Friday, 16 October 2015

UK gas supply outlook for winter 2015/16

It was back in April that I blogged about the cut Centrica had made in the capacity at Rough, due to problems with some of the wells limiting the maximum operating pressure. At the time, Centrica hoped that by now the capacity would have been restored, but a press release in July said that they now didn't expect to know if this would be possible until some time between September and December 2016! The net result is that the capacity of Rough has been reduced by 25%.

Clearly this presents a problem for UK winter gas supply, so it's not surprising that another July press release stated that the Oil and Gas Authority had given Centrica permission to reduce the minimum operating pressure of Rough, thus 'converting' some of the cushion gas (which would normally be left in the store) into working gas, which can be withdrawn and re-injected. This shows up on the chart below (black line = 2015), where a sudden jump up in July can be seen, due to the addition of about 4,625 GWh (or about 400 mcm). The same trick was pulled in 2013 (red line in chart below), after dipping into the cushion gas in April 2013, capacity was increased arbitrarily in the October 2013. It's a bit like keeping driving your car after the fuel gauge has gone into the red - it works OK for a while, but you can't do it for long...

Despite this bit of creative accounting, the chart below shows that we are still going into this winter with a record low amount of gas in storage, and National Grid's Winter Outlook notes this on page 43, saying storage is reduced by 14%, from 4.9 bcm to 4.2 bcm. It would have been 22% less if Centrica hadn't fiddled the figures by dipping even further into the cushion gas.

UK long range gas storage 16 Oct 2015

Medium range storage is looking better, with increased capacity and a record amount in storage, but nowhere near enough to make up for the shortfall at Rough.

UK medium range gas storage 16 Oct 2015

So, the big question has to be about demand. We have fewer coal power stations than we did a year ago (which is a good thing, of course!), which could in theory mean that more gas gets burned to generate electricity. But the big factor will be the weather as always, which is hard to predict at this stage, as there are several extra factors to bear in mind:
Time will tell, and we'll soon see if this winter looks like this:

or like this:

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Saturday, 11 April 2015

UK gas storage capacity slashed

A couple of weeks ago Centrica Storage quietly made an announcement on its website:

As part of CSL’s assurance programme and as a responsible operator and given the age of the field and installation, CSL has decided to limit the maximum operating pressure of the Rough wells to 3000 psi. CSL has decided to take the prudent step to test and verify the operating parameters of the Rough wells. It is anticipated that this limitation will last up to 6 months.
 Rough is an undersea gas storage facility, connected by pipeline to the terminal at Easington in Yorkshire:
Easington Langeled Terminal

It's able to store about 4 billion cubic metres of gas - or at least it was before the above announcement. Some more detail from Platts indicates that the reduction in operating pressure will reduce Rough's capacity by about a quarter. Because Rough comprises about 72% of the UK's total gas storage, this is equivalent to losing just under 20% from total storage capacity.

Now, Centrica Storage has said this is for six months, while tests are carried out, but Platts notes that the tests are needed because of concerns about well integrity - so it's possible that the capacity will be permanently reduced. Even if it isn't, the coming six months are exactly when the storage is normally refilled, so if full capacity is restored at the end of the testing period, it may well be too late to completely fill the storage.

So, let's assume the UK goes into next winter with 1 billion cubic metres of gas less in storage than usual - what might the impact be? 2013/14 was a mild winter, and Rough still had over 1.5 billion cubic metres left in it in March 2014. It was a different matter in April 2013, when it had actually gone below 'zero', eating into the gas cushion that was supposed to be left untouched. This year, there's about 0.5 billion cubic meters left in it right now - the situation was similar every year from 2008-2011 inclusive. This means that if the coming winter is mild, we should have no problems; if it is average, then we will probably need to increase imports, which will bump up prices; if it is cold, then we could well have a problem.

The graph below shows the levels in Rough over the past few years in GWh (10 GWh is about the same as 1 million cubic metres), so you can see the situation for yourself. Any year where the level dropped below 10,000 GWh is a year when the announced capacity reduction might have been a problem:
UK long range gas storage

Let's hope and pray for a mild winter!

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