Amber Rudd has been promoted to secretary of state for energy and climate change, replacing Ed Davey who lost his seat in last week's election.
The MP for Hastings and Rye was appointed minister for energy and climate change in the coalition government last year.
She attended the New York climate change negotiations in September, but was prevented from travelling to Lima for further talks in December after Conservative whips ordered her to stay in the UK for a parliamentary vote on counter-terrorism.
She has also worked as parliamentary private secretary to the chancellor, George Osborne. Before becoming a politician she worked for an investment bank and in recruitment.
Her appointment has been welcomed by the environment sector. The UK Green Building Council (UKGBC), which worked with Rudd on several policies, including the energy savings opportunity scheme and minimum energy efficiency standards, said the new Decc secretary understood the business case for energy efficiency and the low-carbon economy, and had a strong commitment to tackling climate change.
"Her appointment is important as it not only represents much needed continuity between the previous and new regimes on environmental issues, but hopefully indicates the direction of travel of this Conservative government on the green economy and climate change," said Julie Hirigoyen, chief executive at the UKGBC.
Paul Barwell, chief executive of the Solar Trade Association (STA) said that he hoped that Rudd's experience in finance and the Treasury will mean she recognises the value that small and medium-sized solar companies bring the UK.
However, Rudd has a mixed voting record on energy and climate issues. Although she voted in favour of the creation of the Green Investment Bank, Rudd voted against it explicitly acting in support of the UK's carbon reduction targets, according to the theyworkforyou.com website, which provides a record on MPs vote.
It also reveals that Rudd voted in favour of cutting subsidies for renewable or low-carbon electricity generation technologies, and against bringing forward to 2016 the deadline by which landlords of private- rented property must meet energy efficiency regulations.
Meanwhile, Labour has announced its shadow cabinet. Caroline Flint and Maria Eagle will retain their posts as shadow secretaries for energy and climate and the environment. Emma Reynolds has been promoted to shadow secretary of state for communities, having previously been shadow housing minister.