Loads of rot to the rescue
Now the biogas sector is cooking with gas, thanks to load-shedding
The odometer on Mark Tiepelt’s bakkie is about to roll past 800,000km, and he’s hoping 2023 might be the year he can afford to replace the vehicle.
After “hanging in there” for 15 years in an energy sector that’s refused to take off, biogas expert Tiepelt says his phone has started ringing off the hook.
“I’ve appointed a marketing agent, it’s not costing me anything and it’s doing a fantastic job,” he says. “The agent is called Eskom.”
The day after speaking to the FM, the MD of BiogasSA had appointments with two KwaZulu-Natal pig farmers keen to find out if biodigesters fed with manure can solve their load-shedding problem by providing methane to run their generators.
“They risk going out of business because of the hundreds of thousands of rand of diesel they are buying every month,” says Tiepelt. “They are desperate to find an alternative source of baseload power.”
Gordon Ayres, MD of Agama Biogas, says people behind aborted projects he worked on a decade ago “have started to come back to us, and we have a whole lot of new customers. There’s suddenly a huge amount of interest.”
Load-shedding, Ayres says, could be a tipping point for biogas, which has until now struggled to gain traction on the strength of its boasts that it reduces organic waste going into landfills, creates jobs and produces a digestate that can be used as fertiliser.
Those claims stand up to scrutiny, says Karen Surridge, acting general manager of the South African National Energy Development Institute (Sanedi), and they’re part of the plan her organisation has developed to stimulate interest in biodigesters, which can operate from household level all the way up to utility scale.
Germany, with more than 230 large plants and about 10,000 smaller ones, relies on biogas for about 8% of its energy needs almost as much as solar and Ayres says: “If you’re a farmer in Germany, you’d never dream of not having biogas.”
Surridge says this is where biogas can make a worthwhile and relatively quick contribution in South Africa. “It’s not about putting electricity on the grid to mitigate the load. It’s about taking load off the grid by using biogas instead. And that can happen at different scales.”
At the basic level, a microdigester fed with food waste and other organic material such as cow dung or grass clippings can produce up to an hour’s supply of biogas daily. Surridge is a regular visitor to a larger digester at a Limpopo military base that transforms food waste from a kitchen that feeds 200 people into gas for tomorrow’s meals. “They’re
cooking on it twice a day for four hours,” she says.
Then there are plants such as the Bio2Watt digester in Bronkhorstspruit that can generate 4.6MW of electricity daily, much of it sold to BMW’s Rosslyn plant, and a 9.8MW plant under construction on a large dairy farm in Malmesbury, north of Cape Town.
Tiepelt says biodigesters can be temperamental and biogas will never be able to compete with other renewables on a rand-per-kilowatt basis. “Developers, investors and financiers look at an internal rate of return of 20%-plus, and biogas doesn’t touch that in the majority of cases,” he says.
But when you look at a jobsper-kilowatt rate about 10 times bigger than solar or hydro, a supply of organic fertiliser that can improve food security, and a shortage of landfill space, the sums begin to add up.
Then, enter load-shedding, “and it makes a lot more sense to spend R25,000 a month to pay off a biogas plant than spending that on diesel over the next three years, because
the likelihood of the Eskom scenario changing in the next three to five years is very slim”, says Tiepelt.
A study by Sanedi last year found no reason South Africa cannot emulate China, India, Nepal, Kenya and Tanzania by rolling out tens of thousands of microdigesters. It envisages small businesses collecting food waste, processing it in biodigesters and then selling biogas for generators, battery charging, lights and clean cooking.
“That’s where small-scale biodigesters can develop a huge opportunity,” says Ayres. “A pilot programme could be launched in three months, but the biogas industry has been starved of money and that will need to change.”
Sanedi’s work feeds into a larger study, funded by the department of science & innovation, which aims to produce a waste-to-energy roadmap for South Africa later this year. If it follows the lead of the Western Cape and puts landfills off limits for organic waste, it could give biogas the final push it needs to go mainstream.