The first large-scale waste-to-energy project in Africa
In January 2017, the first large-scale waste-to-energy (W2E)plant in Africa opened in Athlone in Cape Town. It was fully commissioned in May 2017.
Five years in planning, it is thought to have cost around R400 million (US$28 million) and created 80 full-time jobs – plus, estimates suggest, a few hundred indirect jobs too. South Africa’s Industrial Development Corporation (IDC) financed 60% of the plants value. Half of that funding was provided in turn by KfW, the German Development Bank as a Green Fund. Return on investment is expected to be around “7-8 years”.
The plant is owned by New Horizons Energy, a subsidiary of Clean Energy Africa, and will be provided with its waste “fuel” by waste management company Waste Mart (one of the largest waste collectors in the city).
This example is unusual compared to the others on my site, in that it is not about power generation. Indeed it is for this reason, in addition to its “first in Africa” status, that I decided to include it when I discovered it. It makes an important point that IS relevant to power generation: in the bioenergy sector, electricity is always in competition with other potential market opportunities. Power generation may be one technological option, but will not always be the most profitable business approach.
Let the bacteria do the work
The plant converts normal, “black bag” municipal solid waste, along with organic-rich waste from food manufacturers, shops, bakeries, restaurants and breweries, into biogas. Tipping fees are charged for the plant to take this waste. In total, the plant will consume around 560 tons of solid waste each day.
After being placed into large vats, in oxygen-poor conditions, organic matter from the waste is converted by bacteria into a methane-rich “biogas”. Besides methane, CO2 is the other major component of biogas. This creation of biogas is the process known as anaerobic digestion (AD).
The AD process needs some starting up, in order to breed the bacteria. So, at first the bacteria in the Athlone plant were fed nothing but cow manure, before moving on to 50 tons of apricot juice. It took a couple more months before the bugs were mature enough to eat through waste paper and other rubbish, and turn it into gas.
Not Cape Town’s most beautiful site, but doing good things.
As a result of the ongoing AD process, and following separation of the methane and CO2, the plant produces more than 18 tons of food grade carbon dioxide and over 540 GJ of compressed biomethane each day. The biomethane produced has a methane content in excess of 97%, exceeding current specifications for natural gas pipelines. It is compressed, odourised and stored in tank trailers, ready for regular collection, while the liquid CO2 is pumped into storage tanks.
The off-taker for the biomethane and carbon dioxide is African Oxygen (Afrox). Afrox entered a 15-year purchase agreement with New Horizons Energy in 2015, under which they are the sole off-taker and distributor.
The upgraded biomethane from the New Horizons plant has a number of advantages over other fuel sources currently available in the Western Cape. It is cleaner burning with far less sulphur (S) or nitrogen (N) by-products. It also has a more consistent quality which will be especially valuable to processing industries.
Prior to this new plant, CO2 for the Western Cape market was predominantly sourced from Mossel Bay, more than 380 km away, while South Africa is reliant on methane from Mozambique.
New Horizons Energy plans to supply local bio-methane to businesses across South Africa as well as rolling out more AD plants to other provinces. This scale-up will utilise Afrox’s existing and extensive supply chain.
Biomethane is also a cost-effective alternative fuel ideal for trucks currently running on diesel. It can of course also be burned to generate electricity: this waste-to-energy example is perhaps unusual in not exploiting that as a revenue stream.
Other revenue opportunities and local advantages
In addition to biomethane and CO2, the plant’s output products include organic fertiliser, separated solid recyclables (such as glass, metal, paper and plastics) and refuse-derived fuel (RDF). Future products could, according to the plant operator, include plastic bricks and roof tiles.
7-10% of Cape Town’s total waste will go through the plant, diverted from landfill. Indeed it was a shortage of landfill sites in fast-growing Cape Town, along with summer shortages of both methane and CO2, which helped spark the development. The project helps to address both problems at once.
Last updated: November 2017