Prepared for Energy Efficiency and Conservation Authority June 2007 Assessment of Possible Renewable Energy Targets – Direct Use: Geothermal East Harbour By East Harbour Management Services and GNS Science GNS Science East Harbour Management Services Wairakei Research Centre P O Box 11 595 WELLINGTON Private Bag 2000, TAUPO Tel: 64 4 385 3398 Tel: 07 374 8211 Fax: 64 4 385 3397 Fax: 07 374 8199 www.eastharbour.co.nz www.gnsscience.cri.nz Renewable Energy Target – Geothermal Direct Use Contents EXECUTIVE SUMMARY ................................................................................................................................................... 4 1 INTRODUCTION ...................................................................................................................................................... 13 2 GEOTHERMAL RESOURCES .............................................................................................................................. 13 2.1 RESOURCE ASSESSMENT .................................................................................................................................. 14 2.2 EXISTING LAND USE IN THE VICINITY OF GEOTHERMAL RESOURCES .............................................................. 24 2.3 ISSUES ARISING FROM INTENSITY OF ENERGY USE ......................................................................................... 25 2.4 SUMMARY ........................................................................................................................................................... 26 3 TECHNOLOGIES FOR DIRECT USE OF GEOTHERMAL (INCLUDING HEAT PUMPS) ......................... 27 3.1 ACCESSING GEOTHERMAL HEAT ....................................................................................................................... 27 3.2 DISPOSING OF WASTE FLUIDS........................................................................................................................... 29 3.3 DRILLING AND WELLS ........................................................................................................................................ 30 3.4 HEAT EXCHANGERS ........................................................................................................................................... 30 3.5 HEAT PUMPS ...................................................................................................................................................... 32 3.6 OTHER SPECIFIC TECHNOLOGIES AND APPLICATIONS ..................................................................................... 34 3.7 SUMMARY ........................................................................................................................................................... 34 4 TRADITIONAL AND POTENTIAL DIRECT USERS OF GEOTHERMAL ENERGY .................................... 36 4.1 HISTORICAL AND CURRENT USE AND USERS ................................................................................................... 36 4.2 A BASELINE FOR GEOTHERMAL DIRECT HEAT USE.......................................................................................... 40 4.3 POTENTIAL DIRECT USERS OF GEOTHERMAL HEAT ......................................................................................... 41 4.4 SECTOR CONSIDERATIONS ................................................................................................................................ 43 4.5 SUMMARY ........................................................................................................................................................... 48 5 QUALITATIVE REVIEW OF KEY DRIVERS....................................................................................................... 50 5.1 KEY DRIVERS FROM A USER’S PERSPECTIVE ................................................................................................... 50 5.2 KEY DRIVERS FROM A DEVELOPER’S PERSPECTIVE ........................................................................................ 54 5.3 BREAKING THE DISCONNECTION BETWEEN USERS AND DEVELOPERS ............................................................ 59 5.4 SUMMARY ........................................................................................................................................................... 60 6 DIRECT COST COMPARISONS FOR SOME SPECIFIC TECHNOLOGIES AND APPLICATIONS ....... 62 6.1 INDUSTRIAL SUPPLIES OF GEOTHERMAL HEAT ................................................................................................. 62 6.2 TRADITIONAL DIRECT USE APPLICATIONS AT THE SMALLER SCALE ................................................................ 63 6.3 GEOTHERMAL HEAT PUMPS .............................................................................................................................. 64 6.4 SUMMARY ........................................................................................................................................................... 65 7 A VIEW OF POTENTIAL UPTAKE OF DIRECT HEAT USE ........................................................................... 67 7.1 MINISTRY OF ECONOMIC DEVELOPMENT BASELINE PROJECTION ................................................................... 67 7.2 RESOURCE AND USER CONSIDERATIONS ......................................................................................................... 67 7.3 THREE SCENARIOS ............................................................................................................................................ 69 7.4 A QUANTITATIVE VIEW ON UPTAKE ................................................................................................................... 71 7.5 POTENTIAL WAYS OF ASSISTING TARGETS ...................................................................................................... 74 7.6 MEASUREMENT OF TARGETS ............................................................................................................................. 75 7.7 FINAL RECOMMENDATIONS ................................................................................................................................ 75 8 REFERENCES ......................................................................................................................................................... 77 APPENDIX 1. ABANDONED HYDROCARBON WELLS......................................................................................... 79 APPENDIX 2. CALCULATION OF AVAILABLE STORED HEAT IN DEEP WELLS IN SEDIMENTARY BASINS AND IGNEOUS TERRAIN FOR DIRECT USE ............................................................................................ 84 APPENDIX 3. CALCULATION OF AVAILABLE STORED HEAT IN SHALLOW LEVELS AVAILABLE TO HEAT PUMPS ................................................................................................................................................................... 85 APPENDIX 4: GEOTHERMAL RESOURCES AND THEIR USE ............................................................................. 87 GNS Science Page 2 East Harbour Management Services Renewable Energy Target – Geothermal Direct Use APPENDIX 5. HEAT SUPPLY CURVES ................................................................................................................... 103 APPENDIX 6. SPECIFIC DATA USED IN APPORTIONMENT BETWEEN REGIONS .................................... 107 APPENDIX 7. SPECIFIC RESULTS OF MODELLING BY REGION AND BY SECTOR ................................. 109 APPENDIX 8. REPLACING OR SUPPLEMENTING EXISTING HEAT DEMAND VERSUS ENCOURAGING NEW DEMAND FOR HEAT .......................................................................................................................................... 113 Disclaimer While every attempt has been made to ensure the accuracy of the material in this report, East Harbour Management Services Ltd and GNS Science make no warranty as to the accuracy, completeness or usefulness for any particular purpose of the material in this report; and they accept no liability for errors of fact or opinion in this report, whether or not due to negligence on the part of any party. GNS Science Page 3 East Harbour Management Services Renewable Energy Target – Geothermal Direct Use Executive Summary Background The Energy Efficiency and Conservation Authority (EECA) sought assistance in furthering its understanding of possible renewable energy targets for direct use of energy in particular for the geothermal sector. This is part of the process of informing the final New Zealand Energy Efficiency and Conservation Strategy in order to state targets to achieve policies and objectives that are measurable, reasonable, practical and appropriate. As such, the scenario development in this report is tied back in to the Ministry of Economic Development’s “New Zealand’s Energy Outlook to 2030” (Energy Outlook). Report Outline Current assessed usage of geothermal energy for direct use applications is around 10.7PJ/year. The report provides a review of the likely types of future uses and users by sector and indicates that there is likely to be a strong future for heat pump applications despite current low usage in New Zealand, there is a strong correlation of geothermal resources with forestry, and encouragement for shallow wells and downhole heat exchangers through Regional Policy Statements could encourage greater uptake. Various drivers are discussed from both the users perspective and developers perspective with a view