From 4% to 45%: Energy Department Lays Out Ambitious Blueprint for Solar Power

Building and installing enough solar panels to generate up to 45 percent of the country’s power needs will strain manufacturers and the energy industry, increasing demand for materials like aluminum, silicon, steel and glass. The industry will also need to find and train tens of thousands of workers and quickly. Some labor groups have said that in the rush to quickly build solar farms, developers often hire lower-paid nonunion workers rather than the union members Mr. Biden frequently champions.

Challenges like trade disputes could also complicate the push for solar power. China dominates the supply chain for solar panels, and the administration recently began blocking imports connected with the Xinjiang region of China over concerns about the use of forced labor. While many solar companies say they are working to shift away from materials made in Xinjiang, energy experts say the import ban could slow the construction of solar projects throughout the United States in the short term.

Yet, energy analysts said it would be impossible for Mr. Biden to achieve his climate goals without a big increase in the use of solar energy. “No matter how you slice it, you need solar deployments to double or quadruple in the near term,” said Michelle Davis, a principal analyst at Wood Mackenzie, an energy research and consulting firm. “Supply chain constraints are certainly on everyone’s mind.”

Administration officials pointed to changes being made by state and local officials as an example of how the country could begin to move faster toward renewable energy. Regulators in California, for example, are changing the state’s building code to require solar and batteries in new buildings.

Another big area of focus for the administration is greater use of batteries to store energy generated by solar panels and wind turbines for use at night or when the wind is not blowing. The cost of batteries has been falling but remains too high for a rapid shift to renewables and electric cars, according to many analysts.

To some solar industry officials, the Energy Department report ought to help to focus people’s minds on what is possible even if lawmakers haven’t worked out the details.

“In essence the D.O.E. is saying America needs a ton more solar, not less, and we need it today, not tomorrow,” said Bernadette Del Chiaro, executive director of the California Solar and Storage Association, which represents solar developers in the state with by far the largest number of solar installations. “That simple call to action should guide every policymaking decision from city councils to legislatures and regulatory agencies across the country.”

Brad Plumer contributed reporting.