The Edison Electric Institute has floated the idea that demand charges should be renamed as “efficiency rates.” Demand charges measure the maximum use in a month, and once a customer reaches that demand level in a month, a portion of the usage is free below that demand level. Providing power for free encourages more use, not less, which is the opposite of what “efficiency rates” should do. Apparently this proposal is part of a larger effort to relabel everything that utilities find objectionable, such as distributed energy resources.
Demand charges can have a place in rate making, but the best such tool, made feasible by the rollout of “smart meters,” is daily demand charges that reset each day.
The California Public Utilities Commission (CPUC) held a two-day workshop on rate design principles for commercial and industrial customers. To the the extent possible, rates are designed in California to reflect the temporal changes in underlying costs–the “marginal costs” of power production and delivery.
Professor Severin Borenstein’s opening presentation doesn’t discuss a very important aspect of marginal costs that we have too long ignored in rate making. That’s the issue of “putty/clay” differences. This is an issue of temporal consistency in marginal cost calculation. The “putty” costs are those short term costs of operating the existing infrastructure. The “clay” costs are those of adding infrastructure which are longer term costs. Sometimes the operational costs can be substitutes for infrastructure. However we are now adding infrastructure (clay) in renewables have have negligible operating (putty) costs. The issue we now face is how to transition from focusing on putty to clay costs as the appropriate marginal cost signals.
Carl Linvill from the Regulatory Assistance Project (RAP) made a contrasting presentation that incorporated those differences in temporal perspectives for marginal costs.
Another issue raised by Doug Ledbetter of Opterra is that customers require certainty as well as expected returns to invest in energy-saving projects. We can have certainty for customers if the utilities vintage/grandfather rates and/or structures at the time they make the investment. Then rates / structures for other customers can vary and reflect the benefits that were created by those customers making investments.
Jamie Fine of EDF emphasized that rate design needs to focus on what is actionable by customers more so than on a best reflection of underlying costs. As an intervenor group representative, we are constantly having this discussion with utilities. Often when we make a suggestion about easing customer acceptance, they say “we didn’t think of that,” but then just move along with their original plan. The rise of DERs and CCAs are in part a response to that tone-deaf approach by the incumbent utilities.
“A Rochester Institute of Technology study says a customer must face high electricity bills and unfavorable net metering or feed-in policies for grid defection to work.”
Yet…this study used current battery costs (at $350/KW-Hr), ignoring probably cost decreases, and then made more restrictive assumptions about how such a system might work. It’s not clear if “defection” meant complete self sufficiency, or reducing the generation portion (which in California about half of electricity bill.) Regardless, the study shows that grid defection is cost-effective in Hawaii, confirm the RMI findings. Even so, RMI said it would take at least 10 years before such defection was cost-effective in even the high-cost states like New York and California.
A more interesting study would be to look at the “break-even” cost thresholds for solar panels and batteries to make these competitive with utility service. Then planners and decision makers could assess the likelihood of reaching those levels within a range of time periods.
Source: A study throws cold water on residential solar-plus-storage economics | Utility Dive
One of the key questions about how to bring in more renewables is how do we provide low-cost storage? Batteries can cost $350 per kilowatt (kW) and pumped storage somewhat lower. Maybe we should think about another potential storage source that will be very low cost: automobiles.
California has about 24 million autos. The average horsepower is about 190 HP which converts to about 140 kW. Let’s assume that an EV will have on average a 100 kW engine. Generally cars are parked about 90% of the time, which of course varies diurnally. A rough calculation shows that about 2,000 GW of EV capacity is available with EVs at 100% of the fleet. To get to 22 GW of storage, about 1% of the state’s automobile fleet would need to be connected as storage devices. That seems to be an attainable goal. Of course, it may not be possible for the local grid to accommodate 100 kW of charging and discharging and current charging technologies are limited to 3 to 19 kW. So assuming an average of a 5 kW capability, having 20% of the auto fleet connected would still provide the 22 GW of storage that we might expect will be required to fully integrate renewables.
The onboard storage largely would be free–there probably are some opportunity costs in lower charging periods that would have to be compensated. The only substantial costs would be in installing charging stations and incorporating smart charging/storage software. I suspect those are the order of tens of dollars per kW.
Here’s a good description of different types of community solar garden configurations:
You can read about community solar garden policies in one of my past blogs.