In a country that has long suffered from electricity shortages, many North Koreans are taking power into their hands by installing cheap household solar panels to charge mobile phones and light up their homes.
Apartment blocks in Pyongyang and other cities are increasingly adorned with the panels, hung from balconies and windows, according to recent visitors to the isolated country and photographs obtained by Reuters.
"There must be at least a threefold increase in solar panels compared to last year,'' Simon Cockerell, who visits North Korea regularly as general manager of Beijing-based Koryo Tours, told Reuters from Pyongyang. "Some are domestically made, so that may have driven prices down.''
The soaring sales of the panels reflect rising demand for electricity in North Korea as incomes rise and people buy electronic goods like mobile phones and media players that need regular charging. North Korea, one of the poorest countries in the world, is home to 2.5 million mobile phone users, about 10 percent of the population.
Once reserved for Workers' Party cadres, solar panels and voltage stabilizers are now sold openly both in markets and in the hardware sections of Pyongyang department stores, where small 20-watt panels cost just under 350,000 won ($44 at the widely used black market exchange rate, where a dollar is worth about 8,000 won, instead of the official 96 won).
Obtaining accurate data from North Korea is difficult, but roughly 10 percent to 15 percent of urban apartments in a series of recent photographs in North Korean cities obtained by Reuters appeared to have small solar panels attached to windows or balconies.
Private solar panels are not illegal in authoritarian North Korea, where in recent years the government has tacitly allowed greater economic freedoms. However, some local authorities may demand a bribe for permission to install them, a defector said.
Electricity supply in North Korea is prioritized for factories or areas of political importance, but those with money or connections are often able to tap those lines illegally.
The country could be generating about 33 terawatt-hours of electricity a year, or just 7 percent of what South Korea generates, according to Tristan Webb, a former British Foreign Office analyst who visited North Korean power plants in 2013.