Is your electric car as eco-friendly as you thought?

Lithium-ion batteries are only able to store energy at full capacity for up to around four hours, meaning even countries sourcing significant amounts of solar and wind power during the day struggle to keep it on tap for nighttime charging.

Electric vehicles (EVs) are a powerful weapon in the world's battle to beat global warming, yet their impact varies hugely from nation-to-nation and in some places they pollute more than gasoline models, data analysis shows.