Gas Networks, Energy Storage and Renewable Power Generation

With an increase in variable and sometimes uncertain renewable generation coming on-line, there is an associated increase in the importance of energy storage to balance supply and demand. The gas network already stores and transports energy, and it has the potential to play a significant role for longer term energy storage. In addition, gas and electrical grids are becoming more integrated with fast responding gas-fired power stations, providing the main source of back up for renewable electricity in many systems. In 2017, Ireland’s renewable generation accounted for 19 % of electricity generated and was the second largest source of electricity generation after natural gas and coal with 51 % and 18 % respectively. The percentage of renewable electricity is rising and there is a 40 % target to be met by 2020. Using a simplified version of Ireland's gas network, with 14 nodes and 15 pipes, the objective of this paper is to investigate how hydrogen, generated through power-to-gas (P2G) from curtailed wind power, impacts the operation of the gas network system. A quasi-transient model was constructed in MATLAB to calculate the main characteristics of the gas network. The results show, with an increasing mass fraction of hydrogen in the gas network, that the pipeline flow rate needs to be increased to compensate for reduced energy quality due to the lower energy density of the blended gas. There is significant potential for the gas network to store and transport excess and/or otherwise non-transportable renewable electricity to maximize renewable energy utilization.