Solar power has many devotees: manufacturers, investors, green energy enthusiasts... and thieves. Criminal gangs are increasingly targeting the valuable PV panels, cabling and other hardware in solar installations - but the industry is taking on the challenge of stopping them.

‘These panels are worth inordinate amounts and are relatively easy to steal,’ says Benoit Rolland, managing director of Tenesol. ‘Entire systems can disappear in a few hours.’

These well-organised crimes often take place in the dead of night when a group of thieves armed with tools and a truck can quickly remove large quantities of solar panels or - in some cases - every part of a complete PV system. According to a recent study by US specialist insurer SolarInsure, the past few years has seen a significant increase in solar panel robbery. Solar thefts grew by 15% in 2009 compared with the previous year and some believe that figure has risen by 15% each year since 2002.

‘There was 19% increase year over year from 2009 to 2010,’ says Mike Smith, senior vice president of sales at SolarInsure. ‘The top three locations for theft are solar arrays located in rural areas, wineries and schools.’

American schools are being hit particularly hard. Smith gives a figure of approximately US$8.5 million for solar panel theft losses in school districts over the last two years. And the problem isn’t just confined to the US. In the UK, for example, 304 panels worth some £100,000 (€121,124) were stolen from a solar project in North Yorkshire in the November of 2011.

Though manufacturers warranty solar panels and can even guarantee their electricity generation, increasingly some form of physical protection that prevents panel removal is needed. Indeed, some insurers now demand that security measures are in place before they will cover an installation. With premiums rising by 20%-50% following a claim and doubling or more in the event of multiple claims, investing in a security system looks like common sense.

‘Security measures we recommend and sometimes require on all systems include fencing, security fasteners, alarms and system monitoring tools, movement detection lights and on-site security guards,’ says Smith.

Using ‘tighten-and-break’ anti-theft screws to fasten panels to mounting frames is a popular solution. Simple to install, they are a straightforward way to increase security. When the applied tightening torque reaches a critical value, the hexagonal head of the nut breaks off completely, leaving a conical head that no wrench can grip.

‘On easily accessible flat roofs or with small ground-mounted systems, where customers are worried about potential theft we use snap-off headed bolts which must be drilled out to remove the module frame clamps,’ says Smith. ‘This generally will deter potential thieves. Installations using standard fixing bolts could be at risk.’

Some installations are secure simply due to their location. For example, the majority of UK solar installations are on the roofs of houses and offices. Generally two storeys high or more, a crook would need scaffolding to access the panels and plenty of time to remove them - hard to achieve in an urban environment. However, rural systems are vulnerable, with CCTV or on-site security guards seemingly the only ways to prevent theft.

‘Remote systems, often powering batteries, are stolen, no matter what precautions are taken,’ says Smith. ‘These include river monitoring equipment and road signs, and because they are in the countryside, it gives thieves more time to remove them without getting caught.’

As well as anti-theft fasteners, SolarInsure recommends using security lighting in the form of floodlights linked to motion sensors. Further options include building a reinforced concrete wall around the panel mountings, so preventing access to the supporting structure and its bolts. The only accessible part of the array is then the upper glass side of the PV modules and access for maintenance is via a door in the wall.

Mounting panels on high poles is another common solution, giving more flexibility to add or remove panels as required compared to a fixed wall. Beyond these passive physical deterrents, more sophisticated alarm systems can be put in place to actively alert the appropriate staff or authorities to the presence of burglars.

Connecting wires to each panel in an array to form simple electrical loops is one solution used in both remote and urban installations. When the cables are cut during a robbery, the current in the loops drops to zero. This change can be used to trip an alarm or trigger a message via a mobile transmitter, so giving the signal for security intervention by police or others.

Many vendors in different industries use this type of technology, but GridLock Solar Security has developed its own solar-specific packaged solution. This can manage five separate cable loops, meaning that each unit can protect from 50 to 100 kW of solar modules and a security lockout key allows only authorised personnel to disable and access the alarm system while a tamper-resistant access panel protects the control system.

Auxiliary control relays allow for the operation of external devices such as cameras, video and additional lighting, and a backup battery ensures that the system will operate even if grid power is absent. Using a 12 V supply is an option, as is using a PV power source; the vendor can supply a fitting kit that includes a PV module, charge controller, battery enclosure and pole mount.

California-based Tigo Energy has built security functions into its solar system management software that can send alerts to solar system owners when a panel is disconnected. A chip embedded in the panel communicates wirelessly with a central monitoring unit. If this communication is interrupted, the panel is automatically deactivated and the system sends out alerts. The deactivated panel cannot be brought online in another location without a special security code.

Another solution is to deploy an infra-red security barrier around the installation. This again can trigger alarms, lights or a mobile transmitter - and has the advantage of tripping before the thieves start to dismantle the modules. A disadvantage is that stray animals or windblown debris can cause false alarms, so some sort of physical barrier outside the infra-red detectors is also required.

Security off the Grid

Off-grid installations in distant areas of undeveloped countries bring their own security challenges.