[chris222]

I’ve just done a legtimate 425 mile solar powered round trip which is the culmination of many things I will explain below. I can now effectively drive anywhere in a 225 mile radius and back for about $10 total cost and on 100% solar power.

I have a two complete solar systems on my house the first one was 10.98kW AC installed 4 years ago with the panels facing south. The second was just installed a few days ago and is a 9.9kW AC with the panels facing east/west. Combined the system will produce over 20MWh of power per year. Both systems are grid tied used EnPhase microinverters and are now combined together for monitoring in one site.

I have an EnPhase IQ EV Charger. This has a mode where it communicates with the solar system, understands how much power is being produced and consumed in the house and then adjusts the EV charger output to match the excess solar production.

I have an EV with the largest battery that is available. The Chevy Silverado EV truck has 24 battery modules with a total gross capacity of slightly over 200kWh. The efficiency on road trips at high speeds is about 2.1miles per kWh. I have verified this with a real world road trip of over 400 miles.

The cost of the solar is around 5 cents per kWh over the 25+ year lifespan of the system.

[toddmorey]

Another less commonly discussed option is community solar (also called offsite solar). It's especially attractive if the roof line of your house isn't ideal for solar panels or if you expect to be replacing your roof within the lifespan of your panels. (Or if you have a historic association like I do that makes almost every home project impossible.)

You still purchase and own the panels, but often a third party maintains them for you and they are installed as part of a large, offsite array. Since they're usually installed at ground level, they can also do more interesting things like follow the sun. The way it works is the power your panels produce is subtracted from your energy usage via an arrangement made with your utility provider.

Like any solar purchase, the cost of your panels can be financed over time and charged against your energy production. So the net effect is your power bill just goes down until the panels are paid for. At that point all the power you generate is deducted from your power bill. To me, it's most all the upside of owning panels on my roof.

[SlowTao]

I have always liked this idea, it is such a neat middle ground between massive grid scale systems and the hassle of individual system maintenance.

[chris222]

The described version of community solar is nice. How it is usually implemented like in Maine ends up sucking.

The root cause is that they wanted community solar customers to be able to opt-in and opt-out any time. As such it isn’t really what you describe which is owning panels offsite, you are more or less doing a short term rental on them. As such you don’t get the full benefit from them but simply a 15% discount on the current residential rate.

https://www.wabi.tv/2025/02/18/maine-public-advocate-claims-...

I very much think that proper community solar would be a larger upfront investment just like panels on your roof are. With a small monthly cost to maintain the grounds and pay taxes on the real estate where the panels exist. All power generated would be metered for the specific panels you own using microinverters.

[cman1444]

I don't understand the purpose of consumers owning individual solar panels in a large array. How is that better than a single entity owning the whole array, and what function does the consumer provide?

[nordsieck]

> I don't understand the purpose of consumers owning individual solar panels in a large array. How is that better than a single entity owning the whole array, and what function does the consumer provide?

I don't now if it's better, but it is different.

The benefit to the utility in this case is much lower capex - it's basically like the restaurant franchise model, but for power.

But like you imply, there's a tradeoff that can be made between capex and opex - in this case, the utility could own everything and consumers could pay for electricity on an ongoing basis. IMO, this model is superior due to reduced principal-agent problems.

[killingtime74]

Just to be clear you're talking about variable costs not total costs. Total costing include time value of money, amortization etc. (I'm no hater I also drive an EV).

[chupchap]

> I have an EV with the largest battery that is available. The Chevy Silverado EV truck has 24 battery modules with a total gross capacity of slightly over 200kWh. The efficiency on road trips at high speeds is about 2.1miles per kWh. I have verified this with a real world road trip of over 400 miles.

This is interesting. While it has the most storage capacity, the range is not good for that much battery.

[mbreese]

I don’t think the Silverado is optimized for driving range, but rather - can it do typical “truck” stuff. For example hauling and/or towing. For this workload, having more towing capacity in a slightly less aerodynamic package is probably a good trade off. You don’t get a truck for the efficiency, you get one so you can do stuff with it.

Still, having a 400 mile range also makes this more useful for the middle of the country where there are wide open spaces between towns for charging. Also, having a legitimate truck EV makes it more likely for traditional truck buyers to think of getting an EV.

[chupchap]

Thanks for the perspective

[chris222]

Part of it is the weight of a battery this size but the bigger issue is the aerodynamics of the large frontal area.

The Lucid Gravity has a 450 mile range with a 123kWh pack. It’s the only other vehicle with a range close to the GM large packs.

[1dom]

I'm looking at doing similar stuff right now. I already have a house battery.

However, looking at getting an EV - were you able to get bidirectional charging going?

I saw a few places mentioning demos of it over the past 5 years, but I can't find any v2x charger/car configurations I can buy and use in the UK.

Before looking at any of this stuff, I didn't realise how large and cheap the battery in an EV is compared to house batteries. Now I'm struggling to justify getting an EV if I can't do at least V2H bidirectional charging.

[chris222]

You can do bidirectional with most GM vehicles now with the GM energy solution. I don’t have this but I did have a call with them.

Thier max output is only 9.6kW so it can’t do a whole home backup and the car can only run in backup mode when the grid is out.

https://gmenergy.gm.com/

[1dom]

Interesting thanks! It looks like most of the GM vehicles that v2x works with are... uh... not really something a European would consider an option (not even sure if some of them will fit on our roads). Ford UK makes no mention anywhere of anything to do with v2x though.

There's a few places that apparently offered it here, but when I've contacted them, they've all explained it was a tech demo, or trial, or some other PR type thing which means they didn't take it any further and regular humans can't buy it. I think there's some nuance or regulation around the UK power network which is stopping any progress with bidirectional charging here.

Over here though, if you don't have old electric heating, or an electric shower, 9.6kw is very much more than enough for the average household. I have a relatively high usage, and a 6kw inverter can power my house in a powercut, as long as I don't use the electric shower. The various retired people in my life tend to use 2 - 4kwh /day, the peak draw is the kettle which uses 3kw for a minute or so.

[scarby2]

> Thier max output is only 9.6kW so it can’t do a whole home backup and the car can only run in backup mode when the grid is out.

9.6kW should be enough to backup your entire house, that's 87A... Lots of people only have a 100A supply in general. Depending on your setup you may have to limit what you use at one time but even in a large house that will be more than enough for AC, lights and electronic devices.

[quickthrowman]

9.6kW is 40A at 240V, and a 240V 100A single-phase residential service is 24kW.

Still, 9.6kW should be more than enough to run a fridge, lights, receptacles, sump pump, a 2-3 ton A/C unit, and a furnace fan. It would be challenging to impossible to back up a home with electric (resistive) furnace and electric (resistive) water heater with only 9.6kW.

[_w1tm]

That’s peak production, without battery storage the fluctuation during the year will likely be too much to keep the “lights on”. Would be cool to have a smart home that prioritizes the electricity supply to different systems based on how much is available.

[amy214]

>This has a mode where it communicates with the solar system,

I just find this so cool. We have projects like SETI where the solar system tries to communicate with us. Here, you, just one person, have set up a machine talking with outer space and the solar system. Space is talking and we are listening. Amazing. Rock on space cowboy.

[hex4def6]

I assume you're on a pretty attractive net metering agreement? That's a huge system.

Unless you're consuming a significant portion of that, the payback rate is going to be pretty badly impacted by having such a large system for most people.

[chris222]

I consume about 17MWh a year between two EVs and a large heat pump for winter heating.

I will have overproduction now with the 2nd array. We do have net metering at about 80% of the cost on NEM 2.0. Our bill is split by transmission, generation, distribution and fees. We get 100% on transmission and generation and 25% on distribution.

https://www.energy.nh.gov/sites/g/files/ehbemt551/files/inli...

[cryptoegorophy]

$0.05 is the rate we pay in BC at night. I was still debating whether to add solar or not, I guess your post answers the question. Until we can get to $0.01 there is no point in solar in BC at least.

[slavik81]

From an efficiency standpoint, we should probably be building grid-scale solar in Alberta and pumped storage in BC. There's more sunshine on the east side of the Rockies.

As a resident of Alberta, I pay $0.205/kWh for energy and delivery, which I largely attribute to bad decisions made by our provincial government. Even still, my 10 kW rooftop solar install is barely financially viable at those rates.

With that said, it would help if the Canadian government didn't have enormous tariffs on solar panels. Canada levies taxes such that solar panels here cost nearly triple what they cost elsewhere.

[thegrim33]

The article is about installing solar panels on vehicles. Your truck has no solar panels installed on it. What is the relevance of your anecdote to this discussion?

[theoreticalmal]

The relevance is readily apparent to people who aren’t grumpy yahoos.