Ideas & Debate

How to make garbage power plan a success

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Dandora dumpsite. FILE PHOTO | NMG

A news item last week mentioned that Nairobi Metropolitan Services (NMS) and Kenya Electricity Generating Company (KenGen ) have entered into an agreement for KenGen to develop a power generating plant using city solid waste - call it Waste to Energy (WTE) power plant. This is not an entirely novel technology as it is in use in many cities around the world.

Nairobi city has in the past undertaken WTE studies, but these were never implemented. Any new feasibility study will therefore not be starting from scratch. The proposed WTE project must be viewed as an economic, environmental, and social opportunity to not only increase renewable energy generation, but also to sort out a malignant garbage problem that has overwhelmed the city of Nairobi for many years.

Without trying to pre-empt the feasibility study, the project must be viewed as a commercial investment with a slant towards a public utility. Any feed-in-tariff negotiated and the power purchase agreement (PPA) may need to recognise that government fiscal incentives may be necessary should project economics fail to match those of competing lower cost power generators like solar energy. In this respect, best practices around the world should advise the appropriate PPA model and tariff structure.

It will also matter a lot how the investment partnership between NMS, KenGen, and any other equity participant is structured. For NMS it will mostly be motivated by reduced costs of garbage management plus a new revenue stream, while the other participants will be looking at making reasonable returns on capital invested. Project guarantees from multilateral agencies should not be difficult to get for such a project.

The WTE is classified as a renewable energy project, albeit with some carbon emissions which are less onerous than the methane (biogas) emitted by traditional landfills. Many job opportunities will be created considering the sheer efforts of garbage collection, transportation, sorting and recycling the recyclable. The quality of waste will be dependent on origins (domestic, vegetable markets, industrial, institutional) and how burnable the waste is, and this will have a major bearing on the WTE project operating costs.

According to me, the existing Dandora site may be the wrong location for the proposed WTE project. When Dandora dump site was started, it was far outside the city, but now it is in the very inside of the city. The recently re-possessed government Ruai land will be the perfect setting for a Waste Management Zone to include both the WTE and the sewerage works. This is if the scavenging birds and smoke from the WTE do not jeopardise the safety of JKIA flights take offs.

To significantly increase the WTE economies of scale, the garbage capture should include the wider metropolitan outer towns in Kiambu, Machakos, and Kajiado counties. The location of the power plant should therefore be carefully evaluated to ensure convenient garbage transportation from the inner city and the outer towns. And now that we are talking about transportation, the garbage vehicles should be designed covered to reduce nuisance from smelly putrid garbage.

The other challenge will be the large water requirement for the plant. This should not be allowed to compete with the struggling city water supply capacity. The project should consider tapping own dedicated water supply from one of the streams in Kiambu county. The existing KenGen thermal plant at Ruiru has a dammed source of water, and this can be tapped if the WTE is in nearby Ruai.

Literature suggests that 500 tonnes per day of waste will produce about 10 megawatt(MW) of power. Nairobi city produces about 3,000 tonnes per day of garbage, giving a potential plant sizing of 60 MW. Including the outer metropolitan towns will boost potential capacity to 100 MW of new renewable energy.

I am quite confident that the WTE project will be implemented fast. KenGen has a progressive Board and Management which have demonstrated readiness to go for new horizons- geothermal steam drilling in Ethiopia, floating solar panels on Tana reservoirs, and Electric Vehicles charging capacity. The NMS on its part appears to be riding on a well-planned RRI (Rapid Results Initiative) to reclaim lost city glory.