Clean Dispatchable Power Sources
Non-staff authors: Daniel Aycock, Stephen Leff
With the signing of the Virginia Clean Economy Act (VCEA), the Commonwealth of Virginia joined a chorus of state-level and utility company commitments to achieve a 100 percent carbon-free electricity system by 2050. Such commitments are a new phenomenon because they have only recently become viewed as feasible, as the costs of wind and solar power and lithium-ion energy storage technologies have fallen precipitously.
Reviews of the recent academic literature modeling pathways to a 100 percent carbon-free electricity system show that combinations of commercially available tools and technologies (wind, solar, lithium-ion batteries, energy efficiency, demand flexibility, etc.) can likely achieve high-percentage carbon-free grids (perhaps 80-90 percent) cost competitively, but getting to 100 percent becomes significantly more expensive due to the variable nature of today’s renewable generation sources and the resulting need to overbuild generation and storage infrastructure.
In order to achieve a 100 percent carbon-free grid, additional technologies will be needed to provide “clean dispatchable generation” and/or “long-duration storage” to avoid multi-day or seasonal incongruences between supply and demand for power. In this report, we review a set of technologies at advanced stages of development that could meet these needs, including various forms of “clean” natural gas and synthetic fuels, advanced nuclear, biomass, numerous battery technologies, gravity- and compressed air-based storage, hydrogen, and others.
We describe the basic principles of each technology for a non-technical reader and summarize their current status and projected future development based on information in the academic literature and commercial press. We also assess and compare each technology along six qualitative criteria (technical readiness, scalability, reliability, flexibility, environmental attributes, and applicability to Virginia). Economic viability based on current and future projected levelized costs is considered for a variety of use cases, including maximum utilization (baseload), low utilization (peaking), and long-duration storage (up to weeks or months of discharge capability). Although these assessments are not location dependent, we highlight key advantages and challenges for implementation in the Commonwealth of Virginia.
Our assessment indicates that several of these technologies could become important contributors to a carbon-free electricity system. We provide three recommendations to accelerate development and commercialization of longer term storage and clean dispatchable power technologies in Virginia.
1. Establish a policy environment that supports private investment and enables broad innovation:
- Develop market structures that reward the full “value stack” provided by energy storage technologies,
- Provide policy and regulatory support for pilot- and demonstration-scale projects for later-stage technologies, and
- Promote development of infrastructure required for full commercialization.
2. Support development and commercialization of promising technologies where Virginia could provide leadership in the energy transition:
- Maintain a broad technology and market development focus beyond lithium-ion for energy storage policy and regulation, beginning with the energy storage task force that recent legislation requires the Virginia State Corporation Commission (SCC) to convene,
- Evaluate geological capacity for long-term carbon sequestration and energy storage in Virginia,
- Leverage existing industry clusters in the Commonwealth to accelerate evaluation and, where appropriate, deployment of advanced nuclear technologies in Virginia,
- Promote development of a green hydrogen industrial network in Virginia for use in electric power generation as well as transportation, industrial processes, and other applications
- Conduct a study of CCS retrofit opportunities at Virginia’s existing natural gas power plants, and
- Support expansion of the Commonwealth’s renewable natural gas capacity.
3. Conduct additional modeling of the Virginia electric grid to explore pathways to a 100% clean electric supply and assess the role of longer-duration storage and clean dispatchable power in a decarbonized energy system