As per your energy hierarchy, reducing energy demand is the first thing you look at. How much do you find is actually doable in that stage of the process?
Well, that’s a very good question. I think it depends on what it is. Usually there are opportunities for low cost energy consumption reduction through improving the controls, particularly heating. You can do it with lighting as well through occupancy sensors - people go out the room the lights go off. What we tend to find with heating is that someone might have fiddled with the controls, and then they were left for some time. You might have heating for 24 hours and you just don’t know about it. When you analyse the energy consumption data or log temperatures, you can see that there’s heating at night and do something about it. People often have heating starting too early and - say they leave the building at 18:00 - they might have it switching off at 18:00 whereas if you turn it off an hour earlier, or a certain amount of time earlier, there’s still thermal mass within the building. So the building is kept at an acceptable temperature till people go. Temperature control is also important because often places are overheated and each degree of temperature turned down on the thermostat will have a significant impact on reducing heating consumption. So, those are the easiest ways to lower cost.
When it comes to insulation, then that starts to get expensive. Roof insulation can often have a payback on investment over a small number of years. Wall insulation is very expensive and it’s not generally regarded as having a payback or at least not one that’s economically acceptable in most cases.
I always apply the energy hierarchy in my work and prioritise reducing demand before looking at renewable energy. That’s partly because renewable energy is constrained. If you think of the UK, we’re very blessed with a good renewable energy resource: we’ve got a lot of wind, we also got a tidal resource, and a wave resource, but wind is the big one. But even in the UK it’s a challenge for renewable energy to supply our current projected levels of consumption because people are resistant to onshore wind. This government particularly so, which, I should say, isn’t representative of people in general. Most people are in support of wind energy, but, without getting too political, it’s widely accepted that some large landowners included are donors to the Conservative party. The moratorium on wind energy that’s been out until recently and will likely be re-established by whoever gets into power [This interview was conducted before Truss became PM]. Most Brits support wind according to polls. The pushback of wind energy makes it more expensive, since we end up building offshore wind and as you go further offshore, it get’s deeper, requiring more expensive structures, and further from shore more electrical cabling is required. So, it’s constrained quite significantly.
There’s a book called Sustainable Energy without the Hot Air. You can buy the book you can also download the pdf free. He [the author] died a few years ago, no doubt you can find it. If you can’t, let me know I’ll send it to you. It illustrates really well the challenges with renewable energy and energy demand reduction, and looks at the national match between energy supply and demand in a very accessible way. In the back of the book there are more calculations if you want to go into it a bit more deeply. He’s not got a background in renewable energy - he’s a physicist - he takes a very logical and applies rules of thumb just to get a sense of the size of the challenge. It’s a very good approach - there’re a few things you could question in it but in general it’s helpful.
The point I’m really getting to here is that renewable energy is constrained so realistically we have to focus on energy demand reduction in order to supply everybody with renewable energy. When applying this to a project, some things will be worth doing cause they’re low cost. On projects I’ve worked on often what I do for clients is compare different energy improvement measures. I’ll include: energy demand reduction, energy efficiency measures, renewable energy measures, and do life cycle cost assessments of those which looks at the cost of implementation, any maintenance over the life cycle, and then balances that against the saving money over the life cycle, taking into account capital costs, operation costs, operational savings, and energy cost reduction. When energy demand reduction measures get more expensive people are likely to go for the renewable energy option. If I can give you an example of biomass heating, there used to be government support for that - the renewable heat incentive. By applying the renewable energy hierarchy, we want to focus on insulating the building. You don’t want to be heating a building that’s leaking loads of heat, wasting biomass, and it’s too expensive as well. You get diminishing benefits with insulation: if you double the thickness of insulation, you don’t halve the heat loss because of the thermal dynamics. Even just the fixed cost of any level of insulation is quite high, so there’s a balance to be made between how far do you insulate a building and at what point do you say “well I’m not going to be able to insulate it so it doesn’t need any heat, so I’m now going to size the biomass boiler for this level of insulation.” If you go to passivhaus standard with residential, you pretty much don’t need to heat the building because you’ve got solar gains and internal gains but that’s very expensive so in most cases so it would be cheaper not to do so much insulation and have more renewable energy. There’s an economic decision there.
What’s happening more often now is that organisations are focusing on getting to net zero greenhouse gas emissions in line with the government target of getting to net zero by 2050. A lot of pressure for that to happen is not yet through regulation, but big companies are signing up to science-based targets for emissions reductions. When trying to reduce their scope 3 emissions, they apply pressure down the supply chain. For them to get to net zero, you need their supply chain to be net zero. So for companies now, it’s not just about making cost savings in relation to energy costs, it’s also about potentially missing out on contracts with customers. In the tender process companies are expected to commit to getting to net zero and maybe sign up to a programme or standard or initiative of science based targets; this way they have a formal commitment to the target to get the contract. What that means is that the value of the contract and the potential loss of business from not getting the contract can be far greater than the energy cost of implementation of sustainable energy measures. Now corporations might put in more insulation, and it might not have a payback in terms of energy savings, but if it means they can get towards net zero and get the contracts through the tender process then it could be worth doing.
It’s about resilience too because the more you do energy demand reduction, the less energy supply you need, the less exposure to the volatility of the energy market you have. In the UK renewables pricing is linked to fossil fuel pricing because the price that everyone pays is down to the marginal cost of the most expensive energy generator. Renewables are making a lot more money now because of gas prices. That’s just the way the market is at the moment. So whether it’s renewables of fossils, at the moment it’s very volatile so it makes sense to minimise your exposure to the market with demand reduction.
One thing you came back to was energy demand reduction, for example, changing the temperature of your home. We’ve haven’t really seen any concerted effort from the govt. or any sort of push towards getting people to make energy demand reductions, which may be essential to making the necessary shifts towards renewables. Why haven’t we seen that kind of messaging?
I think it’s largely political. For example, our building standards are much worse than those of other European countries but the building developers lobby the govt. and they have a lot of influence and again a lot of them are donors to the Conservative party. It applies to different degrees to all parties probably, but certainly under David Cameron’s govt. there was a watering down of the building regulations in the code for the sustainable homes (not the emissions targets). I think it’s vested interest since what are we’re exposed to in our energy prices really doesn’t make sense. I suppose it is because of a failure of govt. to do anything about this. Now Liz Truss is saying she’ll remove the green energy tariff to help people pay their bills which is only £150/year, and the only reason we have the problems with bills is cause of our dependency on fossil fuels. It’s just madness. The problem is it all gets political. It’s about getting into power and who puts you there to a large extent.
You’re the Chair the IMechE Environment, Energy, and Sustainability Group, so what do you do there?
It’s voluntary work. The IMechE is a charity and to be a member you have to be an engineer or practising engineering. You don’t necessarily have to have an engineering degree, you just have to be one. The point is, to be a professional engineer you have to be part of an institution approved by the engineering council. One of the main objectives is educational - we aim to support the development of engineering and to help spread the message more widely. The Environment, Energy, and Sustainability Group is a committee that is promoting sustainable engineering. We do this through a series of about 6 webinars we put on a year. We also make a newsletter and sometimes get involved in responding to government consultation on relevant topics. Within the group there are people who are in different sectors - energy, waste, water, transport, manufacturing, etc. - which is great, because we can develop an integrated approach to sustainable engineering. We used to put on events but it was hard to make them profit-making which the institution required. Sometimes we’ll contribute to seminars which other groups are putting on.
What kind of longer-term policies do we need to see to address the Cost of Living crisis as well as moving to renewables? It seems like one of the big things is demand reduction and you were also writing about community energy projects.
The good thing about community energy projects is that they get people thinking about their energy. They make people think through what implementing renewable energy means in practice and think about energy demand. This helps build an understanding of what it to means to transition and what the challenges and other benefits are.
Those are the upsides, but it can only really be - I believe - a relatively small contribution. A successful community energy project requires a lot of enthusiasm and people with a lot of time to give to thinking about energy systems. Relatively few people work full time on a community energy project. It’s mostly people working part time. Community energy projects are not necessarily replicable across the country, since it’s not necessarily the case that where people live is the best place for renewable energy generation: consider wind energy, it’s best on top of a hill in a remote place, generally away from people. That’s not the sort of things communities have access to. Sometimes there are benefits for economies of scale with certain types of renewable energy which can be a disbenefit of community scale generation.
Do you see small scale storage playing a significant role?
I think it will. It will need to, because sometimes renewable energy generation might be appropriate at the far ends of the distribution network. The network has been designed for one way flow of electricity so it’s like a tree: you’ve got a trunk and branches and leaves and it gets thinner and thinner. This means that there is less capacity at the end of the network. If you want to get renewable energy generation at the far reaches of the distribution network, you either have to upgrade the network or create local storage and that’s often a commercial decision. There is storage on a national scale which will help with balancing the intermittency of renewable energy as the dominant renewables in UK are wind energy (mainly), and solar. The problem with solar is that there is an interseason mismatch between supply and demand. There is the highest generation in the summer and highest demand in the winter. If you meet your winter demand with wind energy, that wind energy resource is still going to be there in the summer, so the question is how much PV is really useful at scale. PV is more predictable than wind energy, but it’s still intermittent. We need a combination of storage and demand management. That would mean switching off loads when the energy supply is low and switching things on when the sun is shining or the wind is blowing. Interconnectors with other countries are also an option, because the more renewable energy you have across the continent, the lower chance of periods when no wind blowing. Most of the time, there’s wind energy and solar to some extent. The more you interconnect, the more balanced the supply is, so I think energy storage locally and on a large scale is a good thing.
It just doesn’t make economic sense, at the moment, to put a battery in your house. It’s actually not necessarily good either because while we have a low penetration of renewables - where renewables aren’t supplying the majority of demand - if you demand renewable energy and then you supply that renewable energy to that user, there’ll be fewer round trip cycle loses of a battery than if the battery was charged, which is a problem because you lose 20% through charging and discharging a battery.
Could you say a little bit about the costs of renewable energy?
I can’t answer with certainty in all areas. The thing is that costs are varying so wildly at the moment it’s hard to get an understanding. Wind energy is the cheapest form of electricity generation in this country, although to what extent that takes into account the requirement for energy storage and energy demand management, I couldn’t say for sure. There have been studies that have taken that into account. You can’t just look at a wind turbine if you want to have wind energy, you’ve really got to have some sort of balancing infrastructure with the generation. Anyway, wind energy is a very low cost form of electricity generation relative to alternatives. It’s projected that PV projects will be cheaper than many fossil fuel projects. Some people say solar is cheaper than wind, but it’s not in my experience because, per kW the capital cost is comparable with wind, but you don’t generate as much energy over the year with PV as you do with a well sited wind turbine. PVs are getting a lot cheaper, so there could be some sort of convergence there. For biomass: wood fuel tends to track oil; wood pellets are also similar to the oil price per kWh; and wood chip tends to be a bit cheaper depending on where it’s from. However, an actual biomass boiler is more expensive than a gas boiler, so life cycle costs without any support are higher than the fossil fuel equivalents for biomass heating and the same generally applies to heat pumps. It might be that it’s changing with electricity prices changing - I don’t track it every week or even month. One important thing to note is external costs; often the economics are misleading because fossil fuels don’t price in the externalities. [inserted by me since the call cut off] Deciding on a fair price for emissions is hard, because converting from suffering to pounds is hard, so economists tend to ignore that and call it an externality, which can create misleading results.