What the shutoffs actually looked like
Xcel’s December 2025 shutoff de-energized about 50,000 customers in Boulder, Clear Creek, Jefferson, Larimer and Weld counties. The March 14, 2026 event was concentrated here, with about 14,400 customers in Boulder County and 3,400 in Jefferson. Restoration took from roughly 24 to 72 hours or more, because lines have to be inspected before they’re re-energized.
Shutoffs tend to come during high-wind, low-humidity days in winter and spring — often cold ones. That makes the furnace blower and heat-tape circuits as important as the fridge.
Sizing for a 72-hour event
For essentials only — fridge, furnace blower, internet, lights, a CPAP — one Powerwall 3 (13.5 kWh, about $19,000 installed) can often stretch across a multi-day shutoff when paired with solar, since panels recharge it on sunny days. Homes wanting to keep a well pump, electric cooking or larger loads going usually need two (the second is about $12,000).
Winter shutoffs come with short days and sometimes snow on the panels, so we size for the possibility that solar contributes little. We’ll show you the hours of runtime per load before you decide.
Money on the table in 2026
Colorado’s 10% state tax credit on home batteries runs through tax year 2026, and batteries are exempt from state sales tax. City of Boulder residents can also recover part of the city tax on battery materials and permits, a benefit added in April 2026.
In Longmont, the value-of-solar export credit means solar stored and used at home is worth more than solar exported — which gives a battery everyday value on top of backup. On Xcel, a battery can cover the 5–9 pm weekday peak, and Xcel’s Renewable Battery Connect program has offered an upfront incentive in exchange for occasional grid dispatch; verify its current terms before enrolling.
FAQ
Questions we hear
How long will a battery last during an Xcel shutoff in Boulder County?
It depends on what you run. For essentials, a single 13.5 kWh Powerwall 3 plus solar recharge can often cover a multi-day event; heavy loads or snowy winter days can shorten that a lot. Our runtime calculator shows hours by load.
Is a battery worth more in Longmont than in Boulder?
Its everyday value is often higher in Longmont, because value-of-solar makes self-consumption worth more than exporting. In Boulder on Xcel, the value comes from peak shifting and backup.
Can I get the City of Boulder tax rebate for a battery added to existing solar?
The city added battery systems to the rebate in April 2026. Check its program page for eligibility details and apply within 12 months.
When does Colorado’s 10% battery tax credit end?
It applies to tax years 2023 through 2026 under current law, so a battery purchased and installed in 2026 is the last year it’s available unless the legislature extends it.
Can a battery keep my well pump running in the foothills?
Yes with the right sizing — well pumps need a big startup surge, so we check the pump and usually recommend two Powerwalls or an expandable SigEnergy system.