The Truth About EVs And Solar

[ChasingCoral]

Our solar is part of a community solar array at a nearby municipal airport. We purchased a share equal to access to 1/2 of our monthly average electricity use. The buy in price was pretty low but our electricity cost is now locked in to no more than 10.9 cents per kilowatt hour for the next 20 years even if we move elsewhere in the service area. Does not have potential advantages of a private rooftop array but has many other advantages.

We did the same. In our case, we were allowed to buy up to 70% of our monthly and the array is on a former landfill. We buy our other 30% from a regional wind energy supplier. Except for losing the potential of off-grid, it has most of the advantages of solar with a power-purchase agreement.

BTW, our house has too many trees around it for solar to make sense on our roof.

Sponsored

 

[Scarpia]

I watched the video, and his system and observations were interesting.

I just installed a PV system (with Tesla Powerwall battery for backup) less than a month ago. I'm fortunate to live in SoCal, so plenty of sunlight and a roof with good exposure. Big bonus: the panels are on the backside of the roof, so not visible from the street.

Premise: driving 15K miles/yr and averaging 3 miles/kWh = 5K kWh/year to charge your car. 5,000/365 is a daily average of 13.7.

Feb. isn't over yet and I'm getting 45 kWh per day out of my system. Our household is using 21-24 kWh/day. The catch is that I'm working from home because of the pandemic, so not charging much. But, our output will go up substantially as we get into spring and summer. (We don't use the A/C much, but our usage will also increase during that time.) Point is, though - the system was designed with charging in mind, and we will have plenty of juice to cover our usage AND car charging. Also, the MME will be my third EV (I have driven over 100K all-electric miles) and I guarantee I will get far better than 3 miles/kWh. My last two cars (Fit EV and Clarity BEV) I've averaged 5.2 and 4.3, respectively. I'd be shocked if I didn't get 3.5 in the MME.

So, my truth is that solar is absolutely terrific - for my situation, living where I live. Conditions are admittedly close to perfect, though.

 

[engnrng]

Holy smokes! What a setup!

He just about talked me out of ever considering solar as a home installation.

He is possibly in the 0.01% group of solar installations (1 in 10,000). He makes it sound like he is mainstream or "average" - used that word a lot! - but I do not agree. By comparison, I have 2 ground mounted arrays in SoCal, 10 kW peak - and I put myself into about a 0.1% group (1 in 1000). Note: in SoCalEdison territory, there are strong administrative dis-incentives to going higher than 10 kW peak power. During 3 seasons of the year, my panels deliver over 60 kWh daily, depending on weather, with my output during cloudy/short daylight season about half that on "average". Of course, we no longer get much rain in SoCal!! My bill 10 years ago pre-solar was about $350 per month. I now get about $600 per year back from SCE - on Net Metering and TOU rates. My solar powers my house and fills up 3 Tesla PowerWalls by 12 noon most days, and exports the rest of the afternoon to the grid at moderate TOU rates. The batteries (Li-Ion) carry me through the high $$ evening hours and through the night. If I charge my Kona (every 3rd or 4th day at 12,000 miles per year) then I will deplete the battery below my backup setting of 30% and draw a small amount from the grid during the early morning at the lowest TOU rates. I figure that my investment is returning about 7% tax free - where else can you get that rate of return on an investment? Safe and the return goes up a bit each year. Even with EV, I am net positive energy to the grid, I have battery backup for blackouts. Operating my EV is "free" and I drive it quite fun-wise and average over 4 mi/kWh. My wife will love driving the Mach-E (maybe next week?!!) so we can semi-retire our Highlander Hybrid and save it for long trips only.

 

[bellyer]

I have rooftop solar going up on my roof tomorrow in Chicago - a 14 panel system. It was only estimated to cover about 45% of my home's energy needs. I am hoping to add more panels to my detached garage in the next year or so, but the way I see it, as long as it is reducing my need to draw from the grid and helping to offset our additional electricity usage for the Mach E that is supposed to be delivered to the dealer this week and some of the other electric appliances and tankless water heaters that we have added in the past 6 months in our efforts to get off of gas, I am content for the most part. I will definitely be hoping to add solar to a house we are buying in Wisconsin on a few acres as well.

 

[Fat Mach]

I think my SolarCity system (hold the laughter..) is an 11KW system. Yesterday (2/22/21) was very sunny, and I got 34 KWH's out of it. In mid-June I'll get 60 KWH's per day, I think. I'm an hour south of SF, so still in a reasonable solar area. I'd love to get a couple of powerwall batteries, but I don't think the return on investment would really be there yet.

How are the rebates/incentives in CA these days for the batteries?

BTW- I said hold the laughter since I got them for free. I made an offer on my house prior to being told they essentially owed $40k on them. I promptly rescinded my offer, and re-offered $40k less- which they accepted. I pay SolarCity and PGE for electricity.

 

[Scarpia]

The PV system was ~$24,400 before incentives, $18K after FTC.
The Powerwall battery was $12,500 ($9,250 after FTC), plus an add'l $2K rebate from our utility.

 

[Scarpia]

Almost everything is 25 years, parts and labor.
During the first 10 years, performance will not decrease more than 10%. (20% in 25 years.)
Powerwall battery: 10 years. Battery will maintain at least 70% capacity at the end of 10 years.
There are no moving parts that I am aware of.

 

[CHeil402]

I also think that it wasn't the best 'average' comparison. I've posted in other threads here about my Tesla solar system that was installed in September 2020.

https://www.macheforum.com/site/threads/anyone-here-gone-solar.902/page-5#post-65409
https://www.macheforum.com/site/thr...-handle-electric-cars.3323/page-2#post-106036

From September 2019 - September 2020, I consumed 10,154 kWh. I'm lucky enough to have good solar roof exposure. As I linked in my other post, you can play around with Google's Project Sunroof to see how good your roof is: https://www.google.com/get/sunroof.

I oversized my system by about 34%. Tesla estimated that my annual production would be 13,589 kWh. If I drive 12,000 miles per year (assuming a post-Covid world) at 3 mi/kWh that's another 4,000 kWh per year which is only an additional 39% on my house loads, so pretty much covered.

Now I'm grid-tied and it's not very economical to be off-grid as was already pointed out because you have to oversize your system by a TON. And when I feed back to the grid, that solar power is being used by my neighbors. So I come out about net-zero grid consumption.

 

[Scarpia]

Our electric bill jumps around a bit, but seems to average about $225. It's hard because usage is different during the pandemic (working at home, and not charging as much). So I think it's probably saving us closer to $3K. The PV system will pay for itself in around 6 years or so, and it's guaranteed for 25, so that's a lot of "free" electricity.
Also, don't forget that the utilities raise rates, so the savings will increase as time goes on. If it goes up just 1-2% a year, that's a big increase over 10, 15, 25 years, and our costs are fixed.

 

[Scarpia]

Based on how utilities operate here, chances of that are slim and none, and slim just left town.
That would be an opportunity to raise prices as new equipment needs to be purchased and installed, migrate from old systems, upgrade everyone, etc., etc.

Sponsored