All of the ASEAN-5 countries are currently operating FIT systems with fixed tariffs. Although Thailand first introduced a feed-in premium through the Adder programme in 2007, the country replaced it with a new feed-in tariff scheme in 2015 (Watson Farley & Williams, 2015). As Thailand differentiates electricity prices between off-peak and peak hours, the fixed FIT will reduce the price risk and potentially increase revenues for renewable energy (RE) power plants that generate during off-peak hours.