If I want 20kW available at a moments notice... fine... charge me a demand fee based on that. If I want to export a MWh then import it later... fine... charge me a fee for that.
That's exactly what SRP did, in its solar rate design. A demand charge, and it won't be the last. It's how punitive they were in double-whamming users with ~$20 base rate upcharges and then triple-whamming with reduced Net Metered rates, down to the rate they buy from solar farms ($.06/kwh). All that stood out in what, as an analyst, I still would treat as the model example of the opposite extreme. There's too lavish, in solar, and then there's SRP. Here's some text, on the model fixed (Grid) costs, versus variable cost argument that has started showing up as a pretense to drill-out grid solar:
From SRP:
“Electric utilities face two types of costs: fixed and variable. Fixed costs are costs that are incurred irrespective of customer energy usage (kilowatt-hour usage) and which are necessary to make a safe and reliable grid possible. Examples of fixed costs are generating unit capacity, transmission lines, certain distribution system components and costs associated with providing customer service, metering, billing and payment processing. Variable costs are associated with the actual electricity that is supplied to customers, which is measured by the customer’s meter. Examples of variable costs are fuel and purchased power charges.”
When I modeled costs, for a ~30kwh/day consumer that had enough solar to
net zero consumption, I arrived at a monthly bill of
$130, versus about $160 for all-consumption on the base rate plan. Keep in mind, if anyone thinks what SRP is doing is fair, there is no default time of use peak punishment in SRP's base rates. The guy cranking his A/C, at 4PM, is paying the same rate he would at 4AM.
What is hugely important is attributing this fixed cost BS onto the user responsible for pushing the peak, not the solar home. That's what calls for the next plant. Moody's neglected this reality and was totally on board with this rate plan. Honestly, it keeps up the good times when another fossil plant is justified, and bonds and fees become necessary.
At the end of the day, numbers close to the ones I get from looking at SRP show unfair retribution in the days of "beyond solar cap" net metering. Some in the U.S. pay $0, or get paid for being net zero (MA SRECs). I'm not on board with that, long term. Whether called nwdiver's charge for "self-generation", or anything else that can produce bills as high as those faced in Arizona, you can see the retail stationary storage market becoming more economic, and, frankly, more desirable even if its not.
It's a huge assumption, on the part of both utilities and environmental regulators, that you can be passed costs for things like the next plant, or decoupling. It's hard to justify off-grid, on AZ rates, but pretty soon the bears aren't going to like they way they're being poked.