# The Potential for the Use of Hydrogen Storage in Energy Cooperatives
## 2 Background and Main Provisions
### Main Provisions Concerning the Analyses Carried Out  
This paper continues the work carried out by the authors, so the previous convention of presenting the analyses and results will be maintained.  
1. The first classification being a basis for the analyses concerns the selection of cooperative members. It will be based on an imposed and a random selection of cooperative members. 1. The former will deal with specific sample cooperatives established on the basis of real and differently profiled demand data for farms, assigned to different tariff groups and with different levels of power demand. The characteristics of the members for the simulated cooperatives are shown in Table 1. 2. Within the second group, the composition of the cooperatives will be formed by randomly selecting the prosumers that make up the cooperatives (EC1, EC2, EC3, EC4) characterized in the authors' previous works [40; 43]. The analysis will cover 68 actual prosumer profiles, some of which we will randomly select for the structures of the cooperatives taking into account their different sizes. 500 cooperatives will be drawn separately for each of the following numbers of members: 5, 10, 20, 40. A total of 2000 energy cooperatives will be analyzed. 3. No special key was used to select cooperative members e.g., in terms of matching demand profiles. The demand profile of the cooperative drawn (created) was the sum of the demand profiles of the cooperative members drawn.
2. For each energy cooperative, the impact of RES generation will be analyzed under three different and independent options, which are the most common in the Polish reality: 1. The entire installed capacity will come from PV sources. 2. The entire installed capacity will come from wind turbines. 3. The installed capacity will be a hybrid combination of wind and PV sources with the share of each source selected through an optimization process.
3. Three simulations will be conducted for each energy cooperative and each generation option: 1. The minimum size of the generating source, assuming that the energy cooperative operates on the basis of the discount mechanism described in Section 2.1 and, in more detail, in the authors' earlier papers [40; 43], with a discount factor of 0.6, and uses the power grid as a virtual storage. 2. The minimum size of the generating source, assuming that the energy cooperative forgoes energy exchange with the grid, thereby forgoing the use of the power grid as a virtual storage. In this scenario, it is assumed that a hydrogen storage will be used to store the energy. 3. The minimum size of a hydrogen storage.
4. The following assumptions were made for each of the above simulations: 1. The optimization begins at the beginning of the calendar year and covers 15 consecutive years. 2. All calculations are performed in an hourly window based on actual data given at hourly resolution. 3. The energy independence of an energy cooperative comes after the first quarter of its operation, which means that the capacity of the generating source(s) and of the storage must be properly selected. 4. The inability to discharge surplus electricity into the power grid, which affects the storage capacity as it is required to capture any surplus energy. 5. The aggregate electricity demand within the arbitrarily selected structures of the energy cooperatives was selected so that it could be met using micro-installations, being a source of up to 50 kW.