Search results

I think it's going to be very difficult for Tesla to compete in the small car segment with the Chinese. The cheaper and less luxurious the car, the smaller the margins will be, even if he can hold market share with the Chinese. That may not happen in the US but definitely will be the case...

Given the decision today to lay off the whole supercharger team, it sure sounds like he's not interested in building (or supporting existing) cars for individual users. This kinds of makes sense if your bet is all on robotaxis to go after Uber and Lyft. That kind of fleet could not user...

There will never be a significant impact on greenhouse gas emission if the ROI for battery systems isn't positive. Some like you may make financial compromises as part of your economic calculation, but that is not going to be a significant number of households, not just in the US, but across...

I disagree. If reliability is the number one goal, it's very hard to beat a quality diesel or natural gas/propane generator. They work when it's cold and overcast, and they work in the dead of winter when you have fewer hours of charging time available, and they work when you have a large...

PS I was wrong about 1 item: 1) The bi-directional inverter does 400V and 800V DC fast changing, not 200V and 400V

The Solaredge bi-directional V2H charger seems a much better design. It charges the vehicle with 200V or 400V DC from the inverters DC bus input. When pulling power from the vehicle, it puts that on the DC bus and uses the solar inverter to power the house. For Solar to vehicle charging that...

I think it might cut into Powerwall sales. I assume in CA they are selling a lot less of those as the number of solar installs have come down thanks to NEM 3.0. I think the margin on the PW's is not insigificant. It also will increase the number of cycles on the battery, driving more service...

I am looking forward to the Solaredge bidirectional EV charger that is supposed to ship this year. It DC charges the car battery direct from solar, and powers the house through the solar inverter from the DC bus if Solar is inadequate. This seems like an easy way to do load shifting through a...

Kohler makes a number on industrial 400A transfer switches. Very programmable too. I got one on Ebay that had never been installed for about $1200 and mated it with my 30 KW diesel generator. A great pair, and have modbus interfaces to a remote control and display panel in my house. Tesla...

I am a big generator fan (as opposed to Powerwall$), but these small gensets are not made to run for extended run times without maintenance. That's fine for a few hours here and there, but if you need multiday continuous operation, these may not survive that sort of use.

Interesting, Are they still going to produce Powerwall 2's? If not it definitely signals a move into a completely vertical environment - you can't have Powerwalls with Enphase or Solaredge systems, and no retrofit markets will work. I guess if you had Sunnyboy or Fronius string inverters you...

I think he is asking if there is any reason he needs a Powerwall when he has an amazing net metering agreement that has no TOU charging. If that's the case, I think is answer is a resounding no! If there is no TOU, then you don't need load shifting. For backup power in an outage, a...

That sounds about right for NEM 2.0. What would happen if you plugged in the NEM 3.0 rates into your model and actual experience in terms of ROI?

What is the cost of capital you are using? The money you are spending on the solar+ESS could be earning money in a money market account, or investment in the stock market. So there is an opportunity cost that has to be considered in the calcs - a lot of people use 7% for these sorts of calcs...

If backup power is the goal, a generator is a far cheaper and more reliable solution. Agreed that ROI on NEM3 is non-existent. You should forget about deploying solar - it doesn't pencil out anymore, and that's why the installer is giving you these crazy numbers.

I was thinking about it mostly for a 2nd car, with the first being an ICE based one. I agree it doesn't make sense as the only or primary vehicle for the reason you described. But rather than paying $ for PW's, I'd like to pay the same $, get a lot more storage, and be able to use it as a car...

I agree with this completely. Powerwalls will never be a mass market product with the anemic ROI they seem to be stuck worth. And I don't think Tesla seems interested in V2H because it would take a big chunk of sales out of powerwalls. Recent news seems to indicate GM, Ford and others are...

I guess it will be V2H equipped vehicles that will force them to reasonable prices. Though maybe the ROI is a lot better outside PGE land and that will never happen.

This is interesting. When we built the house, we ran all the wiring to be able to support powerwalls, but the economics of them didn't make any sense, and they were a pain to get. At these prices, I am wondering if it makes sense to relook at the ROI of powerwalls. Are they still the...

I agree with most of your points, but the biggest thing to advance Climate goals that affects non-commercial users is electrifying the transportation fleet and moving to electricity for HVAC. The best way to do this is lowering electricity prices, so gas becomes less cost effective. Sure...

Aside from the basic shock about this proposal, who is going to trust PG&E with their income information? How would they verify it? You now have to file your 1040 with PG&E as well as the state? Maybe give them access to all your credit bureau info into order to get power? Will be fun to see...

+1 Propane is quite safe, but if natural gas is available in your area, that is even easier. I wouldn't recommend nat gas here in the SF Bay Area because of the earthquake risk, as pipeline service may not be functional after a quake, and our insurance companies like automatic seismic shutoff...

This is really all about competition. I doubt that will come from specialized ESS products, but maybe from EV's equipped with V2H capabilities. Tesla seems to not be interested in this capability on their vehicles, so maybe the other automakers can be more aggressive and differentiate that...

Yes, I don't think I can make this pencil out in terms of increased rent... Looks like no solar is the best choice.

Ok. And is that by the size of the inverter, or the size of the array?

I thought if you replaced the system with the same or less wattage, that no change in the NEM agreement was required. Are you saying that if the system breaks and is repaired with something else that it's like installing a new system?

Hi. We own a house in the SF Bay Area that we rent out today, but had a 7 KW solar install done back in the 2005 timeframe with 36 panels that face almost due south with no trees in the way, perfect for a string inverter. A few years ago the Fronius inverter failed, and parts to replace it...

We have a Mitsubishi multi-split system that we really like. Very efficient, and super quiet in operation. No issues with running in generator backup because like all scrolling inverter systems it starts slowly and doesn't need soft start capacitors etc... I think there are offers available...

If you are on NEM 2.0 with solar now, and add solar generation capacity or batteries later, does that force a transition to NEM 3.0?

First off, I was mostly trying to make the point that Powerwalls are pretty expensive for the storage they provide. Just do the kWh comparison for the cost of storage. It's true that a base F150 needs a 1.3K charger, and electrical work to add it to your home, but the electrical work is...

Well, the Powerwalls seems very overpriced for the storage. Perhaps a better "portable" solution is an EV. :) A new F-150 lightning trick costs about $40K in the base configuration and has 98 KWh of storage. Yes, it does take a lot more room than the powerwalls, but has has the equivalent of...

Ah yes, Sacramento is "owned" by PG&E and the rest. However even the most aggressive plan for NEM 3.0 I have seen would grandfather NEM 2.0 users for at least 10 yrs. So for me, who built a new house and have solar etc... already installed, I will likely not be affected by it for a long time...

Interesting. How does one factor in these additional payments in planning? Sounds like at least Ohmconnect is changing the fee structure (downwards)? Those numbers are pretty material given the basic business case for load shifting.

I'm not sure what you mean by highly lucrative. How does this change the basic economics of Powerwalls? Peak hour pricing is already high enough in PG&E land that I can effectively run the house on my diesel generator for less than the cost of PG&E on a $/KWh basis during summer prices.

I'm not sure I understand the point you are making. I pay (now winter rate) 0.42 a KWh in peak hour. Displacing that usage from peak to off-peak would save $0.43-0.25 or $0.18 a KWh. About 1/3 of my total use is in the peak hour. I am not a net generator of power in the offpeak time except...

Thanks. That is an excellent way to get an upper bound on ROI. If it doesn't make sense in the best case, there is no point in looking at the more complicated math. So with 4 PW's it would be almost $5K a year is maximum savings. If you wanted a 5 yr payback, then the cost would need to be...

Hi. Given the new tax rules for standalone battery installation and continued PG&E price increases, I figured it would be good to look again at the math on whether or not installing powerwalls makes sense for us. We have a large house in the Menlo park area, and a fairly large solar array that...

Thanks everyone. I have to confess I was not reading my bill properly, and the generation charges are the actual SVCE charges, not what credit I am getting. I am not close to being a net exporter. I do get a generation credit during the month, but even off peak I only exceed the what I use a...

Well, I have about 7K due in a true up next month, so there is room to improve. The gas bill is is a lot more than the lectricity though because of the pool heating (the girls like their pool warm!). Is SGIP still available? I thought it was not an option anymore. Maybe I should look at the...

Again, I gave up on using the powerwalls for ANY backup. That's why my business case is just for load shifting, and they would be wired on the line side of the generator transfer switch, and with NO loads of any kind behind the gateway. So there is no interaction with the generator at all -...

Exactly - the solar would drop offline during an outage, just like it does now. I have a diesel genset that works great for backup, doesn't depend on nat gas lines working after an earthquake, and has a 400A transfer switch that backs everything up without a fuss. The house is very efficient...

We do have 3 solaredge inverters, so the solar generation can be separated out, but why don't the powerwalls just shut off when full? Why wouldn't the system just output the excess to PG&E the way it's done now? Are you saying the PW's would have to charge using all the solar generation? I...

Hi. We have a large house in SF Bay Area with a large solar array (25 kW) that always generates excess power during the day, and quite a bit during the off-peak times when PG&E is paying us $0.03/kWH. I am trying to see if the economics pays off to add one solely on the basis of load...

Ha... Would be nice if someone would run on an anti-PG&E agenda. It would be a winner in Northern California. After all, Arnold got Gray Davis swapped out over the first PG&E failure and increased DMV license fees...

Well, they are much more loved by Gov Newsom and his PUC than we are, and that's what really matters. :)

That is a bit of a misleading statement. Variable Refrigerant flow heatpumps allow the use of much smaller generators to support them than traditional units. A traditional compressor based system kicks on at full power, and needs up to 100A to start the compressor and then runs at 40A after...

It's not just heat pumps, but hot water heating needs, for both homes and pools if you have them. We built a new house a couple years ago and used Mitsubishi heat pumps without gas heating stages. In our mild climate, the efficiency is quite good, and costs less than gas even with PG&E prices...

Actually Menlo Park mandates the use of SVCE, a CCA. So that isn't the issue... See here: Peninsula Clean Energy | City of Menlo Park - Official Website, and I do owe a fair amount at true up time...

I hate PG&E too - who doesn't? But that doesn't mean I should burn a ton of money just to somehow try and get even with them. They only get away with what they are doing because of the CPUC and state government allowing them to do it. You can't really criticize a company for acting in it's...

So it seems like there a a horrible economic case for powerwalls! I do have to compute how much peak energy I pay over the last year, because it is fair to look at it as offsetting all the high cost energy, but I don't understand why powerwalls are seemingly so popular in PG&E areas if the...