The wider world

Decarbonising domestic heating

There’s a… not quiet, but also not mainstream, debate raging at the moment, about how we’re going to heat our homes in the future. Actually it’s about how people who live on the gas grid will heat their homes, but that is the majority, and it includes most journalists.

An important caveat

I’m not an expert here – if I was, I would be writing a journal article rather than blathering on my blog – and I haven’t done the maths. I welcome correction by people who have.

From 2035 (earlier for new builds) people won’t be allowed to install new natural gas boilers in homes in the UK. There are a few possible ways of replacing them.

One approach, as with most things, is “electrify it, then use low carbon electricity”. In the case of the UK the answer to this is electric heat pumps, which are basically air conditioners run in reverse, to move heat from outside the house to inside it. They’re more common on the continent than here, but they’re reasonably common here in commercial premises and are becoming better known as a domestic option. Heat pumps are stupendously efficient[1], doing between 2.5 and 4 times better than a basic electric heater.

There are some disadvantages to heat pumps: firstly, that they’re not a direct drop-in replacement for a boiler. You need to find somewhere to put the unit that goes on the outside of the building, and because they don’t deliver water at such a high temperature as a boiler, poorly-insulated houses will need to be insulated better. In some cases they may need to have larger radiators fitted. The UK has a lot of poorly-insulated houses, although many would argue that insulating them better is one of the first things we should be doing anyway… Another difficulty is that we’ll need more low carbon electricity to power all these heat pumps, and we might need some grid reinforcements to deliver that power to where it needs to be.

The other approach that’s being talked about is using hydrogen, produced using electrolysis with renewable electricity. Replace gas boilers with hydrogen boilers – at worst a drop-in replacement, at best a simple adjustment – run hydrogen through the old gas pipes, and bingo, low carbon heating without much cost or disruption, and because we’re still sending the energy via the gas grid there’s no need for electricity grid reinforcement.

There are a couple of downsides to this plan. One is that it’s much, much, less efficient. The total amount of energy needed to produce the hydrogen and transport it is (very roughly) 4x the amount you’d use in a heat pump that was doing the same job.

Image: ICCT

The second problem is that renewable energy is a scarce resource. We’ll struggle enough to find enough to power all those heat pumps in the short or medium term, so we’ll struggle even more to find four times that much to electrolyse all that water into hydrogen.

And this is where it gets controversial. Instead of finding enough renewable electricity to produce hydrogen by electrolysis (so-called “green hydrogen”), we could make it from natural gas. The “blue hydrogen” concept is to continue extracting natural gas, and split it into carbon and hydrogen when it gets ashore. Put the hydrogen into the gas grid, and bury the carbon back under the North Sea using carbon capture and storage (CCS). It’s quick, relatively cheap, and uses existing infrastructure. It’s not forever, of course, because both natural gas and carbon sequestration space are finite resources, but it’ll tide us over until we can produce enough green hydrogen. Right?

The strongest proponents of this plan are, unsurprisingly, the natural gas industry (fascinating scholarly report from UKERC). The next strongest are politicans who have good relations with the natural gas industry, and would like to minimise disruption. There’s a lot of lobbying power there, and this is a tempting proposition. Some people look at this and say “it’s a way for the natural gas industry to keep going with business as usual, and lock us in to a whole new gas infrastructure in the process”. Blue hydrogen champions say “but what choice is there? You can’t build renewables fast enough otherwise”. They’re usually using a straw man of building renewables fast enough for green hydrogen, rather than simply electrification, but they might be right about that too – I’m no expert on build-out rates and supply chain limitations.

But if they’re right, and if they’re speaking in good faith, then surely there’s a way to get the same stopgap benefit as blue hydrogen without locking us into the hydrogen route in the long term? Use natural gas, and use CCS, just like with blue hydrogen – but when the gas comes ashore, don’t make hydrogen with it. Burn it in a CCGT power plant, with carbon capture, and then supply electricity. Sure, you lose 2/3 of the energy in the power station, but the efficiency gains in using heat pumps rather than boilers roughly cancel that out. In the future it’s easy to let renewables replace the CCGT+CCS, at which point we’re left with a much more efficient system. And in the short term the gas companies get to keep extracting – but without locking us in for the long haul.

I don’t see anybody recommending that. Maybe it’s because it still leaves the supply chain “problem” (people will argue problem vs opportunity), in how quickly we can get homes converted to heat pumps. Maybe it’s because it will still require electrical grid reinforcement. Maybe because the whole argument for blue hydrogen is being made in bad faith.

I honestly don’t know which. It could be all of the above! Or it could be something that I haven’t thought of.

[1] Pendants and physicists are correct that this isn’t actually an efficiency, it’s a Coefficient of Performance – and hence it doesn’t break any laws of thermodynamics for it to be over 100%.

Posted by simon in The wider world

The A-level results mess

GoT meme: "Brace yourself: Results are coming"

I should caveat this post by mentioning that I know nothing of secondary education, and am not involved in undergrad admissions for my university – so this is purely the view of an uninformed layperson.

As most of my readers will know, there’s a row in the UK at present about A-level results. A-levels are the exams that people sit at age ~18, at the end of secondary school, and are key to getting into universities. As of a few years ago, thanks to the views of Michael Gove on how education should work, they contain no modular exams or coursework and are judged entirely on one set of exams at the end of the year. And this year, thanks to COVID-19, those exams didn’t happen.

Students apply to universities long before they know their A-level results, and so their applications are based on predictions made by their teachers of what grades they will probably get. The universities then make “conditional offers” that commit to providing a place to the student so long as they achieve a given set of grades at the real exams. This has a host of problems that have led some to campaign for years for a change to the system, but that’s a different story.

Thanks to the lack of actual exams this year, students’ final grades have been based on their teachers’ predictions. But for various (mostly sensible) reasons, teachers tend to be generous / optimistic in their predicted grades, and so simply using these would have led to what the government and the tabloids call “grade inflation” – more people getting high grades this year than usual. To avoid this, the regulatory body OfQual was charged with adjusting the predicted grades using a statistical approach. As near as I can understand it, the grades of students in each school were adjusted according to how students from that school usually do. Many have been downgraded from their predictions, leaving them surprised to find they are rejected from their chosen universities. Some smaller number have presumably been upgraded, though we don’t hear about that, and though that won’t impact them as much as they are unlikely to have conditional offers above their predicted grades.

Of course, students are disappointed every year. But there’s a huge difference between being predicted good grades but then failing to achieve them through your own efforts in an exam, and being predicted good grades and then having them reduced because a government algorithm said so – however accurate that algorithm may be when validated through hindcast. One is, ultimately, down to individual performance (albeit in a single exam, which nobody except Michael Gove thinks is a good way of assessing ability), while the other is something that the individual in question is unable to affect.

The task that OfQual were set was clearly impossible to do with any sense of justice. They have probably succeeded in producing a set of national marks which in a big-picture, statistical, sense, reflects what this year’s cohort of students would have achieved. But however good their statisticians, there’s no way that they could achieve that while remaining fair to individuals. As somebody beautifully put it on Twitter:

So given a choice between the problem of “grade inflation” and the problem of arbitrary-seeming marks for students, I find myself asking… is grade inflation really a problem? If, for one year only, the aggregate student body does better than usual, what harm does that cause? This entire year is inherently a set of mitigating circumstances, and there doesn’t seem to be any gain in punishing students even more for the year in which they happen to turn 18.

Sure, an excess of high grades would cause some trouble for the most prestigious universities, as they may not have room to take all the students they gave conditional offers to (I say “may”, because they’ll have lost international numbers this time around). But given how keen these universities usually are to increase recruitment, I’m sure they can find inventive ways to deal with that. Maybe some of the students are even asked to defer to the following year. That feels like much less of a problem than effectively telling a generation of new adults, “What you do doesn’t matter, you will be assigned a place in society according to the school that you come from”.

Given the situation all around us, would it really be so terrible to be kind?

Posted by simon in The wider world

Losing is not binary

This article from Mary Heglar is a powerful, and worthwhile, thing to read. I’m not going to talk about it, because you can go and read it yourself – it isn’t long – but it reminded me of something I wrote a long time ago, on a blog far far away. It was just after the 2009 COP summit in Copenhagen, which was perhaps the first time that calls for climate action really became a mainstream mass campaign, rather than something for environmentalists. I’m going to quote some bits.

A lot of commenters are being despondent in the aftermath of COP-15. I can understand why, because it was the first climate summit where it had actually become a mainstream public issue, and the first in recent memory when a (arguably) sympathetic line from the White House meant that there was some chance of co-operation from the US. Additionally, time is pressing, and this was the first time so far as I remember that anybody had identified “this is what we need to aim for NOW”. Which we’re not going to do…

…I feel that while the solutions are technically within our grasp – just about – at present, there is no way that they are politically possible.

I’ve spent a certain amount of time thinking “If I think that the cause is hopeless, why am I wanting to work in the renewable energy and/or energy efficiency fields?”. The answer is that although the goals being debated at Copenhagen are politically hopeless, every little still helps…

…millions – if not billions – will suffer… but for every bit that we can reduce our emissions, less of this will happen. The fact that the situation is so terrifying, depressing, and hopeless… doesn’t mean that we can’t try to lessen it.

That… was a while ago. Time has moved on by a decade, and so has climate change. It’s reached a stage where effects are evident to many people. And perhaps partly because of this, and partly because of youth protests and Extinction Rebellion, and partly because of so many other people, the politics have moved on as well, to a place that I honestly didn’t think was possible just a few years ago. The support from the White House has vanished, but we’ve discovered that it wasn’t really needed after all.

In 2019, it’s probably too late to stick to a 2°C rise, let alone 1.5°C. We’re already well past the 350 or 400ppm that was being discussed in the run-up to Copenhagen. In that sense, we “lost”. But what I wrote in 2009 is still true: that that loss isn’t binary, and we can still influence how much worse things get.

As Heglar says in her article, simply giving up on the problem because we can’t totally avoid it is not helpful. Nor is criticising people for being optimistic. Or pessimistic. Or any other natural reaction that they may have. As a friend put it once, there’s a grieving process here, and everybody grieves differently. Recognising that climate change is going to have impacts, and putting effort into adapting to or mitigating those impacts, does not require us to give up on trying to limit the amount of change that is not yet locked in, but to do this we need to embrace everybody’s input[1], rather than shutting people down.

[1] That is, everybody who acknowledges that there is a problem.

Posted by simon in Reflective, The wider world

That UK power cut in August

You probably all remember that power cut earlier in the year? There was all sorts of unfounded speculation about the causes. The initial report into the causes is out; it’s actually been out for a week or two, but I just got around to reading it. You can read it here if you want to – it’s not overwhelmingly technical – but here’s a brief summary, as I understand things:

First off, this was not because of any inherent problem with wind power – although it did involve a wind farm – and nor was it because we don’t have enough generation capacity in the UK (that’s a scare story that arises every winter, but this happened in summer in any case). The timeline went as follows,

  1. Lighting struck a 400kV power line in Cambridgeshire. That’s a fairly normal occurrence, and protective systems are designed for it. Those systems worked, and the transmission line was back to normal operation in a tenth of a second.
  2. Less than a half second later, as a direct or indirect result of the lightning strike, a large offshore wind farm stopped supplying the grid. This should not have happened, and the wind farm operators are investigating why it did. At the same time (within a second), part of a nearby gas power station also disconnected. It is not clear why that happened either, and that’s also being investigated.
  3. The grid was operating with enough reserve generating capacity to cover the loss of the single largest generator that was in use. This equated to a reserve of about 1GW. Losing two generators at the same time is not something that is normally allowed for, but as it happened the loss of generation from those two combined was a little under 1GW. The automatic systems detected the loss of generation and compensated with reserve generation 20 seconds later. So far, so good.
  4. About a minute after the initial event, another chunk of the same gas power station tripped. Again, it’s not yet clear why.
  5. This additional loss of generation was more than could be compensated for by the immediately available reserve. With demand greater than supply, an automatic system triggered the disconnection of about 5% of electricity users across England and Wales, in order to bring the two back into balance. This is the power cut that people noticed, and it is exactly what is supposed to happen in this scenario.
  6. In disconnecting 900MW of demand, the automatic system also caused about 600MW of embedded generation (mostly small-scale renewables) to be disconnected, so the net loss in demand was only 300MW. This is a problem in principal, but in this case dropping 300MW of demand was sufficient to stabilise the situation.
  7. Over the next four minutes, additional generation was brought online to return things to a normal operating condition.
  8. Customers disconnected in step 6 started being reconnected a few minutes later, and all were back to normal within 45 minutes of the initial event. Except for the railways, but that’s a separate question about how the railways respond to loss of power, rather than why the power was lost.

So, by and large things worked as they are meant to. The system carries enough reserve for any one generator to disconnect unexpectedly, but in this case two generators did so at the same time. Hence, the power cut.

There are three outstanding questions, which are being investigated further: (a) Why did the wind farm trip after the lightning strike? (b) Why did the gas power station trip after the lightning strike? and (c) How should embedded generation on the distribution system be handled when parts of that system are automatically disconnected?

The first two of those questions are purely technical ones: something happened that shouldn’t have happened, so the engineers need to know why so that it can be fixed. The third one is a bit more interesting, and is the only potential area in which the shift towards renewables is involved (although it’s important to note that in this particular case, it made no difference). It’s not clear to me at present, because I’m not a grid expert, whether there is supposed to be a mechanism by which distribution-connected consumers get dropped while distribution-connected generators stay online – in which case that system failed – or whether the issue is more that the generators are going to be dropped, and that the amount of the distribution grid that is automatically disconnected needs to be adjusted to account for that generation, so that the correct amount of net demand is removed.

Perhaps the final report in November will tell us more.

Posted by simon in The wider world

What could we do with $10-20bn?

A few weeks ago, Vanessa Harris asked an interesting question on Twitter:

I think that’s close to what Elon Musk thinks he’s doing, though I’m not personally convinced that most of his solutions are the ones we need. But naturally, it got me thinking about energy, and where private investment of that order – provided with a long-term view rather than the VC approach that’s caused so much trouble – might make a difference.

Let me caveat this by saying that this post goes waaaay beyond my actual areas of expertise. Consider it the idle musings of a slightly informed layperson. But here are some ideas:

  • Fusion: Too expensive, in the traditional big-project approach. And too far off to address the urgency that we feel at the moment.
  • Small / cheap innovative fusion: Still too far off, if we include time for rollout. And it’s already happening privately.
  • Traditional fission: Nope. This is mature, and the new ideas that are out there (Gen IV reactors, thorium reactors, etc) are too expensive for this sort of investment. Demonstrating uranium extraction from seawater would be interesting, but it’s unnecessary unless we have a massive nuclear rollout going on.
  • Small “modular” fission reactors: Maybe. I don’t know a lot about this, and how feasible and/or useful it would be… but I can imagine that $1-10bn might be the order of magnitude of the investment that’d be needed to make it work (or to show that it doesn’t).
  • Marine renewables: No individual idea needs this much cash; we’re used to “big” announcements in the $10m range. A few hundred million could do a lot in pushing a nascent technology to either being ready for commercial rollout or turning out not to work. For billions, we could adopt a scattergun approach of funding plenty of ideas, knowing that some would fail. There’s a chance of turning a profit, too!
  • Other renewables… don’t really need it any more, so far as I’m aware?
  • Energy storage: Maybe. Musk is already doing good things with batteries, but perhaps other routes.
  • Demand response: Difficult to see how cash would help; as I understand it, the difficult challenges here are social, regulatory, and to do with system integration – not technical in a way that money will necessarily help. Maybe I’m wrong, though?
  • Negative emissions technology: Yes. This feels as though it’s probably the right order of magnitude to develop CCS, and other techniques are probably worth a shot as well. Realistically, some way of pulling CO2 out of the atmosphere is going to be necessary when we overshoot the targets that the politicians are talking about.
  • Transport: One of the big questions in my mind is how to decarbonise things that batteries probably won’t be suitable for (many ships, most planes, IMHO). Hydrogen and fuel cells? Maybe. Some other fuel synthesised with electricity? Maybe. Crop-sourced biofuel? Maybe. Most of the specific projects I can think of are either too cheap or too expensive, but it’s not my field, and making significant progress in figuring out how to decarbonise transport would be a worthy use of the cash.
  • Reducing agricultural or industrial emissions? I’m not convinced that that this is something that it’s useful to throw money at (except for CCS for some industries).

Most of the ideas above are about getting necessary technologies ready to go. Many of them would need either large corporate or state-level support in place to make them actually happen at a commercial scale; but if the development is done, then the big-money investment is relatively low-risk.

I can’t help feeling that I’m being blinkered, though. Energy is what I do, so energy is what I think about… would there be better bang-for-the-buck, in terms of effect on climate change, to invest in something completely different? For example, how much impact could this sort of money have on women’s health and education – the improvement of which tends to reduce birth rates? What other interventions might be viable at this sort of scale? Somebody on Twitter suggested that the most effective investment multiplier is to “buy” US senators, but I’m trying to avoid that level of cynicism here…

Posted by simon in The wider world