| Title | Future Geothermal Generation Stack Factors Influencing New Geothermal Projects in NZ to 2060 |
|---|---|
| Authors | J. Lawless, B. van Campen, J. Randle |
| Year | 2020 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Geothermal, generation, New Zealand, 2060, GHG |
| Abstract | This paper is based on a review that was commissioned by the Ministry for Business, Innovation and Employment (MBIE) in consultation with Transpower, with the objective of estimating the possible timing and cost of future geothermal projects in New Zealand over a 40-year horizon. Access to resources is likely to constrain the pace of development as well as project cost and electricity price. Regulatory and consenting difficulties may lead to delays for future projects. It is not expected that new technology will greatly reduce the cost of future geothermal generation nor significantly extend the geographical spread of its coverage to many lower-temperature resources. Thus, future large-scale development is likely to continue to be within the Taupō Volcanic Zone and at Ngāwhā in Northland. Geothermal generation can run in a load-following manner, but the most economic use of geothermal generation will remain as base load because of the high fixed cost associated with the resource development. Previous studies in New Zealand have over-stated the greenhouse gas (GHG) emissions of existing and future geothermal plants. More specific figures are given based on actual recent data for developed fields, as well as revised estimates for greenfields. The present MW-weighted average emissions intensity for existing geothermal projects is 76 gCO2eq/kWh (2018), which has been steadily declining (from 91g CO2eq/kWh in 2015). Greater future direct use of geothermal energy is generally expected to be complementary with rather than competitive to electricity generation or to be based on lower-temperature resources. Scaling factors based on enthalpy and project size have been applied to the power plant portion of the project cost. On this basis capital costs range from 4,734 to 9,767 NZD/kW with a weighted average of 5,782 NZD/kW. The total estimated available future geothermal generation by 2060 is 1,035 MW. This total is slightly higher than previously presented (MBIE 2016), but it is likely that many projects will be commissioned later than previously assumed. |