Biogas projects could add 200 MW to SA power mix

About 200 MW of electricity could potentially be generated from biogas-from-waste projects around the country

About 200 MW of electricity could potentially be generated from biogas-from-waste projects around the country, with a number of projects potentially being able to generate up to 10 MW of electricity on site, developer and operator of industrial organic waste to energy systems CAE Energy MD Dr Andrew Taylor said on Friday.

He emphasised, however, that the National Energy Regulator of South Africa’s (Nersa’s) decision on the renewable energy feed-in tariff (Refit) for biogas and power utility Eskom’s response to that decision would be “pivotal” to the success of these projects.

Nersa had held public hearings on the second phase of Refit, which would include biogas, earlier in September.

CAE Energy had partnered with Humphries Boerdery, near Bela-Bela, in the Limpopo province, to develop a project to convert biogas to electricity, with the plant already having produced 10 MWh of electricity since August, said Taylor.

Humphries Boerdery, along with other partners, had previously constructed and commissioned a biodigester at its piggery, which successfully processed and sanitised waste from the piggery with about 1 400 breeding sows and about 10 000 pigs in total.

It had then partnered with CAE Energy to develop a power generation project at the piggery, which was currently capable of producing more than 500 kilowatts of electricity.

However, only about 10% to 20% of the biogas was currently being used to produce electricity, with the remainder being flared and wasted, as the Refit structure has not yet been finalised by Nersa, Taylor said.

He noted that both Humphries Boerdery and CAE were, however, hopeful that the regulator would announce a tariff of about R1/kWh at the end of this month, and that Eskom would respond favourably to this decision and enter into power purchase agreements with power producers.

While Nersa had initially proposed a 96c/kWh tariff for biogas, Taylor noted that a number of producers had made submissions at the hearing that a higher tariff would be needed.

This was owing to the fact that, unlike with landfill gas where no or little material handling was required, biogas producers had to pump material in and out of the power plant on a daily basis, as well as dispose of material.

CAE was hopeful that a tariff of between R1,20/kWh and R1,40/kWh for biogas would be set.

Once the tariff structure was decided on and PPAs signed with Eskom, this would allow the project developers to increase the size of the power generation plant.

Taylor noted that CAE was hoping to boost the output of the plant to about 500 kW by the end of this year and to 750 kW by early 2010.

The power plant was already fully imbedded into the national grid, but used an electronic switchgear, which managed the amount of power generated by the plant. This allowed it to ensure that the farm imported between five and ten kilowatts of power from Eskom at all times, but did not push any of its generated power to the grid, as it did not yet have a generating licence.

The rest of the piggery’s power requirements of about 75 kW, above the five to ten kilowatts imported power, was generated by its own plant, saving the piggery some electricity costs, said Taylor.

The switchgear adjusted the power generation of the plant in accordance with the rise or drop in consumption of the piggery.

Taylor highlighted that the plant would be able to immediately export up to 70 kW/d to the national grid as soon as it receives permission to do so. This could increase to about 700 kW within a few months.

The electronic switchgear was the only imported equipment at the power generation plant, with all other equipment and software having been designed and constructed in South Africa, said Taylor.

He noted that CAE had put an emphasis on assembling and developing local technology, reducing the need to import equipment on a Euro-based cost.

This approach could save developers up to 30% when compared with imported equipment.

Taylor explained that the electronic switchgear was, however, imported as this was equipment that Eskom had previously scrutinised and approved for use.

This was imported from the US through another partner on the project, Denco Automated, said Taylor.

Meanwhile, Taylor noted that the Humphries Boerdery was a “pioneering project”, with many other opportunities to develop similar power generation projects in South Africa available.

CAE was aiming to provide services as a complete turnkey project developers for other piggeries in the country.

Taylor noted that there were at least 40 other piggeries that could immediately follow the model used at Humphries Boerdery. CAE was currently negotiating with 20 piggeries in Gauteng and KwaZulu-Natal, while another piggery in the Western Cape had shown an interest in rolling out the model at ten of its farms.

While piggeries were the most attractive projects, total mixed ration diaries, intensive chicken farming operations and wastewater treatment plants could also benefit from biodigester and power generation projects.

All these operations had significant opportunity to develop projects under the Clean Development Mechanism and trade carbon credits.

LEGISLATION

Taylor, meanwhile, highlighted that the Refit legislation, as well as amendments to the National Environmental Management: Waste Act No 59 of 2008 would further promote the benefits of biogas projects.

The amendments made to the National Environmental Management: Waste Act would make it essential for implement proper biodigesters and conduct proper processing of waste.

The Refit would also allow for reasonable profits that could justify the initial investment in power generation equipment, if projects were run in a professional manner, said Taylor.