Fuel cell plan to turn household waste into cheap electricity
Monday 22 December 2008
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| Fuel cells may be three to five years away from full commercialisation, but alkaline fuel cells like this AFC Energy system could transform the economics of energy-from-waste |
A new company has been launched to take forward an energy-from-waste it claims could eventually see renewable energy plants developed at a cost as low as £250,000 per MW of capacity, writes James Cartledge.
Waste2Tricity has former defence minister Lord Moonie as its chairman elect and a board that includes former environment minister Tim Yeo MP, as well as both waste management and fuel cell industry experts.
The company is planning to develop community or business-scale plants around the country to turn household or commercial waste into a hydrogen-rich gas that can then be used to generate electricity on-site.
It will turn the waste into the hydrogen "syngas" using an advanced gasification system.
The company's first gasification plant is expected to require £50 million investment, and will initially use a combustion engine to turn the syngas into electricity, but will use fuel cells to generate more efficient power within "three or four years".
Waste2Tricity's business plan should ultimately see the company setting up a series of plants around the country, designed to generate 2MW to 5MW of power from up to 50,000 tonnes of waste feedstock a year.
Using fuel cells would increase the efficiency by at least 60% compared to an internal combustion system and 130% compared to a steam turbine based system, the company believes.
It estimates that a tonne of waste could produce 2,100kWh of power, with electricity costing as little as three pence per kilowatt-hour at today's prices. As well as its efficiency, the company says its gasification-fuel cell process will improve on other energy-from-waste processes in having fewer emissions and no fly ash.
Lord Moonie said: "Our system will have significant environmental and cost benefits over other methods of electricity generation."
Energy
Waste2Tricity's lead consultant, Howard White, brings fuel cell expertise with him to the new company, having founded alkaline fuel cell manufacturers AFC Energy in 2006. Waste2Tricity itself looks likely to source its alkaline fuel cells from AFC, and could see a full system up and running by 2011/12, Mr White said.
The Technology
Gasification: Heating solid waste in controlled conditions, causing a hydrogen-rich synthetic gas ("syngas") to be emitted, leaving behind an inert slag. Syngas can be burned to produce electricity.
Plasma gasification: Passing waste through a plasma chamber, in which electricity passes through to obliterate the material and produce a supposedly cleaner syngas that can be further cleaned up to produce hydrogen suitable to feed into a fuel cell.
Fuel cell: A conversion device that converts a fuel like hydrogen or methane into electricity – almost like a battery, except that they require a constant supply of the fuel.
Mr White said the return on investment with a combustion unit for a plasma gasification plant would be 14%, but when the fuel cells were added into the equation, returns would be 25%.
"We are launching this company purely from a commercial perspective," he said. "We are talking to waste management company Biffa already, since we would be looking for Biffa to supply a homogenous stream of refuse-derived fuel, or a homogenised mix of waste."
Mr White explained that plasma gasification involves solid waste being turned into a synthetic gas at high temperatures, leaving behind an inert slag representing 5% of the original mass of material. He said this material could be used in construction materials.
Waste2Tricity is to use a plasma gasification process from Alter-NRG Westinghouse that saw a similar-scale plant starting up in Japan last month. Mr White said the gasification process had been confirmed by advanced waste treatment technology specialists Juniper Consulting.
The company is also in discussions with US firm Air Products to secure systems to prepare syngas from the gasification process ready for use in fuel cells.
Surrey-based AFC, which is currently working to supply fuel cells to the chemicals industry, would provide fuel cells to Waste2Tricity plants and pick up a royalty fee.
"Alkaline fuel cells are the most proven fuel cell technology," Mr White said. "They are low-temperature, low-cost systems, eliminating instability, and they're very maintainable systems and can achieve a 55-60% conversion efficiency when purely generating electricity."
Waste2Tricity plants could be positioned wherever there are local demands for 2-5MW of power, from housing developments to commercial or industrial premises, the company says.
Waste
As well as providing important baseload generation capacity for the UK grid, the combination of gasification and fuel cells could completely transform the economics of UK waste management according to Peter Jones, the OBE-winning formed Biffa director now on the Waste2Tricity board.
Previously, drying out waste in pre-treatment plants to form refuse-derived fuel for gasification plants, which would then burn resulting syngas, has been seen as an expensive middle step in the incineration process.
With fuel cells increasing the efficiencies of combustion systems from around 30% up to 50% and more, energy-from-waste plants would sell more electricity for their waste, gaining more income from subsidies like the Renewable Obligation Certificate (ROC) system. From April next year, the government will offer double ROCs for advanced gasification plants.
Mr Jones told New Energy Focus: "This system would mean gate fees for waste are a thing of the past - companies will be bidding for waste. The double ROCs you get, along with feed-in tariffs, heat incentive tariffs, electricity, heat and gas prices means you could see non-recyclable waste worth £200-£300 per tonne."
A well-known figure in the waste industry, Mr Jones is currently talking to regional development agencies to forge partnerships that might see public sector land used to host the gasification plants, which would then deal with local waste while providing a good income.
Private sector companies are also being courted to operate plants, supply waste or use energy from the plants under localised ESCO-like arrangements.
This system would mean gate fees for waste are a thing of the past.
Mr Jones' former bosses at Biffa are talking to Waste2Tricity about the prospects for supplying waste to the new company. Biffa already works with gasification company Energos on the Isle of Wight, but the Waste2Tricity process involves plasma gasification, which offers a low-tar syngas suitable for fuel cell use.
The former Biffa director said up to 40 million tonnes of suitable waste was currently going to landfill in the UK. He suggested that a single Waste2Tricity plant might service an entire district council's residual waste needs, providing an income rather than authorities paying out for landfill fees and Landfill Tax.
Lord Moonie agreed, saying: "It has the potential to play a major role in the reduction of waste going to landfill, and provide local authorities with a revenue stream."
For the commercial sector, such a plant could also provide both a solution to waste and the decarbonising energy requirements of the Carbon Reduction Commitment, Mr Jones explained.
"Under the Carbon Reduction Commitment, there will be a lot of energy users this would help," he said. "Put one of these in your distribution centre, and you could back-haul waste from your restaurants to provide the fuel, and the energy could then run the refridgeration for your distribution centre."
A series of announcements is expected during 2009 as the company puts in place financing and prepares to build its first plant.
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