A regulatory mandate on Renewable Portfolio Standards(RPS) applied to major domestic power plants is set to rise from nine percent this year to 12-and-a-half percent next year, and then to 25 percent from 2026.

The Trade, Industry and Energy Ministry on Wednesday said it issued an advance notice on a revision to a law concerning the development, use and distribution of renewable energy. The revision calls for raising the RPS under presidential decree.

RPS is a mandate for operators of facilities with a capacity of over 500 megawatts to use renewable sources - such as wind and solar - for a certain percentage of their power supply. 

When first introduced in 2012, the RPS began at two percent but has steadily climbed over the years.

Large power plants that fail to meet the RPS must purchase Renewable Energy Certificates(RECs) from small-scale renewable energy suppliers for the lacking amount.