Business View Oceania | September 2020

54 BUSINESS VIEW OCEANIA SEPTEMBER 2020 Energy Supply Geothermal energy contributes 18% (7,660 GWh) to NZ’s annual electricity supply; this exceeds the contributions of wind and solar PV combined (Figure 1). Annual industry income from the wholesale electricity sales recently surged to NZ $539 million due to recent rises in the wholesale prices. High-temperature systems also provide over 5,600 TJs (heat) per year to industrial processes, mainly pasteurisation, drying and evaporating water for the dairy and forest industries. Low- temperature systems supply roughly 8,000 TJs (heat) to residences and commercial customers, and heat pumps now supply another 400 TJs for space heating and cooling. On a primary energy basis (i.e. before energy conversion losses), geothermal is the largest indigenous energy source in New Zealand, exceeding oil and gas as well as coal. Figure 1: NZ Quarterly Generation by Fuel Geothermal Resources New Zealand resides on an active plate boundary and contains 129 conductive and convective thermal systems resulting from high crustal heat flows. The 15 high-temperature convection systems in the North Island are thought to result from bodies of magma ponding in the upper 10 km of the crust. Elsewhere, the deep circulation