According to engineers at the Kenya Electricity Generation Company (KenGen), it takes a number of years to construct a single geothermal power plant, because it has to be fed by steam from several wells, which are often drilled and left open for years awaiting completion of the main plant.

 

"We are taking advantage of these single wells to generate power using the steam, which would otherwise have gone to waste while the main plant is being constructed," said Johnson Ndege, the Chief Engineer in charge of wellheads at KenGen.

 

Geothermal energy is generated when super hot steam from the earth crust is used to rotate turbines of power generators. The steam is ejected through drilled wells sometimes up to more than three kilometres deep into the ground.

 

Ideally, wellheads take the shape of a normal geothermal power plant, but in a smaller version. While a geothermal power plant is run by steam piped from tens of wells, a wellhead utilises steam from just a single well. Once the main plant is fully constructed, the wellheads are removed and moved to different stations, so that steam from the wells can then feed into the main plant.

 

"The wellhead technique was just but an experiment, and it turned out to be a very good way of generating power from wells that would otherwise have remained idle for years," said Ndege. Kenya is therefore the first country in the world to generate geothermal power directly from wellheads.

 

So far, the company has mounted 11 wellheads that now account for 56.1 megawatts of the country's total geothermal energy production, as it constructs the sixth and seventh geothermal power plants at Olkaria site in the Rift Valley, which will be completed by 2018. Four more wellheads are under construction, and experts say they will produce a total of 20 more megawatts of electricity in the next few months.

 

Investment in geothermal power generation has therefore turned the tide, where Kenya, which was a net importer of electricity from Uganda by last year, is now exporting electric power to Uganda.

 

"We do not want to leave anything to chances, and that is why we have started generating electric energy using wellheads as we keep developing more and more geothermal power plants," said Albert Mugo, the Managing Director and KenGen's Chief Executive Officer.

 

Investing in the five major geothermal plants namely Olkaria I, II, III, IV and V, with supplementation from smaller sources such as the wellheads, has put Kenya on the global map of geothermal power production.

 

As a result, Kenya has become the world's eighth largest supplier of geothermal energy with a total installed capacity of 585 megawatts. This represents five per cent of the total global geothermal production, as rated by the World Geothermal Council.

 

According to Mugo, geothermal sources of energy in Kenya have already surpassed hydro sources following the commissioning of the latest Olkaria IV and IV, with a combined capacity of 280 megawatts. The two power plants were commissioned by President Uhuru Kenyatta in October 2014.

 

In general, geothermal now accounts for 51 per cent of the national power mix in Kenya, while hydroelectric, which was the leading source of energy some months ago, now accounts for 40 percent. Other sources including thermal and wind account for the remaining nine per cent.

 

"The beauty is that geothermal plants typically achieve over 90 per cent efficiency, which is much better that hydro sources that run at around 70 per cent efficiency at the best," said Mugo.

 

The other advantage is that geothermal power generation is not affected by climatic conditions, and does not pollute the environment. "It is clean energy," said Mugo.

 

He however notes that the country cannot entirely kick out diesel generated electricity because of rising demand, cases of emergency and routine maintenance of other power plants.

 

"As leaders, we shall do our best to support efforts geared towards tapping renewable energy as a way of adapting and mitigating the impacts of climate change," said Dr Wilbur Ottichilo, a Member of Parliament and the founder of Parliamentary Network on Renewable Energy and Climate Change.

 

According to the country's ministry of Petroleum and Energy, Kenya's Rift Valley alone has an estimated potential of more than 10,000 megawatts of electricity from geothermal sources.

 

"By 2018, we plan to develop a further 460 megawatts of geothermal energy," Mugo told IPS. If that is achieved, he says, the amount of electricity generated from hydro power could be reduced by 28 percent of the total mix.

Source : allafrica.com