The engineers' plan uses a huge array of mirrors to focus the sun's power like a giant magnifying glass and use it to split water into oxygen and hydrogen.
Sunlight would be focused at a point atop a central tower that could be hundreds of metres tall, generating temperatures up to 1350 °C. That would heat a reactor containing metal oxides, causing them to release oxygen atoms and leaving them hungry to replace that lost oxygen. Steam – also generated by the sun's heat – would then be pumped through the reactor. Oxygen from the water molecules bonds with the metal oxides, leaving behind precious hydrogen gas.
Some other water-splitting methods require alternating temperatures, making them less efficient.