ScotAsh - waste or a whole new business opportunity

In a partnership between ScottishPower and Lafarge Cement UK, supported by academia and government, residual materials from energy production are being used in the construction industry.

Business Insight

ScotAsh take ash output from ScottishPower’s coal fired power stations and turns it into sustainable building products. Before this some 600,000 tonnes of ash was disposed of in ash lagoons each year. Whilst this was deemed to be environmentally safe it was the end of the lifecycle for the materials and far from the most sustainable option.

Transformation

When ScottishPower completed an £8 million upgrade of its production centre at the Longannet Power Station at Kincade-on-Forth it installed an ash benefication plant. This enabled the carbon content of the ash to be modified to create pulverised fuel ash (PFA), a highly versatile material suitable for use in a range of products including cement and concrete enhancers, fill material, grout and waste stabilisation products.

Rather than being discarded much of the ash content is now recycled. It is used to increase the long-term strength and durability of cement as well as improving resistance to chemical attack.

The company’s new bedding mortar and joint filling grout works as a structural system with stone setts, making it a cost effective and durable option for the repair of heritage roads. Other ash products are used within the oil sector in the lining of oil wells.

End Game

ScotAsh has been able to create new markets out of what was once considered a waste product, relieving the company of the need to dispose of the material and associated landfill issues. At the same time it has provided an enhanced product solution to the construction industry. As we have seen in this edition’s CSR briefing paper it works to reduce the embodied energy component of a building’s impact by using materials that have already been processed to create energy. This removes the need to use hundreds of thousands of tonnes of virgin aggregates each year in addition to the carbon dioxide emissions that would be generated to crush, grind and heat raw materials.

The team are continuing to work on applications for PFA together with Scottish Universities. This includes the development of high early strength cements, cements with microsilicas and cement with fibres. It is also working with local authorities to explore potential applications for ash products in sealing old landfill sites.

Although a by-product from the burning of coal, a major contributor to global warming, it is also being used in some of the solutions including the creation of windfarms and improving the environmental performance of buildings and roads.

In addition, is a project with Strathclyde University working to use PFA to bind anti-fouling contaminants including tributyl tin from ships which can settle in harbour sludges.

Ultimately ScotAsh’s objective is to recycle all of ScottishPower’s ash output. With recycling rates currently at 80% and ongoing product development projects underway it is an objective that looks achievable and should encourage all of us to look at potential uses of production ‘waste’.

References:

1. WBCSD website
2. ScotAsh website 

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• UNGC Cities Programme 
• Stora Enso CSR case study - dealing with potentially heated conversations