LnP

Given that hydrogen as an energy carrier is a non starter for the economic and safety reasons mentioned above, there are other ways to deal with curtailment. Interconnectors can solve not only curtailment but also Dunkelflauten. Time of use tariffs will help. Also, the Royal Society recently published a report recommending hydrogen as a means of storing energy to deal with the ups and downs of renewables - electricity via electrolysers to hydrogen then via fuel cells back to electricity for distribution to consumers - it's expensive though. It's also worth pointing out that, despite the marketing blurb from the gas companies, even green hydrogen has a climate impact. It's very leaky stuff and when released into the atmosphere, has a significant global warming potential. Grey hydrogen (produced by reforming natural gas) even with carbon capture and storage (CCS) is also no climate angel. Natural gas extraction and distribution leaks methane (a global warmer), the reforming process creates CO2 , the CCS process has a parasitic energy requirement, is expensive and doesn't capture all the CO2 . It will be a sad day for the climate, for our bank accounts and for our safety if we start burning hydrogen to heat our homes.

It's telling that the clip @nod shared on the switch to hydrogen is from British Gas. The fossil industries, gas network operators and boiler manufacturers are lobbying hard on this.... naturally, because without it, they're sunk. Consider this, to heat your house by burning green hydrogen will require 5.5 times as much renewable electricity as heating it with a heat pump or twice as much if you heat your house with resistive electrical heating. That's 5.5 times as many wind farms. And as @Mike says, as more people make the switch to electrical heating, the fixed costs of operating the gas network will have to be shared among fewer consumers. For these reasons, hydrogen will be prohibitively expensive. Additionally, the safety issues of having hydrogen in your home are problematic. It has a wider flammable range, is easier to ignite, generates higher overpressures when it explodes and is harder to keep equipment leak tight. Additionally, hydrogen gas hobs release more NOx that natural gas. NOx has been implicated in respiratory diseases. There have been three trials proposed for domestic hydrogen in the UK, Whitby (near Ellesmere Port), Redcar and Fife - notably all disadvantaged areas where consumers might be more attracted by inducements from the vested interests sponsoring the proposed trials - Cadent, Northern Gas Networks, Scottish Gas Networks. Whitby and Redcar have been abandoned largely due to independent academics and engineers stepping in to shine a light on the safety issues and misinformation being provided to the residents. Cadent engaged the engineering company Arup to do the risk assessment for Whitby, to estimate the expected frequency of leaks and explosions. Introducing hydrogen with no additional engineering mitigation measures gave unacceptably high risks, higher than gas. They proposed measures to get the risk down to the same level as gas. They considered this level of risk to be tolerable which is in itself flawed, since legislation here requires risks to be managed to be as low as reasonably practicable - heat pumps are a practicable way to heat your home with less risk of fire and explosion. Some experts challenged other conclusions of the Arup risk assessment. There will be challenges to decarbonising by renewable electrification - grid capacity, curtailment, Dunkelflauten. But solutions are available. There are uses for hydrogen for which, unlike heating, there is no alternative - e.g. making ammonia or methanol and desulphurising fuels in refineries. That's the first priority for green hydrogen. But if science and economics are allowed to prevail over politics and lobbying, we won't be heating our homes with hydrogen. @Wadrian, I don't think you need a gas connection!

I was in hotel accommodation recently which had bathroom wall finishes which we liked. Wherever there might otherwise have been tiles, so shower surrounds, backsplashes etc., they'd used approx 5 mm thick sheets of what I imagine was stone filled resin. It had the look and feel of stone and was better than some of the formica laminate sheet type material I've seen. I'm attaching some photographs. Does anybody know what this material is and where I can get it? Thanks Thanks

This demand calculator might help https://www.ssen.co.uk/our-services/tools-and-maps/demand-calculator/

How will you heat your DHW in winter? If it's with the heat pump, what recovery time will you get with 3.5 kW?

Generators already have to buy, trade and surrender carbon credits through the UK Emissions Trading Scheme. At the consumer level, you're talking about a carbon tax and you're right, a lot of economists think it's the right way to incentivise reducing carbon emissions. Unfortunately it's politically difficult. Canada used to have one and it was very unpopular. The first thing Mark Carney did when he became prime minister was to ditch it. Pity.

Perhaps because the regulator sets it up to work this way, since the context to the proposal is to help the UK achieve its net zero target. They want to incentivise renewable generation close to the demand to reduce the required changes to the grid. Beefing up the grid to get electricity from far away places is expensive and the pylons are politically difficult.

I'm still learning. Thanks for the clarification, yes designed and commissioned, but not installed. And I noted your earlier comment "When I shared my detailed calcs with them they stopped talking to me!" So they won't guarantee your 6.5 kW requirement. They say they take care of: System Design & Diagrams Installation Support & Installer Training On Site System Check & Commission The Latest Cool Energy InverTech Heat Pump With Remote Support Over Wifi High-Quality INOX Stainless Steel Unvented Pre-Wired Cylinder Full Handover Pack & Insurance Backed Guarantee They also "take care of the paperwork" to claim the £7,500 grant.... does that mean they keep all of the grant money? Otherwise, how would they make their money? £7,500 might seem a lot for what they're delivering, but for the customer, it's still a free heat pump, cylinder etc, so could be attractive. But the question would be, is there an umbrella scheme operator out there who will work with the client on the design? Or do they all insist on over-designing by a factor of two? Or is the over-design inherent in the MCS heat loss calculation methodology?

Sorry, no I meant hybrid in the sense of the way we work. It'll be just an ASHP.

Definitely a good solution and hats off to you for sorting that out. I'm not planning to DIY but am thinking about a hybrid arrangement with a guy who's a qualified plumber and electrician - Gas Safe, NICEIC etc. He's done work for me before and we get on well together. I'm more involved in the work than a typical customer and he's happy with that. We'll discuss what we need and he's happy for me to buy the kit and for him to install it. I value and respect his experience and occasionally I bring a different perspective. He's not MCS certified as he thinks it's a rip-off for something he's already qualified to do. For our self build, we've discussed him installing the heat pump under an umbrella scheme, but we haven't finalised that yet, hence my interest. This would be his first heat pump installation but he's up for that and interested in the project. Maybe I can buy the kit cheaply, as you have done, have him install it and I still get the grant. We can work this out so he and I both benefit. He's also interested in installing the PV, but that's another story!

Coolenergy are not the only people offering an MCS umbrella scheme. If you do an internet search there are several others including for example this one from Vaillant. Does anybody have any thoughts about or experience with those?

Great blog and nicely written. Regarding goggles misting up, the mist is tiny droplets of water condensing onto the lens. If you put something on the lens which breaks the surface tension of the water droplets, they all merge into a continuous layer, which you can see through. Dilute detergent or soapy water works. Dilute baby shampoo won't sting if it gets in your eyes. Licking the lens can also work .... depending whether you like the taste of dusty goggles!

I think I posted Warrington's UU elsewhere, but here it is again. I'm not a lawyer, but a couple of differences I noticed: Warrington provide for the possibility that the self builder could be released from their obligations if their circumstances change. Unless I missed it, Dorset does not. The Warrington UU says: "PROVIDED THAT the requirements in paragraphs 4 and 5 shall not apply in the event of a change of circumstances acknowledged by the Council in writing acting reasonably which prevents the Original Owner from Occupying and/or not Disposing of the relevant Dwelling within such three (3) year period." I'd be thinking about ways in which my circumstances might change, for example my place of employment changes, I lose my job and have to move house, I need to move closer to aged parents, I get sick and need to move into care, etc. It looks like the Dorset UU would prevent me from doing that. In the Dorset agreement, your self build has to continue to be your "sole or principal residence" for three years. Does this prevent you from owning a second or holiday home? None of this is legally required by the Act or Regulations. The self build exemption is provided in The Biodiversity Gain Requirements (Exemptions) Regulations 2024. They very simply exempt self builders. And self builders are simply defined in the Self-build and Custom Housebuilding Act 2015, Local authorities are over-reaching their legal mandate. I continue to believe that the way they're implementing the self build exemption is outrageous. Warrington Self Build - draft UU26.9.24 - FORMATTED 16.10.2024 CLEAN (1).docx

You can't beat the second law. Once you've converted the electricity (work energy) into heat energy, any device you design to get back to work energy can never get you back all the energy as work. Some energy will always be rejected as heat. The best you can theoretically do is a Carnot heat engine which has an efficiency of (Th - Tc )/Th - hot and cold temperatures in Kelvin. And there's no actual such thing as a Carnot engine. Yes, great if you can find a use for the rejected heat. I've got a fantastic energy project I think you might be interested in investing in ....

At the moment, curtailment is usually because the grid doesn't have sufficient capacity. We should spend the money on increasing the capacity of the the grid so it can handle all the wind and solar, rather than expensive energy storage just because the grid can't handle it. Eventually though we will need storage to balance supply and demand. How to manage intermittency and curtailment was studied by the Royal Society and reported here, and indeed they found a potential use for hydrogen, i.e. renewable electricity via an electrolyser to hydrogen, stored in a salt cavern and back to electricity by a fuel cell or ICE and generator. It's expensive both in terms of capital cost and the round trip efficiency of 41%, i.e. you only get 41 kWh of electricity back for every 100 kWh of renewable electricity you put in. Back to my original point though, advocates of hydrogen who don't understand the thermodynamics will assume that we can improve on the 41% as we get better with electrolyser and fuel cell technology. I'm afraid lobbyists and parties with vested interests looking for subsidies, exploit this and persuade politicians that the economics will improve. We can't and they won't. These are second law losses and you can't beat the thermodynamics. Some people correctly argue that interconnectors, which were not included in the RS study, could be a better solution - you connect to renewable sources where the wind and sun blow and shine at different times. Interconnectors avoid second law losses. It all about the difference between the two types of energy, heat and work!

Power is to work as speed is to distance 🙂. One is the rate of the other.

I don't understand your point about enthalpy. Did you mean entropy? Either way, there are different ways to state the second law. I tried to make it simple and deliberately didn't bring entropy into it. I just saw something which was incorrect, is a common misconception and incorrect in a way which sometimes leads to poor energy policy making. So I hoped to straighten that out. A political example ... if our politicians understood this science better, they wouldn't be wasting tax payers' money on subsidising projects which use hydrogen as an energy vector, for example this one in Aberdeen, especially given that in Montpellier they already learned the hard way. Compare: Renewable electricity -> hydrogen (heat energy) via an electrolyser -> electricity via a fuel cell -> work energy via an electric motor .... or -> work energy via hydrogen internal combustion engine. Versus: Renewable electricity -> work energy via an electric motor in a BEV. Apologies if this has hijacked the thread!

No. Heat and work are the two different types of energy, measured in Joules. Power is the rate of doing work measured in Joules per second. A J/s is a Watt. The first law (conservation of energy) is easy. The second law is tricky. Politicians don’t understand it which is one reason why we get incoherent energy policies.

Actually not correct. Second law of thermodynamics, there are two types of energy, heat and work. Work can be converted completely into heat; but heat cannot be converted completely into work, the best you can theoretically achieve is a Carnot heat engine. Fossil fuels provide heat energy and electricity provides work energy. The second law is not well understood but important in the context of plotting a course to net zero.

Is this because the BNG gains cannot be legally secured through a 30-year monitoring plan in a private garden? @Benpointer, so what are you going to do? What conditions are in the proposed S106 agreement? I'm more concerned about ecologists setting up biodiversity offset sites, because they on the one hand tell you how many points you have to buy and on the other sell you the points. A clear conflict of interest. This is a mess.

@Benpointer Since you have plenty of space to add the 10% biodiversity points, you might be better off foregoing the self build exemption, with its associated costs and S106 restrictions. I’ve heard a habitat survey and assessment costs about £2k. Its another irritating and unnecessary professional fee, but being pragmatic, maybe the BNG self build exemption is more trouble than it’s worth.

+1 for FH Brundle. If you open an account you can sometimes get a discount.

... not to mention the costs you'll incur to implement and monitor the S106 agreement. Have they told you how much that will be? It seems some LAs are using UUs and some S106 agreements. Maybe some are still accepting a signed letter declaring yourself as a self builder. I'm not familiar with S106 agreements, but will the agreement prevent you from selling your house for a period of time, e.g. 3 years, after completion? Do you need finance for your build? If so, what does your lender say about this restriction? I've heard some lenders won't accept it. It's worth considering whether it might be cheaper and easier to do the BNG assessment and agree to the mitigations required to achieve the 10% net gain. Be careful though if you go this route. I recently saw a small garden plot where the proposed house would cover most of the plot and leave very little space for adding biodiversity. So they needed to buy offsets to replace the lost biodiversity points and the required 10% additional. The ecologist company which did the assessment also operates a biodiversity offset bank and were - surprise, surprise - more than happy to offer to solve the builder's problem by selling them offsets ...... for £36,000!! It's a huge conflict of interest with no checks and balances. So if you decide not to avail yourself of the self build exemption, it might be better to use an ecologist who is not selling offsets. LAs say they are ensuring that sneaky commercial builders are not dishonestly using the self build exemption. But the number of self build planning applications is tiny. Is it really necessary to go to these lengths and in many cases close the door on the exemption. How the self build BNG exemption should work has not been thought through and is unfair to self builders.

I wanted to paint a screeded workshop floor. The small print on the solvent based floor paints I looked at said they weren't suitable for screed, only suitable for concrete. So I went for the two part epoxy paint. Yes it was expensive and you have to discard your rollers and brushes afterwards, but I preferred to do the job once. It's been down a couple of years now and is holding up wel ... l and I like the high gloss finish 🙂 . I've dropped things on it and it hasn't chipped.

Are you claiming the self build exemption from having to demonstrate biodiversity net gain? If so, are the LA doing anything to prevent you from subsequently selling? My LA require us to sign a unilateral undertaking and will put a charge on the house to prevent us from selling in 3 years from completion.