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Renew your energy: August 2010 Archives

Floating offshore wind turbines are one of the big new ideas in the renewable energy field. They allow us to go far out to sea in deep water in which would be impossible, or vastly expensive, to install devices fixed to the sea-bed. They also avoid the environmental intrusion of sea bed foundations or monopiles.

There is a range of systems being tested, many of them owing much to experience with offshore oil and gas rigs. So perhaps it's not surprising that the leaders in the field are the Norwegians. Statoil/Norsk Hydro have developed and tested a 2.3 MW Hywind system in water 220 metres deep off the coast of Norway, while Sway is developing a novel 10MW floating turbine. They both are essentially like the vertical bobbing floats used for fishing, with a long tail under the water providing buoyancy and supporting a conventional propeller-type wind turbine above the water line. They are kept vertical by sea-bed tethers, although the Sway system is designed to be able tilt by up to 8 degrees.

The Dutch have also developed a tension leg platform system, based on oil rig technology, called Blue H. A prototype is being tested in the Mediterranean- in 108 meters waters at a distance of 10.6 nautical miles from the coast of Puglia in Southern Italy. France plans to install four floating offshore wind turbines and a 3.5 MW. Blue H is a candidate.

The UK is also in the race. Engineering firm Arup is working with an academic consortium backed by Rolls Royce, Shell and BP and linked to architects Grimshaw, on a 10MW "Aerogenerator X", a novel V- shaped vertical axis floating offshore wind machine, measuring 300m from blade tip to tip. The first unit could be ready in 2013-14. See and

This grew out of the NOVA (Novel Offshore Vertical Axis) project, backed by the Energy Technology Institute (ETI) and involving Cranfield University, QinetiQ, Strathclyde University, Sheffield University.

The ETI has also funded development work on a concrete version of the Blue H design, with involvement from amongst others BAE Systems. In parallel US wind company Clipper, is planning to build the more conventional 7.5 MW "Britannia" deep-sea offshore turbine in north-east England in conjunction with NaREC, the New and Renewable Energy Centre. The first in UK waters though could be a version of Hywind- Statoil is planning to build an offshore wind farm using 3 to 5 floating turbines developed for its HyWind project off the northeast coast of Scotland.

Feargal Brennan, head of offshore engineering at Cranfield University, where much of the Aerogenerator X development work has been carried out, told the Guardian (26/7/10) 'There is a wonderful race on. It's very tight and the prize is domination of the global offshore wind energy market. The UK has come late to the race, but with 40 years of oil and gas experience we have the chance to lead the world. The new [Aero-generator] turbine is based on semi-submersible oil platform technology and does not have the same weight constraints as a normal wind turbine. The radical new design is half the height of an equivalent [conventional] turbine.' He added that the design could be expanded to produce turbines that generated 20MW or more.

Bigger machine have both advantages and problems. Doubling the diameter leads to four times as much power, but eight times as much weight and can also increase costs by a factor of eight. However vertical axis machines may be lighter, since they need no tower, and may also have the advantage of easier maintenance access and higher stability in high winds.

The USA, so far rather back-ward in developing off shore wind, has now also got into the race. One argument had been that, unlike the UK, which has shallow water offshore (with 1 GW of offshore wind now in place), US coastal waters were deep, so that offshore wind wasn't very practical. There were also environmental and visual intrusion objections to location near-shore. For example the wind farm proposed for off Cape Cod has only just now been given the go ahead after 10 years of regulatory and legal battles. It will be the USA first offshore wind project. But deepwater floating turbines may change the game.

The US National Science Foundation, has now funded a 3 year project to see if the construction of floating wind turbines in the deep- ocean is a viable. And the State of Maine has just proposed a plan for installing up to 30MW of deepwater marine power, of which only 5MW can be tidal the rest being wind, which must be floating -and be expandable to 100MW or more. Hywind is said to be a candidate.

Back in the UK, the potential for floating offshore wind is very large.. The PIRC Offshore Valuation puts the practical potential at 870TWh/yr, with 660TWh/yr more beyond 100nm out. In all, that's about four times UK electricity consumption.

Of course location that far out will mean that the cost of the undersea grid links will be high, but deep sea wind seems likely to become increasingly attractive as a north sea supergrid network is established, with new UK- to-continental HVDC power grids linking in offshore wind farms across the area, helping the balance local and regional variations in wind availability.

For updates on renewable energy developments in the UK and elsewhere see :

A Desertec 'energy from the deserts' initiative was launched last year as a feasibility study by a group of major German energy companies and banks keen to install large Concentrating Solar Power (CSP) arrays in desert areas and transmit some of the power back to the EU by undersea High Voltage Direct Current supergrids.

Desertec is not the only player however. Transgreen is a new French led supergrid project now being developed as part of the Mediterranean Union's Solar Med programme. Solar Med includes proposals for installing 20 Gigawatts (GW) of renewables by 2020, using a mix of technologies: around 6GW of wind, 5.5GW of CSP and nearly 1GW of PV solar in North Africa and the Middle east. And to link it up the Mediterranean Union has proposed a 'Mediterranean Ring' - a grid system linking up countries around the Med, including power from CSP in North Africa/the Middle East being transmitted to the EU via HVDC links under the sea.

That's where Transgreen comes in. It might be seen as a rival to the German-led Desertec project, given that Transgreen's aim is to bring together power companies, network operators and high-tension equipment makers under the leadership of French energy giant EDF. But the idea seems to be that Transgreen will focus on transmission, and just deliver part of the energy generated by the Desertec CSP projects to the EU- and there is already some overlapping membership. A €5m study phase is underway.

The energy potential for CSP is huge- there is a lot of desert! There is talk of 200GW or more eventually being installed. The technology exists (in Spain and the USA) and its economics and performance is improving, with molten salt heat stores allowing for continued use of solar power overnight. So CSP could become a large-scale reality, while HVDC transmission losses are put a 1-2 % per 1000km, so long distance export seems credible. An EU commissioner recently said that the first power could arrive in the EU in 5 years.

However, despite talk of a $400bn programme, at present the Desertec initiative is only just a concept- not yet a formally funded project, although some independent CSP projects are already underway e.g. in Egypt, Jordon Algeria and Morocco, which could become part of it. A 470 Megawatt (MW) hybrid solar/ gas fired unit, with 22 MW of CSP, has just been started up in Morocco, Egypt is nearing completion of a €250m 150MW hybrid unit near Cairo, while the UAE has plans for 1000MW CSP unit.

These and other projects may of course just stay independent, at least initially and not export any power. After all, Transgreen too is only just starting up as a concept. And there will certainly be some interesting routing issues for it face. For example, does the proposed French Transgreen link-up to Morocco have to go across Spain, or can it go undersea direct? That's much more expensive, 1200km of marine cable at maybe €1m/km, rather than two stretches of 200km undersea. The trans-Spain option does also allow Spanish wind power to be fed in, but the undersea line avoids land use and local or regional or indeed national political conflicts. Spain has recently had a major a battle getting a HVDC grid link across the Pyrenees to France. It had to be put underground, at increased cost- although it's worth noting that it is evidently easier to put HVDC cables underground than conventional AC grid links, since there are less heat losses to deal with.

There are also some wider regional and indeed international political issues. We have suffered enough from the politics of oil, it is to be hoped that the politics of solar would be different.But there is the risk of a neocolonial resource grab- with investors rushing to get sites in North Africa and the Middle East and then seeking to get access to the power at favorable rates. At the very least it will be important to negotiate fair trading arrangements. However there is also a need to consider what is wanted locally. While the EU media has often waxed lyrical about the concept of power from the desert, some of the countries who would be the likely hosts to CSP projects to supply the supergrid, evidently feel they had not been sufficiently consulted. They may have their own views.

The trade journal Sun and Wind recently carried an interview with a leading Egyptian renewable energy supporter, Prof. Amin Mobarak, and others involved with a Masters course run jointly by the Universities of Kassel and Cairo, aiming to help local people to get on top of the technical and political issues associated with CSP. (Sun and Wind 5/20/10). One point that emerged was that the use of CSP for the desalination of water might be more important locally than electricity production (That actually is part of the Desertec plan). In addition, electricity demand was rising rapidly in the region, so there might not actually be that much spare for the EU! However, electricity prices were often subsidised locally (e.g. in Egypt) for social policy reasons, and that would be hard to change. So, initially at least, the relatively high price of CSP power might mean that it could only realistically be sold abroad.

But then comes the accreditation issue. EU Commissioner Guenther Oettinger recently said that, to avoid the import of non-renewable electricity from coal and gas-fired plant in north Africa, 'we need ways to ensure that our import of electricity is from renewables' However he believed it was technically possible to monitor electricity imports to the EU to see if they came from renewables. It is not immediately obvious how. And of course there is the wider question of overall security of supply: if it was getting 15% of its electricity from desert project, as Desertec plans, the EU would not want to risk being cut off. Plenty of issues to haggle over then- quite apart from the issue of local environmental impacts on fragile desert ecosystems. That has already led to some limitations on projects in the USA in relation to the protection of desert wildlife.

Some argue that we should not import green power, but should focus on our own resources in the EU. Certainly we should not use remote desert CSP as an excuse not to develop our own extensive renewable resources as fast as we can- large and small, locally and nationally. However a fully integrated supergrid system, including links to offshore wind, wave and tidal in the North West, as well as to CSP in desert areas, could offer benefits to all, in terms of helping to balance variations in the availability of renewable energy around the entire region. And locally, CSP could offer power, fresh water, jobs and income. Moreover, as far as the planet is concerned, it doesn't matter where the projects are located, as long as they reduce/avoid emissions. If the best sites for solar are in desert areas, so be it. But politics and economics intervene. The CSP/supergrid concept opens up range of new- and old- geopolitical and development issues. Not least who gets the power, and at what cost, and who gets the profits.

Parts of the above are from my presentation to a Summer Academy on 'Transnational Energy Grids' at Greifswald University, Germany, in July.

The Department of Energy and Climate Change has produced a new DIY energy supply-and-demand model, running up to 2050, developed under the supervision of Prof. David MacKay, DECC's chief scientific advisor. You can try it out:

It allows you to vary the energy supply mix so as to try to meet emission targets in line with various possible demand patterns, including charging electric car batteries overnight. Following the line adopted in earlier DECC scenarios, what emerges is that it's hard to stay in balance and get emissions down, without nuclear and Carbon Capture and Storage (CCS). The model tests the ability of the chosen supply mix to meet demand during a five-day anticyclone, with five days of low wind output and an increase in heating demand associated with the cold weather. But there are ways to balance variations like this, and the DECC report on '2050 energy pathways', which sets the model in context, does explore some of these options.

Even so, it concludes that, if CCS is not widely used, 'because of the large amount of renewables in this pathway, the challenges of balancing the electricity grid in the event of a five-day peak in heating and a drop in wind are more substantial. We would need a very significant increase in energy storage capacity, demand shifting and interconnection, together with 5GW of fossil-fuel-powered standby generation that would be inactive for most of the year.' And if nuclear was not used, 'the challenges of balancing the electricity grid are very substantial: we would need an extremely substantial increase in storage, demand shifting and interconnection'. By contrast 'without renewables in the system, it is easier to balance the electricity grid and no additional back-up capacity beyond what exists today is required'. Nuclear then dominates, and, DECC seems to say, that path gives lowest overall costs long term.

Not everyone may agree with that. Indeed, Chris Huhne, the new Lib Dem Energy and Climate Change Secretary of State, is on record as saying that nuclear economics means that it will need state support to be competitive – something he and the coalition government were not prepared to provide. A recent version of this view was his response to Lord Marlands statement on behalf of the government that 'there should be no dramatic increase' in current plans for around 14GW of on land wind power. Defending wind, Huhne commented: 'We have seen that with onshore wind, whose cost has come down dramatically precisely because of the encouragement of the public sector. I am afraid that the same argument cannot be made for nuclear power, which has been around for a long time. It is not an infant industry, but an established and mature one and it can and should compete on that basis, along with all other comers.'

However he seems to have been under pressure to back nuclear none the less. In a letter to The Financial Times (4 Aug) he said: 'Given our policy framework, and the outlook for oil, gas and carbon prices, I am nevertheless confident that there will be new nuclear power as planned by 2018.'

He went on: 'What nuclear will not have – and this is common across all three parties in Britain – is public subsidy specific to the industry.' But there will – or could – be a susbsidy, in all but name, in the form of a floor price for carbon, which will benefit all non and low carbon options.

So what could actually emerge? DECC's 2050 Pathways are not based on funding or support programmes, but simply offer four different 'levels' of possible technical response – from more or less none (1) to the absolute maximum (4), and then uses that as a basis for assembling a range of pathways with different mixes on both the supply and demand side, on the way to 2050.

Focusing here just on the supply side, on land wind comes out reasonably well with, by 2050, at Level 2, it being assumed that there could be 20 GW in place (delivering 55TWh of electricity then); at Level 3, 32GW (delivering 84TWh) and at the maximum Level 4, 50GW (132TWh). But offshore wind does much better – 60GW (delivering 184TWh) at Level 2,100GW (307TWh) at Level 3 and a massive 140 GW (430 TWh) at level 4. Wave/tidal stream devices do quite well at, respectively, 11.5GW (delivering 25TWh), 29 GW (68 TWh) and, at maximum, 58 GW (139 TWh), with wave leading tidal currents up to Level 4, when wave is put at 70TWh, tidal stream at 69TWh. But Tidal Range projects (barrages and lagoons) only manage, respectively, 1.7GW (3.4TWh), 13 GW (6TWh), and 20 GW (40 TWh) at Level 4 – significantly less than either wave or tidal stream in each case.

PV solar comes out of almost nowhere to yield, by 2050, 80 TWh at Level 3 and a massive 140 TWh at Level 4, although DECC is at pains to point out that the latter is very ambitious, expansion of this scale presenting 'an unprecedented challenge'. In addition, small-scale wind only delivers 8.6 TWh/yr max, while geothermal reaches just 5 GW by 2030 at Level 4, and hydro moves up to 4 GW in Level 4.

More radically, by 2050, there are 140 TWh of imports from Concentrating Solar Power in desert areas, covering 5000 sq km, in level 4. It's assumed that the UK's share of this is 20%. There are also some imports of biomass – at the maximum, around 135 TWh each of wet and dry biofuels, by 2050.

In terms of grid balancing for variable renewables, DECC notes that, being relatively inflexible, neither nuclear or CCS can be relied on for very large balancing capacity. So it looks to others options – energy storage, new grid interconnections to and from the continent, and flexibility (e.g. by using the proposed electric vehicles (EVs) or plug-in hydbrid electric vehicles (PHEV) car battery fleet as an overnight store). At Level 3 the storage capacity peak output increases to 7 GW by 2050. Interconnection increases to 15 GW, and around a half of all EVs and PHEVs have a shiftable electricity demand capacity. At Level 4, storage capacity peak output reaches 20 GW, interconnection 30 GW; and 75% of all EVs' and 90% of all PHEVs' storage capacity are utilised for shifting demand.

Finally there's nuclear. While at Level 1 it is assumed that 'the Government no longer wishes to take new nuclear forward and that a lack of clarity over planning and licensing timescales would lead to no planning applications coming forward and potentially the suspension of activities at sites where planning applications had been submitted'. At Level 2 there would be 'continued government and public support for new nuclear and that the facilitative actions would progress', with a total capacity of 39 GW at 2050 delivering 275 TWh of electricity per year with a build rate of just over 1GW/year. (Interestingly, by comparison, it notes that in Germany in recent years the build rate for wind has averaged around 2.1 GW/year.)

At Level 3, a nuclear build rate of 3 GW/year is achievable from 2025, leading to 90 GW at 2050 (633 TWh). And at Level 4 we move from a build rate of 3 GW/yr up to 2025 to a max of 5 GW/yr thereafter, with government interventions being needed, so that 146 GW in reached at 2050, delivering 1025 TWh. But we couldn't do that by ourselves – we would need overseas help!

Looking 40 years ahead is risky and hard to cost, but it's a brave effort, especially as it also tries to cover a range of heat suppliers, like solar, and end-use sectors, including transport. There is a call for evidence and there will no doubt be plenty of debate on the details and the viability and desirability of some of the Level 4 suggestions, not least of 146GW of nuclear!

The EU is set to contribute 45% of the construction costs for ITER, the new international fusion reactor being built in France, which some estimates now put at €15 bn, three times the 2006 cost estimate. But the EU's financial problems may mean that it can't deliver all of its share of around €7.2 bn.

The most pressing problem is a €1.4 bn gap in Europe's budget for ITER in 2012–13. Nature commented: "Left unresolved, the impasse in Europe will, at best, delay the project further. At worst, it could cause ITER to unravel entirely." It added: "The crunch is so serious that some European states have gone as far as to ask the commission to investigate the possibility of withdrawing from ITER, according to sources familiar with the negotiations. The price of such a withdrawal would probably be in the billions, as the treaty governing ITER requires heavy compensation to other partners."

A temporary solution would be a loan from the European Investment Bank to cover the immediate €1.4 bn budget gap. Another possibility would be to build a smaller version. But that could compromise its viability and aims.

Following a crisis meeting in July, it now seems that some interim refinancing has been agreed, but details of who is paying more are scare. However, the larger point remains. As Stephen Dean, president of Fusion Power Associates, a US non-profit advocacy group, told Nature: "There are serious questions about the affordability of fusion as a whole as a result of ITER."

On their website, Fusion Power Associates say that: "It would be premature at this stage to judge which of the variety of magnetic and inertial fusion concepts will ultimately succeed commercially." But, although part of the ITER magnetic containment programme, the US is also pushing laser-powered inertia fusion strongly these days, while the UK is also the base for an international HiPER laser fusion project.

HiPER is being supported by a consortium of 25 institutions from 11 nations, including representation at a national level from six countries. Following positive reviews from the EC in July 2007, the preparatory phase project will run up to 2011, aiming to establish the scientific and business case for full-scale development of the HiPER laser fusion facility. This phase is timed to coincide with the anticipated achievement of laser fusion ignition and energy gain (on the National Ignition Facility laser in the US). Then the website says "…future phases can proceed on the basis of demonstrable evidence. Construction of the HiPER facility is envisaged to start mid-decade, with operation in the early 2020s…", possibly at Rutherford Appleton Lab in Oxfordshire, since the UK is a leading contender to host the HiPER laser facility.

The physics is tricky, but the engineering is even more so – 1 mm pellets of deuterium and tritium have to be presented accurately and fired by lasers continually, many times a second, and the debris cleared away. But the HiPer group seems confident it can be done and that inertial fusion may be easier than the "magnetic containment" fusion approach being adopted by the ITER project. They say that "Inertial fusion offers some unique benefits – for example the potential to use advanced fuels (with little or no tritium). This greatly reduces the complexity of the process and further reduces the residual radioactivity. Inertial Fusion also allows for the use of flowing liquid wall chambers, thus overcoming a principal challenge: how to construct a chamber to withstand thermonuclear temperatures for the lifetime of a commercial reactor. In addition, Inertial Fusion allows for the direct conversion of the fusion products into electricity. This avoids the process of heating water, and so increases the net efficiency of the electricity generation process." It would be good to hear more about that. Otherwise it's back to running pipes through the outer blanket to raise steam!

Interestingly though, electricity production may not be the main aim. As with other fusion projects, and some new fission projects, there is now talk of focusing more on hydrogen or synfuel production (e.g. for the transport sector, presumably either by electrolysis or by using the heat direct for high-temperature dissociation of water). Or the heat could be used for other industrial processing heating purposes.

Whatever the final end-use, the engineering does sound mind-boggling, even if the Hiper website does try to make it seem familiar: "The principle is conceptually similar to a combustion engine – a fuel compression stage and an ignition stage" (i.e. "analogous to a petrol engine (compression plus spark plug) approach").

Well yes, but it's at 100 million  °C, and, after a few firings, the whole thing will become fiercely radioactive due to the blast of neutrons that will be produced.

They are also the source of the energy that would have to be tapped if power is to be produced. But this bombardment means that, as with ITER, the containment materials and other components will be activated by the neutron flux, and have to be stripped out periodically and stored somewhere, although the half-lives would be relatively short – decades. The radioactive tritium in the reactor also represents a hazard; although the quantities at any one time would be small, accidental release could be very serious.

Overall it all sounds very complex and daunting and not a little worrying. On current plans we might be seeing a prototype working in the 2030s, although that sounds a little optimistic. Meanwhile, other ideas may yet emerge. There is talk of hybrid fusion/fission systems – perhaps using the neutron flux to convert thorium into a fissile material, or to transmute some of the active wastes from fission. And there was me thinking that fusion was meant to replace fission – not support it!

The UK is spending about half its energy R&D budget on fusion, including a contribution via EURATOM to ITER, as well as its national programme (£20 m last year), following on from JET at Culham. HiPER may achieve an earlier breakthrough than ITER, but the UK Atomic Energy Authority has said that, assuming all goes well with ITER and the follow up plants that will be needed before anything like commercial scale is reached, fusion only "has the potential to supply 20% of the world's electricity by the year 2100". Renewables already supply that now globally, including hydro, and the new renewables like wind, solar, tidal and wave power, are moving ahead rapidly – and could be accelerated.

As I said in a previous blog, since we need to start responding to the climate problem now, it might make more sense to speed the development and deployment of full range of renewable technologies, and make use of the free energy we get from fusion reactor we already have – the sun.