Across vast tracts of African landscape, nature produces an unlimited supply of a renewable, intrinsically safe and clean recycling resource from invasive alien and unwanted encroacher trees, with the potential to produce considerable quantities of power in a much more environmentally friendly manner than fossil fuels.
Organic waste as an energy source is as ancient as the Earth, and tends to be very carbon-rich; and where there is carbon, there is energy. Using invasive alien and encroacher tree species, when harvested and turned into woodchip as a biofuel, makes a strong case for the introduction of a new generation of small baseload power stations that can generate between one and 10 MW of electrical power.
The potential for energy production from woodchip is somewhat staggering. Willem van der Merwe, CEO of Africa Biomass Company (ABC), which is headquartered in Worcester, South Africa, says that to generate enough power and/or heat for a household or small business requires as little as 50 kg of woodchip per day; or 150 000 to 200 000 tons annually for a large manufacturing plant or small town.
‘As a general rule of thumb, 40 000 tons of woodchip per year will sustain electricity generation of 5 MW, which makes biofuel-fired power stations a strong competitor to national electricity suppliers, especially in terms of cost per kWh.’
When compared to coal-based power stations, biomass presents a number of superior benefits. Generally, biomass chips, measured in rands per ton, can be delivered cheaper, across distances of up to 100 km from the harvesting site. ‘This is certainly true in the Western and Eastern Cape provinces of South Africa, and Namibia,’ says Van der Merwe.
Coal also expels toxic ash, which adds to the already heavily burdened CO2 atmosphere. ‘Trees do not release any more carbon dioxide when burnt as fuel as they do during their natural photosynthesis process,’ according to Van der Merwe. ‘Provided they are replaced, trees present a closed-circle footprint and furthermore, the non-toxic ash of burned biofuel can be returned to agricultural soils as an ameliorant to improve soil health.’
ABC is currently harvesting 180 000 tons per annum (tpa) of biomass, equating to 21.5 MW, from clearing predominantly the Western and Eastern Cape of alien and invasive tree species in riparian areas, and end-of-life cycle fruit and nut orchards. These Cape regions, together with KwaZulu-Natal, Mpumalanga and Namibia, present the densest and most prolific zones for biomass harvesting, says Van der Merwe – particularly Namibia, which has more than 33 million ha of encroacher bush that has accumulated over the past seven decades.
‘This is typical of the rate at which alien-infested areas expand, and is far quicker than the efforts to clear them.’ This has escalated ABC’s growth over the past decade from its small beginnings in 2004 as a feller of high-risk trees with four employees, to the strength of 170 today.
The company’s expansion has evolved to encompass mulching, orchard/vineyard recovery and recycling, river and land clearing, biomass production and the supply of woodchip, and related workshop and field services. The latter relates to ABC’s appointment as sole agent in Africa of Bandit Industries, a manufacturer and supplier of key heavy-duty chipping and milling equipment.
With the award of the Bandit agency, ABC opened two large maintenance workshops in the Cape, to support the after-sale and hire of associated chipper machinery. ABC also manufactures selected components of its harvesting trains; the mobile units that undertake tree-felling, loading, chipping, off-road shuttling and hook-on-hook-off bulk bins; and road transport equipment to deliver chips to proposed power plants or other end-users.
Ten such trains, each with an annual capacity of some 20 000 tpa, are currently in use in South Africa, producing the aforementioned 180 000 tpa of chipped biomass. In Namibia, because of site sizes, locations and terrain, the same 10 trains would more than double the output in 10 months, supplying the neighbouring country with some 300 000 tpa, enough to provide 37.5 MW a year for up to 25 years and beyond.
‘Using 25 trains, 760 000 tpa of biomass could be harvested, translating into 100 MW – enough for 50 years or more,’ according to Van der Merwe. ‘Such a quantity can be harvested from less than 1% of the encroacher bush. To prevent that resource from growing larger, however, more than 1.4 to 2.2 million tpa needs to be harvested.’
There are many other positive spin-offs in converting bio-waste to energy, not least of which is the potential for the development of related small and microenterprises. Van der Merwe explains that hand felling is still required ‘particularly when clearing steep slopes. Contractors that specialise in hand clearing are in demand for sweeping forest floor waste and chipping small branches using hand-fed chippers’.
‘There is also the potential for small private power producers to emerge, especially if they are sited in a radius of 100 km from large biomass-clearing areas to ensure that costs of transporting woodchip are minimised.’
In 2017, Van der Merwe was awarded the Entrepreneur of the Year award from Sanlam and Business Partners Limited, an annual competition that recognises and honours South African entrepreneurs in the SME sector. ABC was acknowledged for providing a specialist service in the waste-wood recycling industry.
The industry can contribute significantly to the economic and social development of communities, particularly those in rural areas. One such example, a project to clear alien trees in the catchment areas of the Western Cape’s Breede and Berg rivers, resulted in extensive water savings, enough to account for some 46 000 households’ daily water consumption for a year; this at a time when the Western Cape declared a water shortage.
The biomass industry is, however, a young and undeveloped market in Africa compared to Europe and the US but the potential is huge. ClimeDev-Africa claims that sub-Saharan Africa has the greatest bio-energy potential of all world regions ‘owing to large areas of suitable crop and pastureland, favourable climatic conditions and the low cost of labour’.
Despite this, projects and production facilities are few and far between, says Van der Merwe. ‘The large ones that exist are mainly within the sugar industry.
‘The concept of using woody biomass as an energy resource is definitely not mainstream on the continent. I would say it’s not yet even a niche market, which is ironic because wood is the oldest solid-fuel source known to mankind, but the least developed.’
Identifying environments where end-of-life as well as alien plant and tree matter can be acquired and harvested is not a significant challenge. What is lacking, however, is educating and informing the public and business of the potential of biomass as a renewable fuel.
A further inhibitor is that few have the technical knowledge and capability to either enter the industry or expand a biomass company both vertically and horizontally as ABC has done.
‘ABC is the only private and fully mechanised business able to process large quantities of biomass in South Africa, and having developed a strong reputation for customer relations and service in the nation, we are now targeting Tanzania, Kenya and Zambia, along with neighbouring states, as our next growth markets.
‘Biomass is a fuel for now and the future,’ says Van der Merwe. ‘Ours is an industry that exists purely to feed off waste streams and unwanted invasive alien and encroacher tree species, and turn those into a valuable asset for all.’