Power-to-gas for injection into the gas grid: What can we learn from real-life projects, economic assessments and systems modelling?

• Published in: Renewable & sustainable energy reviews 2018-12, Vol.98, p.302-316
• Main Authors: Quarton, Christopher J., Samsatli, Sheila
• Format: Article
• Language: English
• Subjects: Electrolysis; Energy storage; Hydrogen; Hydrogen injection into gas grid; Intermittency; Linepack flexibility; Power-to-gas
• ISSN: 1364-0321; 1879-0690
• DOI: 10.1016/j.rser.2018.09.007

Power-to-gas is a key area of interest for decarbonisation and increasing flexibility in energy systems, as it has the potential both to absorb renewable electricity at times of excess supply and to provide backup energy at times of excess demand. By integrating power-to-gas with the natural gas grid, it is possible to exploit the inherent linepack flexibility of the grid, and shift some electricity variability onto the gas grid. Furthermore, provided the gas injected into the gas grid is low-carbon, such as hydrogen from renewable power-to-gas, then overall greenhouse gas emissions from the gas grid can be reduced. This work presents the first review of power-to-gas to consider real-life projects, economic assessments and systems modelling studies, and to compare them based on scope, assumptions and outcomes. The review focuses on power-to-gas for injection into the gas grid, as this application has specific economic, technical and modelling opportunities and challenges. The review identified significant interest in, and potential for, power-to-gas in combination with the gas grid, however there are still challenges to overcome to find profitable business cases and manage local and system-wide technical issues. Whilst significant modelling of power-to-gas has been undertaken, more is needed to fully understand the impacts of power-to-gas and gas grid injection on the operational behaviour of the gas grid, taking into account dynamic and spatial effects. •Review found great interest in power-to-gas (P2G) & H2 injection into the gas grid (HIGG).•Strong potential for P2G & HIGG to increase penetration of renewables in energy system.•Studies generally agree that efficiency of P2G and HIGG will increase by 2030.•Electricity balancing market and government support will drive viable business cases.•There is a lack of whole-systems optimisation studies with HIGG and linepack storage.