The future of the electric grid in a carbon-free future

Transpower is preparing for major changes in the energy sector, from growing demand for renewable sources, to more households going off grid. Its latest report on the country's energy future - Te Mauri Hiko - predicts a doubling of electricity demand in the next 30 years, much of which will come from industry demands and from converting cars and trucks to being powered by electricity. Transpower's chief executive Alison Andrew, talks to Kathryn Ryan.