Christchurch, Dorset - Roz Drinkwater is living proof that alternative energy is both workable and sustainable: the solar panels on her home supply the power for her plug-in hybrid car.
The English mother of two doesn't spend a cent on the electricity she uses during the day, which means she can use that power at night (when it's cheaper!) to charge the battery of her Mitsubishi Outlander PHEV and drive without having to pay for petrol.
The family-sized SUV uses both electric and petrol power; the plug-in Outlander can travel substantially further on battery power than conventional hybrid vehicles - as much as 50km - which is enough to cover Drinkwater's daily driving, whether it's the school run, weekly shopping or visiting her mother.
"There's plenty of battery power to do everything I need to do. I just stick it on charge when I get home and I never need to go to a petrol station."
Want proof? Drinkwater bought the Outlander new in July 2014 and has filled its petrol tank only once since then, to allow for the occasional longer journey.
"I'm literally running it for free," said Drinkwater, who has an 11-year-old son and 15-year-old daughter. “There's no road tax on hybrids and I'm not paying for charging it!"