Octopus are running a trial of vehicle-to-grid where they lease you a Leaf. Then you allow them to discharge and recharge it overnight, to play the market for power prices, and they give you a discount.

They promise not to discharge it below 30% which they say would leave you 40 miles capacity for unexpected journeys.

Interested that they want to complete a G99 application on your behalf before installing the V2G charger. Presumably because they need to discharge at higher instantaneous current to get the value out of V2G.

I wonder if this G99 will be required for most V2G connections in future? Makes sense I suppose, no point having a high power two-way charger which cant be set to discharge at high power because it doesn't know that the dno can cope.

https://www.octopusev.com/powerloop - see the FAQ for installation info

The first quote in PiH's post looks like it was quoting me but it was actually Revor who was talking about washing machines, this is a 'feature' of the forum software!


I agree with PiH's comments that the V2G system doesn't know (or care) how much is being used in the household and how much is being exported. It just discharges the EV when the grid needs electricity, then recharges it when there's electricity to spare. The V2G operator uses price as a signal, but fortunately that aligns pretty well with green-ness because most UK renewables are Wind or PS with low (or negative) marginal costs.

It would be quite reasonable for the householder to run hob, kettle, oven, lights, TVs in the evening and want to use their V2G instead of buying in peak-price electricity. This would need the V2G inverter to be rated for rather more than 3.6kW. The G99 application is required if the V2G is *rated* for more than 3.6kW, irrespective of whether the householder or operator ever planned to export that much or self-consume it.

If you bought a 40kWh EV and wanted to help pay for it while saving the planet, you're going to want to discharge say 70% of it during the 3-hour evening peak period, so export at about 8 to 10kW - well into G99 territory - and you're not going to self-consume all that.

So there might need to be a lot of G99s in future, and it might be worth getting one now to snap up your rights to the local network capacity before your neighbours do!

I forgot to post this!

I emailed Ofgem to ask for clarification over the defintion of Total Installed Capacity when considering adding panels to a system where the generatiion capacity is already limited by the inverter to 16amp/3.6 kw. The response was-

"We are however unable to provide specific advice on the issues you raise. All changes made to a FIT accredited installation would be assessed on a case-by-case basis once the works are completed and submitted to the FIT Licensee. 

Payments, amendments and issues of MCS scale are handled by electricity suppliers themselves (FIT licensees).  Your FIT licensee would make a decision on any amendments made by referring to the FIT Supplier Guidance mentioned previously"

Basically you'd have to pay for an MCS installation and hope it got approved. Bit of a risk if it didnt!!

Posted By: djhHave you asked your FIT licensee the same questions?

Nope. Scottish Power provide our payments and they are shockingly useless. Have just made a formal complaint to the Energy Ombudsman about them erroneously suspending my account a year ago, so wouldnt hold out much hope of getting an un biased answer from them. Maybe when the complaint is sorted.

<blockquote><cite>Posted By: djh</cite>I lost interest rapidly once I discovered that the only possible car is one I have no interest in (short range).</blockquote>

A modern leaf will do 200 miles between charges, which is pretty typical for current EVS and not what I'd call 'short range'. There are better cars in various ways, but it's range is fine. Perhaps you meant early (and thus now relatively cheap) leafs which only did about 90?