As the share of renewable energy sources increases, the grid frequency becomes more unstable. Therefore, grid balancing services will become more important in the future. Dedicated devices can be installed close to the point where offshore wind farms are connected to the transmission grid on land. There, it can be used to attenuate power variations, reduce congestion and offer grid balancing. These ancillary services can create significant economic revenue. In this paper, the provision of the primary reserve by means of a large hydrogen electrolyser of 25 MW is investigated for the specific case of the Belgian transmission system. The electrolyser is used to convert water and excess power to hydrogen gas, which is injected into the natural gas grid. The revenue for primary reserve (R1) provision is analysed on a techno-economic model, including capital costs, operational costs, the revenue of the generated hydrogen and oxygen products and the ancillary service income. The revenue depends strongly on the contracted power-band. Therefore, it is optimised to yield maximum revenue. The results show that providing R1 creates a considerable revenue. Therefore, a large electrolyser can be a good candidate to buffer excess renewable energy into green gas while simultaneously providing grid support.

As the share of renewable energy sources increases, the grid frequency becomes more unstable. Therefore, grid balancing services will become more important in the future. Dedicated devices can be installed close to the point where offshore wind farms are connected to the transmission grid on land. There, it can be used to attenuate power variations, reduce congestion and offer grid balancing. These ancillary services can create significant economic revenue. In this paper, the provision of the primary reserve by means of a large hydrogen electrolyser of 25 MW is investigated for the specific case of the Belgian transmission system. The electrolyser is used to convert water and excess power to hydrogen gas, which is injected into the natural gas grid. The revenue for primary reserve (R1) provision is analysed on a techno-economic model, including capital costs, operational costs, the revenue of the generated hydrogen and oxygen products and the ancillary service income. The revenue depends strongly on the contracted power-band. Therefore, it is optimised to yield maximum revenue. The results show that providing R1 creates a considerable revenue. Therefore, a large electrolyser can be a good candidate to buffer excess renewable energy into green gas while simultaneously providing grid support.