Steel For Fuel N° 022 of 56 24 Sep 2024
A chicken in every pot, a battery in every garage?
by Andy Lubershane, Partner and Head of Research, Energy Impact Partners
In this note
The question
Is a battery becoming standard equipment on a home solar system?
The answer
In three markets yes, or nearly, and in Texas for close to half. Almost nowhere else. What separates them is not appetite for storage but local tariffs, outage risk and wholesale price volatility.
03The argument
The chart is Sunrun’s, and the share of its rooftop solar customers adding a battery tripled in a single year. Lubershane’s point is that the national figure averages markets with almost nothing in common. Where economics or weather make a battery obvious it is close to universal: Hawaii on tariffs and incentives, Puerto Rico on storm resilience, California now matching the first on incentives and the second on backup demand. The case he says surprised him is Texas, which arrives without the usual ingredients. Retail power is cheap there and no statewide rule obliges utilities to credit exported solar, so rooftop solar itself has only lately taken off. His reading is that the battery rather than the panel carries the value: the household buys set-and-forget backup while retailers and municipal utilities buy a hedge against extreme peak wholesale prices. He calls the moment a market inflection, then supplies the counterweight himself: outside those states the attach rate is about 5%.
04What you need to know first
- Attach rate
- The share of an installer’s solar customers who also buy a battery.
- Net energy metering
- A utility crediting a rooftop owner for exported power; Texas has no statewide requirement.
05Details worth keeping
- California’s backup demand is attributed to deliberate outages imposed to limit wildfire risk.
- Base Power, a new retailer, is built on that dual value.
- He closes on Sparkfund, whose services aim to turn distributed resources into gigawatt-scale capacity for utilities, and Block Energy, selling neighborhood-scale solar and storage microgrids.
06Claims worth citing
All figures as stated on 2024-09-24, from one installer’s own deck.
- Sunrun’s storage attach rate tripled year over year. Sunrun, cited by Lubershane
- Basically 100% in Hawaii and Puerto Rico, about 86% in California, 46% in Texas, about 5% everywhere else. Sunrun, cited by Lubershane
07Where it’s contested
Nothing is disputed; there is no second voice. The inflection is offered as a feeling rather than a finding, it rests on one company’s numbers, and the tailwinds he names, cheaper batteries and what he calls the gauntlet facing the electricity sector, are asserted rather than shown.