Rwandan Ministry of Infrastructure Permanent Secretary James Kamanzi said "We are already doing some drilling in Karisimbi and signed a contract with a drilling company. There are three boreholes in Karisimbi, but most drilling work will start in December".

Kamanzi said there would be a clearer picture of what to expect by next year.

He said three potential sites with a depth of up to 2 miles have tentatively been identified on the southern slopes of the Mount Karisimbi volcano, the New Times newspaper reported Tuesday.

East Africa's geothermal energy potential is immense. In August 2011, Frost and Sullivan issued its "Mega Trends in Africa: A bright vision for the growing continent" report, which projected investment in renewable power in Africa is set to grow from the 2011 total of $3.6 billion to $57 billion by 2020.

"The key growth sectors will be wind power, solar power, geothermal power and foreign direct investment into energy and power infrastructure," the report stated.

Africa's renewable power ambitions have been endorsed by the United Nations. Two years ago the U.N. General Assembly unanimously endorsed a resolution designating 2012 as "The International Year of Sustainable Energy for All."

U.N. Secretary-General Ban Ki-moon has promulgated a series of objectives to support the goal of achieving "Sustainable Energy for All" by 2030, which include ensuring universal access to modern energy services, doubling the rate of improvement in energy efficiency and doubling the share of renewable energy in the global energy mix.

The Rwandan government began searching for potential geothermal resources in 2006 in order to diversify the country's renewable energy sources to generate electricity.

Among the potential zones for geothermal power plants were the Volcanoes National Park and the hot springs of Gisenyi and Bugarama in western Rwanda.

Since 2008 Karisimbi has been studied as a potential geothermal energy source by the German Federal Institute of Geosciences and Natural Resources, Kenya Electricity Generating Co. and Rwanda's Infrastructure Ministry.

Geologists note that Rwanda straddles one of the world's best zones for geothermal activity and that that the geothermal potential of the East African Rift Valley, which stretches across 11 nations, could potentially generate more than 15,000 megawatts. Currently, however, the Rift Valley's geothermal project is the only one under way in Kenya and Ethiopia.

Electricity accounts for only about 4 percent of primary energy use in Rwanda, with the nation having roughly 96 megawatts of installed capacity, with only 13 percent of households connected to the national grid.