A new policy brief from the Regulatory Assistance Project (RAP), Clean Energy Keeps the Lights On, dispels the myth that electricity portfolios with high penetrations of variable renewable resources threaten reliability. The authors review eight recent studies commissioned by utilities, governments, and non-governmental organizations to address this issue, and find that none suggest insurmountable reliability problems.

“Over the last few years we have seen one technically sophisticated study after another come to the same conclusion — clean energy portfolios can keep the lights on,” said Dr. Carl Linvill, principal and lead author.

“While the studies we reviewed cover different geographic footprints and examine different levels of renewable energy penetration, each was conducted by respected technical experts using state-of-the-art methodologies and the best available data,” added Linvill. “The results reinforce each other: energy portfolios with more renewable power than we commonly see today can provide reliable electric service, and demand response, energy efficiency, storage, and regional resources play an important role in ensuring reliability at least cost.”

The studies reviewed by RAP conclude that renewable penetrations beyond state renewable portfolio standards can be accommodated with current electric system flexibility; proven technologies and practices can dramatically reduce the cost of operating high penetration variable renewable energy portfolios; and the studies that examined very high penetration levels showed that these same technologies and practices can improve system flexibility and enable the electric system to operate reliably with renewable penetrations well above 50 percent.

“We have the tools to manage a diverse and robust array of energy resources. The question is not whether a low-carbon, high-renewable energy future is technically feasible. The question is, will utilities, system operators, and regulators work together to ensure the necessary investments and changes in operations, markets, and planning are made to achieve a low-carbon future at least cost?” Linvill emphasized.