A new report from Massachusetts Institute of Technology (MIT) explores pathways for using variable energy resources (VREs), such as wind and solar power, and energy storage to remove carbon dioxide emissions from electricity systems efficiently by 2050.
“Our study finds that energy storage can help VRE-dominated electricity systems balance electricity supply and demand while maintaining reliability in a cost-effective manner — that in turn can support the electrification of many end-use activities beyond the electricity sector,” Robert Armstrong, MIT Energy Initiative (MITEI) director, Chevron professor of chemical engineering and chair of the Future of Energy Storage study, said in a statement.
Because storage technologies will have the ability to substitute for or complement all aspects of a power system, including generation, transmission, and demand response, they will be critical to electricity system designers, operators, and regulators in the future, the report’s authors said, adding that the report is designed to help government, industry, and academia chart a path to developing and deploying electrical energy storage technologies as a way of encouraging electrification and decarbonization throughout the economy, while avoiding excessive or inequitable burdens.
The report focused on three regions of the United States – the Northeast, the Southeast, and Texas – using models to look out to 2050. The results indicated that the deployment of long-duration energy storage technologies would have the greatest impact on electricity system decarbonization when natural gas generation without carbon capture and storage technology is not an option. Generally, the authors said, long-duration energy storage when optimally deployed substitutes for natural gas capacity, increases the value of variable renewable generation, and produces moderate reductions in system average electricity cost.
The report identified four categories of long-duration energy storage, redox flow batteries, metal-air batteries, hydrogen storage, and thermal storage, and said the long-duration technologies win out in the long term over lithium-ion batteries because they have lower energy capacity costs and lower round-trip efficiencies.
The authors did, however, say that using hydrogen for energy storage would likely depend on the extent to which hydrogen is used in the overall economy and its broad use “will be driven by future costs of hydrogen production, transportation, and storage — and by the pace of innovation in hydrogen end-use applications.”
The study also predicted that the distribution of hourly wholesale prices or the hourly marginal value of energy will change in deeply decarbonized power systems with many more hours of very low prices and more hours of high prices compared with current wholesale market prices, which could increase challenges for financing future investments in grid assets, including storage. “This issue impacts all resources and underscores the need for thoughtful electricity market reforms and retail rate design to encourage efficient economy-wide decarbonization,” the authors said.
The authors recommended the adoption of retail pricing and retail load management options that reward all consumers for shifting electricity use away from times when high wholesale prices indicate scarcity, to times when low wholesale prices signal abundance.
The MITEI report also said that many existing power plants that are being shut down and otherwise might be abandoned could be converted to energy storage facilities by replacing fossil fuel boilers with thermal storage and new steam generators using commercially available technologies.