Personal Consumer Issues • Solar: how do you ever break even?

Let’s look at your example using Saturday’s prices. The HL prices (daytime) were 32.70 and the LL (evening/night) were 42.07. if you produce 500kWh during low prices and consume 500kWh during high prices and it nets to a zero bill for you then using Saturdays prices you have cost the utility $5. Note that these prices do get dramatically different by hour where the true cost is much more than $5. (And yes I understand your consumption is over a a longer period than one day but it’s an example).

The $5 calculation ignores that the solar infrastructure is a primary reason the power company is enjoying a $10 discount in wholesale rates during the day in the first place. 90% of residences in my city do not have rooftop solar and are being supplied with cheaper power and still charged the retail rate. It's a huge win that power companies don't need to spin up their most expensive generation methods to meet the daytime peak demand.

Also, the $5 cost is just a time of use difference -- it's only a cost with respect to a different time of energy use that is profit-maximizing for the utility. It is not an actual cost. It is no different than someone who used to charge their car during the day deciding to charge their car at night instead. For whatever reason, I never hear people complain that EV owners or laundry users are costing the power companies, even though it is the same time-of-use issue.

To the extent that time-of-use arbitrage is increasing costs to the utility, they can implement time-of-use billing to solve the problem. In effect, there is a bill for daytime use and a bill for nighttime use, reflecting the different rates. This would encourage people to use batteries at times that are convenient for the utility. My utility doesn't choose to do time-of-use billing, but they have chosen to pay EV owners $12/month if they agree to charge at night. (I don't know why they find night to be preferred. That seems backwards! Maybe because solar adoption is lower where I am.)

You mention “ It can happen on some hours of some days that solar provides more than 100% of what the entire customer base needs -- not often, but it can happen occasionally”. I’m not sure what you consider occasionally, but in the first half of 2024 20% of the hours in Southern California were negatively priced (as in more supply than total demand). That’s only going to continue to rise as more people get solar.

Thank you for this information. It was just last year that I remember reading that California had first hist 100% renewable energy generation during some days. It looks like it is more common now.

Statistics: Posted by MoreTaxes — Mon Jul 29, 2024 12:59 pm — Replies 167 — Views 10132

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