Biffa

Surveying the wasteland

The UK dumps a higher proportion of household waste into landfill than any other EU state -- 21 million tonnes of a total of 27 million tonnes of domestic waste is disposed of in this way.  Over 250 landfill sites are located around the UK, for a combined total of 109 square miles, or roughly the size of Warwick.  Over the next six years, around 200 of these sites will close and not be replaced as landfill taxes drive landfill gate fees above those for new technology options.

Up until now, the relatively low cost of landfill has helped to put the UK roughly 10 years behind the rest of Europe in terms of landfill substitution technologies.  But Biffa Waste Services Limited is working to buck the trend.

Moving away from landfill

Biffa is the UK’s largest waste resources companies.  Each year it disposes of around nine million tonnes of material to landfill.  Mindful of increases to the landfill tax and new UK and EU directives aimed at shifting waste away from landfill, as well as uncertainty regarding the future cost and availability of existing nuclear and coal-fired energy supplies, Biffa is actively exploring different technologies by which it can convert a greater proportion of landfill waste into usable energy.

An estimated 60% to 70% of the nine million tonnes of waste that Biffa landfills annually consists of biogenic and fossil carbon waste material.  This rots down in the ground to produce methane, which generates in the region of 110 megawatts of electricity.  In addition, it operates the UK’s largest anaerobic digester facility, which processes around 35,000 tonnes of biogenic carbon annually to produce a further two megawatts of electricity via new technology.  All electricity is fed to the National Grid.

Waste into energy

But Biffa’s data analysis suggests that waste currently being sent to landfill could be providing a far larger proportion of the UK’s energy supply.  Specifically, of the 70 million tonnes of waste landfilled in the UK each year, around 30 to 40 million tonnes are estimated to consist of what is known as renewable carbon -- biogenic and fossil carbon from high carbon value wood, plastics, food, tyres and car fragmentiser waste. Many of these materials do not decompose in landfill and so do not convert to methane.  Effectively processed, however, this waste could generate in the region of three to four gigawatts of electricity (reducing the demand for fossil fuels) for powering large, single site users such as food processing and chilling, air separation, pharmaceutical, and similar plants with big appetites for power and heat.

The key to processing this waste lies in advanced technology enclosed systems, such as anaerobic digesters and gasifiers.  Gasification is a well-established process in northern Germany, Denmark and Sweden, countries that send far less waste to landfill than the UK.  Enclosed systems are popular in these countries and with environmental groups, such as Greenpeace and Friends of the Earth, because they produce little in the way of emissions apart from vented steam and water vapour, and lower levels of CO₂ compared with traditional incineration.  The ash they produce is also substantially less.

Biffa has contracted with Ener-G, one of the UK’s leading suppliers of smaller-scale energy from waste plants.  The plan is to operate a 40,000-tonne gasifier fed by waste fuel floc (a coal-like feed stock made from biogenic and fossil fuel waste, which Biffa produces at its Leicester site) on the Isle of Wight.  This will be operational in late spring 2008, and is expected to generate around three megawatts of electricity for the Island Grid -- enough to power 3,000 households.

Using this plant as a model, Biffa will then be working to find ways of co-locating resource recovery and energy-from-waste power plants next to large, electricity-hungry consumers in industries such as engineering, food, air separation and logistics.

A network of small, distributed plants

Biffa envisages a national network of facilities, either 400 x 100,000 tonnes per annum or 800 x 50,000 distributed energy plants, which would produce electricity using processed and dried floc.  These 400 or 800 sites would be geographically dispersed, and thus close to where waste is generated.  If road fuel costs rise, as is expected, over the next few years, small, localised plants will prove to be more flexible and economical than large-scale centralised systems, particularly if they are not connected by rail.  They are also more feasible in terms of emergent conventional Grid weak/at risk areas as nuclear and ’dirty coal’ close between now and 2020.

So, what next?

Biffa has the technology and expertise to make this network of small, distributed plants a reality.  Doing so would help to release the hidden potential of some 40 million tonnes of biogenic and fossil waste--renewable carbon--that is currently going to landfill.

What will make it happen?  For one, a major public education and communication exercise is needed to promote the energy from waste option around lowered carbon ‘footprints’.  For another option, the conversion programme, which needs to be sold on the basis that it is a green energy project rather than a waste processing solution.  Finally, government may need to encourage ‘green procurement’ on public sector contracts, particularly by hospitals, prisons, the police, airports and local government buildings, as a way of kick-starting the installation of trial sites and demystifying the threats.

Up until now, 40 million tonnes of renewable carbon has not been considered significant when compared to the 68 gigawatt supply capacity of the UK electricity network.  Look again, however, and it would appear that a network of distributed, single point locations, adjacent to high consumption industries, offers better value for money and improved security of supply compared to the billions of pounds needed to prop up a reconfigured, centralised power network.

Sources:

1. Telephone interview with Peter Jones, Director of Development and External Relations, Biffa Waste Services Limited
2. Biffa website

Also in this feature:

• Combating climate change with hydrogen energy, Rio Tinto CSR view from the field 
• Mother Earth: we grow fat while she grows thin