Guy Martin visits the most important place in the entire national grid - the central control room - where electricity is bought, sold and routed every single second of the day. Temporarily tasked with the challenging job of keeping the country's lights on, Guy spends thousands of pounds in just a few minutes balancing the electricity supply-and-demand market, before his attention turns to the rise of renewable energy. He works with the army, who are pioneering a new solar-powered workshop, before embarking on the gruelling training required to become an off-shore wind farm technician.