The Kenyan stretch of the Great Rift Valley is breathtaking. Vast plains between the two escarpments teem with wildlife, creating one of the world’s largest animal migrations – the Mara-Serengeti wildebeest migration. The alkaline lakes in the east African rift system are home to elegant and graceful flamingos, pink wonders that reels in visitors from around the world and are a vital cog in Kenya’s thriving tourism industry.
But it is what lies beneath the valley floor that has had a literally seismic impact on Kenya in recent years – vast geothermal resources that have made the country a world leader in clean energy.
Peketsa Mangi is the general manager in charge of geothermal development at KenGen, the country’s energy generating company. “We are lucky the African rift runs through Kenya,” he told me when I visited last week. “We just happened to be in the right place with several volcanic centres. Olkaria is one of these centres.”
Mangi and I are sitting in a gazebo overlooking a spa pool that uses brine, the byproduct of the geothermal development process. Visitors from all over Kenya come to enjoy the pool’s “healing” properties. With a power plant humming away nearby, my first visit to the heart of Kenya’s geothermal power generation turns out to be a lesson on what is going on below our feet.
According to the Geological Society, the Somalian and Nubian tectonic plates pulled away in opposite directions about 25m years ago, with the surface between the two fault lines sinking and bringing magmatic fluids closer to Earth’s surface and creating the famous rift, a vast valley that stretches 6,400km from Jordan to Mozambique. Under the valley, water percolates easily and comes into contact with hot rocks found 1-3km beneath the surface, creating a mix of superheated water and steam at 75% and 25% respectively, with temperatures averaging 300C (572F) and pressures of 1,000 PSI. These are, it turns out, the perfect conditions for generating geothermal energy.
“This is the steam we are tapping to run the turbines that generate electricity. It is rough down there, and that is where we go,” says Mangi. “A dangerous but necessary mission.”
Mangi has observed the behaviour of the valley for 27 years and knows exactly where to drill a well that will yield geothermal power. “Kenya has developed the capacity for precision geoscientific studies that help us to identify potential areas to drill. Exploration and drilling are cost-intensive endeavours and investors don’t want to go to a greenfield without confirmed viable resources,” he says.
Geothermal energy had its start in the small settlement of Larderello, Italy in 1904. The small plant provided a mere 10kW of energy, just enough to power five lightbulbs. Since then, a number of countries have dug deep in order to exploit similar resources. The US, Indonesia, the Philippines, Turkey and New Zealand are the top five geothermal power producers in the world.
In Kenya, the search for underground energy began nearly 70 years ago, but stalled almost immediately. In 1956, the government drilled two wells specifically to harness geothermal power, at a depth of 950 metres and 1,200 metres respectively. “Temperatures averaged 235C (445F) but the wells failed to discharge due to poor permeability as the surrounding area was a bit solid,” says Mangi.
Then the oil crisis of the early 1970s happened and, once again, Kenya peered beneath the ground for an answer. Global organisations including United Nations Development Programme, The World Bank and Japan International Cooperation Agency stepped in to provide financial and technical support for further exploration. In 1971, a well was drilled and discharged. Everybody got excited again, Mangi says. Between 1981 and 1985, Kenya had an installed capacity of 45MW through the first three power plants in Olkaria.
“We don’t know where the country would be had the oil crisis not hastened this process,” Mangi says. “Geothermal is available 24/7 for 365 days. It is not affected by climate fluctuations since we are using water that has accumulated deep in the ground over the millenniums. The alternative would have been the installation of diesel generators that pollute the environment. This is our contribution to a cleaner world.”
Now, here at Olkaria, near the flower-growing town of Naivasha 56 miles (90km) from Nairobi, there are close to 300 geothermal wells providing steam that runs turbines in five geothermal power plants operated by KenGen.
The power plants and 15 wellheads have a combined capacity of 799MW. With additional geothermal power generated by independent power producers, Kenya’s total geothermal power capacity is 988.7MW, putting the country in sixth position globally (and first in Africa) in terms of geothermal power development.
As a result, Kenya sources up to 91% of its energy from renewables: 47% geothermal, 30% hydro, 12% wind and 2% solar. The country hopes to transition fully to renewables by 2030, with KenGen saying the country has the potential to increase its capacity to as much as 10,000MW of geothermal energy. That would more than match peak demand in Kenya, currently about 2,000MW. Peak time consumption in the UK is about 61,000MW.
Several wells sit within Hell’s Gate national park, the location that inspired the movie The Lion King. The park is patrolled by antelopes, giraffes, zebras and buffaloes, all roaming freely and oblivious to the immense energy trapped beneath their hooves and delivered to the power plants through a labyrinth of a high-pressure piping system averaging 74 miles (120km).
“Geothermal power is clean and poses no harm to the wildlife as the animals have adapted to this system,” says Gastone Odhiambo, a safety officer at the power plants. “These pipes are delivering steam to the turbines at 180C (356F) to produce 11 kilovolts of electricity that is then stepped up to 220 kilovolts to travel long distances. You need a sober mind since a single mishap can bring the country to a halt.”
Odhiambo’s childhood home in western Kenya did not have electricity. “I grew up in darkness,” he tells me at the plant’s control room full of switches, dials and strobe lights. “It is a heavy responsibility to help in generating clean energy that can go for ages. When you understand the process, how your tasks affect the day to day running of the economy, you remain humble.”
The Kenyan president, William Ruto, is now spearheading an African campaign to wean the continent off fossil fuels. In September last year, a declaration was signed, which called for reform of international finance and castigated the global north for the skewed global financial system that makes it difficult for Africa to harness its vast renewable energy resources.
“Despite Africa having an estimated 40% of the world’s renewable energy resources, only $60bn or 2% of $3tn renewable energy investments in the last decade have come to Africa,” read the declaration.
While Kenya and the rest of Africa await the financial reforms, it is a fulfilling assignment for the team that works at the geothermal plants in Olkaria, as Mangi sums it up: “A good day here is when the whole process works like clockwork. When all scientific studies and financial resources are poured into the ground, a well is drilled and it discharges, that is power to the country. You feel the investments are well used. And such good days are many.”
