How to get the most from waste-to-energy

Generating energy from waste is attracting increasing attention. But incineration causes concerns. Andrew Hamilton says his company has a technology that bypasses the issue

The average European citizen currently produces 500kg of waste a year, and that amount is growing faster than the EU economy.

The European Commission is attempting to transform the waste management industry. And, to encourage best practice, it has adopted a five-tiered hierarchy of methods: prevention, reuse, recycling, recovery and environmentally sound disposal.

This is having a direct impact on the UK’s waste management industry. By 2020, under the existing European Waste Directive, local authorities in the UK are going to need to divert up to 33M tonnes of waste from landfill and find other waste processing methods. At the moment, the UK only recycles 27% of its domestic waste – one of the worst rates in Europe. There is no question that waste management is becoming an increasingly important issue both in national and regional politics.

Hard pressed

At the same time, the UK government has a target of generating 10% of its power from renewable sources by 2010, a figure it has admitted it will be hard pressed to meet.

There is increasing pressure for this kind of power, combined with the need to find alternatives to landfill for waste. Hence, the concept of generating energy from waste (recovery) is attracting a lot of attention, and some opposition, in the media and within local communities.

That opposition is hardly surprising given that the government has thrown its weight behind waste-to-energy as a solution to landfill diversion without a proper assessment of the technologies on offer. As a result, the public’s overwhelming opinion seems to be that waste-to-energy means incineration.

As well as concerns over efficiency of generation, emissions, and adverse impacts on recycling, incineration still produces large amounts of ash residue – up to 25% by volume of waste – which can contain toxins and other heavy metals, and which has to be dumped in landfill.

A majority of the waste-to-energy plants operating in the UK offer only a partial solution to meeting our waste targets. In fact, most of the waste management technologies in general offer only partial solutions, or only one step toward the complete transformation of waste to energy. Indeed, many just offer processing technologies toward an end-point of either landfill or incineration.

The UK Waste Review certainly takes a narrow view of what technologies come under the term “energy from waste”. The two technologies seemingly considered critical for the generation of energy from waste are mechanical biological treatment (MBT) with refuse-derived fuel (RDF) production and waste incineration with energy recovery.

MBT, often seen as the green choice due to its lack of thermal treatment, only provides a partial solution, through processing waste to create an RDF. But MBT can result in sending up to a third of its waste by volume, after processing, to landfill.

Even if the RDF generated is sent to an incinerator, most incineration plants then produce significant quantities of ash. And this is also sent to landfill.

They mostly operate steam-cycle turbines, which, on anything other than very large scale, achieve relatively low generating efficiencies. While this combination of technologies represents a workable solution, it is only a partial one given the substantial quantities of residues still going into landfill. It is also likely to be more expensive as MBT technologies producing a refined biomass or RDF do not come cheap. And combining this with incineration is layering on costs.

Incineration also suffers from an image problem. Many local communities object to the development of incinerators. Despite the efforts of the Waste Incineration Directive to limit emissions from plants, the massive transportation of waste is deemed unacceptable to many of them.

Large regional incinerators demand expensive logistical programmes, and a network of transfer stations, all adding to cost.

As landfills reduce in number, this is likely to become an even more serious issue in many parts of the country.

The government needs to look at alternative complementary technologies, which can provide near total solutions. Advanced Plasma Power’s (APP) Gasplasma Process currently offers the only solution for the complete transformation of waste to energy.

It converts the organic matter in waste streams to a clean synthetic gas for renewable energy generation. And it converts the inorganic matter to an inert vitrified aggregate for use in the building industry. The Gasplasma process produces small volumes of benign emissions comprising almost entirely hot air. Little to no polluting gases or emissions are produced, and almost nothing is left (less than 1% of input volumes) to go to landfill.

Very efficient

Just as importantly, the power generation is very efficient. APP plants can work with a variety of local-authority recycling programs. Waste is sorted and shredded before being put through the Gasplasma Process.

The removal of recyclates such as metal and glass actually improves efficiencies. This is because, if they were left in, they would absorb energy not release it. As the gas generated is so clean, there are no tars and particulates left to foul or clog the gas engines.

APP-generated synthetic gas goes straight into gas engines, which achieve gross electrical efficiencies of up to 40%. And, with use made of the heat generated as well, more than 60% of the energy can be recovered. Only about a third of the power generated by the APP system is used on site to power the process enabling the plants to be a substantial net exporter of power back into the local community.

Unlike other facilities, the process requires a limited area roughly the same size as a retail warehouse. So, from a planning point of view, APP’s facilities can be built on a scale to meet the needs of local communities. This avoids the large regional solutions that require waste to be transported from a wide catchment area.

With commercial waste predicted by the government to increase by 50% by 2020, the ability to build small-footprint plants in industrial areas could, over the next 12 years, transform not just the financial position of the local authorities, but the wider economics of the waste industry.

APP provides the only complete end-to-end waste to energy solution and, over the long term, offers the most sustainable and cost-competitive solution for local authorities.

Waste-to-energy can provide a solution that works for local authorities and local communities, using waste as a resource and generating clean power to put back into the community. We can help create a truly sustainable environment, but only if the right technologies are backed.

The European Parliament recently rejected a proposal to re-identify municipal waste incinerators under recovery mechanisms rather than disposal, due to concerns on future energy efficiency criteria. Yet, in the UK, the focus on incineration has led to recent debates on whether planning rules should be relaxed to allow the fast-tracking of applications and the development of more incinerators.

Given the wider consensus that incineration does not qualify as recovery, the government can no longer afford to concentrate its attention so narrowly on a solution that will, eventually, be bypassed.

Local authorities and communities must be encouraged to exploit new approaches. And that means that the government must broaden its horizons and accept that efficient, clean and cost-competitive alternatives to incineration exist. Once it does, we could be well on the way to truly sustainable waste management.

Andrew Hamilton is CEO of Advanced Plasma Power. www.advancedplasma

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