Batteries and the harnessing of solar energy have been around in one form or another for centuries, but only in 2016 did these technologies, arguably, become world-changing. This was when Elon Musk, before his controversial political career began, opened the first “gigafactory” in Nevada, producing advanced battery technology, electric motors and solar cells on a massive scale – giga meaning 1 billion, or “giant”.

You could fairly describe the amount of renewable energy – in the form of solar, wind and hydropower – available to extract on Earth as gigantic too. In just a few days, the sun delivers more energy to our planet than is in all the reserves of fossil fuels we have ever discovered.

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Reliably harnessing that power is another matter. Even though the photovoltaic effect, where light energy produces electrical current, was discovered in 1839 by Edmond Becquerel, and the first practical solar panels were made in the 1950s, it wasn’t until the 2010s that technology had advanced enough for solar electricity to become competitive with fossil fuels. Parallel to this, the invention of lithium-ion batteries in the 1980s provided somewhere to store this energy.

The gigafactory certainly helped advance these solar cell and battery technologies too. Yet its impact was less down to any specific invention and more in how it brought all the parts of electric car production under one roof. This supply-chain integration reflects what Henry Ford did a century earlier – just populating the planet with Teslas instead of fossil fuel-powered Model Ts. “It gave us dispatchable solar thanks to batteries, and it gave us electric vehicles,” says Dave Jones at Ember, an energy think tank in the UK.

The economies of scale unleashed by the gigafactory had knock-on effects beyond electric cars, too. “That battery unlocks all kinds of new things: the phone, the computer and the ability to have relatively low-cost, high amounts of energy you carry around,” says Sara Hastings-Simon at the University of Calgary in Canada.

In fact, in recent years, the cost of these technologies has plummeted so much that many experts say electrification of our energy systems is inevitable. In California and Australia, solar energy is so plentiful that grid operators give it to people for free. Commensurate with that, batteries are getting closer to storing energy as densely as fossil fuels do, so we can start to build solar airplanes, ships and long-haul trucks – and completely detach our transport and energy systems from their centuries-long dependence on fossil fuels.