The calm, blue waters of Lake Kivu in the west of Rwanda belie the energy powerhouse it stores deep underwater.
Hundreds of metres down in the inky blackness, the lake is holding enough unexploited energy to meet Rwanda’s needs for 200 years.
Rotting vegetation which has been deposited for millions of years at the bottom of the lake is giving off a constant regenerating supply of methane gas.
There are billions of cubic metres of methane at the bottom of the lake and recent studies have shown that enough is regenerated every year to supply all of Rwanda’s energy needs.
So this is a resource that could cut the country’s reliance on oil, and potentially bring in huge foreign earnings – Uganda to the north and the Democratic Republic of Congo to the west are crying out for power.
Plus, of course, there are the environmental benefits; methane in this form is renewable and relatively clean. It is a powerful greenhouse gas, at least 20 times more harmful than carbon dioxide. Getting it out of the environment will be very beneficial.
So the methane operation ticks all the right environmental boxes.
It may in the long term even reduce the wanton tree-cutting that is going on all over Rwanda. Massive forests have disappeared to be used for firewood and charcoal.
Progress to grid is going well. Listen to the BBC’s One Planet radio programme to get further detail (avail next 5 days).