planned and built hydroelectric plants under a licensure scheme regulating the size and output of projects. In January 2008, the government amalgamated its three wholly owned hydroelectric companies—Chukha Hydro Power Corporation, Basochhu Hydro Power Corporation, and Kurichhu Hydro Power Corporation—into Druk Green Power Corporation. In addition to its first three plants, Druk Green assumed control of Tala Hydropower Plant in 2009. Druk Green operates as a holding company to oversee and accelerate hydropower and alternative energy development. Both the Bhutan Power Corporation and Druk Green are owned by Druk Holding and Investments, which exercises oversight in the investment and development activities of the energy companies. Both companies faced decreased profit margins largely because of losses due to increased energy price on repurchase from India. Production and consumption In the early 21st century, about 70 percent of all energy consumption in Bhutan was in the household sector. Heating and cooking with firewood in particular accounted for between 70 and 90 percent of total energy consumption and virtually 100 percent of household energy consumption. In contrast, commercial activities in Bhutan were fueled mostly by hydroelectricity (about 97 percent), some fossil-fuel based thermal power (about 3 percent), and a minimal amount of other fossil fuels. As a result, Bhutan sold much of its hydroelectricity to India during summer months. To date, the Bhutanese electric energy supply has been virtually entirely hydroelectric. Due to the vulnerability of the water supply amid climate change, the Bhutanese government began exploring alternative energies such as solar, wind, and biogas in the early 21st century. Climate change also poses risks to Bhutan as the country could suffer weather extremes causing more floods, intense monsoons, and glacier dam bursts in the summer and drought in the winter. Hydropower plants Bhutan's installed hydropower capacity stands at 1,615 megawatts as of 2016, out of an estimated hydropower potential of 30,000 megawatts (23,760 megawatts of which is considered technologically and economically feasible). Hydropower generation drops significantly in the winter due to mountain streams freezing over. On-grid hydropower is the country's main energy source. Bhutan operates four major hydroelectric facilities, several small and mini hydroelectric generators, and has a handful of further sites in development. Many of the small and mini hydropower plants in Bhutan serve remote villages that remain disconnected from the main power grid. Almost all of hydroelectric plants in Bhutan generate power through run-of-the-river hydroelectricity. Earlier international aid efforts were