Inside Britain’s first heat pump village

July 20, 2023 9:15 AM

Inside Britain’s first heat pump village. How did a rural Cambridgeshire village switch en masse to renewable energy? Thanks to one fateful pizza night, 100 huge boreholes and heroic navigation of the planning system, they have trailblazed their own zero-carbon heat network.
posted by chariot pulled by cassowaries (43 comments total)

Seems like a good trend to continue. I don’t think it’s mentioned, but heat pumps work for cooling as well as heating, which seems especially important as UK homes generally don’t have air conditioning and the world is getting hotter.
posted by Artw at 9:21 AM on July 20, 2023 [1 favorite]

I don't think you could switch an entire district heating network to cooling that easily, but it can be a plus if you plan for it. Domestic rads don't tend to work too well for cooling, so you'd want a system that doesn't just interface with existing central heating.
posted by Dysk at 9:28 AM on July 20, 2023 [1 favorite]

What a nice thing. Amazing they were able to do it without a sort of top-down push - but I imagine once you get the ball rolling and people see the light at the end of the borehole, it just works.
posted by BlackLeotardFront at 9:44 AM on July 20, 2023 [3 favorites]

Though it’s easy to dismiss the UK as TERF island and mom it for Brexit, and I do both of those things frequently, a lot of the rot there comes from the top - actual normal people, at least those not caught in a permanent Daily Mail induced frothing rage, tend to be a lot more reasonable and progressive and keen on things like this.
posted by Artw at 9:51 AM on July 20, 2023 [6 favorites]

community ground loop heat pump sounds awesome.

With PG&E's $2/therm (& 29kWh/therm), natgas heating works out to 7c/kWh plus the furnace inefficiency factor, so PG&E's 31c power rate isn't a real money saver, even when getting ~2x efficiency over resistive heating, so digging down to access room-temperature rock looks to be a better capital investment.

"Critics have seized on the project’s £12m cost, which averages out at £80,000 a head"

oof. my winter heating bill is ~$300/yr or so, with the water heater adding ~$150.

$80k in the bank at 5% pays $300/mo . . .
posted by Heywood Mogroot III at 10:06 AM on July 20, 2023 [1 favorite]

tend to be a lot more reasonable and progressive and keen on things like this.

Very much this. As another example, rural community fiber.
posted by aramaic at 10:06 AM on July 20, 2023 [1 favorite]

Gas boiler lobby trying to delay UK’s heat pump plans, leak shows

posted by lalochezia at 10:19 AM on July 20, 2023 [4 favorites]

Heat pumps in general are great, it's a lot cheaper to move heat than generate it. In a cold environment ground-source makes a lot of sense for heating: they're rapidly growing. Here in temperate California I hope to switch to air-source heating for both my home and my hot water, that's fine and easier in a less cold climate.

Ground source is an expensive initial investment Wikipedia puts the time-to-payoff at 2-12 years depending on your alternative. But the natural gas and heating oil alternatives are generating CO2, an externality not factored into the cost equation like it should be.
posted by Nelson at 10:42 AM on July 20, 2023 [1 favorite]

Oftentimes the oil burners are pretty old, so might be close to end of life anyway.
posted by Artw at 10:48 AM on July 20, 2023

Am I so jaded that I thought, "Is it newsworthy that a local government actually built infrastructure to benefit its residents instead of just nagging them to be better?"

I was slightly surprised that the problem here is lack of heating, since the world is currently in a heat wave, and apparently "the ground is too hot" is becoming a problem, and this project is using ground heat sinks:

Why is London’s Tube so hot?
Underground climate change poses a ‘silent hazard’ in Chicago and other cities, researchers find
posted by meowzilla at 10:49 AM on July 20, 2023 [2 favorites]

The UK is currently in a massive Brexit and Ukraine driven energy costs crisis so winter heating remains a pressing issue, especially as the climate crisis manifests as extreme swings of temperature as well as general warming.
posted by Artw at 10:58 AM on July 20, 2023 [8 favorites]

But the natural gas and heating oil alternatives are generating CO2, an externality not factored into the cost equation like it should be

yeah but the upside of natgas is the more you burn now the less you'll have to burn in 2050🤪
posted by Heywood Mogroot III at 11:15 AM on July 20, 2023 [2 favorites]

Ground source is an expensive initial investment Wikipedia puts the time-to-payoff at 2-12 years depending on your alternative.

Ground source also requires a good bit of clear land in which to bury the loop. I'd love to have a ground source heatpump, but my suburban yard is just too tiny and run-through with various other utilities (power, water, cable, gas, etc.)
posted by Thorzdad at 11:46 AM on July 20, 2023

Metafilter: one fateful pizza night, 100 huge boreholes and heroic navigation of the planning system
posted by Multicellular Exothermic at 11:58 AM on July 20, 2023 [1 favorite]

ASHPs are essentially the default HP choice in the UK currently. There are a few stakeholders trying to investigate using GSHPs in different models, including this one. Support for households to switch to low carbon heating has been hit and miss and there is little to address the high upfront costs issue. There is also no meaningful regulatory architecture for district heating, which doesn't help.

Plus the gas sector has been accused of acting to halt or slow any move away from gas: Gas boiler lobby trying to delay UK’s heat pump plans, leak shows
posted by biffa at 12:03 PM on July 20, 2023 [1 favorite]

It would be nice to see some numbers for how much PV area this sort of scheme needs to run through the winter, and how that compares to the size of the village.

Here's Google Maps links to the village, the energy centre with the heat pumps, and the council-owned 12MW solar farm that it's getting power from, 8km away.

That solar farm is bigger than the village, but it's also exporting power to the grid. Would be nice to see some numbers for how big an array would be needed to supply the village alone.
posted by automatronic at 12:11 PM on July 20, 2023 [1 favorite]

For anyone cherrypicking the infrastructure costs and ignoring the stated homeowner outlay to compare to their home bills, minus their own infra and subsidies: kindly go chase yourself.

Then try to order a brand new gas line from the plant right to your house and tell us what the quote is. (They will likely tell you to go chase yourself.)

TFA leads me to believe a new home can join the party with much of the plumbing (if you will) in place at the area level. No up front costs and a low annual fee. And their out of pocket monthly is capped to be lower than oil. So pretty rational on the homeowner level.

If I skimmed correctly, all the pumps are concentrated in one lot, so this is akin to steam tunnels, where each home does not need to generate the steam. It does seem that then the cooling aspect is lost but maybe they crank cooled fluid through in summer. I would wonder about all the evaporative details…

Anyway good on them for doing it! Thank you for posting this.
posted by drowsy at 1:06 PM on July 20, 2023 [4 favorites]

(To avoid an edit party foul - I’ll apologize for sounding overly smug. I am betting that all thread participants know the diff above and I am jumping off needlessly pointing out the obvs like I’m some genius.)
posted by drowsy at 1:12 PM on July 20, 2023 [1 favorite]

actual normal people, at least those not caught in a permanent Daily Mail induced frothing rage, tend to be a lot more reasonable and progressive and keen on things like this.

It also probably helps that energy in England has always been pretty expensive and is getting for more expensive every year. People are already trained on things like energy consumption shifting by differential day and night electricity rates. So many are very conscious of energy decisions in a way that North Americans often are not.
posted by srboisvert at 1:37 PM on July 20, 2023 [2 favorites]

The US has selected 11 cities to do the same: DOE Announces $13 Million to Support Community Geothermal Heating and Cooling Solutions

Here's a basic FAQ about one of the pilot projects in Framingham, MA: Geothermal Pilot Reference Guide
posted by meowzilla at 1:40 PM on July 20, 2023 [5 favorites]

It also probably helps that energy in England has always been pretty expensive and is getting for more expensive every year. People are already trained on things like energy consumption shifting by differential day and night electricity rates. So many are very conscious of energy decisions in a way that North Americans often are not.

Not sure about that. England is far more temperate on the cool side than even the northern US, so the issues experienced are so different as to barely be comparable. England basically gets half as many sunlight hours as Maine, the most northern state. That translates to 50 full 24 hour days worth of sun vs 100+. Southern Spain is comparable to the northern US in terms of sunlight.
posted by The_Vegetables at 2:05 PM on July 20, 2023 [1 favorite]

Forgot to add:
The US also has wilder temperature swings because of this, and is far ahead of England in terms of insulation and cooling.

Basically both countries are trying to solve different indoor-comfort problems.
posted by The_Vegetables at 2:06 PM on July 20, 2023

For being supposedly very energy-conscious, the quality of construction and insulation here is pretty poor compared to a lot of the rest of Northern Europe.
posted by Dysk at 2:54 PM on July 20, 2023

It would be nice to see some numbers for how much PV area this sort of scheme needs to run through the winter, and how that compares to the size of the village.

Any PV won't really be sized on that basis. Typically they would estimate annual energy use for the heat pump network, then size the PV to deliver enough energy over the year.

You could back of the envelope it if you wanted to but you'd need to wrap in storage for the winter since the heat demand will be mostly outside daylight hours.

using the balance over the year approach, on average UK home uses about 12 MWh pa for heat so you are looking at 3-4 MWh of electrcity for that from a heat pump. Capacity factor is about 10% for UK PV so about 4kW of panels per household, 600 kW for the 150 houses, or roughly 2.5-3 acres of panels for the current system.
posted by biffa at 3:57 PM on July 20, 2023 [1 favorite]

Purely an aside to the story: in the headline picture you can see Swaffham Prior's oddest feature - two churches, right next to each other and both more than 800 years old. This is a village that even today has less than a thousand people and is in the arse end of nowhere (hence no gas, hence heat pumps). I'm sure that in the distant past there was some perfectly logical reason for putting a second church next to the first at great expense...
posted by How much is that froggie in the window at 11:29 PM on July 20, 2023 [5 favorites]

This is super interesting - I grew up in a similar rural English village where only part of the village has gas and therefore am enormous proportion of the residents were hit by incredibly high oil prices last winter. In the UK, gas and electricity prices are capped but oil is not and therefore people buying one tank full pay through the nose. The village has come together to try and batch order a larger amount, allowing a bit more negotiation power with the oil suppliers, but it's a huge, volatile cost. I'm sending this to my parish councillor father now!
posted by In Your Shell Like at 3:59 AM on July 21, 2023 [2 favorites]

Historically, oil heating (and wood heating) is about double the cost of networked gas heating in a UK home, so the economics of heat pumps is way better for off gas grid homes. Some of the UK's HP policy has been targeted at off grid homes but overall has not produced very high delivery rates for new heat pumps.
posted by biffa at 4:06 AM on July 21, 2023

Plus the gas sector has been accused of acting to halt or slow any move away from gas: Gas boiler lobby trying to delay UK’s heat pump plans, leak shows

Following up on my comment, there is an amusing twitter spat going on, with a current energy minster basically saying they are wasting their money to lobby against heat pumps, as one commenter suggests, this is actually one of the more definitive statements on the government position we have seen.
posted by biffa at 5:11 AM on July 21, 2023

Any PV won't really be sized on that basis. Typically they would estimate annual energy use for the heat pump network, then size the PV to deliver enough energy over the year.

Yes, but that's a quite misleading approach. If someone's saying "We use X MWh/yr of energy and we also feed X MWh/yr of solar back to the grid, so we've done our share", they're not actually contributing their full share of what we need to build. That approach only works because there's sufficient non-renewable energy for them to buy in the winter, and sufficient demand for them to sell their excess solar capacity in the summer. If everyone tried to do the same thing, there'd just be a winter shortfall and no market for the summer excess.

using the balance over the year approach, on average UK home uses about 12 MWh pa for heat so you are looking at 3-4 MWh of electrcity for that from a heat pump. Capacity factor is about 10% for UK PV so about 4kW of panels per household, 600 kW for the 150 houses, or roughly 2.5-3 acres of panels for the current system.

That seems quite manageable. You could fit that much in the small field on the north side of the energy centre.
posted by automatronic at 5:24 AM on July 21, 2023

In reality though, if everywhere were to do this then you'd need several times more area than that, and it starts looking like you need a solar array that's much of the size of the village.
posted by automatronic at 5:33 AM on July 21, 2023

That approach only works because there's sufficient non-renewable energy for them to buy in the winter, and sufficient demand for them to sell their excess solar capacity in the summer. If everyone tried to do the same thing, there'd just be a winter shortfall and no market for the summer excess.

The reality is more complicated and depends on what the marginal fuel is through the year. Adding large volumes of solar to the grid would have different impacts in the summer and winter. Since solar is cheaper than gas it offers the potential to reduce the amount of time that gas is the marginal offering, which would potentially reduce the price for all electricity at the times when it is sunny as well as reducing the average carbon per kWh. In practical terms, that summer excess means cheaper electricity for consumers and low carbon.

Since it would be less sunny in the winter there would be less of this impact, but still some impact, on both electricity price and on carbon produced. Of course the UK has quite a lot of wind energy and plans to build a lot more, so there will be a cumulative impact going on.
posted by biffa at 5:38 AM on July 21, 2023

In reality though, if everywhere were to do this then you'd need several times more area than that, and it starts looking like you need a solar array that's much of the size of the village.

It'd be 2.5-3 acres per village of this size. The UK is heading for 40-50 GW of offshore wind energy though, which can be expected to meet 40-50% of total current electrical demand over the year, and already gets about 10% from onshore wind, plus some solar, so you won't need every village to have those 3 acres.
posted by biffa at 5:41 AM on July 21, 2023 [2 favorites]

Would a village of that size historically have needed more or less than 3 acres of fuel woodland? (Not directly comparable, but not irrelevant.)
posted by clew at 7:07 AM on July 21, 2023

ASHPs are essentially the default HP choice in the UK currently.

Surely it's still Heinz!
posted by yerfatma at 8:04 AM on July 21, 2023 [2 favorites]

Sorry, that a bit outside what I normally look at, and is complicated by the energy range of woodfuel sources, wet vs dry, how people get their wood, how forest is managed etc. I'll see if I can work something out later.
posted by biffa at 8:25 AM on July 21, 2023 [1 favorite]

Solar might potentially still work on farmland without taking it out of action, since I think at least some of the fields there are pasture rather than crops. Onshore wind in the UK has been hard to get past NIMBY sentiment, but when you're doing to do it so that you can heat your home I guess the idea is a lot more appealing (and the fens have no shortage of wind).

It's also a low lying area that's actively drained with pumps. I wonder if they run the pumps during peak generation times and turn them off when electricity demand is high...
posted by How much is that froggie in the window at 2:58 PM on July 21, 2023

It's not really nimbyism that's stopped onshore wind, it's an effective straight up ban on giving planning permission to onshore windfarms since 2015. Just as onshore wind became the cheapest source of electrical energy - great policy after years of subsidy.

There are plenty of places that would give permission if they could.
posted by biffa at 4:01 PM on July 21, 2023 [1 favorite]

also relevant, how much area is as destroyed as a PV field when this village is heated using other systems? Even ignoring AGW (!!!!eleventy!!!) it’s a nonzero number each year. Just farther away.
posted by clew at 8:24 AM on July 22, 2023

I have a small suburban lot in Bethesda Maryland and put two 350' wells down for a geothermal loop. My utility costs stayed the same even though I tripled the occupied square footage. Better insulation certainly helped, but it was the ground source exchange that made the biggest difference. The drilling was messy but this was a completely new build.

So it definitely CAN be done on small lots. You do not need a large lot of you drill down.
posted by wkearney99 at 7:05 PM on July 23, 2023

For being supposedly very energy-conscious, the quality of construction and insulation here is pretty poor compared to a lot of the rest of Northern Europe.

If you compare properties of a similar age, UK properties tend to be slightly less efficient than Dutch, German, or Danish until very recently when the standards converge. However the average age of UK properties is not just the oldest in Europe but actually the oldest in the world. Countries like Italy might have really old structures, but in terms of volume of ordinary houses still in use from the 19th century and before, the UK actually has a lot more.

Part of the problem is that most of the UK is not *that* cold and therefore you can essentially get away with keeping non-ideal structures for a good long while. If you're in Northern Norway, then the penalty for a poorly insulated property is death, not just two months of slightly damp and overly cool interior conditions with a high-ish heating bill.

It's not really nimbyism that's stopped onshore wind, it's an effective straight up ban on giving planning permission to onshore windfarms since 2015. Just as onshore wind became the cheapest source of electrical energy - great policy after years of subsidy.

It's essentially a ban via nimby-veto, isn't it? There's no outright ban but the threshold of objections is so low that virtually any objection at all from virtually anyone stops the process.

I don't think you could switch an entire district heating network to cooling that easily, but it can be a plus if you plan for it. Domestic rads don't tend to work too well for cooling, so you'd want a system that doesn't just interface with existing central heating.

Using a hydronic system for cooling doesn't work well because it tends to lead to condensation on your radiators / floor (if using underfloor) which is bad and on your pipes in the walls (much worse). There are systems with built in moisture sensors which will only cool the floor down to near but below the local dew point and these are suitable for places which tend to be dry and hot, I've only ever seen them deployed in Madrid.

If you have a "4th" generation water loop system which circulates water at near ambient temperature then you can use that combined with heat pumps / air conditioners in each property and use it for both heating and cooling simultaneously (or more likely one in one season and the other in the opposite). In the summer you dump excess heat into the water loop and in the winter you extract it. However this requires forced air based systems (Central or split) to work for cooling.

The circulating temperature here is 74C out (probably 55 or so return) which is pretty key. That requires ground source to do efficiently, air source will not be able to reach 74C and definitely not on the coldest days. The design heat input for these houses will have 80C/60C radiators so they will do just fine with 74C/55C but reducing that to the typical 50C/40C of an air source system will mean either upgrading insulation to reduce heating need or upgrading radiator surface area (inc. going to underfloor) or a combination of both.
posted by atrazine at 3:51 AM on July 24, 2023 [2 favorites]

What a clever tactic with the floors and the dewpoint.

For places like this village, is it plausible to add a hydronic- to -dehumidifier-to -cooled-air unit, perhaps small, to keep a part of each building safe in heatwaves? At least the summer heat would be pushed somewhere it might be useful in winter, not into our neighbors’ windows.

(We have a air source heat pump retrofitted onto (also retrofitted) forced air in Seattle; really wanted ground loop but we couldn’t find anyone who drilled for it, only big shallow installations, and not many of those. Damnit. We’re on dense wet clay and have a heating and a cooling season.)
posted by clew at 12:41 PM on July 24, 2023

Seattle really has an interested and varied set of reasons why it is absolutely awful to dig in, though mostly it’s glacial till.
posted by Artw at 12:47 PM on July 24, 2023

You can combine circulating water loops with air handlers for cooling, I had that kind of district cooling system in Dubai. Our building didn't have it's own vapour compression/expansion system, just a heat exchanger with a -2C glycol loop from a central cooling centre.

You could use a small air conditioner which dumps its excess heat into an ambient loop for one room in the house to act as a sanctuary for the hottest days.
posted by atrazine at 11:33 PM on July 25, 2023 [1 favorite]