In South Africa, a 500 kVa biogas power plant, situated on the Uilenkraal dairy farm near Darling in the Western Cape, has achieved 1,500MW power production in its first year of operation. According to Cape Advanced Engineering (CAE) MD Dr Andrew Taylor, the biogas plant is in a position to produce far more power.
Taylor claims that if regulations allowing on-farm generators to feed excess power back into the grid had been in place, which was price reflective of the plant’s ability to supply power to the national grid over peak periods, higher production would have been possible, Engineering news reported.
Despite government’s Independent Power Producer (IPP) Office including biogas under its cogeneration procurement programme, Taylor said that the positive outlook for biogas investment was recently dampened by a price cap of less than ZAR1/kWh.
In addition to the price cap, Taylor added that a lot of emphasis and effort was being placed on large-scale solar and wind power projects.
Taylor stated: “One of the main barriers to development of the biogas sector in South Africa is the limitation on revenues, due to projects below 1MW not being able to connect or sell electricity to the national grid.”
According to Taylor, the Southern African Biogas Industry Association is campaigning for biogas projects to be incentivised as “peaking” power plants, which connects with solar and wind power projects whose production cannot be scheduled, Engineering news reported.
Taylor added: “We are looking at the cogeneration IPP programme, but we are still concerned that there is a mismatch between the nature of biogas plants, which are small, and the onerous demands of the procurement process.”
Commercial dairy farmers, Willem and Paul Basson, of the Uilenkraal dairy farm said that the biogas plant is meeting 95% of the farms power needs, which includes the farm’s dairy, animal-feed milling and crop irrigation activities.
The biogas plant is able to produce more than 1,000 t/y of methane through a 7,000 m3 fully mixed, fully heated, lined lagoon biodigester, developed and built by CAE.
Before being privatised in 1999, the biogas plant was conceptualised and used as Stellenbosch University’s engine and fuel technology centre of excellence.
Taylor added that average on-farm usage of 240 kVA falls well below the biodigester’s gas production, which is sufficient for at least 600 kVA—which means that about 360 kVA of potential power is not being exploited and more than half of the biogas produced is being wasted through flaring, Engineering news reported.
Taylor said: “With the installation of additional generators only, the Uilenkraal biogas power generation plant is able to generate 1 MVA [of] electricity back into the grid at periods of peak demand, for at least eight hours per day.”