Say green energy, and the first words that spring to most minds are likely either solar power or wind power. But there’s another important player in the alternative energy marketplace─biogas generation.
Biogas is produced when organic matter breaks down in the absence of oxygen.
It’s produced by anaerobic digestion by bacteria or fermentation of biodegradable materials such as manure, sewage, municipal waste, or plant material.
Like solar and wind power, it’s a renewable energy source.
It can be used as a fuel in a variety of applications; when cleaned and compressed, it can power motor vehicles.
In 1957 South AFRICA, the world’s first commercial anaerobic digester was built.
Anaerobic digesters for farm animal waste are typically large, heated stainless steel tanks fitted with tightly sealed sight glass windows to allow operators to monitor mixing and digestion to ensure efficient operation.
An example for monitoring biogas processes
The safety regulations stipulated by professional farming associations require, amongst other things, that any sight glass fittings and electrically operated processes for the production of biogas are gas-tight and explosion-protected.
You can benefit from Papenmeier’s long experience in the manufacture of electrical plant that meets the highest demands on Ex protection. Because of the safety factor,the popular VISULEX Ex-camera system, part of the Lumiglas range, is ideal for use in this sector.
The remotely operated camera transmits data for visual control or analysis from any desired position. Remote-controlled disc wipers with a spray nozzle ensure an unhindered view.
System Combination for Biogas technology
The combination consists of:
Look at the example representation of a fermenter (Youtube) in operation.
These biogas sight glasses are often equipped with explosion-proof LED lighting and cameras, as well as spray nozzles and wipers to keep the window clean despite the often-messy process material.
Biogas sight glass for digester tanks and methane digester tanks. Our sight glass gasket creates a gas-tight seal by conforming to cement walls and ports used in digester tank construction.
Some Background Facts In The Biogas Industry Within South Africa
The food versus energy debate appears to be silenced by studies which claim that South Africa is blessed with an over-abundance of arable agricultural land opening the way for the production of agricultural biogas and biofuel feedstock crops.
Biogas is but one of seven key bio-energy applications in South Africa, vying for the attention of Government and private investors in the sector. Typical local feed-stock inputs comprise municipal and industrial sewerage, waste and process water, manure, plant (sugar cane) waste and indigenous grasses and municipal solid waste and the role of farmers and large waste management companies should not be underestimated. Other sources and partners for this waste include the South African Local Government Association (SALGA), animal farms, pulp and paper producers, food and dairy industries and abattoirs where the opportunities for waste pre-treatment, the recovery of nutrients from digestate and farm biogas installations present good business cases.
Much time has elapsed since 2005 when the PGBI Group was commissioned by the Central Energy Fund (CEF) to develop a bio-energy programme for South Africa. The time for talking is over as indicated by the recent serious biogas initiatives signalling the acceleration of the development of a sizeable biogas industry in Southern Africa.
Early lessons learnt from failed biogas installations both abroad and at home serve as a timely and expensive reminder that construction shortcuts and simply transposing foreign methodologies and designs are not sustainable. Biogas feedstock options in South Africa differ vastly from developed countries where maize silage, ground cereal, rape and rye seeds represent a common feedstock component. Leaking digestate and methane gas are examples of very serious environmental dangers arising from construction shortcuts.
Some of the clear and obvious benefits of biogas are:
- Employment creation,
- Landfill diversion,
- Reduction of waste disposal costs,
- Diesel substitution in busses, trucks and taxis by purified biogas (600 Johannesburg taxis are powered by compressed natural gas – CNG),
- Satisfying a growing co-generation demand, and
- The aeration and addition of magnesium and phosphates to depleted dis-gestate produces fertiliser and compost.
Key challenges which remain barriers to further biogas growth in South Africa are the scarcity of water and the fact that there is simply no generic solution. You cannot simply transpose a biogas technology from one continent, country and region to another, as local climatic conditions and the availability and proximity to feedstock strongly influence the design of the digester, agitators, and anaerobic technology employed (batch reactor vs. continuous reactor, mesophyllc digestion vs. thermophyllic digestion and digester temperature), which require extensive testing before the correct method, technology and feedstock mix is determined.
This relatively young technology is dynamic, so expect continual improvement of current designs and methodologies. This is clear from ongoing research at the German Biomass Research Centre in Leipzig, Germany, where the objectives of further research focus areas on biogas are:
- Flexibility in terms of substrates and litigation,
- Process monitoring and control,
- Reduction of emissions,
- Increasing efficiency and reducing costs, and Coupling of material and energy use of biomass.
- Nevertheless, further evidence of the growing importance of biogas is borne out by its prioritisation over other forms of renewable energy: at 12.8% it outstrips the contribution to the national electricity grid in Germany of solar PV and wind power generation.
Bio2Watt’s 5MW biogas plant in Bronkhorstspruit supplying electricity to BMW SA is the forerunner of a new commitment to tap into the potential South Africa offers. Clean Energy Africa’s New Horisons and Anaergia have turned the soil on construction sites of new biogas plants in the region, each with future plans of three new commercial biogas plant per year. It can therefore be predicted that a very different biogas landscape will exist in five years from now, where the value of the commercial biogas opportunity is tapped to provide South African industry with a viable alternative energy source.