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Zero-carbon Britain 2030

In 2006 the Centre for Alternative Technology (CAT) in Wales produced a very radical ‘Zero-carbon Britain’ scenario, which envisaged UK fossil fuel consumption being cut down to almost zero by 2027, and renewables being powered up to meet almost 100% of UK electricity, with 50% of that from wind, supplying 474 TWh p.a., while overall energy demand was cut by a half. Although welcomed as a visionary exercise setting the outer limits of what might be conceived, as a practical proposal it was met with more or less polite disbelief from most of the energy-policy fraternity.

Four years on, things have changed. The government is now proposing that we get 32% of our electricity from renewables by 2020 – much of it from offshore wind, with up to 40 GW planned. Still a long way short of the CAT’s 2006 vision for 2027, but this is now beginning to look more credible. So it will be interesting to see what the reactions are to the CAT’s revised ‘Zero-carbon Britain’ scenario, running now to 2030, which was launched recently.

It is still very radical, but is much more convincing, in part because there is now more solid data to call on, including the UKERC’s reports and David MacKay’s book, which the CAT relies on heavily.

The new version’s basic plan is similar to their earlier one – a massive 55% cut in energy use and massive reliance on renewable electricity, from offshore wind especially, which, as before, supplies much of the transport energy (via overnight battery charging of electric cars) and heating demand (via heat pumps). But the contribution envisaged from wind is now even larger – 690 TWh p.a. mostly from around 195 GW offshore. And also 75.5 TWh from wave and tidal projects, plus 50 TWh (thermal and electricity) from biomass CHP. Some biofuels are used for transport (112.6 TWh), but 65.8 TWh of renewable electricity, plus 99.8 TWh of hydrogen derived from renewable sources, is also used for transport. Demand for domestic heat is met via heat pumps (61.2 TWh of electricity delivering 148.2 TWh) and 24 TWh of solar heat, plus the biomass CHP heat input, along with 104.6 TWh of direct biomass heat – all of course being used in well insulated homes with lower heat needs.

Interestingly, the CAT does not include geological Carbon Capture and Storage (CCS), which it sees as expensive, not very efficient and still in the development stage. Instead it restricts itself to ‘the proven technology of land-based Carbon Capture & Storage using natural photosynthesis’ and focuses on below-ground storage in soils, above-ground in-situ storage as biomass, and long-life storage in biomass products and in engineered silos. Indeed much of the very interesting section on land use focuses on sequestration, and also on reducing carbon and other emissions from producing (and importing) food – we move away from meat (beef) and dairy (milk). That could be wise, but hard. Possibly even harder, we move away from flying and towards public transport.

On grid balancing, they say that the new offshore wind farms ‘will be commissioned at dispersed locations around the country and the back-up generation consisting of biogas, biomass, hydro and imports will help to manage the remaining variability. However, all of this will need to be complemented with a large increase in the management of electricity demand. Both the supply and demand sides of the equation are malleable and both will require intensive management’.

In particular they look to demand side management i.e. rescheduling some loads via smart meters when energy is most abundant, and therefore cheaper, for the consumer. They mention electric storage radiators, heat pumps, electric vehicles, air conditioners, washing machines, fridges, freezers, dish-washers and tumble dryers. Not all on that list will be popular choices!

Another grid balancing option, in addition to pumped storage and gas turbine back-ups, is the supergrid – but while some imports of green power are envisaged from the EU (it seems about 14 TWh p.a), the CAT does not see us importing energy from Concentrated Solar Power projects in North Africa by 2030: it argues that ‘security of supply is important, and depending heavily on another region of the world therefore needs to be considered carefully in geopolitical, ethical and financial terms’. And, overall. energy exports (174 TWh p.a) will heavily outweigh imports. In general, reflecting its emphasis on localisation and decentralisation, imports are seen as bad – reducing UK reliance on overseas imports of energy and also food and other consumer items, is seen as a key part in reducing our emissions.

To make it all happen the CAT looks to various changes to the support and pricing system. It backs Feed-In Tariffs, but it says ‘to more effectively balance the grid, the government should implement a form of locationally differentiated pricing for new generators within distribution networks to signal the best places to build new capacity, such as at the ends of constrained distribution networks’.

That’s debatable – differentiated charging by area will mean high charges for some of the largest renewable generators (e.g. in Scotland). The Scottish government has noted that, under the current system, a power station in central Scotland pays £25 m more for transmission than a similar facility in Yorkshire. The government has said that the current system reflects the cost, and raises revenue for grid improvement. Similarly, the CAT sees it as necessary for an ‘interim period, until the transmission network is reinforced’. But basically it sees local micro-grids as a key to a more localised future.

It’s certainly an ambitious vision, developing on the new-energy agenda that seems to be emerging in radical ways. And of course with no new nuclear.

What would it cost? The CAT says: ‘Offshore wind is a central part, if not the core part, of building a green, sustainable economy in Britain. This transition and development of new industry requires investment. The peak of £30 bn in 2022 represents only 2.2% of the UK’s 2008 GDP and delivers an electricity generation system, which has very low fuel costs. If we were instead to generate the proposed output of 599 TWh in 2030 from 50% coal and 50% gas, it would incur a fuel cost of approximately £13.5 bn per annum at 2008 prices. In reality these fuel costs are likely to rise far higher by 2030 and would constitute an enormous unnecessary expense to the general public’. The CAT also notes that, at a price of 4p/kWh, the proposed 159.34 TWh of net exports is worth £6.37 bn and it says that ‘this annual income could really help the UK balance of payments’.

The CAT admits: ‘The construction of wind turbines at the proposed rate would obviously require a considerable amount of materials.’ And, based on 45% being steel and 55% concrete, that is 16.2 million tonnes of steel and 19.8 million tonnes of concrete used over twenty years, ‘the embodied energy of steel and concrete for this total build would be 115 TWh’. However, the CAT says that there is a high-energy return on energy invested for wind (it quotes a 28:1 ratio), so the investment is worth it.

You can access the CAT report at www.cat.org.uk.

Posted by Dave Elliott on June 26, 2010 11:09 AM | Permalink