power generation

Offshore location map of the London Array. Click on the image to see a more detailed map from the London Array website (opens as a PDF).

Shell backed out of its commitment to provide the financing for one third of the world’s largest offshore wind farm off the Kent coast. The London Array, expected to cost about £2bn, now needs to find a new investor. What about tapping the public? The project has reasonable economics, and private individuals could benefit from 40% tax relief by putting shareholdings into pension plans. Perhaps as importantly, such a move would raise understanding of renewable energy generation among the wider community.

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Sizewell B nuclear power station

In the past three months, John Hutton, the UK government minister in charge of industry, has publicly backed an expansion of both nuclear and of offshore wind. Is this good for the UK’s climate targets? Possibly not.

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The new Finnish nuclear reactor at Olkiluoto (OLK3)

Nuclear power may or may not be an unfortunate necessity. But a look at Finland should temper any optimism about construction costs.

The government’s decision in early January 2007 to support (or, more precisely, not oppose) the construction of nuclear power plants in the UK prompted strongly felt responses from all sides. To the electricity generating industry, nuclear power represents an attractive way of reducing emissions. To most – but by no means all – environmentalists, the push for more nuclear power is both a mistake and a missed opportunity: a mistake because no country has yet shown that nuclear waste can be stored effectively, and a missed opportunity because nuclear baseload generation reduces the incentive to develop wind and tidal power.

This article looks at what we can learn from the building of the nuclear power station at Olkiluoto (OLK3) on the western coast of Finland. The ground works started here in early 2004 and the plant is now due to open in 2011. Does this project give us confidence that nuclear power stations can be constructed at a reasonable cost and to a reliable timescale?

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E.ON’s planned Kingsnorth supercritical coal plant

E.ON’s plan to install supercritical coal-burning technology on its Kingsnorth site in Kent was (unsurprisingly) supported by the planning authority. A more interesting question is why E.ON persisted with the application in the first place. Even carbon efficient power stations emit far more carbon than gas plants. A high price of carbon would make the Kingsnorth coal plant uneconomic. The answer to the question must be that E.ON is confident that supercritical coal plants can be economically retrofitted with carbon capture technology (CCS). So even if the carbon price increases dramatically, coal will still be competitive.

E.ON’s US operation is closely aligned with the co-operative FutureGen venture, which plans to build a coal gasification plant in the US within five years. This power station will then capture CO2 and store it in sandstone. FutureGen gasification carbon capture technology is ‘pre-combustion’, unlike the ‘post-combustion’ focus in Europe. US electric utilities are now assuming that coal plants without CCS will not be allowed. But in both the US and Europe there seems to be a prevailing assumption that a $30 per tonne CO2 price is sufficient to cover the cost of CCS technology, meaning coal will eventually be back in the power station mix.

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The UK government has announced an intention to allow offshore wind farm development around most of the UK. John Hutton suggested that about 33 GW capacity could be added by 2020. This would provide about 25% of current UK electricity demand (which is itself rising by 1 to 2% per year).

Simple calculations suggest that this change may add about 15-25% to UK electricity bills. Offshore wind is more expensive to construct and operate than onshore wind farms. The announcement may suggest that the government believes that offshore wind can be pushed through but that onshore farms are likely to be successfully opposed. The big push for offshore wind seems to mean that the government is losing faith in nuclear.

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The Conservative Party published a policy paper in early December on decentralised production of energy. It argues for heavy subsidy for small-scale generation of electricity. The report is useful in focusing on the need to minimise the finance and administrative burdens on small generators. However, it omits any consideration of the costs of the scheme it proposes. It is woefully ill-informed about developments in other countries. The Conservatives have subscribed to a romantic view about micro-generation and are choosing to ignore the huge costs of subsidising inefficient local generators. If they want large-scale low-carbon generation they should either back nuclear, remove the planning problems with wind, subsidise tidal or biomass power, or invest in CO2 capture.

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The environmental community tends to think that Gordon Brown doesn’t understand the complexity and size of the climate challenge. His first speech on the subject gave more detail than expected and reassured some that the prime minister does recognise the severity of the challenge. He moved towards an 80% reduction in GHGs by 2050, but even under optimistic assumptions his plans will not result in emissions reductions on the scale required. All his proposals were pain-free. He does not yet believe that the electorate is ready to face the real challenges of emissions reduction.

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In Denmark and Germany, large numbers of individuals own shares in local wind farms. If the government encouraged this in the UK, a large part of the local opposition would disappear. Onshore wind farms in windy locations are good investments which could form an effective part of many people’s pension plans.

One of the few co-operatively owned wind farms in the country has almost finished raising its funds. Investors have put up £3m to buy two existing turbines in the Fens. Locally owned wind farms should be encouraged as a cost effective means of cutting emissions.

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BT uses over half of 1% of the UK’s electricity and is the single largest purchaser of green electricity in the UK. It buys over 10% of the country’s total supply of renewable electricity. It now seeks to develop wind turbines on some of its own sites. It intends to invest in about 120 2MW turbines to produce about a quarter of its own electricity or between 0.1 and 0.2% of the UK’s total need.

This is an impressively large plan. The cost is about £250m. The financial return will depend on how much of the electricity replaces power BT would have bought from other suppliers and how much is ‘exported’. Assuming very little is used by BT itself, the return will be approximately £50m a year, yielding a return of about 20% on the initial investment. These figures assume that BT gets a yield of about 28% of the rated capacity of the turbines, which is about the UK average.

These figures depend entirely on finding sites. I think that BT may well have substantial difficulties finding as many 120 places where it can capture enough wind to average 28%. Perhaps more importantly, at many of those sites which do have enough wind, I think it will have problems getting connections to the local distribution network. Two of the three initial sites identified by BT are in the Scottish Islands. Although a typical 2MW turbine is not a huge generator to add to the local network, the islands have quite limited electricity needs. Scottish and Southern may not easily be able to add these turbines to their network.

When I asked BT whether it had approached the local distribution companies to check on this point, I was not given an affirmative answer. This raises the possibility that BT announced these plans before detailed consideration of whether its aspirations are technically feasible. So it may be a great idea to erest wind turbines, but it looks like it will be much more difficult than BT realises. Companies like Ecotricity have been developing wind turbines on industrial sites for years. Though planning permission is easier, there are still huge obstacles to overcome. BT needs Ecotricity’s expertise immediately, but it will still struggle to meet its aspirations to grow its wind power capacity.

It is adventurous of E.ON to decide to invest in tidal stream generator farm. The announcement in the last few days confirmed that the company intended to put a tidal plant off the coast of Wales in a partnership with Lunar Energy.

The Severn barrage scheme (see Carbon Commentary Newsletter #3) is a ‘tidal range’ scheme. The electricity is generated by damming the river at high tide and then letting the water flow out through turbines as the tide falls. Tidal stream technology captures the energy of the tide as it flows through constricted channels. The UK has many potential sites for tidal stream power stations, but the best locations are off the north coast of Scotland and around Alderney in the Channel Islands.

Why then has E.ON chosen Wales? Perhaps the company doesn’t want to test the technology in the toughest conditions. An attempt to use similar underwater turbines in New York’s East River has been frustrated by the breaking off of the tips of the turbine blades in the fast flowing tides. The UK’s offshore conditions will be far tougher. Or it might be that E.ON knows that it would be expensive or impossible to connect the turbines to the distribution grid in the locations of highest energy potential (see the news story in this section on BT’s plans for wind turbines in Orkney and Shetland). Previous rumours have suggested that the eventual site chosen will either be off the coast of Pembrokeshire or off Anglesey.

The recent report into the Severn barrage noted that there at least 24 different technologies for capturing tidal stream energy in the UK. The device promoted by Lunar Energy sits on the sea floor, is about 20m long and has a turbine diameter of about 12m. The blades sit within a case which focuses the tidal flow. As a Venturi device, the speed of the water flow within the case is greater than the flow outside, adding to the amount of energy that can be captured.

Is wave power economic? It is probably too early to say. The UK has excellent tidal streams around the country, but even this advantage may not be enough. Lunar Energy optimistically quotes figures of around 2.5p to 5p per kilowatt hour, which would make the technology extremely attractive, but these figures appear only to be based on some guesses made in the US. The Carbon Trust’s recent report suggested figures at least three times as much for the first implementations of tidal stream power plants. On the other hand, informal figures from the New York project have suggested figures close to the Lunar Energy estimates.

E.ON has been working with Lunar Energy for some time. It had been thought that the generator would not commit until after sea trials of the first Lunar device in Scotland next year. Last week’s announcement suggests that E.ON’s confidence in the technology and Lunar Energy is high.

Nobody expects a Severn barrage to be built soon. But government opinion appears to be swinging in favour of the idea. The independent Sustainable Development Commission has just brought out a report that broadly supports a barrage. Though the environmental costs will be high, it says that mitigation measures will counterbalance some of the damage.

We now also have a better feel for the economics of the scheme or, more correctly, for both of the two main options for blocking the Severn. The bigger scheme blocks the estuary between Cardiff and Weston-super-Mare. It will cost about £15bn and deliver just under 5% of the UK’s electricity. The smaller – just downstream of the Severn bridges – will cost a tenth as much, or £1.5bn, but will provide a sixth as much power as the bigger project.

£15bn to build a barrage that decarbonises less than 5% of the UK’s electricity supply is a high price to pay. Scaled up to the whole of the electricity business, this is about 20% of one year’s GNP to replace coal and gas power stations. Even over twenty years, this cost is similar to Stern’s estimate of the cost of reducing the UK’s emissions for the economy as a whole. The smaller barrier delivers much less electricity, but at a capital cost per kWh of little more than half its larger cousin.

The Sustainable Development Commission acknowledges that private financiers are unlikely to put up the cash for the bigger scheme. The report doesn’t really discuss the viability of the smaller barrage but it is much more financially attractive. In terms of total capital cost and expected yearly output, the upstream barrage is very similar to the huge wind farm development called the London Array. The Array will be constructed with private capital. I believe that if the current renewable electricity support scheme remains in place a barrage across the upper Severn can be built with risk capital.

The Sustainable Development Commission thinks that the bigger scheme should be built with public funds. I am not convinced by this. The offshore wind resources around the UK are orders of magnitude greater than the useful energy of Severn tides. If the larger Severn barrage has construction costs of nearly twice the typical figures for offshore wind, wouldn’t it be better simply to speed up the licensing of wind farms?

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Do dedicated biomass electricity generating plants make financial sense?

E.ON UK has recently announced a plan to build a second power station using 100% energy crops as fuel. The first investment – a £90m power plant at Lockerbie in Scotland – will open within the next few months. The second plant, still only in the planning stage, will be in Sheffield on the site of a previous generating station. Both power plants will use wood from forestry and specially planted willow but Sheffield will also burn waste wood from other sources, such as industrial pallets. These are the first two large-scale plants in the UK if we exclude the ill-fated Arbre plant of several years ago. (Arbre was an extremely advanced wood chip gasification plant built in Yorkshire. It was never fully commissioned.)

By the standards of the electricity industry, the E.ON investments are tiny. The proposed Sheffield plant has a price tag of £44m compared to £1bn for E.ON’s intended investment in the new super-critical low(ish) emissions coal power plant at Kingsnorth in Kent. Nevertheless, Lockerbie and Sheffield do appear to make good financial sense, at least in part because of the revisions to the renewable energy subsidy scheme announced in the government’s June 2007 Energy White Paper.

This article looks at the prospective financial return from operating a power plant burning wood and other energy crops.

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