The new green face of incineration technology

Peterborough Renewable Energy Park (artist's impression)
Peterborough Renewable Energy Park (artist's impression)
Incineration is a dirty word amongst environmentalists, its reputation earned through the use of outdated technology. Could new techniques help bring green approval to energy-from-waste facilities?

Chris Williams is an entrepreneur with a lot on his mind. Within six to eight weeks, he hopes to finalise a funding deal worth £420m that will enable him to build a waste processing plant in Peterborough which he claims will turn 650,000 tonnes of rubbish every year into renewable energy and recycled materials.  A group of six American insurance and pension fund investors is poised to lend him the money, Williams says, against the income he will receive from UK power companies for electricity generated from rubbish and from the sale of reclaimed materials.

'We are extremely close,' says Williams. 'The UK banks are in an atrocious state... [but] the States are eager to be involved.' If the funding deal comes off, Williams should be able to start building the plant this year.

Williams is managing director of Peterborough Renewable Energy Ltd, known as PREL. The company, which won planning permission for the plant from the Department for Energy and Climate Change in November last year, promises to use state-of-the-art technology to extract the maximum possible value from the waste it processes.

First, recyclable materials such as plastic and metal will be removed from the waste using mechanical sorting equipment and sold on to local recycling companies, PREL promises. What remains is classed as biomass, which will be burned at very high temperatures in a low-oxygen environment. This process, known as gasification, is said to extract far more energy per tonne of waste than traditional incineration while producing fewer toxins that need to be scrubbed out.

As the term implies, gasification produces a gas that PREL will burn to heat water to make steam, which will drive turbines to generate electricity. The ash residue can be used as fertiliser, PREL says.

The plant will also use plasma chambers to convert batteries, glass, lightbulbs, grit and sand into new metal alloys, hydrochloric acid, mercury (from lightbuilbs) and sulphur products. Plasma technology uses an arc of electricity to break waste material down into its most basic elements.

Williams argues that the 'green energy park', as PREL terms it, will have significant environmental benefits, principally that it takes waste that would otherwise go to landfill and turns it into green energy. The park is projected to export of 52 megawatts to the national grid after a small proportion of the energy is deducted for powering the plant's own systems. He stresses that unlike incinerators, PREL will only gasify the biomass element of the waste it handles, while plastics and other materials will be recycled.

Those opposed...

Yet PREL has its critics. One objection is that because the plant is so large, with its 650,000 tonne annual capacity, huge amounts of waste will have to be transported over long distances by road in order to feed it. In addition to raising CO2 emissions, critics claim this will discourage local recycling and self-sufficiency in dealing with waste. There are doubts about whether the technology will deliver in quite the way PREL promises. Williams admits his park will be the first to combine all the new technologies onto a single site, but says the individual processes have all been proven at other plants in Japan, the US and elsewhere. 'We are unique in the our combination and scale,
but not in the technology we will use,' he says.

There are further questions over whether there will be enough waste to go round, as both Peterborough City Council and incinerator firm Covanta are proposing to build their own waste treatment plants in the area. The East of England Regional Assembly was consulted on PREL's planning application and objected to the scale of the plant. 'The question is, how will they feed this machine?' says Deborah Sacks, regional planning officer.

The assembly was concerned that PREL will import large amounts of waste from London, where recycling rates are much lower than the national average, at 25 per cent compared to 37 per cent for England. 'Our policy is that each area should manage its own waste. London shouldn't be given the easy option of landfill or cheap incineration in the East of England. It would be more sustainable to recapture and recycle materials in London,' says Sacks. 

She adds: 'I don't have a problem with the technology [PREL is using], but I think the plant should be a fifth of the size they are proposing - then you can locate them in the communities they serve and you won't have massive overcapacity holding back recycling and composting in the region.'

Waste eaters

The planning permission granted to PREL stipulates that 80 per cent of the waste it handles much come from within a 32km radius, or from within the boundaries of Cambridgeshire and Peterborough. Sacks says these restrictions are easy to get around, because waste from say, Birmingham, can be carried to a transfer station within PREL's catchment area and then transported on to the plant. 'The reality is that it's very difficult to follow the path of waste,' she says.

Peterborough City Council did not oppose PREL's planning application but a spokesman for the council told the Ecologist that 'some people in our camp are asking whether they can get the financial backing to make it work.'

Regardless of PREL's plans, the council is making its own arrangements to build a new, much smaller facility of its own for turning the city's waste into energy, with a tenth of PREL's capacity. Three companies have been shortlisted to make final bids. The council has not specified which technology should be used, although the spokesman says the council will be looking for an environmentally-friendly solution. 'We've always said PREL looks good on paper, but they haven't started work yet and we need something up and running by 2014 or 2015, because our landfill space is filling up fast and the conditions on it are becoming tighter,' says the spokesman.

In response, Williams says most of the waste handled by PREL will come from commercial, industrial and agricultural sources, which account for the vast majority of the 450 million tonnes of waste generated every year in the UK. Domestic waste collected by councils accounts for just 12-15 per cent of the total. Waste contracts with councils are expensive and time-consuming to bid for and PREL therefore decided not to bid for the Peterborough facility, Williams says. The proposed Covanta incinerator will target council waste and so not compete with PREL's facility, he adds. 'Within the East of England region, 10 million tonnes a year of commercial, industrial, agricultural and municipal waste is going to landfill. We are about removing the need to send waste to landfill,' says Williams.

Other approaches

Chris Williams is just one of many entrepreneurs who are currently seeking to build greener waste-to-energy plants. One industry source reckons there are at least 75 different waste-to-energy projects in the early stages of development in the UK. This frenzied activity has been prompted by the rising cost of sending waste to landfill and the introduction of subsidies for new waste-to-energy technologies including gasification, its close cousin pyrolysis, and anaerobic digestion. Since April 2009, two ROCs, or Renewables Obligation Certificates, can now be claimed for every megawatt hour of electricity generated by these methods. The ROCs are worth about £40 each and can be sold on to the major electricity companies in order for them to meet their targets for renewable energy.

The UK government is anxious to encourage waste-to-energy as part of efforts to reach 15 per cent renewable energy by 2020. According to research group New Energy Finance, only 8 per cent of our municipal solid waste was sent for conversion into energy in 2008, while Denmark, by contrast, sends more than half of its waste for thermal treatment. In 2007 the UK government published a new Waste Strategy which called for 25 per cent of municipal waste to be converted into energy by 2020. Meanwhile landfill taxes are rising rapidly, from £24 per tonne in 2007 to £48 currently to £72 in 2013, which will provide a strong incentive to find alternatives to burial. Most of our landfill sites have some form of methane harvesting plant upon them, but these only qualify for one-quarter of a ROC per megawatt hour of electricity generated.

Incineration currently dominates the UK waste-to-energy market, but the technique should eventually be surpassed by the emergent technologies. There are 20 incineration plants in the UK, with five more under construction or commissioned, but incineration is not classed as a renewable technology and does not qualify for ROCs. Last month a company called Enviroparks won planning permission to build a 250,000 tonne waste processing and energy plant on 17 acres at Hirwaun in south Wales. The company wants to use technologies such as pyrolysis and anaerobic digestion, while the waste would come from local authorities, industry and agriculture. Enviroparks also aims to attract a commercial tenant onto the site, to whom it will supply heat and possibly electricity. David Williams (no relation to PREL's Chris Williams), director of Enviroparks, is now seeking to raise £90m from funders and hopes to start building late in 2011.

Yet Covanta is planning an incinerator with a capacity of 650,000 tonnes near Bristol that Williams admits could be a competitor for the region's waste. Williams is cautious about whether firms like his own and PREL will be able to break the incinerators' stranglehold on the waste-to-energy market. 'I think companies like ours have a long way to go to take over. Only ourselves and PREL have got planning permission at the moment... it'll take a number of years.'

Mark Jansen is a freelance journalist

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