Integration of renewable energy sources into electricity grids
The development of renewable energy sources is not only connected with the energy transformation in terms of diversification of energy sources, but also in terms of infrastructure. One of the elements necessary to use the potential of renewable energy sources is the integration of renewable energy sources with the power grid. How does this process proceed and what are its consequences?
Modern technologies in the energy sector mean that the entire industry is in the process of transformation. The growing role of renewable energy sources can be observed practically all over the world. Renewable energy solutions are a factor accelerating the modernization of power grids in such a way as to be able to use the potential that new technologies bring.
Increasing role of RES in Poland and Europe
In terms of modern energy sources, we can observe a growing role for solar and wind power in Poland. According to data from the Energy Regulatory Office, wind turbines and photovoltaic installations already account for more than 90% of the installed capacity of all renewable energy sources in Poland. According to estimates, before the end of this decade renewable sources may become the most important in the national energy mix, overtaking coal in this field. In fact, the entire European Union has similar energy goals. In September 2023 European Parliament approved a climate target, which states that by 2030, wind farms, photovoltaics and other RES should account for at least 42.5% of the energy consumed in the EU.
Impact of RES development on the electricity grid
Realising the full potential of renewable energy sources requires a new approach to the management of the electricity generation, transmission and distribution system. In order to be able to deliver energy to the end user, a transmission network is needed, of which the substation is a key component. It has the role of distributing and transforming energy, using processes such as the transformation of voltage from one level to another or the transformation of direct current into alternating current or vice versa.
Before the electricity generated, for example, in a photovoltaic installation reaches the recipient, it must pass through the grid connection point (GCP) to the main supply point (MSP), and then through power lines to individual substations, which then distribute the electricity to end users via power connections. However, for this to be possible, it is necessary to guarantee the possibility of connecting the installation using renewable energy sources to the grid.
In this context, the electricity grid in Poland must undergo appropriate modernizations that will enable its balancing. Such a role is to be played by, the aforementioned grid collection points, which often have wind farms or photovoltaic installations, so that it is possible to output the produced energy to the grid. From this point of view, electricity storage also plays an important role, because GCP is an ideal spot to place an energy storage. Storage allows for increased flexibility and balancing of the grid, depending on the variable demand of recipients. It is to be expected that the importance of energy storage will increase with the further development of RES.
Network modernisation and cable pooling
What should the modernization of the grid in order to adapt it to RES consist of? According to the data presented in the report prepared by the Energy Forum, a think tank, entitled “8 ways of integrating renewable energy sources. System security in the face of the growth of variable sources”, the Polish power grid is largely outdated. Therefore, it is so important to include distributed renewable energy sources in the development plans when planning investments in infrastructure renewal, already at the design stage of the works. On a macro scale, this means taking into account the current and potential locations of renewable energy sources, as well as the use of advanced ICT technologies and smart solutions (Smart Grid) in network management.
Micro-scale possibilities should also be taken into account by ensuring that not only large installations, such as wind farms or photovoltaic farms, but also smaller, individual installations are connected to the grid. In this context, the integration of RES with the grid has not only an infrastructural dimension, but also a legal one. A solution that facilitates this process to some extent is the sharing of the connection, the so-called cable pooling, which is regulated by the provisions of the Act of 17 August 2023 amending the Act on Renewable Energy Sources and certain other acts.
Cable pooling enables the connection of at least two (or more) renewable energy source installations belonging to one or more producers to the power grid in one place. These can be installations with both smaller and larger installed capacities. An interesting example of such a solution is the simultaneous use of the potential of a photovoltaic installation (producing the most energy during the day) and wind (producing more energy in the evenings and at night). By sharing a common connection, these installations can complement each other, increasing the potential of integrating RES with the grid.