The grid reliability trap behind solar’s latest milestone | Matthew Kandrach

The danger is not solar power itself. Solar has become a significant part of America’s electricity mix, and will continue to grow. The danger is the increasingly common assumption that more solar or wind generation means America can safely do with less coal and other forms of dispatchable power. That is the grid reliability trap: mistaking energy produced when conditions are favorable for generating capacity that is available when the system needs it most.

Electricity reliability is not measured by how much power a resource can produce over a month or year. It’s measured hour by hour and second by second, especially during the most challenging moments. A power plant that can run throughout a winter storm, a summer heat wave, or a long evening peak provides a fundamentally different reliability value than a resource that depends on the weather or time of day. That critical distinction is being blurred at precisely the wrong time.

Consider the seriousness of the North American Electric Reliability Corporation’s (NERC) latest long-term reliability assessment. NERC has cautioned that large portions of the country face electricity shortfalls over the next decade. The causes are not mysterious. Demand is rising. Existing power plants are retiring. Transmission expansion is lagging. And critically, much of the new capacity being added to the grid is weather-dependent and does not replace dispatchable generation on a one-for-one basis.

Soaring electricity demand has made threading the grid reliability needle that much more difficult. After years of relatively flat demand, the United States is entering a new era of breakneck growth. Data centers, artificial intelligence, advanced manufacturing, and electrification are pushing demand forecasts sharply higher. One estimate sees U.S. power demand jumping nearly 80% by 2050. In some regions where data center development is concentrated, demand is growing even faster.

Rather than energy transition, the nation needs energy addition. Soaring power prices, tight operating reserves, and alarming warnings from grid experts have made that abundantly clear.

China’s approach to this energy moment is instructive. China leads the world in renewable deployment, but it is also continuing to use and build coal generating capacity to support reliability, industrial growth, and energy security. China now uses 40% more coal than the rest of the world combined and is developing 500 gigawatts of new coal capacity, nearly double the entire existing U.S. coal fleet. China recognizes renewable sources of power as fuel savers — but is also clear-eyed about their reliability limitations.

We need not copy China’s approach, but we should recognize the fundamental importance of prioritizing grid reliability and energy security.

Solar overtaking coal for a month is not proof that America has solved the reliability challenge or negated the need for fuel-secure, dispatchable power. In fact, it may be a warning that the nation’s grid reliability is resting on increasingly shaky ground.