The UK Government’s announcement that all coal-fired power plants will close by 2025 has raised questions about the sustainable supply of fly ash and furnace bottom ash to the construction industry. Dr Robert Carroll, Technical Director at UK Quality Ash Association (UKQAA), has explained why there is no cause for concern in the following announcement.
“As the construction products industry will undoubtedly be aware, there is an important link between the extent of coal powered energy generation and the production of fly ash and furnace bottom ash. What’s not necessarily widely understood however is the impact coal-fired power plant closures could have on the availability and supply of ash. The impact is less than you might think.
Fly ash and furnace bottom ash are by-products of the combustion process at coal-fired power plants. Ash provides substantial technical benefits when used in cement, concrete and other production products and reduces significantly the demand for virgin raw materials. Fly ash is a pozzolanic material and works well to improve the technical performance of construction materials. It creates durable products, which can resist chloride induced corrosion and chemical attack and minimises the risk of early age thermal cracking.
These ashes currently come from sustainable sources and are more environmentally friendly to manufacture than virgin raw materials. As a result, coal ash based products have lower embodied CO2 compared with traditional cementitious mixes and can help to significantly reduce the overall levels of carbon in a building or engineering project.
Benefits aside, there are real concerns about what the closure of coal-fired power plants could do to the well established ash market. The UK, along with other European countries, is currently striving for affordable, secure, low-carbon energy generation. To a large extent this involves reducing the role coal will play in the continent’s future energy mix and therefore significantly reducing the amount of ash that is produced. While this is concerning to our members and the wider industry – it’s not the complete picture.
Based on the UKQAA’s figures, ash supplies are secure for the foreseeable future.
We’re currently producing an average of five million tonnes of fly ash a year and overall annual supply continues to outstrip consumption. This means not only is supply currently steady and consistent, but the market for ash still also has room to grow over the next decade.
In addition to the availability of fresh stocks, the UKQAA and its members are also endeavouring to maximise the potential of stockpile ash material, which has been surplus to requirements over recent decades and amounts to some 50 million t.
Firstly we’re starting to develop supply streams from stockpiles, looking for opportunities to recover ash from long-term storage at both operating and decommissioned power plants. Producers have for the past half century produced millions of tonnes of usable fly ash. Rather than lying dormant, this surplus ash is now being carefully extracted, screened and processed for use in a variety of construction products and materials.
What’s more, UKQAA sponsored experimental work – the Innovative Processing of Stockpile Ash Project – is developing a process route by which fly ash is not only recovered from stockpile but also transformed into EN 450 ash, a pozzolanic grade. This extends the possible applications for stockpile ash, including for use within structural concrete and composite cements.
These recovery and research projects are vital to broadening ash supply streams, assessing the extent of available resource and understanding the extent to which stockpile ash can be exploited for a variety of uses.
Ultimately the UKQAA is working hard to unlock the ash industry’s potential to secure and diversify ash supply streams and safeguard future availability. We’re confident that there will be a supply of ash for decades to come, regardless of the Government’s public commitments to coal-fired power plant closures.”
Edited from press release by Joseph Green
Read the article online at: https://www.worldcoal.com/coal/23122015/uk-coal-ash-supplies-to-remain-secure-3346/