Global investment in renewable energy continued its upward trajectory last year, raising the proportion of world electricity generated by green sources like wind, solar, biomass and geothermal to a new high, says a new report.   

A record 157 gigawatts of renewable power were commissioned last year, up from 143 gigawatts in 2016 and far out-stripping the net 70 gigawatts of fossil-fuel generating capacity added (after adjusting for the closure of some existing plants) over the same period, revealed the Global Trends in Renewable Energy Investment 2018 report, released on Thursday by UN Environment, the Frankfurt School-UNEP Collaborating Center and Bloomberg New Energy Finance.

Last year was the eighth in a row in which global investment in renewables exceeded $200 billion (€163.2 billion), the report states, adding that since 2004, the world has invested about $2.9 trillion in green energy sources.

The lion's share of this investment went into expanding solar power production, with the world installing a record 98 gigawatts of new solar capacity last year, far more than the net additions of any other technology — renewable, fossil fuel or nuclear.

Solar surge

In total, solar power drew investment worth $160.8 billion, up 18 percent year-on-year. It accounted for about 57 percent of last year's total investment for all renewables (excluding large hydro) of $279.8 billion. 

The number far outstripped new investment in coal and gas generation capacity, estimated at a lowly $103 billion.

"The extraordinary surge in solar investment, around the world, shows how much can be achieved when we commit to growth without harming the environment," said the head of UN Environment Erik Solheim in a statement. 

"By investing in renewables, countries can power new communities, improving the lives and livelihoods of the people who live in them, and at the same time cleaning up the air they breathe."

The continuing decline in costs for solar electricity is driving the expansion of its production, the report's authors say. 

In fact, the cost of solar power production plunged 73 percent between 2010 and 2017, according to the International Renewable Energy Agency, which predicts it will continue to fall.

Uneven growth paths

China was at the forefront of this solar boom, adding some 53 gigawatts of capacity, equivalent to more than half the global total. The Asian giant's total investment in renewables — at a record $126.6 billion — was also by far the highest in the world.

Despite being the largest investor in renewable energy, China has faced an uphill battle transitioning from coal, which is used to generate roughly three-quarters of its power, according to the International Energy Agency. China burns more coal than any other country worldwide and bears the title of top greenhouse gas emitter.

Still, the country is seen as a potential leader in the fight against climate change after US President Donald Trump withdrew his country from the Paris accord struck in 2015.

Renewable energy investment in some big markets like Europe and the US, meanwhile, have suffered a decline, according to the report.

The US saw a drop of 6 percent in investment, amounting to about $40.5 billion, while Europe faced a much bigger fall of around 36 percent, to $40.9 billion. 

Investment in Germany — viewed as a pioneer of renewable energy technologies — slipped 35 percent due to "lower costs per MW [megawatts] for offshore wind, and uncertainty over a shift to auctions for onshore wind," the report notes. 

"In countries that saw lower investment, it generally reflected a mixture of changes in policy support, the timing of large project financings, such as in offshore wind, and lower capital costs per megawatt," Angus McCrone, chief editor of Bloomberg New Energy Finance and lead author of the report, said in a statement.

Countries worldwide have been increasingly looking for green sources of energy as part of their efforts to combat climate change.