The Asia-Pacific region presents the biggest challenges to major corporations aiming to switch to renewable energy, said a report that names the 10 most problematic national markets for companies to green their supplies.

A study by the RE100 group of 261 companies that are targeting 100% renewable power found significant issues still remain in major Asian markets such as China, South Korea and Japan.

With green energy sourcing higher on the corporate agenda than ever before, the report named 10 markets reported as the most challenging for businesses, which in some cases are being prevented from hitting their renewable goals as a result.

The barriers highlighted range from cost of renewable energy, its availability, regulatory complexity, and issues with tracking and certification.

The RE100 report, compiled in conjunction with the Climate Group and CDP, named the 10 most challenging markets as:

Australia: Renewables costs still higher than other markets

China: Regulatory complexity

Indonesia: Limited options to purchase renewables

Japan: Higher than other markets; limited availability due to shortage of certificates

Singapore: Limited renewables availability; space for new capacity unavailable

South Korea: Corporate sourcing of renewables not yet available

Taiwan: Prohibitive renewables costs

Argentina: Renewables not available for corporate sourcing

Russia: Certificates not available to purchase and other sourcing options limited

New Zealand: Insufficient sourcing options, no tracking system currently in place

The report was released soon after electronics giant Sony and others warned the Japanese government they could site facilities outside the country if the situation over renewables procurement there does not improve.

Despite the challenges, RE100 said 42% of the new corporate recruits to its ranks came from Asia-Pacific last year, with the region showing the fastest-growing appetite for green power procurement by businesses.

“More needs to be done to realise the scale and speed of demand-driven renewables investment that regions such as Europe and North America are already enjoying,” said the report’s authors.

“Fully removing the barriers would be an efficient way to help countries such as South Korea, Japan and China progress quickly towards their recently announced net-zero goals with little to no cost to public finances.”

The report comes as European corporate renewable procurement enjoyed its best year ever, according to data released earlier in December by the RE-Source platform for clean energy buyers and sellers.

The upswing is being driven as more sectors such as heavy industry and pharmaceuticals that pioneered the sourcing of wind and solar to green their operations.

Amazon recently claimed to have passed Google as the world’s largest procurer of renewable power.