National Grid

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Image source: TreeHugger.com.

Image source: TreeHugger.com.

One of the frequent criticisms of wind energy is that national distribution systems (‘the grid’) cannot cope with large number of turbines because of the variability and unpredictability of their output. Grids need to match supply and demand precisely, the critics say, and because wind varies so much it causes huge problems. Recent data from two meteorologically unusual days in Spain – the world leader in the management of renewable energy supplies – shows this assertion is almost certainly false.

  • During part of 8 November, Spain saw over 50% of its electricity come from turbines as an Atlantic depression swept over the country’s wind parks. (They are so big that no one seems to call them ‘farms’.) Unlike similar times in November 2008, when Spanish turbines were disconnected because the grid had an excess of electricity, the system accepted and used all the wind power that was offered to it.
  • A very different event in January of this year saw unexpectedly high winds shut down most of the country’s turbines with little warning. The grid coped with this untoward incident as well. These two events show that a well run transmission system can cope with extreme and unexpected events even with a large fraction of power provided by wind.

Over the course of this year Spain will generate about 14% of its total electricity from wind and this number is likely to rise to the high twenties by 2020. Spain is showing the rest of the world that these figures are not incompatible with grid stability. Although wind is ‘variable’, ‘intermittent’ and ‘unpredictable’, a well functioning grid system can still use wind to help stabilise electricity costs, reduce carbon emissions and improve energy security.

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Mitsubishi Ecodan. Image source: Ecodan Brochure.

Mitsubishi Ecodan. Image source: Ecodan brochure.

(The information in this article has been updated by a more optimistic article that looks at the before and after experience of a ASHP installation in Oxford, Please go to http://www.carboncommentary.com/2010/08/03/1632)

Small heat pumps are increasingly used to provide space and water heating in UK homes. This trend is strongly encouraged by policy-makers and the government’s proposed Renewable Heat Incentive will add further financial support. The enthusiasm for this expensive technology should be moderated: for a home on the mains gas network, the savings in money will be small. Carbon benefits are probable but far from guaranteed. Moreover, air source heat pumps are unlikely to be able to heat many older homes effectively. Government, manufacturers, and installers need to be very much more cautious in encouraging the use of heat pumps and should use far more conservative payback assumptions. Heat pumps will eventually be a good investment for homeowners but probably not yet.

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Copyright: Monkey Business - Fotolia.com.

Copyright: Monkey Business - Fotolia.com.

Electricity demand has fallen substantially in the last couple of years and shows no sign of recovery. The cause could be:

  • The impact of economic slowdown
  • Better energy efficiency
  • Demand reduction because of the high prices seen in recent years.

If the cause is the contraction in the economy, then we can expect electricity use to rise again when growth resumes. On other hand if it is energy efficiency, then it is reasonable to expect that the reduction will persist. Electricity demand is usually thought to be insensitive to the price of power. If it is high prices that are driving usage reductions, we have gained important information about how to reduce electricity use, and thus carbon emissions.

The conclusion of the analysis in this short note is that almost all of the reduction in energy demand comes from cuts in usage in big industrial and commercial users. This means that the most likely cause of the cut is the fall in economic activity. Household demand seems to have remained about constant.

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In today’s Independent newspaper (London, Monday 23 February) I argue that we may need to accept some new nuclear power stations. I put forward the view that the trench warfare between the pro-nuclear groups and those that support renewables means that progress towards ‘decarbonising’ electricity generation in the UK is too slow. We probably need to invest in many different types of non fossil-fuel generation as rapidly as we can if we are to meet the tough targets for UK emissions reduction so painfully won by groups such as Friends of the Earth. We no longer have the luxury of ruling out nuclear expansion.

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Photograph: Christopher Thomond. Source: Guardian.


The new Conservative policy document on energy is keen to emphasise how smart it is. At its core are proposals for smart meters, smart grids, and smart battery charging. The enthusiasm for these technologies is almost palpable. On one page, the word ‘smart’ occurs eight times. But readers of the policy proposals are largely left in the dark about what all these intelligent devices will do. David Cameron’s comments about building ‘an electricity internet’ didn’t shed much light either.

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Renault’s Zoom concept electric car. Image source: Auto Express.

Most major countries in Europe have decided to focus on one or two technologies to reduce carbon emissions. By making concentrated investments in one or two promising areas these countries are likely to achieve substantial cost reductions and rapid increases in deployment. By contrast, the UK is dabbling ineffectually in several areas and achieving little. Despite having large resources of renewable energy sources, the UK’s effort is diffuse, trivial in scope and clearly insufficient. We have almost the lowest percentage of our energy coming from low-carbon sources in the EU.

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The Pentland Firth

The Pentland Firth
The Pentland Firth. Image source: The Crown Estate.

The funnel of water between the north-east tip of Scotland and the Orkney Islands contains some of the most powerful tidal energy in the world. The exploitable resource at the time of the fastest running tides may be as much 8 gigawatts. One source I have talked to suggests the figure could even be as high as 20 gigawatts. As I write this note, the National Grid’s website gives an estimate of the electricity use at this moment – about 55 gigawatts at peak-time on a winter evening. Be in no doubt, the Pentland Firth is the single most important source of renewable energy in the UK. The power concentrated in this narrow stretch of water could comfortably provide London’s electricity need. And it is entirely predictable to within a few percent every minute of every day. The tidal power will peak twice every 24 hours in a cycle that the Grid will be able to plan for decades in advance.

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Sizewell B nuclear power station
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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