“This goal promotes installation of renewable energy on federal land, the development of new solar through power purchase agreements, and procurement of bundled green energy to power federal facilities,” the White House said in a blog posting.

“Additionally, this target will also incentivize projects on federal land where the government is not the sole user, such as enhanced use leases and facilitation of private development,” it added.

The new target builds on last year’s goal that 30% of electricity used by the federal government will come from renewable sources by 2025.

Obama and Hillary Clinton, who has pledged to continue and expand his clean energy agenda if, as expected, she is elected next month to succeed him, both view solar as playing a critical role in helping meet those targets.

Since 2010, federal agencies have increased use of solar five-fold, PV now accounting for 19% of renewable electricity use and 180MW of onsite power. 

In 2012, Obama ordered the US Department of Defense's (DoD) to deploy or procure 3GW of renewable energy at Air Force, Army and Navy installations by 2025 – enough to power 750,000 homes.

The Navy was the first service to meet that target with the 210MW Mesquite III PV facility that was formerly dedicated last Friday. The plant will supply power to 14 Navy and Marine Corps installations in California, providing one-third of their electricity needs for 25 years at a cost savings of more than $90m, according to the blog posting.

Federal leadership in deploying renewable energy has contributed to significant progress in deploying solar. It noted that when Obama took office in January 2009, there wasn’t a single utility-scale PV project in the Us larger than 20MW.

“But beginning in 2009, the Department of Energy’s Loan Programs Office stepped in to provide more than $4.6bn in loan guarantees to support construction of the first five utility-scale PV solar facilities in the US larger than 100MW,” it said..

DOE on its website noted that there are now more than 50 solar projects of that size or larger – 45 privately-funded.

The loan guarantee program remains controversial after a California-based company called Solyndra went spectacularly bankrupt after receiving more than $500m in public money. It was developing unique PV modules based on CIGS thin-film technology.

It later emerged after a lengthy DOE investigation that company officials had lied about the state of the business and its prospects to obtain the department’s support. DOE took its share of the blame, which led to a revamping of its due diligence procedures. The oversight was at least partly due to political pressure to disburse loans quickly.