Exports: a waste of energy?

An article by one my colleagues last year set out an intelligent case for the export of waste from the UK for use as fuel in other European Union (EU) Member States, particularly highlighting that this need not be just a short-term fix. But the debate rumbles on, and has begun to take new forms, so I thought I would examine the numbers and see how the case for retaining our refuse derived fuel (RDF), also known as solid recovered fuel (SRF), for incineration in the UK, stacks up.

The Netherlands and Germany built significant incineration capacity in response to the EU Landfill Directive targets. They have since increased their recycling rates, leaving them with spare capacity that they are eager to use to treat waste from other Member States, including the UK. A smart solution, one might think, which means we don’t need to build expensive infrastructure here, and very much in the spirit of EU free trade.

A large number of overseas incinerators that make use of the heat as well as the power they generate have an insurmountable efficiency advantage over UK facilities, which tend not to use the heat. The clear environmental case for exports that this provides has slowly dawned on some organisations seeking to build thermal processing infrastructure in the UK, who are now trying another angle. The most entertaining expression of this recently came from an engineering consultancy (with a clear vested interest), which claimed that it was shameful that we were handing our neighbours our ‘indigenous’ supplies of renewable energy. Absolute nonsense.

Emission critical

First of all, the biggest mistake that such commentators make is to assume that energy generation from waste is always ‘good’. What they seem to forget is that it is very ‘carbon intense’ compared to other generating capacity currently being built, and I don’t just mean renewables. Government has a renewed enthusiasm for gas in the form of combined cycle gas turbine (CCGT) plant, and although I don’t necessarily agree with this policy, most incinerators will struggle to generate electricity at the 350kg CO₂/MWh achieved by modern CCGTs.

Taking into consideration that, in policy terms, the biomass element of waste is considered to be ‘carbon neutral’, the average incinerator (let’s say, one achieving 25% electrical efficiency) would need a fuel composition of around 65% biomass content in order to produce electricity at a CCGT plant’s level of emissions. This is extremely challenging to achieve, particularly at a time when government is rightly encouraging separate food waste collection for treatment by anaerobic digestion (AD), which will reduce the biomass content of residual waste. So, if CCGTs are less carbon intense, where is the argument for generating energy via incineration?

Despite the recent diversification of our gas supply thanks to new gas pipelines from Norway, forthcoming pipelines from Azerbaijan via Turkey, and massive new supplies of shale gas from the US, perhaps reliance on gas doesn’t give us quite enough security. Could energy from waste (EfW) therefore have a vital role to play in providing a domestic source of fuel? To assess this, let’s put the potential contribution of energy from waste in context.

Talkin’ ‘bout my generation

In the second version of Eunomia’s Residual Waste Infrastructure Review, we found that in 2011/12 there was a ‘capacity gap’ of around 13.5 million tonnes (per annum) between the quantity of residual waste arisings and the amount of treatment infrastructure capacity either ‘operating’ or ‘under construction’. If one were to assume that all of this 13.5 million tonnes, which is currently sent to landfill in the UK, was instead incinerated it would produce just less than 1.2% of annual total electricity generation in the UK.[1] It therefore wouldn’t do much to keep the lights on if the gas stopped flowing.

Plenty of capacity for waste export. Picture by Photocapy (Flickr), via Wikimedia Commons

Those objecting to waste exports may also argue that the virtue of energy from waste is that it is ‘renewable’ electricity. At the current 45% recycling rate in England, untreated residual waste  can be expected to have a biomass content, by weight, of around 60% (although this will decrease if more food waste is collected for AD). The calorific value (CV) of this biomass fraction, which contains significant amounts of wet food, is considerably lower, at 5GJ/tonne, than that of non-biomass fraction of residual wastes, which consists largely of plastics.

This low CV limits the ‘renewable’ energy contribution we can hope to derive from waste, and the value of what we export. The expected spare incineration capacity in Germany, the Netherlands and Denmark is probably at most around 50% of the UK’s aforementioned 13.5 million tonne capacity gap. If we used some of this to fill our neighbours’ incinerators, the energy value of the ‘renewable fuel’ that we might export would equate to around 4% of our current level of 34TWh/annum of renewable electricity generation[2]. Clearly, other renewables are already far outstripping what could ever be achieved by EfW.

The contribution of RDF to both energy security and meeting the UK’s renewable energy targets is plainly a mere ‘drop in the ocean’. The old metaphor is apt: to put this potential 1.4TWh/annum of ‘renewable’ electricity generation from waste into further context, it would be broadly equivalent to twice the output (taking account of the intermittency/load factor) of Centrica’s 194MW Lynn/Inner Dowsing wind farm in the North Sea.

Nor can it be argued that incineration would have the advantages of being a cheap option. The Lynn/Inner Dowsing windfarm is reported to have cost £300-400 million to build. Two of these would still be far cheaper than the cost of treating the 4 million tonnes of residual waste biomass content, which might otherwise be exported, within incinerators in the UK: around £1.6 billion.[3] In austere times, the choice between the two would appear to be a ‘no-brainer’. I’m sure that the local communities in the vicinity of the ten large-scale incinerators that would be required might agree.

There may be cases whereby incinerators can be sized, and related contracts designed, to allow future growth in recycling from households and businesses. Outside of such cases, I can see no respectable argument, whether based on environmental, energy security or economic considerations, for building further incineration capacity in the UK. Export of RDF is in no meaningful sense a waste of an energy resource, and the case for keeping it here is a very poor one. Industry should stop wasting its energy trying to make it.