V2G/H ??

[spread-tee]

One of our customers has moved house to a biggish 1930s built 4 bed detached which is in need of some renovation. They are planning to stay there for good now so they would really like to reduce it's carbon footprint as far as reasonably possible. We had a good chat over various possibilities yesterday and as far as I can gather so far they are serious with a fair budget in mind.

There is a fairly old gas heat only boiler that will be replaced next summer, a 150 ish litre HWCyl on a y plan with room for more hot storage, and a fairly conventional plumbing layout regarding rads, showers etc and luckily there is one electric shower which makes working on the heating system far less fraught.

Obviously the insulation will be upgraded as much as possible, probably the windows will too as each room is decorated, then we talked about PV and solar thermal, all straight forward enough so far. He is really keen on a battery storage system to go with the PV, I am not convinced that is the best way to go when one is grid connected, surely it makes more sense to use the grid as the battery and jiggle the consumption to best use the sun and spend the savings on more insulation or some other tech. He seems pretty wedded to the battery plan so I suggested as he already has a battery in his electric Volvo why not use that instead of buying another.

So basically my question, is it possible without breaking the bank to set up a vehicle to house/grid system to satisfy his battery yearnings or should he just export any excess, if it is feasible how would that be achieved in practice in broad brush strokes? Or indeed would it make sense for him to splash out on another battery? Also if he goes for it I will need a system designed and specced, PV, inverter, cabling and etc , anyone up for that?? I can deal with the plumbing, insulation, windows and etc so no need to get involved in that, although ideas are always helpful.

Cheers

Desp

[Countrypaul]

What size PV system is being considered? If it is much greater than 3.68kW, then will the DNO accept that, or is that where he gets his battery ideas from? Does he have a BEV, or wil he be getting one, again that might benefit from a larger PV system, but if export limited than a battery system might look more attractive? If going for a BEV will a Zappi & Eddi be beneficial?

[Stinsy]

On this forum? We’re battery fanatics around here!

Now that FiT payments are no more, solar doesn’t work financially without batteries. “Using the grid as a battery” makes sense until you realise you get paid 5p for every kWh you send to the grid and get charged 25p (or more) for every kWh you buy from the grid! Also your solar panels tend to produce huge amounts power in the middle of the day when you’re not using much, and little-if-any in the evening when you use the most. How much solar can you fit on the roof? Panels are incredibly cheap right now the cost is in the installation and the inverter. If you’re re-roofing the property the cost of panels vs the cost of saved roofing materials is almost a wash. It is a good idea to fit 1x to 3x your kWp of solar in battery capacity. Batteries are expensive, there is no getting around that, if you chose Pylontech or a similar “modular” solution the pack can be expanded very easily later on. When deciding where to place the batteries you should ensure there is space allocated for many more than originally specified. A ToU tariff such as Octopus Go is a good way to make the batteries pay for themselves (you can charge the batteries in the cheap rate).

Solar thermal isn’t worth the cost/complexity. Better to put up more PV and add a diverter.

It might seem obvious, and you’re clearly on top of it already, but insulation and air tightness is critical. Have you thought about heat-recovery ventilation?

I’d be very hesitant to buy a new gas boiler now. They’re clearly on the way out. Now is a good time to fit a heat pump if the property-owner is environmentally minded and future-looking. It is better to fit extra/oversized rads now compared with in 5-10 years when cosmetic finishes are in place.

V2G isn’t here yet. There have been some “trials” with ChaDeMo Leafs. But nothing is yet live for CCS. Best bet is to fit a Zappi (or similar) charging point that has the ability to divert excess PV-generated electricity into the car rathe than the grid.

[spread-tee]

Ha ha, I have noticed a certain propensity for batteries..........

firstly I should say he is not into this to save, make or justify the money, his primary aim is to reduce CO2 output, fair play to him I say.

Paul, he does already have a hybrid Volvo that he tries to keep in leccy mode, he will sell it and get a polestar within a couple of years. At a guess I reckon he would have room for an 8kW array.

Stinsy, as said earlier he isn't money oriented here, also he does work from home so the EV will be plugged in mostly all day. The roof is pretty new so no re-roof in sight TBH but yes he is keen to stick plenty of PV up there, I'm not so sure about doing away with solar thermal, generating high grade energy and converting it to low grade heat doesn't sit well, how would that add up in terms of CO2 displaced?. A heat pump is going to be tricky, I am guessing he is going to need about 25kW or more of heating on a cold windy winter day even with our best efforts with insulation, there isn't room for a GSHP and in my experience spending north of 10 grand on a heating system that struggles when you need it most isn't going to go down too well.
Solar thermal is a doddle, but I would say that I'm a plumber by trade

The Zappi idea seems sound, also the MVHR might be on the cards, air tightness will be a problem though, I know how hard it is to stop these thirties houses leaking after living in one for 20+ years.

These are gut feelings, as yet I haven't done a proper survey .

Ta very

Desp

[Mr Gus]

Heat pump still makes sense for core areas though desp, IF they plan & section the dwelling well & don't want the bahama's in every room (flip flops n'thongs)

I hear £10,000 touted for them by the press, but if its an attempt to heat & cool a few core rooms only that is realistic & dare I say cheap by comparison, & in truth, never had warm rooms everywhere despite central heating.
Whole house is a different kettle of fish altogether.

Mart recommended Heat easy / cool easy some years ago, I do too.
Check their prices for a few decent multi room mitsubishi units & things of that marque with more likely COP ratings & long life potential.

Any room for a non poncey lower height solar car-port / multi use shaded space? (save climbing on high roof & doing a rod hull in his dotage)

[dan_b]

V2G/V2L/V2H is often talked about as the next big thing, but in reality is a long way from being an industry standard.

V2G currently is only available with
Nissan Leaf/NV200 using ChaDeMo and a very expensive DC charger/inverter (such as PowerLoop)

V2L (vehicle to load) is available now with a 3.6kW dongle attached to the Type 2 socket for
Hyundai Ioniq 5
Kia EV6

V2L is also available via the 240v 13A plug socket inside the cabin in the
Honda-e

And will be fitted to the Sono Motors Sion

[nowty]

Just to clarify what dan _b means by V2L or "Vehicle to Load",

You get a 13amp socket somewhere in the vehicle so you can plug appliances into it, including a granny cable charger so you can transfer charge from one vehicle to another, with probably very bad efficiency but handy if your other half is stranded in an EV (with an empty battery) and you can drive to their rescue in another EV with a Vehicle to Load function.

What you cannot do is run your house off it or export to the grid with it.