Hydro

Hydro electricity is created by moving water through turbines, which in turn drive generators to make electricity. Electricity can be generated by ‘run of river’ schemes, or schemes with significant water storage in a lake. Both typically require dams.

Hydro lakes and dams perform two tasks. They store water to allow generation even when it hasn’t rained for some time, and they allow the water to be dropped from the dam, through pipes called penstocks, to the turbines. The further the water falls, the faster it moves and the greater the amount of electricity generated.

Hydro electricity does not produce greenhouse gasses, aside from those created during the construction phase. Although hydro electricity can be generated for as long as rain keeps falling, the hydro lakes do slowly fill up with silt and may require dredging over time.

Hydro electricity in New Zealand

Unlike other forms of renewable energy, hydro electricity is already a well established technology and a major contributor to energy supplies both in New Zealand and overseas. New Zealand has a range of large and small hydro schemes. Large hydro power schemes generate over 60 per cent of the national electricity supply.