Blackout Britain?

Why is there a perception that the UK faces an ongoing risk of electricity grid failures? At the end of May 2013 the UK had 416 power stations, counting wind farms and hydro dams, ranging in nameplate capacity from 1 to 3870 MW. The combined capacity in 2013, following large combustion plant closures, was 80,514 MW down from 92,044 MW in 2012 (Figure 1). With peak winter demand roughly 55,000 MW there still seems to be ample spare capacity to guarantee electricity supplies (Figure 1). Why then is there so much talk on the media, blogs and from the CEO of National Grid about pending blackouts in Britain? The answer is not what many may presume it to be.

Figure 1 During the 1960s to the 1980s Britain was largely dependent upon coal and nuclear power for electricity supplies. Natural gas (CCGT) was introduced in the early 1990s and expanded year on year until 2004. At the end of that decade a second phase of CCGT building got under way adding a further 9,274 MW of capacity, which with hindsight appears to be an extraordinary investment decision. The closure of 11,530 MW of large combustion plants has resulted in the decline of UK generating capacity. The expansion of wind got underway in the early 21st century. Wind capacity is not varied into the future. It can be expected to grow some, but not at the historic rate since companies are becoming shy of investing in Britain’s chaotic energy market. Data from DECC table dukes5_11.

Britain has 31,637 MW of CCGT capacity (combined cycle gas turbines) but lacks access to sufficient gas to run this fleet at anything close to capacity. During the cold spell at the end of last winter when gas storage was run down to empty the maximum output from the CCGT fleet was 22,000 MW, just 70% of the installed capacity. The closure of 11,530 MW of large combustion plants (coal and oil) has of course created the electricity supply crisis. But given that these power stations are now gone, it is a shortage of gas that creates the current blackout risk.

Figure 2 shows the pattern of electricity demand in the UK for January and July 2009. In 2009, peak demand was 58.9 GW at 6pm on a Tuesday in January and the minimum demand was 22.3 GW at 6 am on a Sunday morning in July.  Peak demand is 2.64 times greater than the minimum demand and the electricity delivery system requires the flexibility and controllability to match supply with demand exactly at all times.

Figure 2 UK electricity demand for January and July 2009 shows three cycles in the pattern of demand. The daily cycle has peaks during day time, with maximum demand normally at 6pm, and troughs at night. The weekly cycle shows increased demand Monday to Friday with reduced demand on Saturday and Sunday. The annual cycle shows increased demand in winter compared with summer. This provides a picture of activity and expectations of the society we live in. We like to stay warm in winter, we go to bed at night and we have weekends off work. 

For the time being, blackout risk in the UK is confined to the short periods of peak winter demand that invariably occur at 6pm in the winter months. And the blackout risk is hightened towards the end of the winter when our’s and Europe’s gas storage has been run down. Figure 3 shows gas generating capacity curtailed to 22,000 MW which is an approximation for current gas supply limits. Wind, that is not dispatchable, is removed.

Figure 3 An approximation for the deliverability from UK power stations with CCGT curtailed to 22,000 MW and wind power removed. On a calm, cold weekday at the end of a long cold winter, there is a risk of blackouts in the UK and that risk will increase as the decade progresses.

This now shows the nature of the blackout risk that we face. Should we have a cold winter that drains storage and cold weather in February or March and little wind across the UK and near continent then there is a blackout risk, especially if there are outages at nuclear or other generating plant, which is quite common. This risk will increase towards the end of the decade if planned nuclear closures go ahead and if there are further closures of large combustion plants.

At present, understanding the blackout risk in Britain boils down to understanding the security of future gas supplies and that is not a simple task. The hightened blackout risk of March 2013 came about because of LNG Heading East as a consequence of the Fukushima nuclear disaster in Japan. Closer to home, UK supplies may get some relief in the next few years as a number of new projects come on line, and if there are significant shale gas discoveries. Offsetting that are plans in the Netherlands to cut production in the giant Groningen field and the inevitability of a future peak in Norwegian gas production. We seem set to become increasingly reliant upon Russia for gas supplies that also provides our electricity security.

Other posts

European gas security
UK electricity demand GDP, and energy policy
The changing face of UK electricity supply
Parasitic wind killing its host
Brave Green World and the Cost of Electricity
The Coire Glas pumped storage scheme – a massive but puny beast
Energy Matters’ 2050 pathway for the UK
How Much Windpower can the UK grid handle?

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17 Responses to Blackout Britain?

  1. Roger Andrews says:


    Excellent summary.

    But as the philosopher Yogi Berra said; “It’s tough to make predictions, especially about the future.”

    This seems to be the case here. Your Figure 3, for example, shows no significant decrease in dispatchable capacity between now and 2018. Ofgem, however, foresees a loss of ~3.5GW over this period. See Figure 1 in:

    And in 2011 Timera Energy came up with the following disaster scenario:

    “To summarise the capacity retirement picture, it is likely that at least 15 GW of coal, oil and nuclear plant will close by 2016, with 20GW closing by the end of the decade. In addition there is the potential for a further 20-25GW of mostly CCGT capacity to retire by 2020. If, for the sake of argument, half of these potential closures eventuate, it would increase total plant retirements to around 20GW by 2016 and 30GW by 2020.”

    More info on plant closures here, but probably out of date already at the speed things are moving:,-where,-and-why/

    The big unknown, of course, is what impact the Electricity Market Reform package will have, but as far as I can see all it does is offer to pay dispatchable power producers to keep their plants on standby so that wind power can continue its uninterrupted march into a bright green future. Whether this plan will work is questionable, but if it does you can be sure of one thing. You will be paying the coal and gas plant operators for not generating electricity too. 😉

    • Euan Mearns says:

      Roger, In my Figure 1, there is 16 GW of net capacity reduction from 2012 to 2020. A couple of years ago that figure would have looked higher but a couple of nukes have been given license extensions. I suspect there will be more of that to come.

      We have too much CCGT capacity, and so if some of that is retired it will make little difference to the security picture unless gas can be found to run them.

      It is how the government manages the idle, unprofitable, reserve CCGT capacity that is key. If what you say is correct about the electricity market reform then prices will be going higher.

      Understanding the investment rationale is a challenge. About 9GW of new CCGT capacity added a few years ago, as far as I can tell proximal to LNG import terminals – it was like a fight was on for the gas. He who was closest to the supply wins.

      • Roger Andrews says:

        Euan: If you have the time to wade through it all I’d be interested in your take on the govt’s EMR proposals:–2/supporting-pages/electricity-market-reform

        • Euan Mearns says:

          Roger, opaque, Orwellian. Contacts for difference (cfd), Wikipedias take (and mine);

          For example, when applied to equities, such a contract is an equity derivative that allows traders to speculate on share price movements, without the need for ownership of the underlying shares.

          But then this at the end:

          Securing the UK’s energy supply

          The UK’s electricity market has historically delivered secure supplies and comfortable capacity margins. There is a risk the investment needed to reform the electricity market may not be forthcoming, which will increase risks to the security of the UK’s energy supply. The Department of Energy & Climate Change (DECC) and the Office of Gas and Electricity markets (Ofgem) have produced models that suggest capacity margins will tighten towards the end of this decade, potentially to levels that significantly increase the risk to reliable supplies.

          New capacity is needed to replace retiring coal, nuclear and older gas power stations and help ensure the continued reliability of electricity supplies. It is therefore crucial that we deliver new investment, and that the market brings this forward in a world where gas-fired plants run less frequently as we move to low-carbon forms of power.

          A core element of Electricity Market Reform, the Capacity Market will incentivise sufficient reliable capacity (both supply and demand side) to ensure a secure electricity supply even at times of peak demand. Government will run the first Capacity Market auction in 2014 for delivery of capacity from the winter of 2018/19, subject to state aid clearance.

          By supporting all forms of low-carbon generation, our reforms will also diversify the UK’s domestic energy supply. This will help improve the UK’s energy security and reduce reliance on energy imports. This will help keep the lights on in the UK and protect consumers against global spikes in fossil fuel prices. We are also taking action to reduce electricity demand. Reducing the amount of electricity the UK uses by being more efficient can help cut energy bills for consumers, reduce costs for businesses and bring down our emissions. Following a consultation earlier this year, we have tabled amendments to the Energy Bill so that a financial incentive to encourage permanent reductions in electricity demand can be delivered through the Capacity Market.

          The UK reality is bound up in this statement – my emphasis added. No mention of climate change!

          • Roger Andrews says:

            Thanks Euan:

            I liked this bit at the beginning: “(T)he policy challenge is to meet our three objectives (energy security, decarbonisation and affordability) by encouraging huge investment in the electricity infrastructure, in the face of pervasive uncertainty.”

            Huge investment in the face of pervasive uncertainty? That’s a neat trick if you can do it.

            However, I do see the ERM as positive in that it shows that the govt has finally realized that you can’t replace good ol’ dispatchable generation with intermittent renewables. It’s too early to say that sanity has set back in, but we do seem to be heading in that direction.

  2. Hi Euan,

    Great post. Any plans to increase the gas storage?


    • Euan Mearns says:

      Dave, UK gas storage used to be in the form of full reservoirs in the N Sea. Now it is in the form of LNG tankers that are supposed to be bobbing up and down in the Mediterranean en route to the UK.

      The storage market used to be driven by gas price differentials between summer and winter time. This differential I imagine is severely eroded in recent years – though these prices are commercial secret.

      The UK will do anything to avoid doing something sensible like a major strategic expansion of gas storage.


  3. G. Watkins says:

    Thanks Euan, again, and Roger.
    Interesting times.
    Can’t wait for the diesel generators to be employed for STOR

  4. A C Osborn says:

    Euan, there is also about 3Gw of ICT from France and Holland.

    • Roger Andrews says:

      Most of the time, but you can’t count on it. For much of the first half of December 2013 the UK grid was exporting power to France, Holland (and Ireland) during peak demand periods:

      Euan also includes a few GW of pumped hydro, but I’m not sure you can’t count on that either because it could rapidly be depleted during a supply squeeze. UK pumped hydro facilities are capable of putting out only about 2.5GW for 8-10 hours, and that assumes the reservoirs are full to begin with.

    • Euan Mearns says:

      AC and Roger, I make the point about calm conditions on the continent. If its calm over the UK but windy on the continent, then the continent may have juice to send our way. But if its calm everywhere, not. I’m also unsure how much surplus nuclear capacity there is in France – a country that seems to bleed electricity in all directions. The pumped hydro I assume can be fully recharged at night from surplus nuclear – but I don’t know for sure.

      Mt main point is how everything at present hinges on gas. If we have access to plenty gas then there will not be a near term blackout problem. As Dave Rutledge observes, what about expanding UK gas storage. The government could and perhaps should decide to build a 30 day strategic storage reserve. Create employment, and then maybe sell to private sector. With many defunct reservoirs in S N Sea, I’m sure one of these empty fields could be converted to long term storage like Rough. Doing that would eliminate the blackout risk until they get a proper energy strategy sorted, as you know I favour nuclear.

  5. Mike Parr says:

    Interconnectors with mainland Europe will expand in the next few years with 1GW through the channel tunnel making for around 4GW. There are also feeds to Ireland.

    Mr Andrews comment “Most of the time, but you can’t count on it” is an unsupported assertion. If there is a “shortage” of power in the UK then spot market prices will reflect this and the flow will be from mainland Europe to the UK (this comment applies to the BritNed merchant connection ditto .the Channel Tunnel connection).

    In the case of French nuclear, & given the comments with respect to cold calm march, this corresponds to problems that the French have with capacity factors of their nuclear fleet at that time of the year – when hydro in the Alps is must-run, & demand is declining leading to a surplus of power looking for somewhere to go. EdF is projecting French nuclear CFs to head towards 50% or less by 2020. It is thus well within the capacity of the Uk to build new interconnectors to France to purchase power from this country. An alternative would be meaningful energy efficiency measures. Either or both would avoid any capacity problems.

    • Roger Andrews says:

      “Mr Andrews comment “Most of the time, but you can’t count on it” is an unsupported assertion.”

      The assertion is supported by National Grid data, as shown on the graph I posted earlier. Here it is again for reference:

      “If there is a “shortage” of power in the UK then spot market prices will reflect this and the flow will be from mainland Europe to the UK”

      National Grid data show flows from mainland Europe tending to decrease, not increase, as UK peak winter demand increases:

    • Euan Mearns says:

      Mike, agreed that inter connectors need to be taken into account when looking at detail. The points you make about French nuclear are useful to know – with of course warmer weather spreading into southern France in the spring. My main message was that the blackout risk was small and for limited time only with exceptional circumstances, and of course adding 3 to 4 GW of interconnection makes that risk even lower. But it leaves me wondering why the chief of National Grid should join in cheerfully warning of blackout risks in the years ahead.

      In the circumstances the UK can ill afford to lose more large, non-gas power stations.

  6. Euan,

    Laggan Tormore comes online this summer and will soon ramp up to 500 million cubic feet per day. I think the UK currently consumes 8,000 million cubis feet per day so a decent uplift.

    Also, the UK has the ability to import electricity from the continent. So in order to truly assess the blackout risk you would need to consider the make up of electricity generation in France and Germany, the Netherlands, etc.

    Treating the UK as a closed system is not quite correct and we know France has ample nuclear (non-gas) capacity.

    You would need to look at how French demand flux fits into our own. Maybe the French spend an extra hour in bed and therefore we can import some of their capacity without much of a problem? Simply because the peaks are offset.

    Maybe the solution is as simple as the UK putting our clocks forward by 1 hour so that we can use French reactors?

    The cost of such a solution is zero. Nil. And it can be implemented at 24 hours notice.

    • Euan Mearns says:

      Stuart, thanks for info on Laggan – UK’s first west of Shetland gas field. I did a little work on that decades ago. Jasmine was also supposed to come on last year but I hear has problems. A comprehensive forecast of UK oil and gas production is on my to do list – but its a big job. Meanwhile the SNS seems to be dying.

      Managing the 6 o’clock peak in demand seems like a no-brainer and I keep wondering why more is not done there. I’m not sure the French would agree to change their clocks 😉 We have grid watch France in the pipeline which will make it easier to understand how peak demand varies either side of the channel. A BBC program this week on The Grid had an interesting piece on a company that was offering peak demand management for industry. Basically switching lots of stuff off that didn’t need to be on. I’m sure 3 to 5 GW could be shed with a little determination.

      • Roger Andrews says:


        I got intrigued by the idea of smoothing out peak demand between the UK and France by moving clocks forward or back so I did a little messing around with peak demand curves. Assuming that the demand curve is the same in France as it is in UK, and it’s probably not too far off, I found that the clocks would have to be shifted by at least three hours to have any significant smoothing effect. I suspect this may be why more isn’t being done here.

        I’ll re-do the analysis when the French grid numbers become available. Any idea when this might happen?

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