What Europe pays for solar panels from China

Reading a customs unit value

Every consignment entering the European Union is declared to customs with a commodity code, a value in euros and a weight in kilograms. Eurostat publishes those declarations monthly as COMEXT, and this view computes from them: the monthly value of what arrived from China under the codes for solar modules, unassembled cells and lithium-ion batteries, and the unit value, which is the declared value divided by the declared weight.

A unit value answers what Europe paid per kilogram of imported goods. A price index answers something stricter: what the same product costs now against what it cost before. The two drift apart whenever the mix of goods inside a commodity code changes, and in solar it changes constantly, as module efficiency rises, glass gets thinner, frames change and buyers move between product tiers. A falling unit value is consistent with cheaper modules, with lighter modules of the same price, and with a shift in what is being bought, and customs data alone cannot tell the three apart.

Modules are finished panels, ready to mount; cells are the wafers before assembly. Europe imports almost all of the first and little of the second, which is consistent with an assembly industry that largely moved away. Batteries appear here as well because they cross the border under the same statistics, and their monthly value has grown into a different order of magnitude from solar.

Customs statistics publish with a lag of a few months and are revised afterwards, so the most recent months on the chart are the least settled. A month of imports is a month of arrivals, which may have been ordered a quarter earlier and may sit in a warehouse for another quarter before anything is installed. The line describes trade, and installation follows it at its own pace.