The world runs on rock · Story 10 of 12

The Grid copper, the metal of electricity

Every power line, transformer, motor and phone charger carries its current through copper. It is so ordinary that the United States only added it to its list of critical minerals in November 2025, along with silver.

Scroll to open a transformer

False-colour satellite image of the Chuquicamata open-pit copper mine: a vast grey terraced pit and pale tailings in the Atacama Desert — Chuquicamata, Chile, from the ASTER instrument on NASA's Terra satellite, 2007. NASA/METI/AIST/Japan Space Systems and the U.S./Japan ASTER Science Team (public domain).

Where it starts

The biggest hole

Chuquicamata, in Chile's Atacama Desert, is the largest open-pit copper mine in the world by volume dug, worked since before the Spanish arrived.¹ Chile mined 23% of the world's copper in 2025.²

Take it apart

Two coils and a core

A transformer steps voltage up for long-distance lines and down again for streets and homes. Inside the steel tank are copper windings wrapped around a core, all soaked in insulating oil that carries the heat out to the cooling fins.

Tank and radiators steel
Bushings porcelain, to bring the lines through the lid
Windings copper: low voltage inside, high voltage outside
Core thin sheets of grain-oriented silicon steel

The core

Steel with 3% silicon

The core is stacked from sheets of grain-oriented electrical steel, iron with up to about 3.2% silicon, cold-rolled so its crystals line up with the field. Thin sheets and the silicon cut the energy lost as heat.³

The backlog

Two and a half years to wait

In Wood Mackenzie's mid-2025 survey, a large US power transformer took about 128 weeks to deliver, and prices had risen 77% since 2019. It estimated US supply fell about 30% short of demand in 2025.⁴

Inside the wire

A sea of electrons

Copper atoms pack into a face-centred cubic crystal, and each lets one outer electron go. Those free electrons move through the whole metal, which is why copper conducts so well; among common metals only silver does better.⁵

Switch on

Apply a voltage and the whole sea drifts one way. In the US, 42% of copper goes into buildings, much of it wiring, and 23% into electrical and electronic products.²

CuAgAlFeSi

More of it

An electric car uses about 53 kg of copper against about 22 kg in a petrol car, in the IEA's figures.⁶ The COMEX copper price averaged a record $4.80 a pound in 2025.²

Follow the supply

1 · Mining

Chile 23%, DR Congo 14% and Peru 12% of world mine output in 2025.²

Satellite image of the Escondida copper mine: grey pits and pale leach pads in brown desert hills

Satellite image of the Chuquicamata open pit in the Atacama Desert

Escondida (left), which also yields gold and silver, and Chuquicamata, from NASA's Terra satellite (public domain).

2 · Refining

Most of that ore is shipped as concentrate. China refined about 14 million of the world's 29 million tonnes of copper in 2025, 48%, while mining under 8%.²

3 · Silver

The best conductor of all is too dear for wires, but every solar cell carries a fine silver paste. Photovoltaics took 15% of US silver use in 2025. Silver averaged $38 an ounce that year and hit $53.60 on 13 November.⁷ Mexico mined 24% of the world's silver.

Satellite view of the Ivanpah solar plant: three circular fields of mirrors in the Mojave Desert

Ivanpah, California, a solar-thermal plant whose mirrors focus sunlight on towers, from NASA's Terra satellite, 2013 (public domain).

The lights of coastal cities around the western Mediterranean at night, seen from orbit, with stars above — The Mediterranean at night from the International Space Station, 262 miles above Barcelona, September 2024. NASA (public domain).

Every light

Copper all the way

From Spain to Libya, every light here reaches its lamp through copper. An offshore wind farm needs thirteen times the minerals of a gas plant of the same size, in the IEA's estimate, much of it copper for cables.⁶

Why "critical"

Ordinary, and suddenly short

Copper is mined in dozens of countries, but refining is concentrated, and the equipment that carries it is backed up for years. The 2025 US critical minerals list added copper, silver, silicon and rhenium.²

CuCopperChile 23% AgSilverMexico 24% SiSiliconelectrical steel, solar FeIrontransformer cores AlAluminiumoverhead lines ZnZincgalvanised pylons NdRare earthswind generators LiLithiumgrid batteries

Next in the series: The Screen, the rare elements in a phone. Before this: The Engine, The Body, The Shield, The Signal, The Rocket, The Magnet, The Battery, The Mind and The Chip.

Sources

Shares of world output are from USGS Mineral Commodity Summaries 2026 via our minerals data; refined copper figures are from the USGS copper chapter. The 3D models are illustrations, not engineering drawings or any one product. Photos: NASA, public domain.