Powerwall export to grid

Powerwall export to grid


Just wondering if there was a way to have your powerwalls export to the grid?

I currently monitor the spot price of power every 5 minutes, if its expensive, i turn off power hungry appliances like spa pools, washer/dryer etc.
I would like for the ability to tell the power wall to export power to the grid in the event spot pricing was high, as with net metering i get paid the spot price.
I currently get paid for exporting solar during the day if the power wall is full.

On occasions, the spot price of power can go up to $11,000 per kw, this happened last night due to an event on a mains power line feeding the country.
If i could have exported a few kw during that time, I could have paid my power walls off over night just about.

Look forward to any assistance with this.

Many thanks

Tesla-David | 24 May 2018

As I understand it and expect as well, after the battery is filled, all excess solar power generated will be exported back to grid. We are on net metering here in Edmonds, WA, and my excess solar energy results in an annual check for $5,000 (net metering, @ $0.54/kWh). Our annual electric bill is ~$170/year, and we generate about 13,000 kWh/year, so with the PW2 system I still expect to send a lot of electricity back to grid as well.

This utube of Powerwall in Australia ~@8:20 minutes shows how the excess goes back to grid after powerwall is toped off.

cwied | 24 May 2018

At this point, I don't think that the Powerwalls can do that. It's no secret that Tesla eventually wants to be able to aggregate Powerwalls across many homeowners to provide grid stabilization, though, so eventually the software on the Powerwalls will be updated to support it. Whether they'll give individual owners enough control to do it themselves remains to be seen. My guess is that they won't, given how limited the customizability of the current software is.

Tesla-David | 24 May 2018

@cwied, not sure I understand your comment, as from what I have been able to ascertain, in utilizing the PW2 to run our home and charge our two EVs off the PW2, which I should be able to do easily given my monitoring or our energy demand over past 6 years, we are producing more than 200 percent of our electricity needs, and I currently send everything back to grid and draw what I need utilizing net metering. I will easily be able to charge up my two PW2 batteries, and expect the excess electricity I generate to go back to the grid as I am doing now.

For the current month, I am generating 62 kWh/day and our total energy demand is only 8.2 kWh/day, so there is a huge excess generation of electricity off our solar system. I f what you are saying is true, I need to discuss this issue with Tesla-Energy as it would represent a huge deal breaker for folks like me who want to be able to utilize our PW2's to be more energy independent, but also still be tied to grid, to enable the net metering income that is helping me to pay off the huge cost of our 2012 13.2 kWh solar PV system. The net metering option will expire in 2020, and the payback at that point would be dramatically reduced, but I would still be generating income from my excess solar.

cwied | 24 May 2018

@Tesla-David - I believe the original question was about exporting energy from the Powerwall to the grid, not exporting excess solar energy. The spot prices typically spike high after the sun goes down since solar keeps the peak demand low before that. This means that you would have to be able to discharge directly from the Powerwall into the grid in order to be able to take advantage of the price.

I'm in the San Francisco Bay Area and my interconnection contract with PG&E specifically calls out the Powerwall as "non-net-metering eligible." This means that I can't discharge from the Powerwall into the grid and get net metering credit. In fact, I suspect that discharging into the grid in general would be prohibited.

@Barry - I'm curious where you're located and what kind of electric service you have that lets you pay or receive the spot price for energy.

Tesla-David | 25 May 2018

@cwied, we do not have TOU here in NW, and have uniform price here @ $0.11/kWh 24/7 here in Edmonds, WA. I will have to check in to your point, but don't think it applies here.

Tesla-David | 26 May 2018

@cwied, I have confirmed that I in fact will not be impacted by PW2, and will export all our excess solar back to grid through Net Metering @ $0.54/kWh as I have been doing for last 6 years.

Tesla-David | 29 May 2018

@cwied, my apologies for misreading the original question OP poised which you correctly answered. I was wrapped around the axel on the Net Metering issue for our excess solar production, and totally missed your point about not being able to export energy from PW2 back to grid.

Barry | 29 May 2018

@cwied - I'm in New Zealand. Most companies will pay a net metering rate of 8c when you export and a fixed 18-21c for import any time of the day. I moved to a company called Flick Electric as I can get my power prices down to as low as 4c import when spot prices are low and its in the early hours of the morning, however flick also pay spot prices for exporting.

Our ToU peaks are 9am-11am and 5pm-9pm.

Spot prices average at around 7c per kw, but between the times of 10am-5pm they can dip as low as 4c, which means when im exporting, im getting less than half what other providers will pay; which is fair because im paying market rate for import & export.

Between the hours of 5pm - 8pm of late, prices have gone up to $1 per kw due to peak demand in the winter time, people getting home and turning on heating while cooking etc; so if i could somehow have my power walls export power between 5pm-8pm I'll very quickly be paying back my installation.

There is a company called deposit power in australia which does something similar with power wall 1's and other batteries; when the grid power is expensive, they sell it from customer power walls and pass on the credits to their customers, though they don't support powerwall2.

I think i know a way to get it to work but would require a bit more technical thought and messing with the PW.
There is a Neurio meter within the unit; if i could hook another CT clamp to it as house load and somehow make the CT think the house is drawing more power than it actually is, then the batteries will generate more power thus feeding back to the grid. Not sure if it would work but certainly is a thought. Would be bad in the event of a power cut and the unit was generating more power than the house could consume though.

Surely there must be an easier way to fool the system?

Barry | 29 May 2018

Sorry that was Reposit Power in Australia not Deposit Power