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Renew your energy: June 2009 Archives

With the climate conference in Copenhagen in December seen by many as the make-or-break event, the EU position is relatively clear- a 20% by 2020 cut in emissions (from 1990 levels), unless a good global agreement can be reached, when the target would be raised to 30%.

The UK is amongst the leaders in pushing for high targets. The Budget in April set what was claimed as the world's first carbon budget, as required by the new Climate Change Act, with a legally binding 34% reduction in emissions by 2020. The government said it will 'increase the level of ambition of carbon budgets once a satisfactory global deal on climate change is reached'. Longer term, there is a firm commitment to an 80% cut by 2050.

While welcome, all that will mean very little if the US and China don't come up with decent targets. The good news from the USA is that, after years of denial under Bush, the US government now sees greenhouse emissions as a major issue: the Environmental Protection Agency is now regulating them. And progress is being made on national targets. Against strong opposition, the House of Representatives has just voted 219 to 212 to bind the US to cutting carbon emissions by 17% from 2005 levels by 2020 and by 83% by 2050. It also agreed that a national carbon 'cap and trade' system should be established and to a 15% 2020 target for electricity from renewables. However this has still all to be passed by Senate- where opposition is likely to be even stronger.

The opposition has already led to watering down of targets. For example, the draft US Clean Energy act called for a 20% cut on 2005 emission levels by 2020, and for the US to get 25% of its electricity from renewables by 2025. The fossil lobby wanted just a 6% cut by 2020 and lower renewable targets. Even so, the emission level now agreed by the House of Representatives (17%) is a significant compromise and the 15% target for electricity from renewables is an even bigger compromise, especially since it seems 12% could be allowed in some regions with poor resources, and energy efficiency gains may be allowed as a substitute for some renewables.

In any case, even if finally passed into law through Senate, these are just paper targets. The crucial thing is the proposed new US Carbon trading system - a key element in translating the targets into reality. Indeed, although much was made of the £150 billion over ten years that Obama allocated to renewables and other green energy projects earlier this year, as part of the US Economic stimulus package, much of that funding will only materialise if the carbon trading system goes ahead. This may explain why the very large stimulus allocation (around 10 times current support levels) was not fought much by Republicans- they may have been waiting to block it at source by opposing the Carbon trading system. If that is proves to be the case, the fear is that the new proposals won't get through in time for the USA to make a clearly positive contribution at the Copenhagen conference.

While this may be a problem, it seems that the simple fact that Obama is now taking the US into climate negotiations has been enough for the Chinese to engage in the process more fruitfully - and that in turn has helped Obama, since one of the main reasons for opposition to the Kyoto protocol in the US was that it didn't apply to newly developing countries like China, whose emissions were expanding rapidly. They have actually recently overtaken the US. But China now seems to be thinking in terms of, if not absolute cuts, then at least a commitment to the reductions in the growth of its rapidly expanding carbon emissions.

Su Wei, a leading figure in China's climate change negotiating team, said that officials were considering introducing a national target that would limit emissions relative to economic growth in the country's next 5-year plan from 2011.'China hasn't reached the stage where we can reduce overall emissions, but we can reduce energy intensity and carbon intensity.' i.e. carbon emissions/GNP. Whether an agreement will be reached on that before the Copenhagen conference remains to be seen.

The stakes are high- for Obama and for the world. The EU is pushing hard, and, whatever might be happening at home, the USA seems to be bending over backwards to get a global agreement. It has proposed that developing nations like China should not be required to commit to specific emission targets, but should be asked to commit to boosting energy efficiency standards and improving the take-up of renewable energy. And there are positive signs, with talk of China being able to go beyond the current target of getting 15% of all energy from renewables by 2020, to 18% and possibly 20% - on a par with the EU and well ahead of the USA.

We may make it yet.

The use of nuclear power and/or renewable energy is seen as part of the response to climate change, but climate change may have a negative impact on some of these energy sources, limiting the contribution they can make.

Most of the UK's nuclear plants are on the coast, so as to get access to sea-water for cooling. In future, some of these sites may be inappropriate as locations for new plants, as has been proposed, due to the risk of flooding and storm-sea ingress. The Nuclear Consultation Group, which includes leading UK experts in the field of environmental risk, said, in response to Governments new Criteria for the Siting of proposed new nuclear plants, that 'the Strategic Siting Assessment process is flawed and inadequate. It is inconceivable that the selection of sites on vulnerable coasts in southern England represents good sense', given that 'the risks from climate change in the form of sea level rise, storm surge and coastal erosion at the favoured sites are serious and increasing over time'. It noted that the Flood Hazard Research Centre at Middlesex University had concluded that there could be problems at four of the favoured sites, Bradwell, Hinkley, Dungeness, and Sizewell.

Nuclear Consutlation Group member Prof. Andy Blowers, writing in the TCPA journal, said the new UK siting criteria amounted to nothing less than a means of trying to justify putting a new generation of power stations and spent fuel waste stores on existing coastal sites, most of which are likely to become submerged during the next century under the impact of sea level rise and storm surges. It's the on-site spent fuel stores, expected to hold old fuel for 100 years, that he felt were particularly worrying.

It's not a trivial issue. Climate Scientists are now predicting that sea levels could rise by 1 metre or more by 2100, and maybe up to 2 metres, and with increased storm surges likely as well, that could pose threats to many locations around the world- the UK included. The Institution of Mechanical Engineering, which recently published a report on 'Climate Change, Adapting to the Inevitable', said that coastal sites like Sizewell might have to be abandoned or relocated in the long term.

Dr Colin Brown, IMechE's director of engineering commented: "The Sizewell B nuclear plant has been built on the Suffolk coast, a site that has been earmarked for the construction of several more nuclear plants. However, Sizewell will certainly be affected by rising sea levels. Engineers say they can build concrete walls that will keep out the water throughout the working lives of these new plants. But that is not enough. Nuclear plants may operate for 50 years, but it could take hundreds of years to decommission them. By that time, who knows what sea-level rises and what kinds of inundations the country will be experiencing?"

Sea level issues are not the only climate related problem that may impact on nuclear projects. In continental Europe, the USA and elsewhere, many plants are located near rivers, but climate change could make this problematic too. Recent episodes of excessively hot summer weather in France led to nuclear plants being closed since the exit cooling water temperature was higher than environmental regulations allowed. Longer term, getting access to cooling water in summer could be a major issue in many countries.  This could well become another key issue in reactor location and design.

Changing climate and weather systems could also undermine the viability of some renewables to some extent. Changing rainfall patterns will have a significant impact on the amount of energy that some hydroelectric plants can generate. Increased temperatures may also lead to more evaporation in some locations. And changed wind patterns may also mean that in some locations wind turbines will not be able to produce as much energy are expected. A recent preliminary study in the Journal of Geophysical Research suggested that average and peak winds may have been slowing across the US midwest and eastern states since 1973, a 10% decline in average wind speed being noted over the past decade. Climate modelling has evidently suggested a further 10% decline in wind levels could occur over the next four decades, although this has not been confirmed, and in any case it may not be a general trend. However, it seems possible that, if temperature differentials between the poles and the equatorial regions decrease, then so will wind flows.

Given that waves are the result of wind moving over the oceans, then if wind flows are reduced, wave energy will also be reduced. Tidal flows should be unaffected by climate change, while direct solar generation may actually benefit, but the impact of changing climate and weather patterns on biomass as an energy source may be more complex.

The Institution of Mechanical Engineers report is at:

Offshore wind is the big new thing, with the UK doing quite well - taking the lead from Denmark, with around 600 MW now installed and more planned. However there may be battles over how these projects, installed by rival companies, are linked up to land via power transmission links.

Most of the project are now being sited several miles off the coast, linked to land via sea-bed marine cables. There are various ways in which these could be arranged. So far however it could be a case of each offshore project having their own parallel (and very expensive) links back to shore. In some cases that seems likely to involve duplication of effort, with links to rival projects running close to each other, in parallel. It would arguably be more rational and cheaper overall to have a network of offshore links, with possibly a single link back to shore for each region, offering a common service for each project to use. That is even more the case as we go further out to sea, and would be vital if we also build links across the North Sea to the continent- as part of the EU supergrid concept.

In its report last year on Renewables, the Innovation, Universities, Science and Skills Select Committee said that they were: 'concerned that the proposed offshore transmission arrangements are not appropriate for the UK's target of 33GW of offshore wind by 2020. We urge the Government to reconsider the development of an offshore grid.'

Imera, who have proposed a Europa Grid linking up North Sea wind to the UK and the continent, made a similar point- there were 'unused cable capacity in traditional radial connections', whereas a grid network would be better especially since it could also be used to import/export power.

However, not everyone is enthusiastic about a supergrid network. In a submission in March 2009 (FBEN 29) to the new Energy and Climate Change Select Committee, the German owed utility E.ON commented: 'A super grid connecting offshore wind farms to adjacent countries is an exciting proposal, but it is unclear whether this is the most cost effective route for connecting new offshore wind. Timely delivery of the supergrid will be an issue. For example, round three offshore windfarms should not be delayed because the connection of a zone is dependent upon a wider interconnection project'.

Ofgem, the energy regulator, has also noted that the advantages with the parallel 'point to point' radial approach is that it 'allows generators to proceed individually and avoid delays due to third parties', but it has said that it's also happy with the more integrated network approach. Ofgem nevertheless got a pretty rough ride on this issue at last years BWEA wind conference - it was argued that the proposed grid regime would not encourage joined up networks, and that change was needed to ensure collaborative development and a strategic approach. Do we really need a host of separate lines just to protect competition in the short term?

That was certainly an issue for Green MEP Claude Turmes, who was the European Parliament's lead negotiator for the Renewable Energy Directive. Speaking at the UK Renewable Energy Associations annual conference earlier this month, he claimed that the competitive tender process favoured by Ofgem was delaying grid connections for offshore wind projects: 'The UK approach, imposed by Ofgem, for competitive bids for chunks of 40 km cables for offshore, is not very productive, to put it mildly. Much better is the Danish model and the German model, where you have one system operator, the Danish grid company or the regional grid operator in Germany. This company is in charge of delivering the cable to the offshore platform where you then have to plug in your wind turbine. You have to get rid of Ofgem's over-liberalised idea, by which you can have competition on grid installation.'


The limits to renewables

Prof. David MacKay from Cambridge University has been getting good media coverage for his seminal self-published book 'Sustainable Energy without the hot air', in which he attempts to construct and then test a range of possible energy mixes for the UK. It's a very stimulating- and sobering- exercise. His clearly presented analysis offers a challenging assessment of the renewable resource, and he is obviously worried that enthusiasts for renewables sometimes overstate what they can deliver- he says 'plans must add up'.

It would be interesting then to see his reactions to a bold new paper in The Electricity Journal (Vol. 22, No.4, May 2009, pp95-111) by Ben Sovacool and Charmaine Watts who ask is 'Going Completely Renewable' possible and desirable - and say yes, for electricity in both the USA and New Zeeland, which they select as case studies, and also, ultimately, for the world as a whole: 'Excluding biomass, and looking at just solar, wind, geothermal, and hydroelectric, the world has roughly 3,439,685 TWh of potential- about 201 times the amount of electricity the world consumed in 2007'.

MacKay's focus is just on the UK and he is at pains to alert people to the fact that if they want to use renewables to meet their energy needs, the scale of deployment will have to be very large in land use terms ('country sized'). Even then he doubts if enough can be obtained- we may also need nuclear or CCS, or both.

His approach is based on an assessment of averaged watts /sq. m, and he calculates that, for example, on-land wind delivers 2 watts/sq. m. He says that he is 'not anti wind, jut pro arithmetic' However his sums seem to ignore the possibility that the land around wind turbine bases can be used for other activities- e.g. farming or energy crop growing. And going off shore avoids land-use limits altogether, as Mackay recognises- although he points out that very large areas ( 'the size of Wales') would have to be involved to get significant amounts of energy.

Looking beyond the UK, Sovacool and Watts mention the potential of concentrating solar arrays in desert areas. As Mackay points out, they certainly use a lot of land, but there are plenty of low value desert areas, for example in North Africa.

Even so, there is major gap between MacKays cautious resource analysis and some of the more speculative data used by Sovacool and Watts. But then again, while we have to avoid over-enthusiastic assessment, there is also a need to challenge overly conservative estimates. One issue is costs. Mackay mostly escapes this by focusing on resources and physical data, By contrast Sovacool and Watts are stronger on the economics - although, once again, there will be disputes about their selection of economic data.

Overall, in looking at these two studies, we have on one hand an attempt at a hard nosed physical assessment, and on the other, a more speculative vision of what we might aim for. That's not to say MacKay's book lacks vision- it's packed with ideas and insights on how we might reduce emissions effectively. However, his overall approach does sometimes feel overly deterministic. While his calculations are clearly valuable in setting order of magnitude boundary conditions, I'm still reminded of Bertrand Russell's dictum that "Science may set limits to knowledge, but should not set limits to imagination."

David MacKay's book can be downloaded for free from