The state energy transition scorecard

New data from S&P Global shows what hurdles are slowing even the greenest states from fully converting their grids to clean electricity.

Why it matters: For the U.S. and other countries to achieve an energy transition, they have to balance decarbonization efforts with several issues that are slowing down the move.

Details: S&P analysts used a new Power Evaluator tool to measure state progress in the energy transition.

What they found: Grid flexibility remains a major stumbling block as states go green.

Zoom in: Renewables like wind and solar supplied half of California's electricity last year. But because they only generate electricity when the sun is shining or the wind is blowing, grid operators have had to start dialing back those resources to keep them from overloading the system.

• Meanwhile in New Jersey and New Hampshire, nuclear plants produce vast volumes of round-the-clock zero-emissions electricity, but they don't easily adjust to changes in demand.

Be smart: All three states offer examples of grids that are clean but not flexible.

• Without flexibility, a grid is more vulnerable to strain or blackouts. It's also less cost-efficient: a nuclear plant or solar farm owner can't simply dial up more power to take advantage of higher prices during high demand.
• That's a contrast with states like coal-heavy West Virginia, where fossil fuel plants can ramp up energy output more easily.

What we're watching: Batteries and geothermal offer two clean technologies that can quickly dispatch power when needed — giving states much-needed flexibility.