LONDON—BP plunged to a $5.7 billion loss last year, its first in a decade, as the pandemic took a heavy toll on oil demand, and the energy company warned of a tough start to 2021 amid widespread travel restrictions. Despite the weak environment, however, CEO Bernard Looney told Reuters the company’s transition to a greener future remained on track. It is aiming to ramp up renewable power generation to 50 gigawatts (GW) by 2030 from 3.3 GW currently, while slashing oil output to reduce greenhouse gas emissions. Capital expenditure is set to rise to $13 billion this year, of which $9 billion will still go to oil and gas, Chief Financial Officer Murray Auchincloss said. That compared with a budget of $12 billion in 2020. For the last quarter of 2020, BP reported a profit of $115 million, falling short of analysts’ forecasts due to weak oil and gas sales …