| Title | Flexible geothermal application within the New Zealand electricity market |
|---|---|
| Authors | A. Marsh, M. Aljubran, I. Konstantopoulos, M. Newton |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Flexible geothermal, intermittent, batteries, hydrogen, methanol, SAF |
| Abstract | Geothermal power production plays an important role as baseload in the New Zealand electricity market, supplying 18% of the total electricity production in the last calendar year. The proportion of gas peaker supply has decreased from 15% to 10%, while wind and solar have grown from 5% to 7% over the last five years and are set to grow rapidly over the coming decade. The change in energy mix and a projected growth in demand pose significant challenges for system management. New Zealand is considering options to cover the risks posed by increasing variability of supply plus a shortfall of hydro storage during drier-than-average years. This is called the New Zealand Battery Project and preliminary studies have identified biomass, flexible geothermal energy, and hydrogen as alternatives to a large-scale pumped hydro scheme. Collectively, these alternatives have the most potential to store enough energy to help solve the “dry-year problem”. In geothermal systems with under utilised generating capacity due to resource depletion, it may be possible to redistribute electricity production across the year to when it is most needed. This lets the resource recharge when electricity demand is low, thus facilitating boosted output for limited durations when demand is high. However, this does not apply in New Zealand where geothermal resources are rarely the limiting factor and the underlying economics bias towards full utilisation of the capital-intensive plants and wells. Consequently, all geothermal in New Zealand has so far run as baseload. This study models, using recent electricity market price data as a baseline, what conditions need to be present and to what extent it may be advantageous to vary output from geothermal power plants in the New Zealand context. Additionally, we consider the role of batteries, thermal energy storage and co-production of fuels, chemicals, and other value-adding products at geothermal sites: can they support flexible geothermal by providing an alternative utilisation path for renewable electricity while market prices are low? |