System-level power-to-gas energy storage for high penetrations of variable renewables

• Published in: International journal of hydrogen energy Vol. 43; no. 4; pp. 1966 - 1979
• Main Authors: Lyseng, B., Niet, T., English, J., Keller, V., Palmer-Wilson, K., Robertson, B., Rowe, A., Wild, P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 25.01.2018
• Subjects: Curtailment; Electrolyzer; Energy storage; Power system; Power-to-gas; Renewable energy; Power system; Renewable energy; Power-to-gas; Curtailment; Electrolyzer; Energy storage
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.11.162

According to outlooks by the IEA and the U.S. EIA, renewables will become the largest source of electricity by 2050 if global temperature rise is to be limited to 2 °C. However, at penetrations greater than 30%, curtailment of wind and solar can be significant in even the most flexible systems. Energy storage can reduce curtailment and increase utilisation of variable renewables. Power-to-gas is a form of long-term storage based on electrolytic production of hydrogen. This research models the co-sizing of wind and solar PV capacity and electrolyser capacity in a jurisdiction targeting 80% penetration of variable renewable electricity. Results indicate that power-to-gas can reduce required wind and solar capacity by as much as 23% and curtailment by as much as 87%. While the majority of charging events last less than 12 h, the majority of the total annual stored energy comes from longer-term events. Additional scenarios reveal that geographic diversity of wind farms reduces capacity requirements, but the same benefit is not found for distributing solar PV. •80% variable renewable electricity (VRE) penetration is targeted.•Power-to-gas (PtG) provides system-level storage.•Electrolyser and VRE capacity are co-sized to meet the VRE target.•PtG reduces VRE capacity by as much as 23% and curtailment by up to 87%.•Charging events longer than 12 h account for most of the stored energy.