A Beginners Guide to Blackouts

Anticipating blackouts has become a new national sport in the UK. I can recall blackouts as a child. I’m guessing this was during the first 1974 oil shock when OPEC first flexed its muscles and Britain had a lot more oil fired power generation then than it does now. But a quick check shows that Britain was also in disarray because of strikes, especially striking coal miners. Blackouts were a time of excitement where whole towns went black, citizens reached for their candles and crooks reached for their crowbars.

Things have moved on in the intervening 40 years with a much more complex society today dependent upon electronic communications, a myriad electronic devices and economic growth that is founded on reliable supplies of electricity.

Figure 1 “100 crowbars were nicked during the last blackout”

So why does the UK find itself on the threshold of blackouts? Or does it?

The difference between power cuts and blackouts

A good starting point is to understand the difference between a power cut and a blackout. Power cuts tend to be localised and caused by local technical problems such as a power line brought down by a tree or a local transformer fault. A Blackout is larger scale affecting a whole grid segment. It may also be caused by a larger scale failure, such as a power station tripping out. But what we will be mainly talking about here is intentional blackouts where National Grid pulls the plug owing to a shortage of generating capacity.

Power demand pattern in the UK

UK demand for electricity and gas follows a very specific pattern. Electricity I have covered a number of times before. The main point is that electricity demand follows three cycles – daily, weekly and annual. 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).

Figure 2 UK electricity demand follows a very specific and predictable pattern.

Peak electricity demand is always going to be on a weekday in January or February at around 6 pm and especially when the weather is cold. This is when the grid will be at it most vulnerable to failure.

Demand for natural gas also follows an annual cycle (Figure 3) with peaks in December and January each year. A point I will emphasise below is that it will be the UK’s ability to source sufficient gas in mid winter to power its large fleet of combined cycle gas turbines that will determine its ability to keep the lights on. But the picture is a bit more complicated since the UK (and Europe) does have and depends upon gas storage to meet peak demand. Storage is normally full going into winter and may be used to meet the December and January peaks. Supply problems are more likely in February and March if there is a late cold snap and storage runs dry which almost happened a couple of years ago.

Figure 3 UK demand for natural gas also follows a very specific annual cycle.

Sharp eyes will notice that demand for gas dropped significantly in 2012. This is linked to the Fukushima Daiichi nuclear accident in Japan. Japan shut down all its nuclear plants and has ever since been sucking in more than its fair share of global liquefied natural gas supply. So what is the UK now using instead?

Figure 4 UK electricity generated according to fuel type.

Figure 4 shows that the significant decline in the use of gas in the UK for electricity generation in 2012 and 2013 was met by increased coal, increased wind and solar, increased bio-mass and a decline in overall demand. This is a fairly chaotic and toxic mix that is a story for another day. At some point Ed Davey may find it regrettable that the UK has shut down about 7 GW of coal fired plant since 2012 (next chart).

Capacity Margins

The capacity margin is that surplus generating capacity a country has over and above that required to meet peak demand. The margin is required to cover for unscheduled outage of generating plant, for example the UK has two nuclear power plants out of business at the moment. Capacity margin is also required to maintain competitiveness.

Figure 5 Installed electricity generating capacity in the UK.

Figure 5 shows that despite recent coal and nuclear plant closures the UK retains a vast capacity margin of about 20 GW, over 30% of peak demand. So where is the problem? The problem lies in the large slice of total capacity that is gas fired and that brings us back to the question of whether or not we can source sufficient gas this winter to keep us warm and to keep the turbines spinning? This is not a simple question to answer. And a significant chunk of the capacity margin is wind, that may or may not be available.

Renewables to the Rescue

Wind and renewables opponents always hate this part. But it is a fact that if it is a windy winter, wind will generate a significant amount of electricity allowing the UK and Europe to save on natural gas that is cycled down or off when the wind blows*. This eases competition for gas on the international markets and saves gas in storage for use later in the winter when the risk of storage running dry increases. In this regard, wind power may enhance energy security, but only if the wind blows which is leaving our security to chance.

Of course it would have been better to have that extra 7 GW of coal fired power and a gigantic pile of coal sitting by the Humber in reserve.

[* note added 11:45 7th November in response to an email. Over the last 5 years wind and solar has amounted to 1.9% of UK electricity generated. 4.2% in 2013. In 2013, wind and solar amounted to one third of gas. “Significance” is in the eye of the beholder.]

Grid instability

There has been much speculation that a blackout in northern Scotland earlier this year was caused by strong gusting winds feeding irregular wind power on to the grid. There was no evidence that this was the actual cause. But it does seem possible that in future as the dependable dispatchable component of power generation is replaced by intermittent wind that grid stability will become increasingly difficult to maintain in blustery, stormy conditions.


The winter weather plays a large role in determining grid resilience to power cuts in two ways. The first is that a prolonged cold spell runs down natural gas supplies in storage making a country more vulnerable to gas shortages late in the heating season. And second, extreme cold weather pushes up demand for electricity raising the peak load that has to be met. And so, in the UK this winter if it is mild and windy there should be no problem with the grid coping and the same will apply throughout most of northern Europe. But if we get a prolonged cold winter that runs down gas in storage with very cold and calm days in February and March then a country like the UK may struggle to meet peak electricity demand.

The Official View

The official view from the UK National Grid Winter Outlook is typically robust (Figures 6 and 7). National grid presents a picture of a well-supplied gas market with supply capacity well in excess of demand, even in the coldest of winters. Russia is too far away to worry the UK. If all this is true, then the UK will have ample gas to fuel its vast fleet of CCGTs and will come nowhere close to blackouts this winter. This is I imagine what Ed Davey has been told.

Figure 6 The summary prognosis for gas supplies to the UK this winter from National Grid.

Figure 7 A cynic might take the view that National Grid have simply adjusted the gas capacity figures to match anticipated demand. Capacity is a hugely flexible variable while actual gas supply is not.

What might go wrong?

Figure 7 shows where National Grid expects UK gas to come from this winter split roughly into 4 equal parts: 1) UK North Sea production; 2) Norway; 3) LNG imports and 4) pipeline imports from the continent. UK gas storage provides the margin of security. Not so long ago, UK North Sea production covered all of our gas needs.

It is beyond the scope of this post to go into the details of European gas security (I may go into that in a week or two). But suffice to say that if the winter is cold, and / or if Ukraine once again disrupts supplies from Russia, then that will set  the whole of Europe scurrying for alternative sources of supply. Europe will look first to Norway and then to LNG. The UK will find itself in competition with the whole of Europe for gas traded on international markets that have in the past proven to be only just enough to keep everyone’s lights on. And that was before the UK took the wrecking ball to 7 GW of coal fired power generating capacity at the behest of our masters in Europe.

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10 Responses to A Beginners Guide to Blackouts

  1. Willem Post says:


    Britain’s gas situation is directly tied to Ukraine and Russian gas, which is much less costly than importing LNG from mostly unstable countries. Any significant US exports of LNG are at least
    6 – 8 years away.

    The EU must be so proud of itself to have finally added, at the urging of the US, deadbeat, corrupt, bankrupt, dysfunctional Ukraine to its stable of countries, about half of which are 2nd – 3rd tier economic basket cases. If US policy aimed to weaken the EU by adding such countries, it has succeeded.

    Russia insists about $3.1 billion of Ukraine’s $5.4 billion gas debt be paid before the end of 2014, with the rest later, and Russia insists on being paid in advance for any gas deliveries, about $1.6 billion before the end of the year, with more later. The IMF, EU, etc., will have to cough up the money, because Ukraine is broke and broken.

    There is the North-Stream pipeline, under the Baltic, with present capacity of 55 bcm, ultimate 110 bcm, of which only 50%, 27.5 bcm, is allowed to be used because of some inane Third Energy Package Brussels has cooked up to hamstring Gazprom. The 55 bcm matches the sum of OPAL 35 bcm and NEL 20 bcm lines.

    Then there is the South-Stream pipeline, ultimate 63 bcm, start of construction has been held up for Third Energy Package reasons.

    Europe’s energy security and economic well-being is being jeopardized by Brussels, by it insisting Russian gas goes through Ukraine, so Ukraine can collect $2 billion of transit fees, and to have “leverage” over Russia.

    Some leverage. Any future gas Russia will not be shipping to Europe will end up in East Asia (China, Japan, etc.) in a few years, thereby shifting the geo-political center of gravity eastwards.

    Brussels has feet full of holes that are self-inflicted. I am surprised the UK, a proud, independent nation, is still a member of the EU.

    • Euan Mearns says:

      Willem, great comment. I quite simply do not understand the geo political stance of the EU and the USA. Gazprom has largely completed South Stream to provide a stable market for its gas and energy security for Europe but the EU has stopped its construction. There are some seriously dysfunctional people in Brussels.

      • Willem Post says:


        That stance is the State Department neo-cons’, who Obama should have ousted 6 years ago.

        They got the US into Iran, Iraq, etc., with disastrous consequences, and that stance got the US to goad the EU to expand NATO into east Europe.

        The major missing piece, according to the neo-cons, was Ukraine, and after a coup d’etat, that was finally “settled”.

        The EU dysfunctionals in Brussels will be bleeding Europe (and the UK) for $billions each year, for years, to keep Ukraine alive.

        Please read this article. It is rather long, but deserves to be.


      • Lars Evensen says:

        “But if we get a prolonged cold winter that runs down gas in storage with very cold and calm days in February and March then a country like the UK may struggle to meet peak electricity demand.”

        If Weather Services International are correct we might find ourselves in this situation in parts of Europe this coming (late) Winter period. I have followed WSI`s long term forecasts for years and they are remarkably good. Actually so good that I am planning my holidays from their forecasts 🙂

        According to them it looks like January will be colder than normal in the UK and so far it seems a cold weather pattern will be the norm for the Northern half of Europe in late winter also, but with a mild winter until new years eve.


        Possibly the lights on or off in good old Britain depend on Putin, what he`s going to do. The 7 GW of coal closures determined by Brussels are a big disgrace, let us seriously hope Brussels will face a big and prolonged blackout this winter due to the unexpected shutdown of much of Belgium`s nuclear capacity. Oh, sorry I forget they will direct the blackouts elsewhere in case…

  2. Joe Public says:

    Thank you Euan & Willem for enlightening this reader on the intricacies of electricity and gas markets.

    I can remember the time, less than 3 decades ago when British Gas refused as a matter of policy, to sell its product to power stations. It was technically correct that it was ‘wasting’ a premium fuel by burning it in a power station at ~50% efficiency, when it could be burnt in gas appliances at the point of use at ~82% efficiency. Ofgas determined a seller had no right to dictate how a customer may use the product.

  3. bobski2014 says:

    Another brilliant post Euan. Thank you.
    One slight error – “Ed Davey might find it regrettable……” Bet you he doesn’t.

    Davey is playing a whole nother game, I think. Something personally benefits him to be a “believer”. I don’t know what it is, but there’s something.

    He has recently done his bit to further destroy what Britain has left of democracy – regarding windfarms for example he has now outlawed landscape considerations as a planning issue; and worse, has in one stroke rendered the “Human Rights” legal issue regarding some properties near Ruthin, N.Wales, as irrelevant and to be ignored “for the greater good”.

    Turning Liberals into Dictators. Things are not looking good.

  4. Nate Hagens says:

    The correlation between uninterrupted electricity access and economic welfare is extremely high. See graphs here:


    Related analysis here:

    • Euan Mearns says:

      Nate, interesting charts from an epic series of posts. Are the charts showing % of population that have electricity or % reliability of the grid? A while back I was working on a “countries” series of posts that I will return to when I run out of other things to write about. I was reaching conclusion then that per capita electricity consumption was a good metric for “prosperity”. If the UK or Germany does experience blackouts in the years ahead attributed to Energiewende there will be repercussions. But those responsible will be long gone. And as detailed in this post, in the UK at least it is the destruction of coal-fired plant, closure of nuclear and availability of nat gas that are the main risk factors.

    • sam Taylor says:


      The following paper asserts that demand can be met with renewables, though entailing a slightly ludicrous build out. Have you seen it before?


  5. Pingback: Ed Davey in Wonderland | Energy Matters

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