Enterprising thieves are snatching a growing number of solar panels from San Francisco Bay Area wineries, schools, homes and municipal land, leaving solar installers scrambling to add theft deterrent measures to their systems.

Reported thefts in the Bay Area include Napa Valley wineries ZD Wines, Honig Vineyard and Harris Ranch Napa Valley as well as 90 panels stolen from the Las Gallinas Valley Sanitary District in San Rafael.

Solar installation thefts have cropped up where there are large pockets of solar installations. That makes California, which has more solar installations than anywhere else, the prime target for solar thieves. But other states may face the same problems as their solar industries grow.

“It’s awful PR for the industry,” said Rob Erlichman, CEO of San Francisco-based solar installer Sunlight Electric, which installed panels at ZD and Honig. Both had solar panels stolen from their vineyards twice in the last year, losing $40,000 in panels each. Insurance covered the replacement of the panels, but not installation or the power used in the meantime.

To curb the problem, Bay Area solar installers said they’re beginning to use breakaway bolts that will snap off if someone attempts to unscrew them, plus bolts with locking heads that can only be unscrewed with custom tools.

Installers also are beginning to offer alarm systems with varying sophistication to customers. Some alarms set off lights and sirens, while others will be tied to a central monitoring system to alert alarm companies or system owners that systems are being tampered with.

“I think we’ve got this problem licked,” said Erlichman. “I know a number of major players in the industry looking more closely at security than ever before and the fact that word has gotten out about the thefts means customers are asking for it.”

Marijuana growers suspected

Many of the panels that have been stolen are in fields or other remote locations where thieves can work undisturbed.

Installers said there’s a small market for used panels from people whose homes are “off-the-grid” or have no other source of electricity. Used panels don’t qualify for state rebates that make solar more affordable.

Second-hand panels are routinely posted for sale on classified ad site Craigslist and on online auction site eBay, installers said. A quick search for panels on Craigslist revealed five different postings for panels offered at far below retail value — $250-$450 per panel, some of which look badly weathered.

Police in Napa — where wineries have been burgled — told local media outlets that marijuana growers might be stealing the panels for their own use, so the electricity required to grow large quantities of marijuana inside a home or building wouldn’t be detected.

Elsewhere in the country, police have conducted “sting” operations, posing as buyers of second-hand panels and then arresting the seller if the goods appear to have been stolen.

Opportunity shines

New companies have found opportunity in addressing the problem.

“These modules are $1,000 each and are held onto the solar system with four bolts,” said Tim Holmes, president of GridLock Solar Security in Santa Rosa. “Thieves have discovered it’s relatively easy to steal them and they can get a relatively high return on their goods.”