Plug-in solar for small businesses

Why a shop does better than a house

Everything about plug-in solar comes down to one ratio: how much of what you make do you use as you make it? Power you use is worth the full retail rate. Power you export is worth nothing.

A business that's open from nine to six is consuming continuously through the exact hours a panel is producing. Lights, refrigeration, point-of-sale, espresso machine, air conditioning. There's almost no surplus to give away.

Estimated. Based on 1,900 kWh a year from a tilted 1,200-watt array and a 33-cent blended rate. Commercial rates vary more than residential ones; see below. Full working.

There's a second, smaller point. A business on a commercial rate plan may be paying a demand charge based on its highest fifteen-minute draw in a month. A panel producing during your busiest afternoon can shave a little off that peak. It's a modest effect at 1,200 watts and we wouldn't build a case on it, but it's real.

The honest complication

SB 868 defines the device by reference to a dwelling unit — the 1,200-watt cap is "per dwelling unit," and the framing throughout is residential. A café in a strip mall is not a dwelling unit.

What that means in practice is genuinely unsettled. The plausible readings:

• The exemption simply doesn't reach commercial premises, and a business installing one is in the same position as before the bill — needing to talk to the utility.
• The utility declines to pursue a 900-watt device on a storefront patio because it isn't worth anyone's time.
• The CPUC or the utilities clarify it in implementation, one way or the other.

We don't know which. Nobody does yet, because the bill isn't law. This is the single question we're chasing hardest, and we'll publish the answer the moment there is one. There is no published utility or CPUC guidance on commercial applicability as of 1 September 2026.

What we'd do in the meantime: if you want to move before there's clarity, a zero-export device — one that throttles its output so nothing ever flows back to the grid — takes the interconnection question off the table, because there's nothing to interconnect. It costs a little more and produces a little less. It's the conservative choice and for a business with a lease and an insurer, conservative is usually right.

The other people who get a say

Your landlord. Commercial leases are stricter about alterations than residential ones, and often have specific language about the exterior of the premises, signage, and anything visible from the street. Read the alterations clause before you buy. The good news is that a clamped-on panel with a removal plan is the easiest kind of request to say yes to.

Your insurer. A plug-in appliance isn't a building alteration, but anything mounted outside that could come loose in wind is something a commercial policy may want to know about. One email to your broker, before the panel arrives.

Your city. Balcony and walkway obstruction rules, egress, and anything to do with a fire lane. SB 868 binds utilities, not building departments.

Your landlord's other tenants, if you share a patio or a wall.

What we'd actually recommend by business type

Where you'd put it

Businesses usually have better options than a balcony railing. A flat awning, a south-facing wall, a patio fence, the sunny end of a parking area, a courtyard. A ground-mounted frame in a service yard is often the easiest of all, because nobody has to look at it.

The constraint is the same as at home: a standard 120-volt outlet within cord reach, outdoors or reached safely, and no more than 1,200 watts total.

Work out what your premises would save →