SMETS2 capable 3-phase meters (and energy suppliers!)

[PITA]

I'd be happy with it to supplement my static battery.

My static battery is sized to be "about right" for a Summer day. In practice that means that on days when we aren't baking and tumble drying we have excess that goes into the car. But ...

... on an overcast summer day we are short, to get through the night. V2H would give me enough top-up that would be worthwhile, and it would also mean that I was exporting less often - I export when we get a run of sunny days and I don't drive far enough to create enough EV battery space. If V2H was used on overcast days there would be battery-space for a run of sunny days.

In Summer I get around 1,000 miles a month off the roof (in addition to 90% of overall house usage). V2H would give me such a big battery that it would easily buffer the other 10% house usage (plus I have 2 EVs should could shuffle which one was providing V2H)

In Winter battery is charged overnight on Off Peak. It covers a winters day provided that the sun shines a reasonable bit AND we are not baking and tumble drying V2H would also help me with top up. Looking at a recent "average winter day" I get roughly 10% from PV, 30% from Off Peak battery charge and 60% from grid on a baking and tumble drying winter day. Of course the PV can be close to 0% if the day is overcast, and on a really sunny non-baking day I get to charge the car a little bit - but that is very very few days during winter.

I think that V2H would give me a more useful buffer than over-specing static battery for "worst case" instead of my current "big enough to rarely export to grid"

Perhaps best (for me) would be that V2H provided low AMPs all day every day (in Winter at least), and then Static Battery only used for "top up" when house is needing more. (On days when I need to drive somewhere and need a full EV battery I could do a STOP on V2H)

Yes... that is a very good idea. Perfect. Love it.

I contacted GivEnergy about this idea a few months ago...

They confirmed we could use their battery storage for a 'base load' supply to the house, and then the Powerwalls would step in for high capability demands.

Similar to your idea... but your idea would be better & cheaper.

 

[WannabeOwner]

cheaper.

Puts the wear and tear on the car battery too ... .which I'm moving on in 3 years (say), whereas my Static Battery will be here for a couple of decades so I'm more incentivised to take care of it

That might put Tesla off, but personally I don't see why "EV has done XX,000 miles and XXX hours V2H" wouldn't be a reasonable addition to odometer (and warranty etc.)

 

[DeejUK]

no mention of storage batteries

Yeah, sorry, I didn't explain very much. We'd definitely like to have batteries in the mix, as I'd like to be 'grid independent' rather than 'off-grid'.

Massive exports are fine in the summer, as presumably that'll make some money! I'm vaguely aware that we might need to register as a power plant or something - this is all in my list of things to research, having nearly wrapped up the fun (really!) of sewage systems when in groundwater source protection zone 1.

Sadly I have a dumb car charger so it's kinda hard to figure out how much goes to the cars, and how much to the house. This is compounded by the non-Tesla being an old Renault Zoe, so getting metrics about how many kWh we've pumped into is a pain.

Splitting batteries between the phases sounds expensive and complex, but I think that's something I'll need to embrace.

There's also then all the space-heating and water-heating stuff to figure out, and the interplays between those systems and the electrical system. I couldn't find a consultancy who did both renewable electric and heating design as one holistic package.

 

[ringi]

I also think Vehicle to Home (V2H) is a fail as well... and I can see why Tesla aren't keen on it

It does not work nearly as well as a powerwall in Tesla home market as their cheap rates are in the middle of the day when many people don't have their car plugged in.

 

[PITA]

Yeah, sorry, I didn't explain very much. We'd definitely like to have batteries in the mix, as I'd like to be 'grid independent' rather than 'off-grid'.

Massive exports are fine in the summer, as presumably that'll make some money! I'm vaguely aware that we might need to register as a power plant or something - this is all in my list of things to research, having nearly wrapped up the fun (really!) of sewage systems when in groundwater source protection zone 1.

Sadly I have a dumb car charger so it's kinda hard to figure out how much goes to the cars, and how much to the house. This is compounded by the non-Tesla being an old Renault Zoe, so getting metrics about how many kWh we've pumped into is a pain.

Splitting batteries between the phases sounds expensive and complex, but I think that's something I'll need to embrace.

There's also then all the space-heating and water-heating stuff to figure out, and the interplays between those systems and the electrical system. I couldn't find a consultancy who did both renewable electric and heating design as one holistic package.

On our house we have a Gas Boiler central heating system. It heats the water and radiators.

I've kept it in situ... as during deep Winter we still use it, to warm wet rooms, ensuite, toilet rooms etc... and it's very hot, not warm, but hot.

By the way, our house is rated at Energy Performance A+ (retro-fitted to this standard but that's another story)

So instead I added a secondary heating (and cooling system) to the house. An Air to Air Heat Pump.

This has wall units in all the main rooms, living space, bedrooms, office, games room etc.

This means during Summer when we have an abundance of Solar, we use the Heat Pump to cool the house... bedtime is bliss at 20 degrees inside & 40 degrees outside.

This now means we can Heat our hot water and house using either Gas or Electric or both.

The A2A wall units can dehumidify, so dryer air warms faster. They also use plasma filters to remove pm2.5 particles so clean the air as well.

Using a mix of the two systems has reduced our Gas use by at least 65%

In the future, I might replace the Gas Boiler with an Air to Water heat pump and run both heat pump systems side by side.

 

[ringi]

For us, having 7kw of V2H would allow us to stop using practically any grid electricity other then at cheap rate times as we can move most load to cheap rate times. Even 3kw of V2H would remove most of our 5-7 PM grid usage.

If we had a heatpump with UFH we could turn the heating off between 5pm and 7pm with the target temperature being 1c higher between 4pm and 5pm.

It would not be hard for us to install the cable to allow 10kw connection to a v2h unit.

I expect without installing PV a v2h system could save as £100 pcm. Logically if v2h system are made at scale they should only add about £400 to the cost of a home charge point.

 

[ringi]

Puts the wear and tear on the car battery too ... .which I'm moving on in 3 years (say), whereas my Static Battery will be here for a couple of decades so I'm more incentivised to take care of it

That might put Tesla off, but personally I don't see why "EV has done XX,000 miles and XXX hours V2H" wouldn't be a reasonable addition to odometer (and warranty etc.)

If a V2h never discharges a battery below 30% and the battery is never charged over 80% other then just before long trips it been shown by the Leaf V2G trails that a V2G system can increase battery life as batteries like slow discharges.

 

[Hessles]

I have a 3 Phase supply with a SMETS2 meter

The National Grid policy now is 80 amps per phase.

National Grid email Quote:

I have been passed your enquiry regarding your supply at the above property for a possible fuse upgrade?

The largest fuse size that we install into 100amp cut-outs is 80amps.

Most devices have a limiter on which is set at 80amps due to this being the largest fuse size that can be installed into the 100amp cut-outs.

it is a policy we as national grid adhere too, there are very strict factors in place where some supplies can have 100amps installed however it is very rare,

older properties may also have 100amp fuses from years gone by. All new supplies/upgrades now are fused at 80amps.

Anything above this needs a 200amp heavy duty cut-out for 100amp fuses, this also is rarely required once load studies with diversity have been carried out.

END QUOTE

100A fuses can be fitted it just depends on the cutouts location. Where is yours?

You don’t want a 200A cutout (it would actually be a 600A cutout) as you’ll need CT metering and you’ll pay massive amounts of standing charges for the reserved capacity. You’ll also need a 185mm cable up to your house instead of the 35mm.

 

[Sean.]

100A fuses can be fitted it just depends on the cutouts location. Where is yours?

You don’t want a 200A cutout (it would actually be a 600A cutout) as you’ll need CT metering and you’ll pay massive amounts of standing charges for the reserved capacity. You’ll also need a 185mm cable up to your house instead of the 35mm.

200A cutout is a chunky beast. Standing charge is 10p per day more 100A, but different suppliers etc. not quite apples for apples.

185mm cable is around 45mm diameter. Not too foul. The custom 6” steel conduit was a PITA to get bent to our requirement.

It’s the AMR cross charges (supplier change long story) on the 100A supply that I’m keen to see go, by moving to SMETS2.

 

[PITA]

100A fuses can be fitted it just depends on the cutouts location. Where is yours?

When you say cutouts location, do you mean County Region location, or physical box location?

For policy we used to be managed by Western Power (Now National Grid) in West Midlands.

Picture below of cutout... with 80 amp fuses per phase

 

[Hessles]

When you say cutouts location, do you mean County Region location, or physical box location?

For policy we used to be managed by Western Power (Now National Grid) in West Midlands.

Picture below of cutout... with 80 amp fuses per phase

View attachment 897412

Physical location - meter box.

 

[PITA]

Physical location - meter box.

View attachment 897445

Oh OK...

Then yes, it's installed outside on the North Facing wall away from any heat source.

The maximum load period would be at night time during the cheap rate 00:30 to 04:30 period.

Can you give me a link to that information picture please

The meter looks rated to 100 amp as well.

 

[Hessles]

Link

 

[PITA]

Link

Thank you, I'll chase that option when the time comes in March...