A concept paper on the compatibility of geothermal and nuclear technology being a viable solution for off-grid communities by Ronoh Kibet, project engineer at KenGenIn a global context, geothermal energy has been labelled as one of the most reliable alternative renewable energy sources, which has proved to be both technically and economically feasible. In East Africa alone, there have been discoveries of an estimated 15,000MW of potential geothermal capacity, according to the United States Energy Association.
However, development of geothermal power is undermined by the long development durations spanning from the drilling of wells through to their connection to a power utility. The cost, as well as the risk involved in drilling commercially viable wells, are enormous and require specialised geoscientific research to mitigate the risk of barren production wells.
Downsizing nuclear technology
On the other hand, nuclear technology has evolved from being conventional gigantic power plants, which cost over US$50 billion, to small portable sized nuclear energy reactors that are extremely secure and quick to implement. The portable nuclear reactors you find today are factory assembled, easily deployable and are completely secure and safe.
The power systems that are easily deployable are a favoured option for emerging and developing communities that are currently not connected to a conventional electrical source. To ensure energy security and sustainability, research institutions are examining which energy technologies complement each other best. With the abundant geothermal resources in East Africa, it is only logical to test nuclear and geothermal compatibility.
The marriage of geothermal and nuclear
Both geothermal and nuclear technologies run on similar generation technology. They both run steam turbines to generate power, use steam condensers and they both use steam cooling towers. In addition to these similarities, both geothermal and nuclear power are clean sources of fuel, meeting the energy trilemma requirements.
[quote]In a clever combination of geothermal and miniaturised portable nuclear power the cost of electricity production can be reduced by over 40% while minding the underlying energy trilemma. The combination will include nuclear energy supplementing geothermal generation while utilising the geothermal power plant facilities.
For a developing country like Kenya, the above combination will be a relief in solving acute power shortages, escalating cost of electricity and the lengthy geothermal power development duration. The concept is new and should revolutionise the energy generation industry by immensely reducing the cost of electricity and the development duration. It is critical to highlight that this combination concept would only work with an existing geothermal power plant.
Nuclear energy supplies 20% of the electricity used in the United States of America and 16% of that used throughout the world. But as the global use of nuclear energy grows, so do concerns about the vulnerability of nuclear plants and fuel materials, which can be misused or lead to terrorist attacks.
Many of the countries in need of nuclear energy are among the 187 nations that have signed the Non-Proliferation Treaty (NPT) enacted in 1970.
These non-nuclear states agreed not to acquire or produce nuclear weapons or nuclear explosive devices, and in exchange, they have access to peaceful nuclear technology developed by the five nuclear signatories. Private investors are also starting to eye nuclear, as developing countries, such as Kenya and Nigeria, search for answers to provide large amounts of carbon-free power.
Geo-nuclear financial viability
When examining the process flow of both the nuclear and geothermal processes, the two technologies are similar in that they both use steam as fuel that drives a steam turbine. In addition to both running cooling towers, they are clean resources of energy.
By developing a clever combination of having the nuclear reactor re-heat condensed steam after running the geothermal turbine to run the additional turbine, this will yield an additional 100MW, an equivalent of 35 geothermal wells.
When examining the cost involved with generating 100MW purely from geothermal resources compared with a combination of geothermal and nuclear, we get the following:
|Pure geothermal in US$||Geothermal-nuclear in US$|
|Cost of wells for 100MW||
|Cost of Olkaria IV||
|Cost of shared geo-nuclear plant||
|High voltage substation & transmission||
When examining the cost involved with generating 240MW purely from geothermal resources compared with a combination of geothermal and nuclear, it becomes clear that the combination will benefit energy development by reducing costs up to 40%, reduce the need for additional land and accelerate power development.
About the author
By examining the research results, from a pure financial perspective, it appears to make complete sense to pursue a project that integrates both geothermal and nuclear resources; both of which support the clean energy drive.
Ronoh Kibet is the geothermal projects engineer in the geothermal development division at KenGen in Kenya. He is in charge of planning, monitoring and evaluating geothermal projects and graduated from Jomo Kenyatta University of Agriculture and Technology (JKUAT) with a B.Sc in Electrical Engineering with a major in Telecommunication and Information Systems Engineering.
He also holds a Higher Diploma in Management Information Systems (MIS) from Strathmore University and was awarded an Excellence Award in Advanced Java Programming & Entrepreneurship from Massachusetts Institute of Technology (M.I.T) – USA. Kibet is presently pursuing Master of Science in Project Management at JKUAT.