Reuters reports that Indonesia could require $15b of investment to meet its 7.2GW target for geothermal capacity by 2025, according to an energy ministry official.

The capacity would be an increase from less than 2GW of geothermal power currently, the Ministry of Energy and Mineral Resources’s Director General of Renewable Energy F.X. Sutijastoto told reporters at a conference on geothermal energy.

Earlier at the conference, Indonesian Vice President Jusuf Kalla said during a speech that progress in geothermal power development in the past decade has been “very slow” and the dependency on coal power has caused air pollution around the capital Jakarta.

Coal currently makes up around 60% of the country’s energy mix versus about 5% from geothermal power, according to data from state utility company PT Perusahaan Listrik Negara (PLN).

The energy ministry is drafting up plans to accelerate ongoing projects to meet the target, Sutijastoto said, including reviewing the possibility of the government reimbursing some part of the development costs.