COVER STORY c l e e tric Coal mine methane is a viable feedstock for electric power generation in South Africa, says Barloworld Power, Caterpillar’s southern African dealer for Energy and Transportation. Barloworld Power experts sharing the advantages of converting coal mine methane to electric power (from left): Nalen Alwar (business development manager: Gas); Mark Mencel (executive director: Barloworld Power southern Africa); Pravesh Kalyan (project manager); and Steven Moss (product support operations manager). T he gas segment is still relatively untapped in southern Africa, with only 2% of South Africa’s energy demand currently met by gas. Nalen Alwar, Barloworld Power’s business development manager: Gas for southern Africa, says the potential value of harnessing methane from coal beds is significant as South Africa is the sixth largest coal producer in the world with reserves estimated at 30 Bt, half of this mined underground. It is estimated that mining of known reserves will continue for well over 100 years. The opportunities are not only in South Africa, but also in coal mining operations in Mozambique, Zimbabwe and Botswana. Methane is a naturally occurring gas formed during the mining of coal. It is highly flammable and hazardous to mining operations, which means that coal seams have to be degassed prior to mining. As a greenhouse gas, methane released into the atmosphere does 20 times more 6 MINING REVIEW AFRICA | AUGUST 2015 damage than carbon dioxide. This is cause for serious concern as coal mining is still the world’s biggest contributor to feedstock for electrical power generation. Unburnt methane can remain in the atmosphere for up to 15 years. The technology to harness coal mine methane for the generation of electric power is gaining traction globally. Alwar points out that greenhouse gas emission in the USA decreased by more than 20% between 1994 and 2005 due to increased recovery and utilisation of coal mine methane. “Methane can be safely extracted and, following a treatment process, fed into Cat gas generator sets to produce electric and thermal power. Infrastructural and energy effi ciency projects can be undertaken by coal mining companies to generate some of their own electricity or provide revenue earning opportunities as independent power producers (IPPs).” He says new methane gas to power projects have the advantages of short lead times in the supply and commissioning of proven and reliable Cat gas engine solutions; assisting the growth of a gas economy; wide acceptance as technology for cogeneration in parallel with the grid supply; private sector participation in the generation of electric power; reduction of stress on the grid; and the potential for hybrid solutions with other IPP technologies. Return on investment in the system would include risk mitigation due to power security, energy effi ciency using freely available feedstock, and possible revenue through grid sales. Lifecycle costs include maintenance and equipment overhauls which, if properly managed, would keep downtime to a minimum. Diagram 1: A possible cost curve scenario depending on utility tariff projections, gas cost indexation and escalation