Home Energy Efficiency
Comments
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Yes, true.
On the subject of solar, my neighbour had solar installed and was chuffed with his 6% yield. I asked him how old he was. 75.
Hopefully he'll live long enough to break even. No, forget that. He's a twat! ( An opinion shared by everyone else in the street, not just me.)😉
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Finland is one of the biggest users of ASHPs in the world. It gets a bit colder than 5⁰C there in the winter. GSHPs are just not cost effective for a typical home even if installed at construction. Bore holes are expensive.
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
I've avoided having one so far. Too many stories of them not working then leaving people witgh large bills when the energy companies realise. They overplay their use in saving money, unless you're running appliances unnecessarily knowing how much your using isn't saving you anything and if you are running things unnecessarily you'd have to be a bit thick to not know you are wasting money. The reason they are pushed so hard is that they are beneficial to the energy companies as far as I can tell.
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I have solars, battery storage and a hybrid ASHP system. The assessor decided my house type qualified for the gas boiler addition to the ASHP and still qualified for the 0% loan funding from EST/HES. Only had to put up initial c.£3k.
The gas boiler kicks in when the temps are down near or below zero, and can also use it as a hot water tank boost. However solars usually heat the water tank via diverter unit before exporting surplus.
My ytd export is still 300 kWh more than total import of electricity. Even with the poor summer weather experienced.
Smart meters essential for utilising the Octopus Flux tariff, they take readings every 1/2 hour which is necessary given the variable kWh tariff price, low 0200-0500 (charge the batteries), standard and peak 1600-1900 (avoid import).
Still learning this new world order but I feel quite happy with how it's going 1 year in.
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But you don't need a bore hole for a GSHP. The pipes can be laid horizontally and only need to be 1.5 - 2 meters down so not much more than the foundations for a house, hence my comment that they should be compulsory on developments of a few houses or more, and absolutely the case on a large development.
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Perhaps, but heating water is just about the cheapest and most effective way to store energy, provided you are going to want to use that energy in the form of hot water before too long. In an ideal world the electricity companies would have the ability to dump spare energy into consumers' hot water cylinders when supply exceeds demand, reducing the need for expensive energy storage infrastructure such as batteries and pumped storage hydroelectric schemes. Octopus push their customers towards this with their Agile tariff where they claim to sometimes pay the customer to take the electricity, if you had some clever monitoring you could switch your immersion heater on whenever the electricity price fell below a certain point.
If you want a decent shower you are going to need about 12 kW to heat the water from cold, this is not difficult with a gas boiler, but a 12 kW electric heater is going to need massive cabling and is going to put a huge spike in your demand. If you have a cylinder already full of hot water this is not a problem.
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How many new build homes do you see with gardens big enough to contain enough coils at that depth to heat the house? We've done the sums ourselves a few times and spoken to people who do the sums for a living and while they are great for people with half an acre, for more typical sized building plots they only work with a borehole and then are very expensive.
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
I don't know a whole lot about this so forgive what may seem like a daft question but is there any scope for a (large) GSHP to be installed under the new road/verges/footpaths on a new development that would serve all the houses in that road/cul-de-sac/block of flats
Wilier Izoard XP0 -
Exactly, you install a communal system.
On a new housing estate development they will be digging up to put in sewers, water, fibre etc anyway.
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District heating has been tried at various points and in various ways. The main thing it does is tie everyone into a service charge, so it's less attractive for homebuilders. There are also a fair few horror stories of systems that have never been made to work and are eventually abandoned in favour of individual gas boilers.
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
I'm sure you could find a few horror stories of individual units not working if you looked 😁
- Genesis Croix de Fer
- Dolan Tuono1 -
District heating relies on a communal boiler. A district set of pipes for a ground sourced heat pump is a bit less wild although I have no idea how much maintenance and ongoing access they might need.
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Tends to be one home and relatively easily fixed. Cost to replace a system for 20 homes is enough to make people try to wriggle out of it and or fold their business.
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
We installed a 9 kWp photovoltaic (PV) on our roof ca 5yr ago. And after I collected 2yr of own PV data, we eventually got quotation for batteries. I was eager to have my own PV data (all our electricity data get stored online at 5min intervals: PV production, feed-in, own use, grid reliance), before considering the battery, in order to extrapolate the effect of the battery on our grid reliance. It turned out, the battery cost was several times the total electricity save it would have caused during its 20yr lifetime. So, no thanks. But the greedy vendor kept saying it would have been great for us.
Battery cost: 10keur, for 10 kWh, 20 yr lifetime
Save: 700 kWh/yr, ca 175 eur/yr, ca 3500 eur total save during 20 yr lifespan. Well, if it doesn't break before.
In addition, battery had to be 10keur paid at front, whereas the 3500eur savings would have been distributed over 20yr.
Have tons of maths analysis on our PV data (maths and data analysis are part of my profession).
Question: why is the effect of the battery very modest?
Simplified answer: in winter daytime light is so modest that come evening when the PV no longer produce and it would be great the batter kicks in, it is actually empty because there was no surplus of PV electricity to charge it up. And the opposite is true in summer: come evening when the PV stop producing the battery is fully loaded so it can kick in for the evening and night. But during summer evening and night, the household need for electricity is very modest. So battery is not very useful, neither in summer nor in winter. True, autumn and spring are ok, but overall integrated over the year, overall effect remains modest.
Selected data:
12th Dec, yesterday, we had a PV surplus of 0.7 kWh, so this got sold to the grid. We also had to take from the grid 4.8 kWh. So if we had a 10keur 10kWh battery, this would have lowered our grid reliance (of that day) from 4.8kWh to 4.1kWh. Very little.
25th June: daytime we used 3.7 kWh of own-produced electricity, during night we had to take an extra 1 kWh from the grid. That day our PV produced a total 49 kWh (46kWh used by us, 3kWh the rest sold into the grid). Had we had a 10keur 10kWh battery, instead of selling 46 to the grid we would have sold 45, and the remaining 1kWh would have first gone into the battery and used by us nighttime. Grid reliance reduced by 1kWh, again very little.
So a 10kWh battery is massively oversized (oh, don't say this if you want to make profit selling them!).
The sweet spot in my fig below is ca 3kWh. This would lower our grid reliance ca 650 kWh/yr. Very little.
Attached own data for our household, 9 kWp modules (27 modules), no shadow, East- and West- orientation.
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Use, reuse, repair, recycle.
Some keep telling me I should sell my old car (market value today perhaps 2-3k), and buy a newer one, maybe for 10-20k. So this would save me on fuel cost. Mind you, fuel cost ca 300 eur/yr.
Question: what does one really want? If you want lower running cost (perhaps you do, but I doubt), go buy the newer stuff, better technology, more efficient, bla bla. If instead you want to save overall (I bet you favor this), keep using what's there. OK, not always true, but by far most often.
Applies to money as well as environmental impact.
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Pep - are you omitting the fact that many tariffs, such as Octopus Cosy, have periods when you pay little for the electrivcity and charge up the battery in those periods to discharge when electrivity is more expensive.
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Fair point.
Yes, I'm omitting this. I heard there's is such a thing, not for our household though, perhaps not at all here in Germany.
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A colleague at work looked at battery storage and was told that potentially they wouldn't insure the house if installed inside. He got himself a Nissan leaf thing and he couldn't put it in his integrated garage because of the fire risk. Now selling it because of the stress it's caused him over charging whilst using it for his job. Personally think the payback on both ev's and solar storage is to long to be feasible. I think Hydrogen is the way to go with cars. Not sure on air source yet and groundsource isn't suitable for my place.
Too many bikes according to Mrs O.0 -
Re hydrogen cars, I recently had a discussion about this where potential downsides were considered. Anybody got an idea about what happens in cold climate winters when cars are laying ice rinks?
The above may be fact, or fiction, I may be serious, I may be jesting.
I am not sure. You have no chance.Veronese68 wrote:PB is the most sensible person on here.0 -
Random thought on this:
I see why it's better for electricity producers to flatten out the production during the day. So to facilitate this, they effectively bribe users, like less expensive electricity when there's normally less demand. Some even gets tempted installing domestic battery, right or wrong... But if so, wouldn't it make more sense for the big electricity companies to have huge batteries of their own? Better manageable, better storage location than your living room, economy of scale, bla bla....
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I saw discussion on that recently and wasn't something I'd ever considered previously. I guess some kind of storage tank but then it would have to be emptied regularly.
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The main issue with hydrogen is that it takes way more electricity to make the stuff than you get back when you burn it. If we go down the hydrogen route we are going to have to generate about double the amount of electricity.
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Also, the occasional gas leaks will be spectacular.
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
Yes, it's not very efficient; however, some places have lots of sun and space, so can make it quite easily. The problem then becomes the cost of transportation as it is necessary to turn it into ammonia. Saudia Arabia is planning a 2.2 GW project called Neom.
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There is a massive amount of grid scale battery deployment going on at the moment in the UK, and Germany is going to follow. The advantage of a domestic battery is that it doesn't need to use the grid network and so isn't subject to all the constraints that exist. Someone I saw speak said that combatting climate change is about "and, and, and" - it requires everything to be deployed.
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I'm more for Hydrogen purely because it's got to be way more environmentally friendly compared to lithium and less likely to burst into flames if you look at it the wrong way. Downside of Hydrogen is if it went wrong it would be a little more spectacular.
Too many bikes according to Mrs O.0 -
The only time I had hydrogen in our house was when I was about 10 and using my Hornby controller to conduct electrolysis experiments and gather gas in test tubes to make "squeaky pops"! No safety glasses. Just a bedroom carpet made from polypropylene probably.
Sometimes. Maybe. Possibly.
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The other advantage of hydrogen is that you can have hydrogen fuelled inernal combustion engines (rather than hydrogen fuel cells), so much more like a petrol car and less like a souped up milk float. We can hope.
"I spent most of my money on birds, booze and fast cars: the rest of it I just squandered." [George Best]1 -
I keep reading about boiler manufacturers looking at hydrogen conversion and I don't think they can solve the fundamental problem of leaks. It's very difficult to design something that is gas tight for hydrogen, let alone a distribution system.
Think it's only ever going to be a niche fuel, especially for cars. Once the majority are just using charging points, who is going to make a living from storing enough hydrogen to take out a small village?
1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
Pinnacle Monzonite
Part of the anti-growth coalition0 -
That's why JCB,s lord Bamford proved it by retrofitting it to a.transit van. He also owns a company that does buses without the JCB plant portfolio.
Too many bikes according to Mrs O.0
