Costing batteries – RoI
I'm going to start costing the RoI on home storage batteries. Has anyone done some basic numbers on a spreadsheet that we could adapt for our property?
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
I have one, However they are very easy to build yourself - it would probably take the same amount of time.
Essentially you just need a few simple figures
- Total cost of the system (£) - what you want to return on
- Cost of your power (£/kw) - your figure you are measuring value against
- Discharged power from the battery (kw) - the actual benefit you are seeing
From those three you can make a simple excel in a few minutes. If you wanted to be extra fancy you could also have a price to charge from the grid and track that (if applicable)
For example if you spent £6,000 on a battery system with 10kw and your power cost 0.2/kw you can store £2 per day, but with depth of discharge this will be 80% of that, so £1.60 is useable. If you used that every day, you are looking at a 10 year payback - £6000 / (£1.6 x 365 days) = 10.27 years
The best thing to do is look at your cost per Wh of storage. In the example your cost is £0.6/Wh or of £600/kWh. For me, this is WAY too much, you wont see the benefit. Unless prices stay crazy. If you are paying £0.4/kw the payback is halved to 5 years.
I know I can build a 15kW system for around £4,300 or £0.28/Wh, or I can build a 30kW system for £6,400 (£0.21/Wh). At these figures the cost and payback become a few years; 4.7 years for the 15kWh system and 2.4 years for the 30kWh system (using £0.2/kW as a price).
As you can see HOW you build your system is critical. Also you cant expect to produce all that with solar over the winter (when you need it). Arguably you will need some kind of feed tariff which will have offset costs to consider. You might want to double those paybacks if you can't have a charging tariff as it might be 6 months of the year its useful.
As an aside this is how I would build my system
Goodwe - GW5000S-BP - 5kW battery charger - HERE - £1,679 - Charging / Discharging output is 5kw (100amps @ 52V); the highest you'll find, so perfect for ASHP
Mason DIY battery Box - HERE - £500
302ah cells x 16 - HERE - £2,144
Total cost of 15.4kwh (12.3kwh @ 80% DoD) system = £4,323 + install (£0.28/Wh)
Total cost of 31kwh (24.7kwh @ 80% DoD) system = £6,967 + install (£0.23/Wh); for this you just buy double the cells and battery box, but you only need one charger. You could also probably get the price down more for buying more cells
Charge time @ 5kw;
- 15.4kwh system = 2.4hrs
- 31kwh system = 4.9 hrs
@batalto It looks like the Goodwe - GW5000S-BP is pretty rare (and correspondingly expensive) nowadays; retailers quoting a price are few and far between (just had a conversation with Waxman Battery Storage who said they sold their last one a fortnight ago, and aren't planning on re-stocking).
I was looking at going down the Victron route (Victron Multiplus-II 48/5000/70-50 for £1460, plus accessories like a DIY VenusOS computer and current sensor for anti-islanding) since there is wider-spread BMS support (e.g. here to bridge RS485 to Victron D-Bus) as well as coming from a trusted (at least in boating circles) company. Victron ratings are complicated so this model supports 4kW continuous at 25 degrees C air temperature, where energy efficiency is down to 86.7%. However I guess the same limitations apply to all other inverters even if they are not advertised.
- 26 Forums
- 2,104 Topics
- 46.3 K Posts
- 123 Online
- 3,393 Members
Join Us!
Latest Posts
-
RE: Ripped Off: How UK Homeowners Are Paying Gas Prices for Wind Energy
@jeff Many, Many thanks Jeff, that is far easier to rea...
By Toodles , 11 minutes ago
-
RE: BUS Grant: removal of all other fossil fuel heat sources
@editor If it is of any interest, we had the BUS grant,...
By Toodles , 2 hours ago
-
@robs ASHP Closure of doc unknown's thank you And man...
By Bart , 5 hours ago
-
Sorry to hear that @bruce. Sadly I’ve heard from multip...
By Mars , 12 hours ago
-
RE: Crystal Ball Time: Communal or even Area Energy Storage?
I am invested in a couple of listed energy storage fund...
By Old_Scientist , 14 hours ago
-
RE: Who's your electricity provider and what's your tariff?
That would be my biggest commitment -time to gain great...
By SUNandAIR , 22 hours ago
-
RE: Who has a V2G EV installation
As has been discussed on other threads, trying to justi...
By Majordennisbloodnok , 2 days ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
Thanks @mikeh. Then I will also go back to non smart ta...
By ChandyKris , 2 days ago
-
RE: Location of hot water isolation valve on cylinder
@transparent Thank you so much and very helpful. Earlie...
By rossowheels , 3 days ago
-
RE: Ecodan consuming 100kwh per day in new build!!!
It does indeed look like that, @skyefarmer. There is ...
By Majordennisbloodnok , 3 days ago
-
RE: Plug and play solar. Thoughts?
Have a read of my previous posts on so-called Balcony S...
By Lucia , 4 days ago
-
RE: Compressor attempts start but fails - Nibe Fighter 2005 8kW
"To tell you the truth, I don't know if HAL is homicida...
By Scalextrix , 4 days ago
-
The Importance of Radiator Balancing for Efficient Heating: Introducing the Flow Regulating Valve
It’s fascinating to watch how low-temperature heating i...
By Mars , 5 days ago
-
RE: Servicing Hitachi HP in rural Somerset
I'd give GreenGenUK a call or email them: sales@greenge...
By Mars , 5 days ago
-
RE: Heating coming on when not required
I played with a max heating temp but there is a world o...
By JamesPa , 6 days ago
-
RE: Pressure drop Primary circuit
I've always regarded topping up heating systems as my j...
By JamesPa , 6 days ago
-
RE: Heat pump solutions and/or installer recommendations for France
I’d travel to France for work if you were struggling wi...
By Damon Blakemore , 6 days ago