The Department of Alternative Energy Development and Efficiency (DEDE) plans to promote an on-grid solar rooftop scheme as part of plans to maximise usage of solar panel power generated by private companies.
DEDE is in talks with the Energy Regulatory Commission (ERC), which grants solar rooftop licences. DEDE provides basic information and expertise in renewable energy.
Both agencies expect to disclose tentative rules and regulations before proposing a plan at the next National Energy Policy Council (NEPC) meeting, led by Prime Minister Prayut Chan-o-cha.
Upon receiving approval from the NEPC, investors could receive solar rooftop licences by mid-2018 to sell excess power to the Metropolitan Electricity Authority and Provincial Electricity Authority.
Private companies and factories have been allowed to install solar panels at their properties for internal use, meaning it is off-grid and they do not have a licence to sell excess power to the state's power authority units.
Praphon Wongtharua, DEDE's director-general, said the upcoming round is expected to grant a combined capacity of 300 megawatts.
This round will be the second after the first batch was launched in September 2013.
Mr Praphon said the power tariff used by state utilities to buy electricity back from property owners is expected to be lower than the average tariff, citing the Electricity Generating Authority of Thailand rate that approaches three baht per kilowatt-hour (unit).
"The government will grant the licence to any provinces that can feed into power transmission lines nationwide," he said.
"Most solar rooftops on buildings and factories have never sold energy to state utilities and gain the biggest advantage during working hours, but panels generates electricity seven days a week."
The excess electricity should be utilised for maximum benefit, he said.
But Mr Praphon refused to disclose whether existing solar rooftop owners will have the right to join the upcoming on-grid round.
According to Pugnatorius, a Bangkok-based specialist provider of bespoke transactional legal and tax advice on foreign investments in Thailand, as of the beginning of 2018, Thailand has seen seven years of mostly favourable solar energy developments and a handful of failures.
While 2010 saw the first significant installations of solar panels, the year 2017 marked the achievement of a significant milestone, with a total of three gigawatts of solar installations in the country. This amounts to 50% of the 2036 target under the alternative energy development plan.
Thailand's 3GW share exceeds 60% of total installed capacity in Asean, followed by the Philippines, Malaysia, and Singapore. To put this into perspective, Germany has already installed 41GW of solar power.