Did you catch our #InnovationLab presentation a few weeks ago on renewable heat in London's civic and domestic buildings? In case you missed it, you can watch it again right here (1.5 hours)!
Just want the highlights? We live tweeted some questions here but, as promised, we have also provided a more detailed breakdown of the attendee Q&A session.
If you're interested in hearing more about our heat pump business plan, give them a read or contact us.
Are CREW actually investing in the domestic heat pump
installations via share offers?
No, we’re not. This is able to pay and potentially things like GHG. Our share offers will be around communal and commercial heating systems, i.e. something with a bit of scale to it that’s worth raising for.
I think the credit issue on doing lots of individual houses is a difficult one to look at up front, so for now we’re looking at the eco-warrior types and where we can get £10,000 of GHG funding for vulnerable people – that will be our starting point.
Ultimately I think it’s an area to get to – finance solutions – and it’s something we can look at with social funders like Parity Partners, but for now it’s a bit more of a credit trade than a heat trade for us. And we’re not credit people.
How do we overcome thE issue OF PRICING OF HEAT PUMPS AND SOLAR PV
AS A BARRIER to reducING carbon footprint?
I think we look at some of the points I’ve made – if we’re talking very much domestically, for instance, let’s look at hybrid systems. Here there’s a scenario where we have £5k of GHG up front. Let’s say the heat pump might cost £8k for a smallish 8kW heat pump installed as a hybrid system. You will probably get £3-4k back in RHI over the next 7 years on top of that.
Just to be clear, the GHG is not additive to the RHI. If you were going to get £12k (the maximum for an ASHP) over 7 years, you only get 5k up front from the GHG, plus £7k afterwards. They kind of claw back the 5k in other ways. It’s a question of looking at home the economics would work.
The other thing to consider is the stacking of other numbers, i.e. saving £90 p.a. over the next 7 years means £630, or £700 when we consider inflation. So, that’s £700 you’ll save by not having to pay a gas standing charge, assuming you get rid of your gas hob as well (the two main areas where you use gas in your home).
You’re also not paying for maintenance – one of the good things about heat pumps is they don’t really break down! I was having a chat recently with Clarion Housing and Moat Housing (Merton Council’s main providers).I asked the guy from Clarion, who have 125,000 properties across the country, 12,000 of which have heat pumps on them. I asked what the difference was in O&M costs for gas boilers and heat pumps and he said it was infinitely better – they don’t have a policy for heat pumps because they’ve installed them for 3-4 years and nothing has gone wrong. Although that seems a bit extreme, it is illustrative that if a big housing association like that considers heat pumps to be something they can install and then not worry about for 10 years, then that is something that home owners can be thinking about as well.
If we consider that boiler cover from a company like British Gas costs around £12-£15 per month on average, but up to £30 per month in some cases, that’s a saving of £270 per year (factoring in inflation). Times that by 7 years you’d be saving £2,000. The more electricity you consume, the more likely you will get a better tariff on that too.
Finally, another area to consider is time of use tariffs/demand-shifting. We’ve done a bit of research where we think, with a 250L tank, you can shift maybe 3 hours of heat, thereby avoiding peak tariffs and getting a cheaper tariff. This feeds into the economics of it being that much cheaper than gas over a longer period.
For communal systems. How do you get everyone to agree to use
the system? What if some householders don’t buy in?
Toby: I think it’s going to be hard. It depends on pipe work. Where we are looking in Islington, it’s already a communal system. This already makes it easier because they’ve already got buy-in into a communal system. If not, it’s more difficult to leave people out, depending on the plumbing.
Guy: It very much depends on the building itself. You can’t really look at the building as a whole, every individual unit has to be looked at. We always start from the point of comfort of each individual and work back. There’s no one rule, I’m afraid.
Toby: And then to increase the buy-in, you have to show the economics of it, like lower running costs, lower O&M costs, less likely to break down (especially in winter, which is the problem with boilers). So, you have this comfort. Think of a heat pump as the reverse of your fridge; if you feel the back of your fridge it’s really hot, and inside it’s really cold. A heat pump is doing the same thing really – and when was the last time your fridge broke down? Those things run forever. I think you sell those points: reliability, running costs, environmental aspect, and local air quality. If you get rid of 100 gas flues, you’re going to have clearer air in your immediate area.
Megan: Yes, I guess it depends on your engagement area and what works for those groups of people.
On ASHP, in a densely populated area, is there concern on
new developments impacting the airflow and therefore SPF & are
there ways to mitigate this?
Guy: I think in the kinds of installations we’re currently talking about and might be talking about for the next 3 or 4 years, I’d be staggered if that was going to be an issue. Although, it does need to be looked at.
There were some questions in the chat regarding the impact on the grid, which I guess falls into the same category – currently when looking at the grid, you need to consider start-up of heat pumps; that creates a bit of a spike, particularly with single-phase heat pumps unbalancing the system, and attention needs to be paid to that (particularly with large numbers operating in blocks). But in terms of the ongoing general running, we’re a long way from the sort of impacts that are going to be upsetting the grid.
The grid operators generally believe that we’re looking at a reasonably long transition of 5-8 years to 20-30% heat pump impact in domestic heating, they will cope with that. Needless to say, there will be localised issues – probably more in the country than London. In the short term, we’re a long way from those kinds of issues and I think the same would apply to small changes in the local climate.
The benefit to particulate pollution by reducing gas boilers will have a way greater impact in the other direction.
Toby: Can I also say on the microclimate bit, we know people would love to put their heat pumps down in the basement, but they do create microclimates – the cool air just sits low and, therefore, you do lose efficiency. So, there’s a lot of consideration given to where heat pumps are placed and how you stack them. There have been examples of people cascading heat pumps where the cold feed is feeding into the hot feed of the one behind it and – low and behold – the efficiency is tragic. But people have learnt from that – spacing them out, making sure they are places where there’s a constant air flow… you can address these issues through placement and spacing.
Where there are grid connection restrictions, has the viability
of including community-scale renewable energy and battery
storage been looked at to roll out these solutions in these
restricted areas? Do you know of any projects?
I’ve had conversations about these issues with Western Power and I have one this afternoon with UKPN. Part of our presentation was about demand shifting, having a buffer tank. If we’re incentivised not to turn our heat pumps on at certain times, and if that means they don’t have to spend more money on making the grid more resilient then great. A lot can be done on that.
Roger Hay from Western Power was keen to run a resilience test of maybe 500 homes with heat pumps with this buffer tank solution (or battery storage, as long as you can shift the demand away from peak periods). Can you stop that massive ramp up at peak periods? I think you can. There are ways to do that without destabilising the grid.
I don’t know where they’ve got to with that trial, but I will find out later today and you can take a look on my social media. But clearly, as Guy said, it’s not as much of an issue in London as there’s such a sync of energy around you at any given time. This would typically be a more rural than an urban issue.
I've heard the Octopus Time of Use tariff is very expensive outside of
the cheapest time of use which may end up costing the homeowner
more overall. has this been looked at in real-time use?
Yeah, I had a look at this and didn’t think it was the case. I think it worked out at about 15-16p if you just ignored the time-of-use element of it (and used 24hrs a day of tariff). So, no I don’t think it is. I would argue that, at the current rate, they don’t want too many people on it as it’s a trial to see how it could work and how they can encourage people.
You have to think back to Triad payments – this is a commercial thing, but the 3 worst half hours for commercial tariffs. They had to be 10 days apart and between 4:00 and 7:30 at night, between Nov and Feb. But if you avoided those, you could avoid 12.5% of your bill. So, the very worst case scenarios have a huge impact on what people pay – you can have tariffs going up to £30k/mWh for that worst half an hour, when they’re normally £50. So, avoiding the most expensive times consistently can have a huge impact on what you’re avoiding and what Octopus can charge you. Clearly, you need to be able to avoid your other electrical use.
Our thinking is that people who are already on that tariff have already got PV and battery storage. We’re just an addition to that. Typically, I think that will be the case.
Have you investigated combining ASHP with MVHR (heat recovery)
for properties that have to be ventilated from rear due to street
Toby: No we haven’t and I think there’s probably also a case there for that with homes that are damp (i.e. blocks of flat with cavity wall but dampness through each floor). Those places need to be ventilated and I think there’ll be a good market for that. I just think that for one of our early projects it’s a bit complicated.
Guy: It’s not something that we’ve looked at at all. It sounds interesting and certainly there are lots of NOX-substandard buildings. One thing that has come up quite often and needs doing ahead of installing heat pumps is looking at the lowest temperatures you can get in heating in existing buildings. That’s something we’ve looked at in terms of air quality and dampness.
Toby: Looking at some of the ground source installers who are trying to reduce the footprint, going down 250m, using steel pipes so efficiency of taking heat out of the ground is better… one company is looking at combining heat recovery and storing heat in the ground. We’re looking at working with them in gyms/health centres to recycle the wastewater from showers, heat from the gym rooms, etc.
Could YOU please clarify the comment about heat pumps being
permitted development and being within 1m of the building
Our understanding in London, at least, is that this is permitted development, but you do have to be 1m away. The only exceptions are if you’re in a conservation area or a listed building, where you’ll need additional permission.
This is a problem in London as I think half of all conservation areas across the country are in London (half a million homes). It’s very similar to PV and I feel the solution will be the same, if the heat pump is in the back and can’t be seen then it will be fine. If it’s a listed building, it’s a much bigger argument to build.
What about the cost of servicing ASHP to vulnerable customers, in
order not to invalidate the warranty on the machine? That costs needs to be included somewhere.
If we take my example of the largest housing association in the country not having a policy on this, it’s kind of interesting. Essentially, what you’d be paying for in this day and age is remote monitoring. All these units have comms units attached – how do we connect the comms? So, what you’re paying for is a GSM card for a year, which is around £9. If they’ve got internet, you’d pick up the messaging from the heat pump on there. Then you’d need some security, which would cost £40/year for a heat pump key to avoid people hacking into your internet via the heat pump system.
So, you’d then have to think about building that cost into the heat pump system. We haven’t done that yet, but as we’re looking at communal buildings, it’s something that we’ll have to consider. That said, when we talk to the manufacturers, they say they are comfortable – and think of the warranty, around 7 years for parts and labour – they are that confident their heat pumps won’t break down.
It comes down to the economics, if you can afford £50 of O&M costs, then great. If you can’t, are you willing to take the risk?
Have you thought about using heat sources which are created as a
result from sewage works?
Black Mountain Developments are looking at this and where you can recover heat from. I’d also say look at Islington Council – they ran an interesting project about two years ago where they took heat from the Northern Line (I think) of the London Underground and used it to heat a block of flats above it. I think there’s an enormous amount to be done around that. Not sure how many people have been on the Underground but it’s pretty hot all year round!
I think it’s interesting and it’s just about finding the right technological partnerships. Someone like Black Mountain Development clearly has that technology. It’s something that we’d love to look at and work with the council on, but I think in Wandsworth and Merton we are all above ground on the Tube network.
how are you performing the CO2 reductions calculations?
Is it using actual grid emissions levels from the national grid or just based on some general estimations/projections? And if it is estimated, are you considering verifying if those projections are being met after the systems are in use?
That’s a good question. At the moment when I am typically modelling on that, I use the Energy Saving Trust, the Carbon Trust and have looked at live data. The reason for this is the ability to shift demand – if we shift from 4pm til 7pm where the carbon concentration may be 300g per kWh, to overnight where we might have a windy evening and 60g, you can have the same amount of consumption but reduce your emissions by 80%.
It’s an area we’re researching at the moment and it’s fascinating; if you go to these sites, they all have different numbers. I can understand why the grid is different as we’re constantly decarbonising.
I actually wrote a blog piece on how far behind BRE are on heat pumps and how they treat heat pumps under RdSAP and therefore your EPC. This touched on a couple of things:
I would love to have a chat with you on what you’re looking at in this. What’s the number for gas, for example, it can’t be different everywhere? There are so many different numbers, so I tend to use Carbon Trust and Energy Saving Trust, which I think most people would accept as a baseline.
We’re also debating ‘how efficient are boilers?’ A typical boiler is 85% efficient, new condensing boilers are supposed to be 90% but only if you run them at 60 degrees. We’re all using then at 70-80 degrees like we always have, so they are back to only being 80% efficient. A lot of it is how you are running your kit and when – because the curve of carbon throughout the day is very different.
have you looked at the acceptability of noise implications?
We haven’t. But as you’ve seen from the presentation it’s something we are really thinking about. If you look at the top end of the scale, people are recommending a new valent heat pump as an interesting hybrid solution, but when I looked at it yesterday, it had a 66dB noise level! What we need to do is find heat pumps that are quieter (but they are expensive!). There are some great examples of split systems, where the fans are outside, and the refrigerant is inside, and they are whisper quiet at 29dB. We’re mostly looking at something in the middle, around 30-40dB which is below London noise level, which we think will be okay.
The other thing is the noise level drops as soon as you move away, the numbers given are the level when you are standing next to it. 2m away from this it will really reduce. So, positioning of the heat pumps will also be really important.
We’re also looking at things that could be added to dampen the noise; we’re working with an insulating product - a spray on resin used to insulate homes. This would also dampen sound. This is a big consideration, particularly in London, where there’s not a lot of space. We do need to find solutions.
Got any more questions? Please get in touch with us in the comments below or via firstname.lastname@example.org.