Renewable-energy company Infinergy has won a £1- million contract to design and build a carbon-neutral power plant, in the UK, which will use wood pellets instead of fossil fuels to generate electricity.

The plant is reportedly the first of its kind and will be used by refractory product firm Intermet at its Oughtibridge Sheffield plant, in England.

The initial units for the plant are being manufactured in the UK and all further units will be manufactured in South Africa. After commissioning, Intermet’s benefits will be significantly lower fuel costs and independence from the national grid, and a cleaner operation. But the plant will also be a source of income, as the firm will sell one megawatt of elec- tricity, worth £1.2-million, to the national grid each year.

The system consists of a controller; a multifuel processor for solids, liquids and gases; a cyclonic furnace; a plurality of heat recovery and exchange modules; a piston steam engine; and a steam-pressure generator.

The system recovers heat from waste fluids and gases, improves the combustion of hydrocarbon fuels and the heat availability through the heat exchange.

The combustion and fuel heat recovery modules recover heat through a repeated process of evaporating and condensing the working fluid. Hot fuel gases are passed through the heat pipe of the fuel gas manifold, where heat is extracted and transferred to the water manifold.

“The steam engine provides an energy benefit in the process of condensing the exhaust steam back to liquid for reuse, therefore retaining the latent heat value of about 2 093.4 kJ/kg of water prior to full operational steam reheat,” explains Infinergy codirector Steve Mongan.

Intermet operations director Julian Gray states the technology will enable the plant to use waste heat to dry its foundry products while it is generating electricity through a steam engine.

The biotechnology was a finalist for Best Green Technology at the International Green Awards last year.

“We are currently focusing on industrial and commercial use, and are in discussions with numerous municipalities about the benefits our technology will have on their two main crises: electricity shortages and getting rid of waste,” states Infinergy codirector Lionel Grewan.

The benefits this kind of plant will have for South Africa are significant, adds Infinergy director Chris Taylor.

Infinergy has developed ways to use waste and generate power. Sewage has 12MJ/kg, which can be pelletised and incinerated to generate power, which would make landfill sites redundant and cut electricity costs; and some of it can be sold back to the national grid, thus creating an income.

“Most biomass has an energy element, so it can be pelletised and incinerated to create electricity for consumption by communities at large industrial plants and mines,” he states.

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