How Much Power Will Be Wasted In A Low Carbon World?

Written by Paul Homewood on October 25, 2019. Posted in Current News

http://fes.nationalgrid.com/

I looked at the National Grid’s latest “Future Energy Scenarios” plan (FES) a few weeks ago. As you may recall, the plan was based around an alarming shortage of  the dispatchable capacity needed to meet projected demand in 2050.

Today though I want to look a separate aspect.

First let’s consider projected capacity and generation. As usual, I will assume the Two Degree (TD) scenario, which is the core one designed for hitting the original Climate Change Act target of a cut in emissions of 80% from 1990 levels. (The government’s switch to a net zero target was too late for the FES to incorporate):

And if we put the actual numbers on the main items:

We can see that capacity utilisation is extremely low on thermal and even CCS, only kicking in when urgently needed. Similarly, other renewables are regarded as low priority.

On the other hand, wind and solar look to be supplying all of the power that they are able to generate. This immediately sounds suspect, given that there will be many occasions when they are producing far more power than the system can possibly take.

Significantly, we also see that nuclear is only running at 64%, a level at which it is totally unviable economically. For instance, the costings for Hinkley Point will, I would guess, assume running at around 95% capacity. EDF’s contract for Hinkley stipulates that they are compensated if its output is curtailed by the government or grid. Therefore, if the market is rigged in favour of wind power, for instance, the government may have to compensate EDF. It is certainly inconceivable that other operators would not insist on the same protection.

It would appear that the FES has deliberately cut its projections for nuclear, in order to make wind and solar look more viable.

Either way, of course, what matters is that the inclusion of so much wind and solar capacity will inevitably create a huge surplus at times, when electricity is effectively just thrown away. The alternative would be to build much less renewable capacity, which in turn would lead to large shortages at other times of year.

To elaborate, the FES is projecting total supply of 457 TWh in 2050, which represents an increase of 37% above today’s figure of 333 TWh.

Last year, supply in the summer half year (Apr to Sep) amounted to 153 TWh, an average of 35 GW. so if we add 37% to that we get 48 GW.

Let’s now make the reasonable assumption that nuclear generation is prioritised, ie that all its output will be used. This is likely to be the case, as nuclear provides an essential baseload and cannot be switched on and off all the time. So that’s 16.6 GW.

Let’s also assume that all solar output is also used. In the summer half year, solar runs at an average of 17% utilisation. With a total capacity of 42 GW, this would yield 7 GW. Note that this assumes hour to hour and day to day variations can be smoothed out by storage.

That gives a base of 23.6 GW, from nuclear and solar. With average summer demand of 48 GW, that would only leave 24.4 GW to be supplied by wind power, and other sources.

About a third of wind capacity is assumed by the FES to be onshore, so a reasonably weighted average loading is 39% (based on 28% and 45% for onshore and offshore respectively). Therefore with a total wind capacity of 78.9 GW, the average would be 30.8 GW.

In others during the six summer months, even if average wind output was maintained 24/7 (or storage was used), 6.4 GW would be thrown away, totalling 28 TWh.

Inevitably however the total wasted would be several times greater, as output is not even. On some days, not enough power would be generated, and on other much too much.

We can of course ignore storage. The FES sets it at 22 GW, yielding little more than 22 GWh if current batteries are anything to go by. That capacity would be barely cover the intra daily fluctuations in solar power. At average capacity of 30.8 GW, daily wind output would amount to 739 GWh.

The other possibility is exporting the surplus, but who would want it? When it’s windy here, it is likely also to be in much of northern Europe. Even if we could sell, it would be at a knockdown price.

The FES does recognise this problem, but seems to underestimate the size of it:

The CCC’s Fifth Carbon Budget did attempt to model the potential surplus, though only on 2030 scenarios.

As we can see, about half of the year sees surpluses, even at a relatively low capacity. (Eyeballing, wind, solar and nuclear capacity looks around 35 GW, compared to 137 GW in FES).

Figure shows hourly demand data in hypothetical 2030 scenario reaching 100 gCO2/kWh sorted high to low against nuclear, wind and solar PV output in that hour.

Remember as well that I have only looked at summer. Even at times of higher demand in winter, there will be many occasions when there is surplus wind power.

My guess is that we could be talking of 100 TWH plus wasted each year. At an average price of say £100/MWh, this would cost £10bn a year.

Which begs the question – who will pay for it? Either way, as the proportion of low carbon electricity increases, the economics of intermittent wind and solar radically change.

Read more at notalotofpeopleknowthat.wordpress.com

***

PRINCIPIA SCIENTIFIC INTERNATIONAL, legally registered in the UK as a company incorporated for charitable purposes. Head Office: 27 Old Gloucester Street, London WC1N 3AX. 

Please DONATE TODAY To Help Our Non-Profit Mission To Defend The Scientific Method.

Trackback from your site.