Energy from Waste

Letting A Resource Go Up In Smoke

As the world becomes more environmentally aware, there is a growing recognition that waste is a valuable commodity.  Traditional methods of dealing with waste such as landfilling or burning and burying produce unacceptable harmful emissions.  Instead, different waste streams should be regarded as differentiated resources which can be re-used or re-manufactured.  For many other types of waste, recovering their value to provide electricity, heat and/or transport fuels is an easy, valuable and more environmentally sound solution than recycling or landfilling.

Energy from Waste (EfW) uses combustion technology and is the only ‘renewable’ technology which can realistically meet the EU and UK 2020 commitments for ‘heat’ and ‘transport’ sector requirements, whilst at the same time also providing significant quantities of electric power. provide remarkable solutions.  In mainland Europe, recycling and EfW are both used to their optimum potential, and, as a result, landfilling is successfully minimised.

For larger waste streams, combustion technology inherently produces both heat and power, in the ratio of two to three times as much heat energy as electrical, which could make a significant contribution to solving the problem of fuel poverty in the UK.

What are the problems with waste in the UK?

Producing 307 million tonnes of waste (per year)  or ‘enough to fill the Albert Hall every two hours’ is not sustainable.  Of that, Defra estimated that 46.4 million tonnes of ‘household and similar waste’ were produced in the UK with 60% of this landfilled, 34% ‘recycled’ and 6% used as fuel in EfW plants.

Types of waste

Approximate percentages of waste arising in the UK indicate that around 36% is from construction (high proportion of minerals, plus wood waste); 28% is from mining and quarrying, (nearly all mineral waste); 24% is household and commercial (food waste, plastics, metals, glass and paper); 10% is industrial; and around 2% is either agricultural or human sewage.  Waste has been regarded as a problem that has to be buried in a landfill.  However, with European directives to meet targets in landfill reduction now enshrined in UK law, we believe that there is a real opportunity to avoid landfilling in the future and to regard waste as a resource from which to produce electricity, heat and/or transport fuels.

Resourcing our waste

In an EfW plant, solid wastes such as wood waste from construction and demolition sources are ideally suited for thermal processes.  Most plastics have a very high energy content which makes them very suitable for the combustion process. Non-combustibles, such as metals, glass and other inert materials, are unsuitable for EfW plants and are normally recycled by other means.

The myths of recycling

Once ‘recyclables’ are delivered to the Material Recycling Facility – which is normally a separating and sorting centre – they are officially declared as ‘recycled’ (i.e. they are counted towards the local or national recycling targets which treat ‘sent for recycling’ the same as ‘recycled’). With very few recycling plants in the UK, many recyclables are actually transported for considerable distances within the country. However, more seriously huge quantities of some major recyclables (particularly paper and plastics), which have already been classified as ‘recycled’ and counted towards UK and local targets, are being shipped to countries such as China, where we do not know whether they are actually recycled or merely used as cheap fuel.

Going to war!

Waste-as-Resource (WaR) facilities are ‘all-in-one’ facilities for energy production and recycling.   A WaR facility recovers as much energy as possible from the thermal process: a higher proportion of energy normally produced as electricity, but much of the thermal energy (waste heat) is recovered and used in district heating schemes and/or in the various industrial processes in the plant. WaR facilities significantly reduce or eliminate sending ash to landfill, and also incorporate a concrete plant where bottom ash is used as aggregate in a variety of building and construction products.

Denmark: a case study

In most European countries, it is normal to build EfW plants as part of the communities that they serve, so the waste from the community is used as fuel in the EfW plant, which then supplies electricity and heat back to the community.

Denmark was probably the first nation to recognise the resource potential of waste, and has the most notable example of the intelligent use of EfW in Europe. Most, if not all, EfW facilities in Denmark are built close to centres of population, so the waste journey is small and energy produced can be more readily utilised. The electricity produced is used in the local community as is the heat from the thermal process which is distributed in large-scale district heating (DH) systems.  The Danes have become world leaders in designing pipelines to deliver heat to buildings over unprecedented distances (over 100 km) with negligible temperature drop.

Is this a wasted opportunity?

The UK has committed to climate change mitigation targets for 2020.  Over 90% of the UK’s energy supply is provided from fossil fuels, and since these are the biggest single contributor to climate change, it follows that increasing energy demand of whatever form will be largely supplied from fossil fuels and will therefore exacerbate, and not mitigate, climate change. EfW, on the other hand, is utilising a renewable resource as fuel and is, therefore, making a significant contribution to climate change mitigation.

So what needs to be done?

We have a growing pile of waste which needs dealing with and energy production should be a solution. The enormous amount of thermal energy (heat) produced by a combustion process is wasted to the atmosphere, but simple technology can capture much of this and use it for space heating in a district – or community – heating scheme.

A long-term commitment to make use of this energy by developing community heat networks could offer a viable and direct solution to the fuel-poverty issue, alongside much needed and highly cost-effective measures to improve the insulation and thermal efficiency of our existing housing stock. Moreover, a community/regional programme would provide a sustainable economic benefit to construction and engineering companies, could be initially targeted at high fuel-poverty areas and resolve many local waste disposal issues throughout the UK.

Recycling will never be the sole solution for the UK’s waste issues– there is quite simply too much waste to deal with and too many waste streams that do not benefit from recycling.  Technologies and options are available to segregate the streams which should be recycled from waste that can be used as a valuable and secure energy source.  Plus, existing landfills could house EfW plants.

A long-term education programme on the merits of recycling is required to allow EfW plants to be created to both generate energy for local communities and remove large amounts of waste being produced by the same communities. Looking further ahead, full-scale Waste-as-Resource plants would deal with the vast majority of what we currently still think of as ‘waste’. Let’s not waste the opportunity. The time for Energy-from-Waste is now!

Download the Energy from Waste report (pdf, 2MB).