Nearly 600,000 US workers in clean energy and energy efficiency sectors have lost their jobs since the beginning of the coronavirus pandemic including almost 100,000 in renewables, representing 18% of their combined total workforce, according to a new analysis of federal unemployment data.

Job losses soared from 147,139 in March to 447,208 last month, more than double the total jobs created in the sectors since 2017, Department of Labour data shows. On 1 January, the clean energy and energy efficiency sectors employed 3.4 million workers.

Without support from President Donald Trump’s administration, the sectors will shed a further 255,653 workers through 30 June, bringing job losses tied to Covid-19 disruptions to 850,000 nationwide, authors of the analysis forecast.

They are BW Research Partnership, a research firm, and three advocacy groups: the American Council on Renewable Energy (ACORE), Environmental Entrepreneurs (E2) and E4TheFuture.

March to April job losses tripled from 103,928 to 310,188 in energy efficiency, 23,739 to 71,835 in renewables, 11,339 to 35,101 in clean vehicles and 6,517 to 19,685 in grid and storage. Clean fuels unemployment soared from 2,186 to 10,398 workers.

California continues to be the hardest hit state in terms of total job losses, losing 77,900 jobs in April alone and more than 100,000 since the crisis began. Texas, Michigan, Florida, and Georgia also had a high total of clean energy unemployment filings in April, with each state experiencing more than 22,000 job losses.

In renewables, the analysis did not specify what jobs had been lost – consulting, management, operations or supply chain – or from what technology such as wind, solar and geothermal.

Wind and solar trade groups are warning their industries face an unprecedented slowdown from the pandemic.

The American Wind Energy Association (AWEA) estimates 25GW in project investments worth $35bn are at risk, plus 35,000 of 120,000 industry jobs, while the Solar Energy Industries Association (SEIA) says 80% of solar projects are delayed or canceled and layoffs are mounting among the sector’s 250,000 workers.

“Congress can help get these Americans back to work, and help get our economy back on track, with commonsense relief for time-sensitive tax credit deadlines and temporary refundability for renewable tax credits that are increasingly difficult to monetise,” said ACORE CEO Greg Wetstone.

A bipartisan group of US senators led by Charles Grassley, an Iowa Republican, is supporting both industries’ requests to extend federal tax credits for wind and solar at present values through 2021 and temporarily make them refundable.

This would ease pressure to meet tax credit-related delivery deadlines and circumvent the time-consuming search for increasingly scarce tax equity.

Last week, the Department of Treasury said it “plans to modify the relevant rules in the near future,” but provided no specifics.