do solar panels make sense in this scenario?
I had plans to install solar panels on my new workshop, but a change in billing schemes by my utility is giving me second thoughts.
Relevant details:
-climate zone 5/6
-winter months are extremely cloudy
-building is oriented with roof facing south
-most of our current usage is in off peak (after 7pm or weekends)
-net metering not allowed
-was planning on a “peak shaving” setup to avoid batteries
-just got an EV, and expect to charge it up about 20kWh per day, which can be easily handled at night time when rates are low
The new rate scheme is an ultralow overnight off-peak deal. From 11pm-7am the rate is something like $0.03 per kWh (none of the figures I’m quoting include delivery charges or other fees, so it’s not perfectly accurate). The mid-peak rates are around $0.09, which covers weekends entirely, plus weekdays 9-11pm and 7am-4pm. The con of this scheme is the peak hours are extended compared to the normal rate plan, and the rate is very high: 4-9pm, $0.29 per kWh.
So this is what has me thinking it’s no longer worth it:
The mid-peak time is where the vast majority of solar production will be. We already use little electricity during this time, and the rate is also not that bad. I can charge the EV at night on the ultralow rate. The time period that I’d really want to use the solar energy is when there won’t be much. In the winter, there’d be essentially nothing during 4-9pm. In the summer, we’d get some, but it’s not going to be a ton.
It seems to me that in order to make use of the panels in this scenario I’d need to forget the “peak shaving”, and add battery storage and an inverter. That adds yet more cost and takes up space and requires maintenance. Am I looking at this correctly?
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Replies
One way to store energy from solar power without batteries is by storing heat in water. Your water heater is designed to keep water hot for a long time- and you can add a cheap blanket. So solar panels can heat that water anytime, and the water is hot anytime. You'd need to figure out how much you pay to heat the water you use. If you use baseboard electric or something inefficient like that, maybe swap one or two out with a modern water radiator, depending on how many BTUs you need out of it, and how big your water heater is. One cool thing you can do, if you have electrical skills, is run DC directly from solar panels to the heating elements in a water heater. No inverter needed. However this requires a high level of electrical skills- not for noobs.
I toyed around with this idea when I built my house. I even bought two panels for the purpose, but never got around to installing them. It required building a free-standing mount, and it just never got to the top of the priority list. It's pretty difficult to set up a system like this at a scale where it actually pays off. A couple of 36V panels is manageable, but you're only getting 600-700W out of that in summer, perhaps half or less in winter. Beyond that, you're either dealing with wire sizes that get pricey and difficult to manage (that is if you're running them in parallel), or if running them in series you're looking for high voltage rated thermostats and contactors, which are also going to be pricey.
With that utility pricing, I'd get some west facing panels in there if going battery-free. Is it $0.29 in the winter too? If so, you would get very little to no production in the winter during peak hours. Batteries might not be a bad deal. They are getting cheaper every day. Getting close to the $200/kwh for packs now.
If I were you I would create so spreadsheets: figure out how much an inverter and batter system would cost, how much you pay at peak rates, and see what the payback is. There are probably also programs for this. One thing to keep mind is gov incentives make it more attractive.
The solarark inverter is nice
The new lithium iron battery’s are getting pretty cheap, and almost all systems you can stack inverters and batteries, adding more later.
Solar is getting very cheap
29 cents a kWh sounds crazy to me.
Seems to me your complaint is with the public service commission or whatever they call the board that oversee your utility. If the board is unresponsive complain to the elected officials that appoint the commission members. Make them understand you will remember them at election time.
Walta
Along those lines, I had to wonder if that rate structure reflects their true cost structure, or was designed to discourage people from adopting solar.
I wonder if it is an optional plan?
Batteries can't compete yet here and are not particularly close. According to energy sage, the average $/kWh stored is well over $1000 before incentives. That's not going to work, even if you have a $.26 on vs. off peak spread.
Even if you stored 260kwh (52 weeks * 5 week days) a year per kwh installed, that's only $68/year/kwh capacity. You would have to be perfect too - if you store some energy and don't use it all the next day, that savings decreases.
Before you buy batteries consider a pumped hydro system use the $0.03 kWh to pump water up hill and use the water to generate power on peak about 80% efficient.
The real problem with the solar battery option is you need to store your summer excess solar for use in the winter and only net metering lets you do that.
https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity#:~:text=The%20round%2Dtrip%20energy%20efficiency,sources%20claiming%20up%20to%2087%25.
Walta
What hill?
That type of energy storage is intended for utility scale, not individual homeowners. Even if I had a hill on my property, I suspect I'd never recover the initial expense.
Deleted
To answer a bunch of questions in one place:
Yes, it's an optional rate plan. The other option, that I'm currently on, is:
Peak $0.182, Mid $0.122, Off peak $0.087
Summer hours peak 11AM-5PM, off peak 7PM-7AM, mid 7AM-11AM and 5PM-7PM
In the winter the peak and mid hours swap.
I used the optional rate plan for comparison because it's the one that makes the most sense for having an EV. I guess if I was to evaluate the worth of solar panels, I'd have to run numbers for both rate plans.
I think the optional rate plan is specifically targeted at EV owners to entice them to charge at the really off-peak times.
I don't have the option of west facing panels.