ChrisDubs Posted August 27 Share Posted August 27 Hi Advice please. We are running an air source heat pump and are wondering if it's allowed to install batteries to store cheaper over night electricity in those batteries to run the air source on more expensive parts of our tariff. Link to comment Share on other sites More sharing options...
PNAmble Posted August 27 Share Posted August 27 Yes, absolutely. Almost 100% of my electricity is cheap rate or free (from solar). Link to comment Share on other sites More sharing options...
SteamyTea Posted August 27 Share Posted August 27 Why not just run the ASHP during the cheaper times and store some of the thermal energy in the slab (assuming UFH) or in water. Chemical battery storage is still a way off being economical. Link to comment Share on other sites More sharing options...
Conor Posted August 27 Share Posted August 27 23 minutes ago, SteamyTea said: Why not just run the ASHP during the cheaper times and store some of the thermal energy in the slab (assuming UFH) or in water. Chemical battery storage is still a way of being economical. +1 That's what we do. Runs flat out for 7 hours each night. Doubt you'd ever make a saving using batteries for that sole purpose. Link to comment Share on other sites More sharing options...
jack Posted August 27 Share Posted August 27 I understand that the best use of batteries is to charge them during the cheap period (and run everything else you can at the same time), then sell back to the grid when the payback is highest (typically around teatime). I have a mate with a small solar array and decent battery who consistently nets a couple to a few quid a day most days during summer doing this. Link to comment Share on other sites More sharing options...
SteamyTea Posted August 27 Share Posted August 27 1 hour ago, jack said: I have a mate with a small solar array and decent battery who consistently nets a couple to a few quid a day most days during summer doing this. Abd pays a premium for imported power the rest of the year, and that is before the cost of installing PV and batteries. (Energy suppliers can change the tariff regime as well) Link to comment Share on other sites More sharing options...
SteamyTea Posted August 27 Share Posted August 27 1 hour ago, Conor said: Runs flat out for 7 hours each night My E7 is 27.5p/kWh day, and 11.08p/kWh night, with the daily theft of 70.1p/day (before VAT). When I am heating, I use an extra 10 kWh/day. That would mean I need a usable storage capacity of 12 kWh, which would be in the region of £6000 I suspect. £6k, at today's prices, would buy me 51,573 kWh, or 16 years price for all my energy usage. Link to comment Share on other sites More sharing options...
Nick Thomas Posted August 27 Share Posted August 27 (edited) 12 minutes ago, SteamyTea said: When I am heating, I use an extra 10 kWh/day. That would mean I need a usable storage capacity of 12 kWh, which would be in the region of £6000 I suspect. Prices have dropped off a cliff recently. The VAT zero-rating was passed on too, which is nice to see. You can get 9.4kWh for £3650, or double that for £5595 - list price, including the inverter. Things are nicer if you can assign the inverter to the solar PV payback period instead - £2200 for a 9.4kWh battery, £4200 for double that. ( https://homeenergygroup.co.uk/lux-ac-battery-storage-hanchu-ess-9-4kw/ ) I've got a measly 3.2kWh battery at older prices and it was marginal as to whether it would pay itself back within its lifetime, but these days it's better-looking. And it all helps to cut down on the amount of gas burnt, of course. Edited August 27 by Nick Thomas add battery-only prices Link to comment Share on other sites More sharing options...
crispy_wafer Posted August 27 Share Posted August 27 Ive been looking at these Fogstar Energy 15.5kWh 48V Battery l Fogstar UK They do some DIY kits too. Maybe something to investigate for when I finish my build... Link to comment Share on other sites More sharing options...
PNAmble Posted August 27 Share Posted August 27 My passive standard house doesn’t have a UFH because it’s an upside down house, so a battery, EV , PV and ASHP with low flow rate radiators does work for me across my financial and environmental goals. given that energy prices and how tariffs work will change significantly over the next few years as more dynamic pricing is introduced as opposed to broad TOU tariffs currently in play, I think batteries will become an important element of home energy management along with V2H and V2G. just my opinion. 1 Link to comment Share on other sites More sharing options...
Nick Thomas Posted August 27 Share Posted August 27 My *god* that's cheap Link to comment Share on other sites More sharing options...
Mattg4321 Posted August 28 Share Posted August 28 9 hours ago, crispy_wafer said: Ive been looking at these Fogstar Energy 15.5kWh 48V Battery l Fogstar UK They do some DIY kits too. Maybe something to investigate for when I finish my build... I was looking at those a couple of months back. There was some 10% off codes kicking around. Possibly now expired, but worth a google. Very cheap, but I decided to spend a little more and match my Sunsynk inverter with Sunsynk batteries as I wanted minimal chance of buck passing should there be any problems. Bit more expensive though, but slightly better spec too iirc. Link to comment Share on other sites More sharing options...
Dave Jones Posted August 28 Share Posted August 28 10 hours ago, SteamyTea said: My E7 is 27.5p/kWh day, and 11.08p/kWh night, with the daily theft of 70.1p/day (before VAT). When I am heating, I use an extra 10 kWh/day. That would mean I need a usable storage capacity of 12 kWh, which would be in the region of £6000 I suspect. £6k, at today's prices, would buy me 51,573 kWh, or 16 years price for all my energy usage. expensive nightly rate and a silly cost analogy. a rock and bucket to do your washing would mean your washing machine would take 35 years to pay off. Link to comment Share on other sites More sharing options...
SteamyTea Posted August 28 Share Posted August 28 24 minutes ago, Dave Jones said: expensive nightly rate and a silly cost analogy. How so, it is a standard contract price with a major supplier. If you based your invest on just one price, that you choose to justify that investment, you are not looking at the long term/whole picture. Link to comment Share on other sites More sharing options...
jack Posted August 28 Share Posted August 28 11 hours ago, SteamyTea said: Abd pays a premium for imported power the rest of the year No he doesn't. What makes you think that? 11 hours ago, SteamyTea said: and that is before the cost of installing PV and batteries. He still ends up ahead long term taking costs into account. 11 hours ago, SteamyTea said: (Energy suppliers can change the tariff regime as well) If course, but ToU tariffs are hardly going away. There will always be some benefit to being able to store energy when it's cheap and use (or sell) it when it's expensive. Tariffs will continue to change, certainly, but every change over the last few years has been to the benefit of those with PV and batteries. Link to comment Share on other sites More sharing options...
Dave Jones Posted August 28 Share Posted August 28 11 hours ago, crispy_wafer said: Ive been looking at these Fogstar Energy 15.5kWh 48V Battery l Fogstar UK They do some DIY kits too. Maybe something to investigate for when I finish my build... doesnt come with an inverter ? Link to comment Share on other sites More sharing options...
crispy_wafer Posted August 28 Share Posted August 28 2 minutes ago, Dave Jones said: doesnt come with an inverter ? That's right, Allows a choice of inverter as many protocols are supported. You can either go victron if you want to tinker lots, or solis if you want a simpler functionality. Anyway, I'm lightyears away yet! Just filling my black book with snippets of info in advance. Link to comment Share on other sites More sharing options...
Dave Jones Posted August 28 Share Posted August 28 wonder if they are DNO approved ? Link to comment Share on other sites More sharing options...
JohnMo Posted August 28 Share Posted August 28 12 minutes ago, Dave Jones said: doesnt come with an inverter ? Why would it, the hybrid inverter would be attached to the PV panel system for example. That would manage flow in and out of the system. Link to comment Share on other sites More sharing options...
Dillsue Posted August 28 Share Posted August 28 33 minutes ago, Dave Jones said: wonder if they are DNO approved ? Batteries?? They can't export to the grid so no ENA approval needed. Its the inverter that needs to be ENA compliant Link to comment Share on other sites More sharing options...
SteamyTea Posted August 28 Share Posted August 28 1 hour ago, jack said: 12 hours ago, SteamyTea said: Abd pays a premium for imported power the rest of the year No he doesn't. What makes you think that? I have not seen a ToU tariff that has a cheap peak rate. It is the price differential times the usable hours that investment in batteries needs to be based on, not some arbitrary high or low price. Link to comment Share on other sites More sharing options...
jack Posted August 28 Share Posted August 28 14 hours ago, SteamyTea said: Abd pays a premium for imported power the rest of the year 2 hours ago, jack said: No he doesn't. What makes you think that? 1 hour ago, SteamyTea said: I have not seen a ToU tariff that has a cheap peak rate. Are you talking about costs at different times of day or at different times of year? It doesn't really matter. There are cheap and expensive times across the day all year. Most days there is the opportunity to buy cheap (usually overnight, and sometimes at other times) and sell back when power is expensive. He doesn't net an income during winter, but his annual bills overall are way down on what they were. Of course energy on a ToU tariff can be extremely expensive at times. But that's exactly the point - he's generally exporting at those times, so that's to his benefit. Some of the cheaper electric car tariffs are a little trickier to value, because for most of the day you pay a little more than you'd pay on a standard (same rate all day) tariff. It probably depends how much you charge your car on the cheap tariff, and how much of your other usage you can push into the cheap period. I'm on one of these at the moment (albeit with no battery) and it definitely makes financial sense for our usage patterns. The fact we have solar at least partly offsets the higher rate during the day, at least when the sun's out. 14 hours ago, SteamyTea said: When I am heating, I use an extra 10 kWh/day. That would mean I need a usable storage capacity of 12 kWh You don't need to size a battery system to completely cover worst case daily consumption. Link to comment Share on other sites More sharing options...
Dave Jones Posted August 28 Share Posted August 28 8 hours ago, JohnMo said: Why would it, the hybrid inverter would be attached to the PV panel system for example. That would manage flow in and out of the system. the best inverters for solar are the micro ones attached to each panel so cant serve a battery as well ? Link to comment Share on other sites More sharing options...
Dillsue Posted August 28 Share Posted August 28 4 hours ago, Dave Jones said: the best inverters for solar are the micro ones attached to each panel so cant serve a battery as well ? I believe Enphase do a battery to integrate with their micro inverters Link to comment Share on other sites More sharing options...
JohnMo Posted August 28 Share Posted August 28 52 minutes ago, Dillsue said: I believe Enphase do a battery to integrate with their micro inverters Any AC coupled battery would do the job they don't care how AC is made 1 Link to comment Share on other sites More sharing options...
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