Carbon Commentary has visited two sites to look at the costs of building houses under the new rules (not yet mandatory) established by the Code for Sustainable Homes (CSH). By 2016, all new UK homes will have to have no net carbon emissions (‘Level 6’) and the implications for construction techniques are profound. Today, most homes are built to about Level 1, or possibly 2. To get to Level 6 will require huge changes in how houses are built, heated, and ventilated. And they will need expensive renewable energy technologies built into the home as well.

At Wimpey’s 145-home development in Milton Keynes, construction costs of houses at Level 3 are running at ‘100-110%’ more than standard. The self-build company Potton is offering a Level 6 design (one of the first in the UK) for an even more expensive £180 a square foot, up from about £75 for a standard Level 3 model. This takes the construction cost of a standard 1,000 sq ft (92 sq metre) home up from £75,000 to £180,000. Much of the increment comes from the need to install large amounts of renewable electricity generation. Some of the cost premium over today’s badly insulated homes will eventually erode as builders get better at building air-tight houses. But we shouldn’t be in any doubt about the huge implications of the CSH for builders, landowners, and buyers.

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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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Will next-generation biofuels have a less destructive effect on agriculture? A study just published by US government scientists suggests that so-called ‘cellulosic’ ethanol has much better energy balance than today’s biofuels.[1] By energy balance, we mean the energy used to make the fuel compared to its energy value when burnt in a car’s engine. News summaries of the paper’s contents focused on one estimate that suggested that to make cellulosic biofuels might only need 6% of the energy value contained in the fuel. Depending on which crop is used, where it is grown, and how it is refined, most of today’s biofuels have only a weakly positive energy balance. So the paper gives hope that we might expect considerable progress towards carbon-neutral transport fuels when we can start refining all vegetable matter, not just foodstuffs, into fuels.

Cellulosic biofuels may well become important sources of motor fuels. There is certainly huge amounts of money flowing into the field. Unfortunately none of the news articles covering the US research pointed out the technology for turning cellulose into fuel is still a long way from commercial viability. Yes, we can turn grass into ethanol, but at prices which will double the price of petrol. And the greenhouse gas savings will almost certainly not be as attractive as the paper suggests, not least because the authors did not include the serious impact of nitrous oxide emissions from fertilised fields.

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Carbon dioxide levels in the atmosphere rise by about 2-3 parts per million every year and the rate is slowly increasing. As well as this upward trend, there is an annual cycle: carbon dioxide levels fall in the northern hemisphere summer and rise strongly in the winter. The reason is that most of the vegetated land area is in the northern hemisphere and during the northern summer plants and trees absorb CO2.One effect of increasing spring and autumn temperatures has been to increase the length of what is loosely called ‘the growing season’. Plant growth can start earlier in spring and can continue until later. It might be thought that this would help vegetation take up more CO2, acting as a counterweight to increased fossil fuel use.

Research published in Nature in early January very strongly suggests that this is not happening. Warmer autumns are associated with a bringing forward of the date at which plants start losing CO2, not the reverse. Higher spring and autumn temperatures are tending to decrease the length of the period each year in which northern hemisphere plants are taking up carbon. If this research is confirmed, this is yet another potential positive feedback because higher temperatures might diminish the ability of biomass to take up carbon.

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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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