Waste: The Options - Burn it - incineration

Could your waste stream be used as a potential source of heat and power?

In the UK, we burn around 4 per cent of our controlled household waste, or about 2.5 million tonnes per year. This includes some top-ups from industry and commerce.

There are, however, obstacles. In the UK, it is the public's belief that incineration is environmentally unacceptable. Waste incineration is seen as dirty, contributing to acid rain, the greenhouse effect and respiratory complaints. This popular view is behind the times - modern furnace technology, combined with efficient wet and dry 'scrubbing' systems, produces very clean emissions. Garden bonfires (weight-for-weight) give off more pollutants than a modern waste incineration plant.

However, modern incineration is capital-intensive. Sophisticated plants, capable of burn temperatures of 1300°C and fitted with flue gas filters, are now required to satisfy Environmental Protection Agency controls on atmospheric emissions. More than 50 per cent of municipal waste incinerators constructed since the mid-'60s have now been mothballed for not matching European standards of incineration. All will have to close unless they are upgraded.

Recently, the prospect of rising landfill costs has prompted authorities to reconsider burning waste. Government support, in the form of the Non-Fossil Fuels Obligation (NFFO), means incineration projects are being re evaluated as combined heat and power plants, although the long term future remains uncertain.

Municipal Solid Waste incineration

Garden bonfires give off more pollutants than modern incineration plants!

Guaranteeing the return from incineration

It can cost from £70 to £1l0m to build a modern incinerator, requiring about 300,000 tonnes of waste per annum to break even. Payback is as much as twenty years, so installers look for certain conditions for the investment to succeed:

• an appreciable saving on landfill costs
• a predictable market for heat and power
• a guaranteed supply of waste to keep the plant burning at maximum capacity

Nearly all waste-to-energy plants are in local authority hands and these face significant upgrading to meet new standards. Civil engineering and power companies are eyeing this market. Investing in energy-from-waste schemes may make economic sense and appeal companies or regions facing:

• high heat/energy needs
• above average landfill costs/ local landfill shortages
• above average energy transmission costs
• large urban concentrations

How green is modern incineration?

Devotees of incineration insist that it is an environmentally friendly mode of disposal. Their arguments are:

• modern technology produces minimal emissions
• much ash is recyclable for ferrous metals' recovery, road construction or building materials
• cost estimates (net of electricity revenue) suggest burning is competitive with landfill at gate prices of £30 per tonne
• burning waste eliminates methane, a 'greenhouse' gas, produced by landfill

Conclusion: the burning issue

Heat-from-waste schemes may offer the best benefits to regions further from the main electricity and gas generating centres, located in Yorkshire, Humberside, and the Trent valley and the East Coast or those lacking convenient landfill.

The introduction of a landfill levy, or the inclusion of energy from waste in the Governments recycling targets, would promote waste incineration as a means of disposal. However, incineration cannot deal with all types of waste and produces up to 30% weight of ash and clinker to be landfilled.

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