrailles Durables	SCIC/SA	2010	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[71]
12	Soleil Eau Vent Energie—SEVE SEML	SEM	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[72]
13	Biocoop du Mantois	SAS	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[73]
14	Centrales Villageoises VercorSoleiL	SAS with cooperative status	2017	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[74]
15	Giraud Agri Énergie	SARL	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[75]
16	Parc photovoltaïque d’Aubais	SAS	2018	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[76]
17	Energie Citoyenne	SCIC/SAS	2014	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[77]
18	La Limouzinière	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[78]
19	Lum del Larzac	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[79]
20	Zusamme Solar Colmar	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[80]
21	Centrales villageoises des Quatre Montagnes	SAS	2018	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[81]
22	Ecopower cvba	Cooperative Limited Liability Company (CVBA)	1991	Belgium	Cooperative electricity supplier	Photovoltaic, Wind	[63]

Table 4. ECs participating as electricity suppliers.

No.	Project Name	Society Type	Year	Country	Operation	Generation Technology	Ref.
1	Energy Cooperative TOER U.A.	Energy cooperative	1994	The Netherlands	Sell the energy production to energy providers	Wind	[64]
2	Energy Cooperative Elektropionir	Energy Cooperative	2022	Serbia	Sell green energy to a company (a supplier company) thought contract	Photovoltaic	[84]
3	Izgrei-BG	REC	2021	Bulgaria	The electricity from 4 kW of panels is used for self-consumption and any excess is sold back to the grid. The electricity is sold on the free market and the price varies every hour.	Photovoltaic	[46]
4	Enercoop	Collective Interest Cooperative Society (SCIC)	2005	France	Green electricity supplier. Energy efficiency	Photovoltaic, Wind, Hydro, Biomass/Biogas	[66]
5	Heidelberg Energy Cooperative	Energy cooperative	2010	Germany	Supplier of green energy to citizens	Photovoltaic, Wind, Hydro	[65]
6	Coopérnico	Energy Cooperative	2013	Portugal	Rents the roofs of socially-orientated institutions for its PV projects. Sell the energy produced on the rooftops to a distributor at a fixed price. Participate in active in the retail sector selling electricity to their members at a fair price.	Photovoltaic, Biogas	[46]
7	Plaine Sud Energies	SCIC/SARL	2012	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[67]
8	Bégawatts	SAS	2014	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[68]
9	Energy Ethics 04	SAS	2013	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[69]
10	Les Ailes des Crêtes	SAS	2016	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[70]
11	Combrailles Durables	SCIC/SA	2010	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[71]
12	Soleil Eau Vent Energie—SEVE SEML	SEM	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[72]
13	Biocoop du Mantois	SAS	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[73]
14	Centrales Villageoises VercorSoleiL	SAS with cooperative status	2017	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[74]
15	Giraud Agri Énergie	SARL	2011	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[75]
16	Parc photovoltaïque d’Aubais	SAS	2018	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[76]
17	Energie Citoyenne	SCIC/SAS	2014	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[77]
18	La Limouzinière	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Wind	[78]
19	Lum del Larzac	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[79]
20	Zusamme Solar Colmar	SAS	2015	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[80]
21	Centrales villageoises des Quatre Montagnes	SAS	2018	France	All or part of the energy produced by this installation is sold to Enercoop, a green electricity supplier.	Photovoltaic	[81]
22	Ecopower cvba	Cooperative Limited Liability Company (CVBA)	1991	Belgium	Cooperative electricity supplier	Photovoltaic, Wind	[63]

4.2.4. Future Flexibility Services Provided by Energy Communities

Rescoop developed the Flexcoop project between 2017 and 2021. In it, they evaluated the opportunity for energy cooperatives to provide flexibility services using the case study of Som Energia in Spain and the cooperative Energie Samen in the Netherlands [85].

Energie Samen is the Dutch association of energy cooperatives. In this project, Energie Samen was evaluated for the possibility of becoming an aggregator with its member Endona in Heeten. Among other things, heat pumps will be used as flexible equipment to participate in the secondary reserve services of the distribution network operator. In the Netherlands, there are the independent aggregator model and seeds; in the future, they can manage the flexibility reserve, and cooperatives could benefit from this, taking balanced responsibility for their production and making firm offers to suppliers or traders and selling their energy [85].

Table 5. Future provider of flexibility services.

No.	Project Name	Society Type	Year	Country	Operation	Technology Devices	Ref.
1	Energie Samen	Energy cooperative	2017	The Netherlands	Endona aims to generate new revenues from services that it can offer to the TSO (secondary reserves).	Heat pumps, renewable energy	[85]
2	Energise Barnsley	Community and energy initiative	2019	England	Energise Barnsley led a consortium through a 3-year domestic demand side response innovation project called Breathe, which aimed to balance energy supply and demand locally.	solar panels, air source heat pumps, smart battery, control system	[86,87]
3	Medina de Pomar	EC (Association)	2021	Spain	It will be involved in renewable generation, distribution, supply, consumption, aggregation, behind-the-meter storage, provision of energy efficiency and electric vehicle charging, and other energy services, demand flexibility, etc.	Renewable Energy	[88]
4	Begonte Genera	EC (Association)	2022	Spain	Self-consumption and electricity, sustainable mobility, demand-side management, and air conditioning.	Renewable Energy	[89]

shows some of the ECs that intend to offer flexibility services.

U.S. regulations treat ECs somewhat differently than European directives. The Inflation Reduction Act of 2022 defines an energy community as a location that falls into one of three categories: Coal Closure Energy Communities refer to a place where a coal mine was closed after 1999, or where a coal-fired electric generating unit was retired after 2009. Fossil Fuel Energy Communities refer to a metropolitan statistical area or non-metropolitan statistical area that has 0.17% or more direct employment and an unemployment rate at or above the national average unemployment rate for the preceding calendar year, or 25% or more local tax revenues related to the extraction, processing, transportation, or storage of coal, oil, or natural gas and the unemployment rate requirement. Brownfields are areas where expansion, redevelopment, or reuse is complicated by the presence or potential presence of hazardous substances, contaminants, or pollutants [90,91]. However, by 2022, the United States Environmental Protection Agency recognized a list of 122 green power communities [92].

Some of these communities are part of community aggregation programs, as it is presented in Table 6. For example, Albany, Ohio. This community is a member of the Ohio Sustainable Public Energy Council (SOPEC) and is part of SOPEC’s Electric Aggregation Program, which provides 100% green certified electricity to eligible residential and small commercial customers. SOPEC is a not-for-profit public service organization that aggregates electricity for various communities. The SOPEC model prioritizes local power generation and uses a portion of the proceeds to support local jobs, special programs, and local clean energy projects [93].

Community Choice Aggregation is a program that allows cities and towns to purchase and/or generate the energy consumed by their citizens. Various states in the United States have activated the implementation of these community choice aggregation programs. The benefits are to obtain better rates from competitive suppliers, to choose clean energy sources, and to participate voluntarily. Two modalities can be found: opt-out provisions, which is when citizens are automatically enrolled in the program along with the community and have the option to opt out of it if they want; and the other option is opt-in provisions, which is when citizens must actively request to be included in this program [94].

These models of community aggregation can serve as a reference base for European utilities to offer flexibility services, as they focus on clean and local energy and generate benefits for the community. The same clusters, together with the development of device control systems, can be used to create flexible service offerings.

Table 6. Communities participating in Community Choice Aggregation in the U.S.

No.	Community	Aggregator	Year	State	Provider	Ref.
1	Albany	Sustainable Ohio Public Energy Council (SOPEC)	2021	Ohio	AEP Energy	[93]
2	Alton	Alton’s Municipal Electricity Aggregation Program	2014	Illinois	Homefield Energy	[95]
3	East Palo Alto	Community Choice Aggregation of San Mateo County’s Peninsula Clean Energy	2018	Carolina	Peninsula Clean Energy	[92]
4	Greenfield	Greenfield Light & Power (GL&P) municipal aggregation	2015	Massachusetts	Dynegy Energy Services	[96]

Table 6. Communities participating in Community Choice Aggregation in the U.S.

No.	Community	Aggregator	Year	State	Provider	Ref.
1	Albany	Sustainable Ohio Public Energy Council (SOPEC)	2021	Ohio	AEP Energy	[93]
2	Alton	Alton’s Municipal Electricity Aggregation Program	2014	Illinois	Homefield Energy	[95]
3	East Palo Alto	Community Choice Aggregation of San Mateo County’s Peninsula Clean Energy	2018	Carolina	Peninsula Clean Energy	[92]
4	Greenfield	Greenfield Light & Power (GL&P) municipal aggregation	2015	Massachusetts	Dynegy Energy Services	[96]

5. Conclusions

This study reviewed real cases of ECs in different European countries. The results have demonstrated the participation of ECs in P2P market platforms through pilot projects. It also showed that several electricity cooperatives, one of the most common forms of ECs, participate in energy trading with their members and other entities. In addition, several citizen projects sell their energy, mainly from renewable sources, to various energy supply cooperatives.

The case studies analyzed in this article highlight the diverse strategies employed by ECs across different countries. These strategies include innovative approaches such as renting public rooftops for photovoltaic installations, restricting membership through codes, and acquiring facilities or purchasing green energy from community projects. This diversity underscores that there is no single model for ECs to secure generation resources but rather a spectrum of approaches tailored to specific regulatory and market conditions.

ECs are also engaged in various activities beyond just electricity supply. These include electric mobility and flexibility services. While these activities are not mutually exclusive, each community often focuses on a particular area that aligns with its strengths or primary market participation strategy. For instance, some ECs may prioritize electricity supply while others might concentrate on offering electric mobility services or providing flexibility to the grid.

The transposition of European directives into national legislation varies considerably from country to country, affecting the development and operation of ECs. Austria, for example, has successfully integrated REC and CEC regulations into its national laws and has a robust number of operational ECs. In contrast, Spain is still in the process of approving its draft law for EC regulation, which has slowed the development of these communities. Meanwhile, countries like Germany and the Netherlands benefit from the long-standing tradition of community energy projects, which has facilitated the proliferation of ECs.

Based on these findings, we recommend that energy policies emphasize enabling ECs to participate effectively in the energy market by providing strategic frameworks tailored to their unique contexts. Additionally, implementing pilot programs for offering flexibility services, supported by solid legal frameworks, can foster confidence among citizens and encourage broader participation. It is crucial to recognize that ECs are more than just energy collectives; they represent a collaborative effort between different stakeholders in the sector, who complement and enhance each other’s capabilities.

This article contributes to the academic discourse by analyzing the various models of EC participation in the electricity sector and disseminating implementation strategies that can serve as a foundation for emerging citizen-led energy projects.

The conclusions drawn in this article are based on the analysis of specific case studies related to ECs and the corresponding regulations. However, it is important to acknowledge certain limitations within this study. The conclusions would benefit from a broader range of case studies, particularly by including examples from countries not covered in this research, such as Croatia and Lithuania. Additionally, most of the analyzed cases are concentrated in European countries, except for the United States. Expanding the scope to include ECs from other continents, like Australia, could provide a more comprehensive understanding of global trends.

Furthermore, the study did not encompass all existing aggregation models. The focus was primarily on community aggregation models, illustrated by real operational cases in the United States. This selective approach leaves room for further exploration of other aggregation models that may also play a significant role in the integration of ECs into the market.

Building on this research, future studies could explore several key areas. These include the implementation of flexibility markets for the participation of ECs, the development of regulatory frameworks that facilitate aggregator participation in electricity markets, and the support of international strategies to enhance the involvement of ECs in both local and national energy markets.

There is a considerable amount of work to be conducted to facilitate the direct engagement of ECs in the market, either independently or through aggregators. While there is evident enthusiasm for such projects, particularly in countries like Spain, the progress is hindered by a lack of regulatory momentum. Strengthening these regulatory frameworks will be crucial for realizing the full potential of ECs in the energy sector.