Thieves are increasingly raiding solar power stations across Japan for copper transmission wiring as prices for the metal have surged globally.

Local governments are planning ordinances to regulate trade in the metal, but they are seeking nationwide legal measures to discourage the thefts.

One solar power farm in Ichikawa, Chiba Prefecture, was hit by copper thieves three times in April alone, suffering an estimated loss of 33 million yen ($213,000).

Police said the perpetrators severed cables extending a total of 10 kilometers, discarded the sheaths and absconded with only the copper wires.

The solar plant generates enough electricity to supply 2,400 households on land equivalent to two Tokyo Domes, the plant’s management company said.

After the first theft came to light, the operator and a security company discussed preventive measures.

But before they could take action, thieves broke fences and stole copper cables at the site on two more occasions.

Copper thieves strike solar plants mainly at night when the electric current is barely flowing and the removal of wires is more likely to go unnoticed.

Cutting cable wires alone does not trigger an alarm. Operators notice irregularities only after checking the power output.

In many cases, the theft group splits up the roles of the members or changes its lineup, according to a police source.

The management company said copper thieves struck four times over five years at another solar power farm it manages in Inashiki, Ibaraki Prefecture. There were also a series of thefts earlier this year.

The cost for repairing and replacing the cable wires was covered by insurance. But the deductible cost for the insurance has increased because of the thefts.

The management company has installed security sensors and is considering hiring guards to patrol the facility, but these measures will be an additional financial burden.

“An increasing security cost is a big headache for us, but we have to find a way to keep thefts from recurring,” a company official said.

The Japan Photovoltaic Energy Association, an industry group, said stolen cables at solar power facilities accounted for 50-60 percent of all thefts involving metals.

“Damage from thefts appears to have nearly doubled in recent years due to the sharp spike in copper prices,” an association official said.

Statistics by the National Police Agency showed 16,276 cases of metal thefts in 2023, up 5,908 from the preceding year.

Chiba prefectural police said more scrap metal dealers have emerged across Japan to buy metal cables--even stolen ones--as metal prices have risen in tandem with inflation.

Demand is so great that wire thieves can easily find buyers, according to a police official.

In March, Gunma prefectural police exposed a metal dealer who was suspected of knowingly bought stolen cables from a group of thieves. Police believe the dealer likely resold the stolen cables overseas.

Prefectures in the greater Tokyo area have had the most metal wire thefts, with the annual number reaching four digits each.

Ibaraki led the nation in 2023 for the fourth straight year, followed by Chiba, where thefts doubled from the previous year, and then Tochigi, Gunma and Saitama.

In Chiba Prefecture, more than 1,000 theft cases involved cables from solar power facilities,
the most among the stolen items in the prefecture.

Local governments are trying to set ordinances to regulate metal buyers.

In April, Chiba prefectural police revealed a draft ordinance that would designate solar power cables and steel grates that cover roadside ditches as “specific metals.” Dealers trading in specific metals would be required to obtain a commercial license from the Chiba Prefectural Public Safety Commission.

The proposed ordinance would also require confirmation of the names and addresses of sellers and buyers during the transactions, and stipulate on-site inspections, business suspension orders and punitive clauses.

Ibaraki Prefecture is preparing to revise an ordinance on scrap metal businesses to require them to confirm the identifications of sellers and preserve copies of such IDs.

But these rules may have only a limited effect in preventing thefts because the ordinances would not apply if the stolen items are taken across prefectural borders.

A senior official with Chiba prefectural police called on the Diet to enact a law that would allow authorities to tackle cable thefts on a national level.

(This article was written by Jun Sugie and Daichi Itakura.)