Donald Trump has ordered the US military to purchase energy from coal-fired power plants in a bid to shore up the flagging domestic industry.

In an executive order issued yesterday, Trump said it was “imperative” for the Department of War to prioritise the “strategic utilization” of coal-based energy assets. The order partially justified the move as a way to ensure a “resilient and reliable” energy grid that is not reliant on “intermittent energy sources” such as renewable energy generators.

US coal output peaked in 2008 and has been steadily dropping since then, with long-term projections showing the trend continuing throughout the 2020s and into the 2030s. As a share of US electricity generation, coal has shrunk from about 50% in 2000 to below 20% today.

Concerns remain about the serious negative effects that coal plants have for air pollution, as well as their significant carbon emissions – even compared to other fossil fuels. However, the primary factor for its decline was the US fracking...