- A long-term energy storage technology is necessary to utilize Oregon’s curtailed renewable energy, an issue the state faces, even with a low percentage of renewable energy in the energy mix. This report proposes a system design that details how hydrogen power-to-gas technology can be used in conjunction with the existing natural gas infrastructure to store energy from intermittent renewable sources during peak generation. The system uses excess electricity and Proton On-Site’s M100 electrolyzer to split water into oxygen and hydrogen gases, the latter of which can be directly injected into the natural gas pipeline and stored in underground reservoirs until months of higher energy demand. From the 304 curtailment hours in 2017, 2,850 kg of hydrogen could have been produced, which could have resulted in a hydrogen and natural gas admixture of 75 ppm hydrogen in NW Natural’s depleted natural gas reservoirs. There are no significant environmental concerns with a system this size. Hydrogen blends up to 35% are compatible with current natural gas appliances and blends up to 8.7% are within energy content limits set by the Oregon Public Utility Commission. This system is not economically feasible without offering a premium price per therm to residential customers to fund the project.
- Key Words: energy, hydrogen, power-to-gas, renewable, storage