Harnessing energy from water
In 1903, the rapid growth in demand for electricity could be foreseen and the government commissioned a series of investigations and reports.
The development of hydropower in New Zealand was initially fostered through a report on national hydropower resources by the Superintending Engineer of the Public Works Department. The report was based on field investigations and provided a basis for systematic and prioritised hydropower development to meet national needs.
Because it was directed to finding cheap sources of hydro-electricity near known or expected centres of load, it didn’t cover the full potential of the country. As such, some sites were excluded as being outside the foreseeable needs of the country, or the technical competence of the day.
Lake Coleridge was the first major hydro power plant to open and is credited with establishing the country’s commitment to renewable hydro energy. Opened in 1915, it was built to supply electricity to Christchurch and high users of power from the new station included tramways, the freezing works, and the dairies and butter factories. The Christchurch tramway had already been electrified, being fed by power generated in four steam turbines, and the switchover to power from Coleridge led to a saving of £2,000 per year in electricity costs.
By 1918, it was widely recognised that water provided the most economical power source for large scale development. The government investigated large schemes in the North Island with the intention of creating an island-wide system and this became the foundation of a fully integrated electricity system based on hydro power.
Demand and supply
In the second half of the 1920s demand for supply dramatically increased, driven by the availability of electricity and electrical appliances. By the start of WWII demand had outstripped supply and the need to generate more electricity was urgent.
An investigation carried out by the Chief Electrical Engineer in 1945 estimated that allowing for a natural rate of growth, the limits of hydro-electric capacity in the North Island would be reached between 1959 and 1962. It was around this time that investigatory work into thermal power also began and, in 1948, the Commissioner of Works went to Italy to study the geothermal scheme at Lardarello.
While the commitment to hydro power existed, at one stage in the 1950s, more money was being spent on power development from steam and coal than on hydro projects. In 1963 the geothermal Wairakei Power Station was delivering more energy than any other station in the North Island.
By the early 1960s most North Island hydro sites had been developed and the opening of the HDVC Inter-Island link in 1965 helped increase hydro capacity in the South Island.
The late 1960s saw the introduction of natural gas from Kapuni and the possibility of exploitation of the Maui gas field.
Following the 1970s global energy crisis which saw oil prices increase exponentially, the Government embarked on the ‘Think Big’ growth strategy. This aimed to make New Zealand at least 60% self-sufficient in energy and to attract foreign investment in energy-intensive industries. The strategy called for more hydro development, intensified oil exploration, and the use of recently-discovered natural gas reserves, either directly or to manufacture synthetic petrol.
Concurrently, a new debate was emerging about how to provide ample electricity without unduly harming the environment. Environmental campaigners were critical of the effect big dams had on the landscape and wildlife and the last major hydro project to be completed was the Clyde Dam.
Now, as Aotearoa transitions towards a 100% renewable electricity future, WSP experts continue the tradition of powering the country. This includes helping to establish the early wind farms, exploration on the potential of hydrogen and ensuring the grid can withstand the impact of increased demand as companies move to electric vehicle fleets.