The US Department of the Interior is proud to have approved nine utility-scale solar projects on public land last year through a fast-track programme, but it now faces a barrage of lawsuits challenging many of those decisions.

Some developers are also struggling to finance projects, and a lack of transmission remains an impediment for others.

“Even though we have permitted, getting the plants constructed, built, operational and on the grid remains a challenge,” says Steve Black, counsellor to Interior Secretary Ken Salazar.

Black