Tesla Virtual Power Plant

Pilot project for Tesla Powerwalls to feed in to the grid during “power events”:

Edit: Pilot as last year, official since June.

$2 per kWh…wow.


The whole thing is just for emergencies declared by the operator though, not a normal feed-in situation.

But, yeah.

Seems like they had ~18 141kW being supplied to the grid from ~2 610 homes.

Seems pretty cool. They got an advanced warning allowing them to opt out, then had a form of “scheduled charge” from 5AM until 6PM when the batteries then discharged until 9PM to cover the load reduction.

1 Like

So will Victron be able to integrate with such a system should CoCT ever launch it… :money_mouth_face:

Tesla is a closed system.


Of course all the control points are there to use the blue equipment in such a system.

One way to do it… is to put people on a TOU tariff with lucrative feed-in rates at certain times of the day.

Then build a kind of energy exchange (a bit like currency trading platforms) where you set a trigger to start selling power. The moment the price is right, the system activates and discharges the battery into the grid.

But of course all of that will have to be built when it becomes a possibility.


Yeah, the only magic here is the agreement with the power company. Everything else exists today.

1 Like

In fact, this could be very similar to a currency trading platform.

You’d have the equivalent of limit orders. For 80 cents/kWh, I will sell 50% of my battery contents. For R1.20/kWh, I will sell 80% of it! Something like that. An external feed of prices comes into the system, and the rest is automated. Your existing tariff and bi-directional meter takes care of being paid.

Edit: This actually ties into an earlier discussion elsewhere about how dispatchable energy may or may not be. How dispatchable is distributed privately-owned batteries really? A grid operator would likely raise the price slowly and see if enough supply comes online, and if it doesn’t, it will have to offload onto something else. Ideally hydro, or gas turbines.

Certainly we wouldn’t go into a Tesla VPP, but other such exchanges could certainly exist.

I wouldn’t sell for less than R5/kWh from my battery though. Something like: R18k for 3.5kWh. Of which 2.8 is usable. And 2.5 will become AC after losses.
Over 10x365=3650 cycles, on average the battery will be at 80 SoH, so roughly 2kWh per cycle to sell, I would have 7300kWh to sell out of my initial investment of R18k. At a real R3/kWh I roughly break even. I don’t just want to break even. And that is assuming I charge the batteries off excess solar and not the grid.

Also remember you will be taxed on that income. At whatever your highest tax rate is.

Oh sheesh, you are correct. Unless they give a tax break, fat chance though. But in that case I presumably would be able to deduct the depreciation of the batteries from the income.

Right. You’d be able to deduct the cost of the batteries as “production cost”, so like other equipment you’d likely be allowed to write it off over 3 or 5 years or something like that.

You’d also have to register for provisional tax. Which in itself attracts a bunch of admin time. I farm mine out to a consultant, but even two hours (one in Feb, and one in August) a year, at what they generally charge per hour…

Sometimes I wonder if countries don’t tax themselves out of opportunities :slight_smile:

They don’t start out to do that, no. Compare where tax laws were 10/50/100 years ago compared to today, same with the Law.

Taxpayers see a legal loophole, they pounce on it. Tax man closes it, anticipating more moves, makes more laws, some good, some stupid. Taxpayers then find loopholes again. Over time it gets more and more complicated with no end in sight, like playing an endless game of chess … your move.

1 Like

Me, I think it’s the other way round. Government wants your money to spend, It’s always the unintended consequences that does everybody in. Nobody repeals old or just plain bad laws, except if they do not sit well with the ideology…

So now they make badly written new laws to get at the money because you used their laws to not give it to them.


I totally see the loophole argument. As the old freakonomics example goes, if you levy a tax on a cup of coffee, the cups will grow larger.

The interesting part for me is how often the tax bracket topples an opportunity. For a long time I simply looked at servicing a car. My own car, for example, needs around R1500 of supplies, plus about 1.5 hours of labour. Now I have the capability to do this myself, but I have a certain hourly cost too. However, my hourly cost is after tax, which is on average at least a third cheaper than the mechanic who still has to pay tax on that income. And VAT. Pretty soon a lawyer, despite making R1000 an hour, might as well service his own (private) vehicle on the weekend, because to him the cost after all taxes are accounted for, is more like R450/hour, which is what many shops charge now…

So perhaps this is a bad example, and lawyers don’t service their own cars, but it is an example of how some jobs (the kind that can be DIYed) are taken from the hands of lower-income earners because the tax makes it more expensive.

Back to Tesla …

Must say, this fiasco Musk has caused with Twitter, feels like a spoilt brat saga.

Actually, the myth of King Midas comes to mind.

So this Tesla Virtual Power Plant idea … touched by King Midas?