In recent months, U.S. renewable energy developers have delayed or cancelled several large battery projects intended to store electrical power on the grid, scuttling plans to replace fossil fuels with wind and solar energy.

At least a dozen storage projects intended to support growing renewable energy supplies have been delayed, canceled, or renegotiated due to labor and transportation bottlenecks, soaring mineral prices, and competition from the electric vehicle industry.

One previously unreported dispute involving a postponed California storage project even ended up in court.

The slowing of utility-scale battery installations jeopardizes the pace of the United States’ transition away from fossil fuels, as the Biden administration aims to decarbonize the grid by 2035. Delays could jeopardize power reliability in states that already rely heavily on renewable energy, such as California.

Power storage is considered critical to the growth of solar and wind energy because it allows electricity generated when the sun shines or the wind blows to be used at the end of the day when consumers need it the most.

According to a review of regulatory documents, corporate statements, and interviews with project developers and power providers, the delays span states such as California, Hawaii, and Georgia, with battery providers such as Tesla and Fluence warning of supply disruptions.

According to Reuters, the delays, some of which have not previously been reported, range from several months to a year.

European energy storage projects are also experiencing delays, but because Europe lags behind the United States in the development of grid-scale storage, the problem is less severe.

Ben Guest, fund manager at Gresham House Energy Storage Fund, which invests in British battery projects, said he has seen two- to three-month delays in projects due to component shortages and shipping issues.

Energy storage accounts for approximately 3% of operating clean energy capacity in the United States and is rapidly expanding. According to the American Clean Power Association, installations increased 170 percent in the first quarter to 758 megawatts, which is roughly enough capacity to power 144,000 homes.

Prices for lithium-ion batteries, three-quarters of which are manufactured in China, have risen by up to 20% since last year as lithium and nickel prices rise, COVID-19 lockdowns disrupt manufacturing, and transportation constraints slow shipments.

The recent upheaval in the solar industry, caused by uncertainty about potential tariffs on Asian imports, has also hampered storage development. Building storage alongside solar allows facilities to claim a federal tax credit that standalone batteries do not have.

In an effort to revitalize solar installations, the Biden administration announced this week that it would waive tariffs on panels from countries impacted by a Commerce Department investigation for two years.

These roadblocks have raised concerns about the fate of 14.7 giga-tonnes of battery storage in the United States, some of which state officials had hoped would be in place to prevent blackouts as early as this summer.

Among the most recent delays is a 535-MW storage project being developed by Ameresco Inc for Southern California Edison, one of the state’s largest utilities. It expects only a portion of the project, about 300 MW, to be operational by August.

According to spokesperson Catherine Stedman, Central Coast Community Energy (CCCE), which purchases power on behalf of 430,000 customers in five California counties, is also facing delays in six clean energy projects, including 122 MW of storage, required to meet state-mandated clean energy requirements.

The developers of the projects, which were supposed to go live this year and next, have warned of delays of six to twelve months, according to Stedman.

Meanwhile, CCCE and its partner in several projects, Silicon Valley Clean Energy Authority, have sued developer EDF Renewables over the termination of contracts for the Big Beau solar and storage project, which began generating power last year.

According to the complaint filed May 9 in California state court in Santa Clara County, EDF asked in March to increase the price for the project’s still unfinished energy storage component by $76.8 million – a 233 percent increase.