During the project, participants aim to create an electricity system where electricity is produced on-site and largely consumed there as well. One practical cornerstone of such a cooperative microgrid could be the energy cooperative as a suitable legal form.
Researchers from Tallinn University of Technology have been studying the nature of energy cooperatives, possible business models, and their viability for some time. According to them, the adoption of energy cooperatives would allow citizens to contribute to achieving renewable energy goals, thereby increasing awareness of energy issues for both citizens and officials.
They also provide an additional opportunity to increase the share of renewable energy in consumed energy. In addition, locally produced and consumed electricity increases community energy independence in terms of both supply reliability and cost. Since cooperative members decide on investment themselves, it engages them in a dialogue about solving and preventing energy issues in their area.
First pilot projects
One of the developers and initiators of the concept for both the Tartu and Pakri pilot areas is Tarmo Korõtko, senior researcher at the Institute of Electrical Power Engineering and Mechatronics at the School of Engineering of Tallinn University of Technology. According to him, the goal of the pilot project is to create specific and functional examples of how energy collaboration could work in practice. If the pilot projects prove successful, they can be replicated and adjusted according to local needs.
Korõtko believes that local governments could be trailblazers in launching energy cooperatives. To do this, they should allow land and network connection and provide clear guidelines for simplifying procedures. Later, once examples of energy cooperatives and their effectiveness exist, citizens themselves should take the initiative.
“We have now established a controllable microgrid in Tartu and the Pakri Industrial Park. Energy storage devices have been installed in both locations, measurement capabilities have been improved, and control devices have been added. Currently, their electricity systems are significantly smarter and more manageable than before,” described Tarmo Korõtko the nature of the two pilot areas. “These areas will be good examples in the future to demonstrate the added value that such a microgrid can offer to different owners and interest groups.”
In Tartu, a significant interest group is the local government, for whom a microgrid was created for the street lighting infrastructure. In the Pakri Industrial Park, the focus is on commercial property owners. Initially, industrial parks are considered. Following the same principle, a microgrid can also be built for larger commercial or production buildings.
Street lighting network as the basis for the microgrid
In Tartu, in the area designated by the city government in Annelinn, researchers linked the creation of a microgrid to the more optimal use of existing resources, namely the electricity infrastructure. According to Tarmo Korõtko, both Tartu and other cities have a significant electricity infrastructure in the form of street lighting networks. The results of the research by the university’s researchers revealed that the use of such networks is extremely inefficient.
“We examined how these resources are used in Tartu. It turned out that they are largely underused. Although the consumed power is significant, in reality, the existing contracted connection power is used only in 80 percent of cases, at 15 percent or even less,” explained Korõtko.
Figuratively speaking, it may be possible to consume, for example, 15 kW through a connection point, which is fixed in the connection agreement and limited by the main fuse size on the connection board. In most cases, however, only about 2 kW is consumed at this connection point. Essentially, this means that with little effort, it is possible to provide power for up to a 12 kW rated load.
“For example, this is sufficient to provide power for the home charger of electric cars. Considering that such connection points are available in the city approximately every 0.5 kilometers, this is already a completely significant resource,” added Korõtko.
Another free resource is related to the cables running from the switchboard to the street lighting masts. The study revealed that the throughput of all examined cables was less than five percent. In other words, the installed cables are too thick. According to Korõtko, this actually has a quite rational reason. Installing a larger cross-section cable than urgently needed has very little effect on the project’s cost. At the same time, technical risks are mitigated, and the possibility of expanding the system in the future is ensured.
The street lighting network belongs to the city, which is connected to a larger electricity distribution network. “Since the street lighting network is already present in all cities, it is a city-wide infrastructure with significantly unused resources. The city can capitalize on this resource, offering local residents and businesses the opportunity to use it. For example, if a company wants to provide a public service to city residents that requires a constant power supply, the city can easily provide it through the street lighting infrastructure,” explained Tarmo Korõtko.
This would significantly expand the possibilities of offering services in the city. As part of the Tartu pilot project, electric car charging is offered as a public service, supported by an energy storage system. “There are many and diverse possibilities,” added the senior researcher.
Korõtko believes that for new street lighting networks to be created, cables could be oversized even more. In this case, it could be assumed from the outset that these will find application in ways other than just illuminating streets. “Street lighting is just one of many public services. Why should the infrastructure be exclusively for one service when it can support others as well?” said the senior researcher.
Suitable solutions for both industry and the community
When designing the cross-use of publicly used and city-owned street lighting networks, the services hooked onto it should be intended for public use, according to the researchers. Whether and how this is done is up to the city government to decide. In principle, it is a public service electricity system, one consumer of which is street lighting, but which can also connect other consumers intended for the provision of public services.
“With the pilot project, we want to show that such solutions are possible and have quite a few practical applications,” said Korõtko. “The larger goal, however, is to create a sense of progress in local people and entrepreneurs, that they understand that even in such complex solutions as energy, it is actually possible to do a lot with your community.”
During the development of the solution, Korõtko believes it should be taken into account who and how will operate the microgrid. Operating the network may prove to be a significant added value for developers and property owners, an opportunity to distribute locally produced energy internally. At the same time, it would help fulfill the requirements arising from green transformation goals.
In his opinion, entrepreneurs could also solve some energy-related issues on their own. “So far, ignorance, fear of risk, and uncertainty have been obstacles. If the local government takes on a pioneering role and builds a sample solution, it reduces ambiguity and encourages citizens and entrepreneurs to be just as capable and replicate it,” said Tarmo Korõtko.