WDB
Full Member
Posts: 7,425 
|
Post by WDB on May 10, 2024 16:22:13 GMT
The prospect of a second EV in the household, plus a few other planned updates to our major energy-using devices, got me thinking at last about choosing a more appropriate energy tariff. First target is to use more electricity but pay less for it (obvs) but the medium-term goal, ideally before the winter, is to move off gas for everything but cooking. Part of my motivation for the Big Garage Tidy was to make access to the consumer unit and electricity meter easier for a smart meter installer, who's now coming in a couple of weeks.
Likely regular usage will be one overnight charge per EV per week, so perhaps 80kWh in total, plus whatever we can shift into nighttime hours in addition to the dishwasher, which we already run at night. (Calm down, Rob!) Preferably without paying a huge penalty for what we have to use during the day.
But in the not-much-longer term, I'd like to heat the house with electricity, either directly or otherwise. One option for that is a Tepeo Zero-Emission Boiler, a giant thermal storage battery the size of a washing machine (or of our gas boiler) that weighs 350kg and stores 40kWh of nighttime electricity as heat to release gradually into a conventional radiator system like ours. For reasons to do with ancient pipes that I don't want to tear the house apart to replace, this may suit us better than a heat pump. But it will require a good window of low-cost, preferably clean electricity to heat it up every night and leave enough capacity to charge a car. Our main fuse can take it - we've had that checked already. It's a question of finding the right energy supplier.
British Gas, which I've stuck with out of inertia till now, has an 'EV' tariff, with a piddly 5-hour nighttime window. E.On Next Drive V3 (!) looks more promising, with 7 hours that don't end till 0700, which might give a ZEB a better chance of lasting the day in a cold snap. Pricing for both is in the 7-8p range, although of course that can vary. Nothing to choose between them on standing charges or gas, and the penalty for using daytime electricity is less than I'd expected at about 3-4p. Octopus Energy's EV tariff is in between at 6 hours and 7.5p, but promises that all the electricity is renewable.
There's clearly more reading I should do, particularly about who offers renewable (or nuclear, which I'd be happy with) and what hardware it will work with. My 2017 BMW wall box has no advanced features that I'm aware of, but the i3 has a programmable charging timer and I imagine the iX will be at least as clever, so that may not matter if the smart meter does its job. But some of you may be ahead of me on this so I'd be glad to benefit from your experience.
|
|
|
|
Post by EspadaIII on May 11, 2024 17:09:18 GMT
Interesting that you want to retain gas for cooking. Research says gas cooking is bad for you so maybe go fit an induction hob at the same time.
Yes British Gas EV tariff is only five hours but it works for us especially when we have the solar panels and 16kWh of battery storage as well. I have set my system up now so I can fill my batteries overnight on cheap electricity.
I wonder why you only want to charge the EVs once a week? A different regime of charging once a car reaches say 50% would probably ease the stress if you remained with BG.
I haven't come across these heaters you refer to, I must research myself but I wonder if investing in panels and batteries would be more efficient, although I appreciate that you would retain gas for space and water heating which doesn't get to zero carbon.
|
|
|
|
Post by Humph on May 11, 2024 18:01:12 GMT
Hey ESP, just curiosity and so on, but what’s the deal with doing things on a Saturday before dark in your community? I thought it was off limits?
Sorry if that seems rude or something, just interested.
|
|
|
|
Post by EspadaIII on May 11, 2024 23:21:04 GMT
Correct we can't but I'm not in the UK so I have gone beyond the time before which we are prohibited from doing such stuff.
|
|
WDB
Full Member
Posts: 7,425
|
Post by WDB on May 12, 2024 7:11:11 GMT
I wonder why you only want to charge the EVs once a week? A different regime of charging once a car reaches say 50% would probably ease the stress if you remained with BG. I doubt it'll be that regular. I just worked back from the likely use the cars will get to a number of kWh they'll require, and turned that into a rough number of plugged-in hours. You're right that it'll be possible to finesse the times but I also have to reckon with MrsB1, who is tech-blind and struggles to manage even the alarms on her phone. I still fully expect to come home at teatime and find the i3 charging "because I'm going out first thing in the morning". Any programming and timeslot management will have to come from me, so the wider the window the better. I haven't come across these heaters you refer to, I must research myself but I wonder if investing in panels and batteries would be more efficient, although I appreciate that you would retain gas for space and water heating which doesn't get to zero carbon. Oh, I'm planning panels and batteries too. They should really have been in a year ago but I've had some, erm, internal resistance to deal with because they won't advance the cause of domestic neatness, so I've had to attend to other things first. My employer will even give me an interest-free loan to pay for that bit, so I've no excuse. The 1990s gas boiler that we've been nursing along since we bought this house has now reached the point where the service engineer sucks his teeth and says, "You know we can't get parts for these any more, don't you?" It's vastly inefficient anyway, so it has to go, and buying a new gas boiler now would feel like putting an AMG E55 on the drive; money must follow mouth. The ZEB is close to a plug-and-play replacement, given that it would stand on the same piece of floor the boiler now occupies. And, being a high-temperature device, it will play nicely with the ancient radiator pipes, once they've had a flush anyway. (Replacing the actual radiators is another project in the planning stage but the two can be independent this way.) I'm not thinking of it as a cost-saving measure so much as a way of (almost - see below) eliminating fossils from my home and an incentive to source the cleanest electricity I can get to power it and the cars. Interesting that you want to retain gas for cooking. Research says gas cooking is bad for you so maybe go fit an induction hob at the same time. I hadn't read that but here it is www.theguardian.com/environment/article/2024/may/03/gas-stoves-nitrogen-dioxide-pollution and of course, the long-term goal must be to stop burning stuff altogether. But my gas hob is a really good one that is great to use and burns a relatively trivial amount of gas. It also has a big extractor vented to the outside, so I'll rely on that for interior air quality for the time being. |
|
|
|
Post by Humph on May 12, 2024 7:17:55 GMT
Correct we can't but I'm not in the UK so I have gone beyond the time before which we are prohibited from doing such stuff. Ah right! All clear now. |
|
|
|
Post by EspadaIII on May 12, 2024 8:41:25 GMT
Yes. It is interesting when a football match in England is during the Sabbath I can't watch it, but if I was in Israel which is two hours ahead, sunset may have already passed, so I can watch it.
|
|
|
|
Post by Humph on May 12, 2024 11:52:28 GMT
Must be tricky for anyone serving on the space station.
🤔
|
|
WDB
Full Member
Posts: 7,425
|
Post by WDB on May 12, 2024 12:02:08 GMT
Doesn't saving lives get an exemption? In which case, one might argue that anything one fails to do aboard a space station is likely to have safety implications, so best claim the exemption for everything, all the time.
|
|
|
|
Post by Humph on May 12, 2024 12:35:11 GMT
Yeah, I think the space station orbits 16 times every day. 16 sunrises and 16 sunsets.
|
|
|
|
Post by EspadaIII on May 12, 2024 18:35:28 GMT
Saving lives is an imperative that overrides all other rules. Doing 'work' on the Sabbath is absolutely permitted if you are even close to saving lives.
|
|
WDB
Full Member
Posts: 7,425
|
Post by WDB on May 13, 2024 11:19:22 GMT
I've been reading a bit about the ZEBs you mention WDB, may work in the south-east of England, a bit rich for my blood knowing what my energy use is, especially when we have a cold snap. It sounds like an update of the 80s Economy7 my wife had in her Edinburgh flat. Always ran out of heat when you wanted it most then had to pay a fortune to heat the place. …  We use around 18,000 kWh energy per year for hot water and heating. We can use around 70kWh/day in a cold, below -10°C, spell. Assuming worst case scenario 70% boiler efficiency means we could drop to around 13,000kWH/year @ 42 cents/kWh = ~5,500€/year vs 1,500€/year I currently pay. You really have to want to save the planet badly to quadruple your annual bills. Thought I’d continue this over here. The ZEB is massively insulated; the core gets to a temperature I forget but several hundred degrees. And, unlike storage heaters (which I’ve lived with too) it releases its heat in a controlled manner through a heat exchanger and a central heating pump, all controlled by its own software, so it’s not warming the house while we’re out at work. There will undoubtedly be a few days in the dead of winter when 40kWh won’t be enough, but UK winters are milder than German ones and we will mitigate this by continuing to improve our insulation to make the heat last longer. (I wrote ‘go further’ but that’s the opposite of what we want.) We’re using 23,000 kWh a year at the moment, half of which is our ancient boiler burning gas to heat the sky. We can address the hot water portion, if we need to reduce the load on the ZEB, with a timed immersion heater using the cheap rate — and by shutting off the pipe that stupidly circulates water from the cylinder through the bathroom towel rail, so we’re out of hot water by lunchtime. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 13, 2024 11:32:09 GMT
I'd never heard of these ZEB things. Very interesting. Similar situation here, ancient inefficient boiler in its twilight years, and considering a replacement. I wonder if this ZEB would work with Octopus Agile? I've had great results on that for over a year now, compared to all their other tarrifs I've saved decent money this year. Also got an old heating system, with pipes buried in floors under parquet. Do not want to change them, nor the pressure going through them. Also have a boiler location problem - current one is in centre of house and flues up a chimney, which is shared with an open fire. Which means a new gas boiler would have to be relocated, adding loads to the cost. Hmmm. 'Ow much are these ZEB things then, mister? EDIT: Ah, found the price. A bit yikes but not that much more than a new boiler plus relocate. 23,000kwh on gas annually, Dubya? Blimey. I thought I was bad. last year we used 12,306 (heating and hot water, obvs). That's a 1971 built 4-bed detached, with 4 people in it including 2 teenagers. Found this on the ZEB website - this is for 12,500kwh per annum:  Remain to be convinced then. And remembering I'm probably selling up in 6-7 years time. |
|
bpg
Full Member
Posts: 2,809
|
Post by bpg on May 13, 2024 12:14:00 GMT
I've been reading a bit about the ZEBs you mention WDB, may work in the south-east of England, a bit rich for my blood knowing what my energy use is, especially when we have a cold snap. It sounds like an update of the 80s Economy7 my wife had in her Edinburgh flat. Always ran out of heat when you wanted it most then had to pay a fortune to heat the place. … We use around 18,000 kWh energy per year for hot water and heating. We can use around 70kWh/day in a cold, below -10°C, spell. Assuming worst case scenario 70% boiler efficiency means we could drop to around 13,000kWH/year @ 42 cents/kWh = ~5,500€/year vs 1,500€/year I currently pay. You really have to want to save the planet badly to quadruple your annual bills. Thought I’d continue this over here. The ZEB is massively insulated; the core gets to a temperature I forget but several hundred degrees. And, unlike storage heaters (which I’ve lived with too) it releases its heat in a controlled manner through a heat exchanger and a central heating pump, all controlled by its own software, so it’s not warming the house while we’re out at work. There will undoubtedly be a few days in the dead of winter when 40kWh won’t be enough, but UK winters are milder than German ones and we will mitigate this by continuing to improve our insulation to make the heat last longer. (I wrote ‘go further’ but that’s the opposite of what we want.) We’re using 23,000 kWh a year at the moment, half of which is our ancient boiler burning gas to heat the sky. We can address the hot water portion, if we need to reduce the load on the ZEB, with a timed immersion heater using the cheap rate — and by shutting off the pipe that stupidly circulates water from the cylinder through the bathroom towel rail, so we’re out of hot water by lunchtime. The insulation is a double edged sword, fantastic in winter, a bugger in the summer to try and dump heat from the house if you accidentally let it build up. My house was built by an insulation meister. He insulated the crap out of everything. It means in the summer having the outside blinds down in the bedrooms pretty much full time which is OK as we only sleep in there. It makes the bedrooms unbearable if the blinds are left up on a hot day. While it's you and MrsB1 in the house heating and hot water will be easily managed. You will need a backup when the 'family' come home for Christmas with partners and potentially more in the future or a big bag of pegs for your noses if the local swimming pool is not open. |
|
WDB
Full Member
Posts: 7,425
|
Post by WDB on May 29, 2024 11:14:47 GMT
Well, the smart meters were installed this morning. Now I can work on my tariff strategy. The second EV won’t be here till July, by which time there will be fixes available at the lower rate, so that may be the time to go for a fix, before the anticipated rise in October.
ZEB installer is coming to assess next week. Feels like progress at last.
|
|
