US Energy Secretary Steven Chu has announced his intention to step down.

In a letter to the US Department of Energy on 1 February, Steven Chu said he would like to return to California and “return to an academic life of teaching and research”. He plans to continue in his position until the end of February but may stay longer if the department has not appointed a replacement.

During Chu’s four-year tenure, the US Department of Energy launched the SunShot Initiative which seeks to make solar energy cost-competitive with other forms of electricity. as well as the first national-scale rooftop solar project that will include commercial buildings in up to 28 states.

In the last four years, US installations of solar photovoltaic systems have nearly doubled in each one of the last three years, exceeding 1.8GW in 2011.

Although significant progress has been made in the field of solar during Chu’s tenure, his career will be tainted by the controversy concerning federal loans to bankrupt module manufacturer Solyndra.