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Wednesday 10 February 2016

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Energy from Waste

Frequently Asked Questions

The FAQs have been grouped into sections. Please select from the list below:


A. The Exeter EfW Facility

What is Energy from Waste (EfW)?

EfW is a process where energy is derived from treatment of waste. Mass Burn Incineration is one form of Energy from Waste, where the combustion process produces high-pressure steam that can be converted to electrical power by the use of a turbine and generator. This electricity can be fed into the national grid or supplied to local industry.

EfW plants can also be used to supply high-pressure hot water or steam that can be used for industrial or domestic heating. This type of facility is known as a combined heat and power plant, because of the two types of energy it produces.

It is proposed that the Exeter facility will initially provide electricity to the national grid, and could also provide heat to neighbouring industrial and municipal facilities in the future.

What has been happening with the project?

The previous incinerator on the site in Marsh Barton has now been demolished. The site is currently vacant, and it is anticipated that the new Energy from Waste facility will be start to be built in March 2012.

Why put the plant in Exeter?

Exeter is the largest settlement in Devon (excluding Plymouth and Torbay), and the Waste Local Plan has identified the site at Marsh Barton Estate as a suitable location for the thermal treatment of waste. This conforms with the proximity principle of waste management (which states that waste should be treated as close as possible to its point of arising) and it also avoids altering existing waste collection rounds.

What happened to the old Exeter incinerator?

The incinerator plant at Marsh Barton Estate closed down in 1996, because it was old and it could not meet new standards introduced during that year. The building that housed the old incinerator was left standing and converted to a transfer station, which remained in operation until 2010 before being demolished.

When will the new facility open and how long will it operate for?

It is anticipated that construction of the new site will begin in Spring 2012, and operations will begin in July 2014 (see the ‘timetable’ page). The plant is planned to operate for at least 30 years.

What types of rubbish are accepted at this facility?

The facility is for the local community so only accepts household and municipal waste (i.e. the rubbish put out by every household to be collected) from Exeter and the surrounding region. The site does not accept agricultural or clinical waste, hazardous waste, sewage sludge, water treatment residues or silts and dredgings.

Will the plant accept waste from outside Devon?

No, the plant can only accept 60,000 tonnes per year of waste, which means that it is only designed to accept waste from Exeter and the immediate surrounding area in Devon.

What will happen to the energy from the plant?

The energy will be initially be transformed into electricity via a steam-powered turbine.  During construction, the potential to export hot water from the plant will be constantly reviewed, so that in the future local business and community facilities may take advantage of this environmentally friendly source of energy.

B. The need for the facility

Why do we need this (or other similar) facilities in the UK?

In the UK most of the waste we produce is still landfilled.  However, existing landfill space is running out.  The EU Landfill Directive requires a phased reduction in the amount of biodegradable municipal waste which is landfilled.

At the same time significant efforts are being made to increase the amount of recycling, but this will not completely solve the problem. There is a practical limit to the amount of waste that can be recycled, so other means of treatment are required in order to meet the landfill avoidance targets.

The Government’s Review of Waste Policy in England (2011), advocates an integrated approach to waste management using several different processes. So to try and reduce our dependence on landfill the Government wants us to look at other processes including recycling and energy recovery

Should we not be trying to recycle more?

Devon's recycling and composting rate for 2010/11 was 55%.  The Devon Local Authorities are aiming to increase this rate to 65% by 2025/26. There is to be no let up in the efforts to recycle and compost more waste.

However, there will always be a proportion of our waste which can’t be recycled that will require other solutions. A modern, appropriately sized and regulated EfW facility provides a good way to achieve the required diversion away from landfill.

Could this EfW plant actually inhibit further recycling in the region?

This is a common claim made against waste treatment facilities in general, but where a sensible approach is taken to the sizing of the facility (i.e. limiting the capacity of the plant) then there will always be plenty of scope to increase recycling to higher levels.

The EfW part of the integrated waste management scheme has therefore deliberately been developed to be appropriate to the amount of waste produced by the region, so as not to ‘crowd out’ recycling. Devon County Council, the District Councils and their contractors are making strenuous efforts to significantly increase the level of materials recycling in the area. However, this also depends to some extent on the market for recycled materials, which is very difficult to control or predict.

Examples of the commitment to the waste hierarchy include:

  • The Don't Let Devon go to Waste campaign raising awareness and providing advice on how to reduce, reuse and recycle
  • Increased source segregated collection of waste from households through additional kerbside collections
  • New and improved Household Waste Recycling Centres which allow the public to deliver bulky or large quantities of waste. For example, please see the press release on the recently opened Pinbrook Recycling Centre
  • A substantial network of ‘bring to’ sites throughout Devon enabling the public to drop off plastic and glass bottles, tins, paper, aluminium cans etc
  • A network of in-vessel composting facilities at Heathfield, Broadpath and Deepmoor, together with use of private facilities and on-farm windrow composting.

For the system to work properly it must be fully integrated; elements cannot be viewed as separate aspects of the process as they are interdependent. This type of integrated scheme is fully in line with UK Government policy and EU Legislation and reflects the move away from landfill towards increased recycling and recovery of waste.

Energy from Waste is therefore just one of these elements in an integrated system.

C. Impact of the site and the process

Is the site safe?

The site and the process is safe. The facility operates proven technology and is heavily regulated and controlled by the Environment Agency to ensure that there is no danger to human health or the environment.

In recent years the standards required for the operation of facilities such as this have increased dramatically, thanks to new legislation from the EU. The performance of modern EfW facilities is in no way comparable to that of older incinerators that have operated in other parts of the UK.

What impact will the site have on local air quality?

The facility will have an insignificant impact on the air quality of the surrounding area and will not increase the risk to human health beyond that which already existed in the area from other activities associated with normal life.

EfW facilities are the most highly regulated industrial plants in the UK in terms of their emissions to atmosphere and are required by law to monitor the levels of any substances emitted.

A thorough Environmental Impact Assessment (EIA) has been carried out for this proposed facility as part of the application process and has concluded that the actual risk to human health from the atmospheric emissions released by the plant is negligible.

This conclusion was checked and supported by independent consultants acting for both the local Council and the Environment Agency. These conclusions are supported by significant and influential organisations and highly qualified individuals in positions of authority and responsibility.

Will this new facility mean extra lorries on local roads?

A full traffic and transport assessment was undertaken as part of the planning application and has concluded that, even assuming ‘worst case’ scenarios, the traffic movements to and from the site will not exceed those which existed when it used to be operated as a transfer station. The full assessment can be found here

Will the site smell?

No, the site will not smell because waste is not stored at the site for very long before being treated. The waste to be burnt is delivered into an enclosed area (the waste hall) and then fed into the kiln; the doors to the waste hall are kept shut, and the area is kept at slightly negative pressure to minimise any odour escape. This is achieved by sucking the air from the waste hall into the furnace as primary combustion air; in effect, any odour which does accumulate inside the plant is burnt.

Who controls the EfW plant and monitors the emission standards?

The Environment Agency (EA) is the regulator for facilities such as this and uses the very tough Intergrated Pollution Prevention and Control (IPPC) legislation to control and monitor operations and emissions. The EA has legal powers to prosecute any organisation that does not operate within the conditions set out in the Integrated Pollution Prevention and Control (IPPC) authorisation.

The Exeter Energy from Waste has now received an Environmental Permit to operate from the EA.

What about dioxins?

Emissions of dioxins are extremely low and well below the threshold at which they could be determined to be a threat to human health. This is supported by a wealth of scientific evidence, and the Environment Agency (which is the body that issues the IPPC Authorisation allowing the plant to operate).

The Authorisation given by the Agency includes strict monitoring of emissions. If these are not maintained, the Agency has the power to shut the plant down.

The Health Protection Agency (HPA) issued a report in 2010 entitled 'The Impact on Health of Emissions to Air from Municipal Waste Incinerators'. It has concluded that “While it is not possible to rule out adverse health effects from modern, well regulated municipal waste incinerators with complete certainty, any potential damage to the health of those living close-by is likely to be very small, if detectable.”

The emission limits themselves are very tight and allow for several margins of safety – i.e. they would have to be exceeded by several orders of magnitude before a significant pollution risk to health, a hypothetical situation because the plant would be forcibly shut down long before this stage were reached.

The Environment Agency has legal powers of access to the plant for inspection with no prior notice 24 hours a day and 365 days a year. Such powers are used by the Agency at plants throughout the country.

It must be remembered that dioxins are emitted by a wide variety of sources, such as power plants, bonfires, diesel engines, cement kilns, steel plants, open fires in the home, jet engines, forest fires to name but a few. The modern standards to which energy from waste plants must now operate mean that dioxin emissions are equivalent to existing, background levels in urban soils.

There is no justification to state that the plant is a risk to human health because of emissions to air, whether dioxins or otherwise.

What are the solid residues from the plant and where will they go?

There are two types of solid residues resulting from the plant operations, called bottom ash and fly ash.

The bottom ash (sometimes called clinker) is an inert substance that has the potential to be recycled as a secondary aggregate, or otherwise used on a landfill site for the construction of site roads or as daily cover. The proportion of bottom ash to the incoming waste is about 20% by weight, although the reduction is volume is much greater, at more than 90%.

The fly ash is a much smaller proportion, at around 2.5% of the incoming waste, although this is increased to around 5% by the addition of spent lime, which has been used in the flue gas treatment (anti-pollution) system. The fly ash is taken by sealed tanker to a secondary treatment plant, and then to a hazardous waste landfill located outside of Devon.

How will pollution be controlled?

The plant has three main methods of controlling pollution, which ensure that it can comply with the extremely stringent standards specified by the European Union, and applied by the Environment Agency through the IPPC Authorisation. These methods are:

  • Always keeping the temperature of the combustion process above 850oC, even when starting the plant up and shutting it down. This is achieved by using gas-fired burners that automatically start if the temperature falls. Burning waste at these high temperatures avoids creating pollutants, thus giving a low ‘starting point’ for the next stage of gas cleaning.
  • By using special reagents to clean the gas stream. For example, lime is used to neutralise the acid components and urea is injected to reduce the NOX (oxides of nitrogen).
  • By using sophisticated filtration systems to remove particulate material – there are more than 600 filter bags present in the system and there is no way for the gas to avoid passing through them before exiting from the plant.

How are the emissions from the plant monitored?

The plant must employ a ‘CEMS’ system – Continuous Emission Monitoring – which constantly checks the level of emissions from the plant, to see that they comply with the strict regulations.

It is a legal requirement that the CEMS system operates at all times; if it is not working, then the plant is not allowed to operate.

The results from the CEMS system are displayed on the company website, and are available as a printed copy from the public register.

What will the plant look like?

Architectural impressions of the new plant can be found as part of the planning application. The building to house the new plant will be slightly lower than the former facility, although it will be longer, in order to house the sophisticated energy recovery and pollution control equipment.

D. National context

Are there other sites like this in the UK?

In general terms, yes. All Councils in the UK are now adopting integrated waste management strategies and, many are planning or building waste treatment plants. In terms of the energy from waste component, there are about 26 EfW plants on mainland UK at present.

Most other EfW facilities in the UK are much larger than the proposed Exeter Area EfW plant.  One exception to this is the plant in Grimsby in North East Lincolnshire. This plant uses the same technology as the proposed plant in Exeter, which is designed and ideally suited for smaller plant capacities of between 30,000 and 75,000 tonnes per year.

The plant in Grimsby operates successfully under a PPC permit issued by the Environment Agency in January 2004; the plant has been in commercial service since April 2004.

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