Extracts from NATTA's journal
Renew, issue 159 Jan-Feb 2006

4. Decarb the UK

The Tyndall Centres new report Decarbonising the UK, which looks ahead at the technical and policy options, has some radical conclusions- the headline one being that emissions from aviation were rising rapidly and could overwhelm cuts in other sectors- see our report later. But equally important were the conclusions on intermittency, which was also the subject of an earlier Tyndall Centre report- see our Features.

The new overview report argues that, since the grid and control system is designed for large centralised generators, ‘meeting variable demand with intermittent, and/or uncontrolled and/or inflexible generation will be a major challenge for the secure operation of sustainable electricity systems of the future’.  It adds that “in order to accommodate intermittent generation, it will be necessary to retain a significant proportion of conventional plant to ensure security of supply”, so as to cope with conditions of high demand and low wind.  So you couldn’t simply substitute wind on a ‘MW for MW’ basis. 

However this was essentially a technical and economic issue. The Tyndall report notes that, assuming around 25GW of wind was in place by 2020, the additional costs for network and balancing capacity, plus the cost of generation, would be 0.61p/kWh more than conventional energy costs. But it says this would be offset by reductions in the need for grid reinforcement, and new conventional capacity, plus fuel savings, which it puts at 0.33p/kWh. The net difference 0.28p/kWh, is 5% of the current domestic price for electricity. It points out that the additional operating cost to accommodate the variable  output from wind turbines represents a ‘relatively small proportion’ of the total, only 0.05p of the total additional costs of 0.61 p/kWh.

Overall, it  concludes  that “the system will be able to accommodate significant increases in intermittent power generation with relatively small increases in overall costs of supply,” with the additional costs being driven mainly by the capital cost of windfarms, at least up to about a 20% contribution. After that, the costs of integration and providing backup start to get larger, and the capacity factors get lower. However, the benefits, in terms of the cost of fuel saved, will be directly influenced by conventional fuel prices- which are rising.

Aviation busts the carbon bank

“If the UK government does not curb aviation growth,  all other sectors of  the economy will eventually be forced to become carbon neutral.”  So says Dr Kevin Anderson who led research at Manchester University, for the new Tyndall Centre study of options for ‘Decarbonising the UK’.   The Government’s  Aviation White Paper predicts that UK passenger numbers will more than double from 180 million to 475 million over the next 25 years, but aircraft fuel efficiency is only  likely to increase by 1.7%. The report shows that, even if aviation’s current growth is halved, massive emission cuts would still be needed in the rest of the economy to meet the overall target of reducing emissions by 60% by 2050. “The failure of all governments to think about international aviation and shipping has led to a  serious underestimation of the actions necessary”, said Dr Simon Shackley from the Tyndall Centre. 

The Tyndall team say that Decarbonising the UK is the first study to look overall at emissions from the energy infrastructure, buildings and industry and those from air, sea & land transport. It explores a range of scenarios with differing levels of energy use and GDP. All use renewables and carbon capture & storage to varying degrees, but one avoids nuclear power- and achieves a 3.3% GDP. However the emphasis is not so much on supply, but on reducing energy demand. Although it claims that supplying low carbon energy is both technically and economically viable, and that improvements in energy efficiency can decarbonise many sectors, it says that policies for reducing energy demand are a more flexible tool than  shifting to low-carbon supplies.  It looks at personal carbon rationing as one  way to achieve this, but also notes that ‘government must implement and enforce minimum energy standards’. However,  the headline message is its insistence that, as the press release put it, ‘international aviation & marine emissions must be included in carbon reduction targets, now!’     We’ll review it in Renew 160