Waste derived fuels
Cement is a widely used construction material, and manufacturing it is an energy-intensive process. We have been addressing this for several years at Dunbar, through replacing fossil fuels with waste-derived fuels and reducing greenhouse gas emissions.
Waste-derived fuels can be a range of things and waste tyres are used as a partial replacement for fossil fuels in the cement-making process. Solid Recovered Fuel (SRF) for example, is a specially prepared blend of non-hazardous materials, which would normally be land-filled, used as a fuel for the cement-making process.
In the past, coal was the main source of fuel at Dunbar. Today, around 45% of Dunbar’s energy requirement comes from waste-derived fuels – something we are proud of. We have worked hard to replace the fossil fuels used in our kilns with lower carbon and carbon-neutral waste-derived fuels for many years.
Here is an overview:
- As a replacement for fuel Dunbar began using processed tyre chippings in the 1990s. Tyres were banned from landfill in 2005, and we now take a large quantity of Scotland’s used tyre stock and consume them completely in the kiln, where they produce as much energy as coal. Tyres contain biomass, which helps us reduce Dunbar’s carbon footprint.
- A few years later we began to use Recycled Liquid Fuel (RLF). RLF is the manufacturing by-product from a number of household items such as paints. Like tyres, RLF has a high energy value.
- In 2012, under guidance from the Scottish Environment Protection Agency (SEPA), we started evaluating Processed Sewage Pellets (PSP) and have been using this fuel successfully since. PSP is a carbon-neutral fuel made from the remnants of sewage treatment. It has a similar energy value to coal.
- Several years ago, we began looking into the introduction of Solid Recovered Fuel (SRF) at Dunbar. This is a specially prepared blend of non-hazardous materials such as paper, cardboard, plastics, textiles and wood chips that cannot be recycled and would mostly go to landfill. Similar fuel is used successfully in power generation and cement manufacture in the UK and elsewhere in Europe.
- In 2014, a new Waste Code of Practice came into force which promotes the wider use of these fuels.
- In early 2019 we signed an agreement with local company Hamilton Waste and Recycling to supply us with Solid Recovered Fuel (SRF). In September 2019, we successfully commissioned a new SRF storage and handling installation on site and have since been using this as our latest waste-derived fuel. Like end-of-life tyres and PSP, SRF contains a high biomass content which helps to reduce our overall CO2 footprint in comparison with using fossil fuels.
- Use of these fuels reduces the Plant's reliance on fossil fuels, increases sustainability, and allows us to harness valuable energy from materials that may have otherwise been destined for landfill. (See news section for more on this.)
Waste code of practice for cement kilns
In March 2014, following detailed consultation with the cement industry, the environmental regulators responsible for monitoring and controlling the use of waste derived fuels in the UK - Scottish Environment Protection Agency, Environment Agency, Natural Resources Wales, and Northern Ireland Environment Agency - introduced a new Code of Practice governing the way waste is used in cement kilns.
The new Code of Practice works by identifying and ‘pre-approving’ a list of 101 waste types that can be used in cement kilns as non-fossil fuels or waste-derived fuels. Prior to March 2014, consultation on the use of new waste fuels was conducted on a fuel by fuel basis.
The changes will make it easier to use waste from a range of approved sources so that companies are able to move more quickly to take advantage of a variety of pre-approved waste fuel sources as they become available.
These changes are very important because they will help us further reduce our use of fossil fuels, which, in turn, will cut carbon emissions and divert more waste away from landfill.
What does this mean for you?
You will see no change to the way Dunbar operates. The same checks and monitoring will remain, and there will be no additional vehicle movements.
The new Code of Practice simply means that, rather than seeking approval to use/ consulting on waste streams on a case-by-case basis, all operators, including Tarmac, will be able to use any of the 101 pre-approved waste materials from the environmental regulators’ approved list.
We will still be required to satisfy strict criteria before we can use any of the pre-approved wastes, including stringent risk-assessments, ensuring safety measures are in place, and providing specific training for our employees.
Importantly, will continue to ensure that we keep you up to date with our plans and the wastes that we are using. If any wastes require major changes at the site - for example, new equipment - then we would continue to consult with you on this.
Changes for the better
The strict regulations regarding safety in the transport, handling and storage of any of these materials have not changed and remain in force, as do all the well-established safeguards and stringent monitoring requirements around emissions from the kilns at Dunbar.
The new Code of Practice will have no impact on the communities around our cement plants in terms of emissions, odours or any increase in vehicle movements.
Ultimately, the changes will mean that more waste-derived fuel can be used in our kilns, leading to less waste going to landfill and ultimately lower carbon emissions to help in the wider battle to tackle climate change.
For more answers on how our site affects the local environment, please visit our FAQs page