Beyond Smart Grid: Alternatives for Transmission and Low-Cost Firming Storage of Stranded Renewables as Hydrogen and Ammonia Fuels via Underground Pipelines

Abstract

We must soon “run the world on renewables” but cannot, and should not try to, accomplish this entirely with electricity transmission. We need to supply all energy, not just electricity, from diverse renewable energy (RE) resources, both distributed and centralized, where the world’s richest RE resources — of large geographic extent and high intensity — are stranded: far from end-users with inadequate or nonexistent gathering and transmission systems to deliver the energy. Electricity energy storage cannot affordably firm large, intermittent renewables at annual scale, while carbon-free gaseous hydrogen (GH2) and liquid anhydrous ammonia (NH3) fuels can: GH2 in large solution-mined salt caverns, NH3 in surface tanks, both pressurized and refrigerated. “Smart Grid” is emerging as primarily a DSM (demand side management) strategy to encourage energy conservation. Making the electricity grid “smarter” does not: 1. Increase physical transmission capacity; 2. Provide affordable annual-scale firming storage for RE; 3. Solve grid integration problem for large, time-varying RE; 4. Alleviate NIMBY objections to new transmission siting; 5. Reduce the high O&M costs of overhead electric lines. The “smarter” grid may be more vulnerable to cyberattack. Adding storage, control, and quality adjunct devices to the electricity grid, to accommodate very high renewables content, may be technically and economically inferior to GH2 and NH3 RE systems. Thus, we need to look beyond “smart grid”, expanding our concept of “transmission”, to synergistically and simultaneously solve the transmission, firming storage, and RE integration “balancing” problems now severely constraining our progress toward “running the world on renewables”.