Agricultural uses of geothermal power in Kenya

Geothermal other uses              by Mwangi Mumero

While the focus on geothermal power in East Africa has mainly been on electricity generation, experts now say that its potential goes beyond into agriculture, health, tourism and hotel industries.

“Steam from geothermal power stations has potential use in agriculture, tourism and in the health sectors. Very little of this potential is currently in use in the country although it has fully been exploited in Europe and other countries”, observed Ms Marietta Mutonga, a Geoscientist Resource and Development officer with the Geothermal Development Company (GDC), at the recently ended Nakuru Agricultural Society of Kenya Show.

 This comes at a time when the Geothermal Development Corporation (GDC) – the government body responsible for geothermal power – is wooing investors to develop this huge potential.

With an estimated geothermal power potential of between 7,000 MW and 10,000 MW, Kenya is yet to fully benefit from their renewable energy as only 200 MW is exploited.  

The country expected to generate 50 per cent of its power needs from geothermal by 2018. GDC has identified 14 high temperature sites in the Great Rift Valley that have potential of producing over 15,000 MW of power if fully developed .

According to Ms Marietta, steam for power generation must have an optimal temperature of 250 degrees Celcius and above. Once this heat has been utilized to turn the turbines, the cooling temperatures can be harnessed for other uses.
“Between 90 and 100 degrees Celcius, the heat can be used in drying grain, wool, hides and skins, vegetables. Already, pyrethrum drying is taking place at Eburru in Naivasha using steam”, she said.
However, it is in horticulture where the biggest potential of geothermal steam use in agriculture lies.
In Oserian Flower Farm in Naivasha, the steam is currently being used to heat greenhouses. In particular, horticulturalists are using heat from steam to control dew point temperatures.
“Dew point temperatures are critical in the proliferation and spread of fungal diseases in the green houses. Once this is controlled, there is reduced use of fungicides, allowing horticultural exporters to escape stringent chemical checks in the European Union market”, added Ms Mutonga.
Increased temperature in the greenhouses has also boosted horticultural production by 40 per cent in companies using steam, according to GDC.

For instance, cucumbers grown at 25-27 degrees Celcius and tomatoes at 22 degrees Celcius mature fast and reach the market quickly compared to those grown in other conditions.

With the many flower companies located near Naivasha, where Ol Karia geothermal stations are based, the potential for growth in the use of steam in horticulture is immense, according to officials.
According to the Kenya Flower Council (KFC) at least 1,200 hectares are under roses in Naivasha. Rose also form the bulk of all flowers produced in the area constituting over 70 per cent and form the main flower exports from the country.
Another use of this steam heating is in aquaculture- warm water fish farming.

While this practice has not been tried in Kenya, officials note that in Iceland and Tunisia, steam from geothermal plants has been used to warm water to 30 degrees Celcius for fish farming.

Research has shown that fresh water fish such as tilapia-common in the tropics- required temperatures of 25- 30 degrees Celcius for better performance.
Pasteurization of milk and fish preservation in cold rooms have also been cited as potential uses of steam from geothermal plants.
GDC officials however acknowledge that the major challenge of using steam in agriculture and other sectors has been the expensive pumping and lagging systems.
According to these officials, it is quite expensive to take steam for long distances without losing heat along the way and therefore, it can only benefit industries that are close to the geothermal plants.
In the hotel industry and health sectors, geothermal steam is already in use in hot water spas and swimming pools.
“A 50 degree Celcius spa has already been developed in Ol Karia Geothermal station in Naivasha although it is yet to be opened to the public. It has been developed within the area under Kenya Wildlife Service meaning tourism will also be boosted by the presence of these saunas”, asserted Ms Mutonga.
A warm water swimming pool is already open to the public in Lake Bogoria in Baringo County- one of the areas where natural hot water pools are found.
Development of Menengai Geothermal plant, expected to produce 5,000 MW of electricity by 2030, will spur growth other sectors such as hotel and flower industries in Nakuru County.
The plant on the dormant Menengai Crater overlooking the fast growing town as well as ever busy Lake Nakuru National Park which received thousands of local and foreign visitors annually.

The World Bank has pledged to inject $ 118 million to toward the project - underpinning the value the Bank puts in green energy.

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