DOCSLIB.ORG

For Ohaaki Power Station

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
For Ohaaki Power Station 55 Roc. 1 New Workshop 1989 THE CIRCULATING WATER AND GAS EXTRACTION SYSTEMS FOR OHAAKI POWER STATION D. P. Brown, N. R. Hall New Zealand Ltd, P 0 Box 668, Wellington 0PTIMISATION The paper provides discussion on two of the The second major influence on the systems key systems installed at Ohaaki Power Station: the being considered is the optimisation process circulating water and gas extraction systems. The required to ensure that minimum costs and maximum authors briefly consider the constraints placed on revenue are achieved. these systems by the environment, operating re- quirements and the optimisation process before The circulating water and gas extraction continuing to discuss the design decisions that led are not only capital and energy intensive to the final design. The systems, in terms of both in themselves but also have a significant effect on equipment and operation, are also described. the performance of the turbo-generator and hence power station efficiency and output. Optimisation procedures are therefore necessary to determine the JNTRODUCTION best solution based on the large number of often apparently conflicting variables. The development of Ohaaki during the a time of increasing concern as to the effects of The optimisation process for Ohaaki considered power developments on the environment, resulted in the turbine in association with the key components steamfield and power station systems designed with of the two systems. Traditionally such processes the environment in mind. would consider a single design point based on the limited meteorological data available; the key This paper addresses two of the power station parameters for the process being wet and dry' bulb systems that have been influenced by environmental temperatures and atmospheric pressure. In the considerations - the circulating water (CW) system, Ohaaki case, four years of on-site climate data was which provides cooling water for the intermediate available and therefore a computer programme was pressure (IP) turbo-generator condensers, and the developed to make use of this data and carry out gas extraction system, which removes the optimisation over the full range of anticipated able gases from the condenser. The approach used to conditions. meet the environmental constraints differs between the two systems - the system by either avoiding The complex model, previously described by discharge or using reinjection, and the gas ex- Pearce combined the effects of capital and traction system by encouraging the widest possible operating costs of the major plant items (turbines, dispersal of the discharge. condensers, CW pumps, gas exhausters, etc), their predicted performance data and predicted operating The paper also provides a brief insight into regime and the climatic data to determine the net the key design decisions and a description of the station value, this value being the difference systems and plant installed. between the capitalised value of the power gener- ated and the total cost of the plant. OPERATIONAL REO By maximising the net station value, the optimum key parameters of CW flow, cooling tower Before considering the design decisions made, design point, condenser pressure range, etc. can be it is necessary to review the other influences on determined. over a range of conditions them. The first of these is the operational re- results in plant sizing for the optimum. and not quirements imposed by both the geothermal resource necessarily the maximum duty point, the effects of and the electricity demand. The impracticality of .which will be discussed later. using a geothermal resource to supply vastly varying quantities of steam and the requirement for cheap continuous power to supplant more expensive generation dictated that Ohaaki would be a base load station. DESIGN DECISIONS Ohaaki is also relatively close to Wairakei A number of design decisions were made at a Power Station and the economics of operating it as very early stage based on anticipated environmental a stand alone power station were unattractive when considerations (Canvin (1989)). Others flowed from compared with making Ohaaki a satellite operation the optimisation process discussed above. from Wairakei. A simple step from the concept of decisions had ultimately to be made on a sound satellite operation was that of unmanned operation, engineering basis with due weight to operational a philosophy which had a significant effect on the factors and the availability of proven hardware. design of the systems. Some of these aspects are discussed in more detail by Tokeley (1989). 56 D P Brown, N Hall a) Plant Operation CIRCULATING WATER SYSTEM As previously discussed, Ohaaki was required This section provides a description of the to be a satellite of Wairakei. This led to the various components of the CW system. ,Figures 1 2 further decision to make it unmanned. indicate the extent of the system. A number of aspects are however common to all or most of the b) CW System components. Concern for the environment led to a decision a) Materials not to apply for water rights to obtain cooling water from the Waikato River and therefore a closed The nature of the fluids present in various parts of the CW system, due to the H and CO cooling system with cooling was adopted. 2 dissolved in the condensate lead to a Condenser Type selection of materials to ensure long-life. The use of direct contact condensers, almost Materials actually used in the system fall standard practice in the geothermal industry, was into two categories; metallic and non metallic. All an early decision. The choice of condenser type, metallic components in contact with the circulating between barometric leg and pumped extraction types, water are manufactured from 316 stainless steel. was eventually decided in favour of the former This includes the condensers, which for economic primarily due to its inherent safety flooding, reasons are fabricated from clad stainless steel particularly important for an unmanned station. plate, being of 316 backed by of carbon steel for structural strength. d) Cooling Tower Type A variety of non metallic materials are used, The economics did not produce a clear advan- the major ones being fibre reinforced plastic (FRP) tage between natural draft or mechanical draft and high density polyethylene (HDPE). is used cooling towers. The decision in favour of the for the barometric legs, the buried culvert and CW single natural draft tower installed was therefore pump discharge pipeline and HDPE for the cooling based largely on environmental considerations. The tower pack and the smaller auxiliary cooling water Waikato River valley at Broadlands is subject to supply lines. fogs which would be made worse by low level dis- charge from mechanical draft cooling towers. Additionally the natural draft tower could be used to aid non-condensable gas dispersion. The power station will operate unattended and therefore extra safeguards have to be built into e) Gas Extraction the system to ensure that it reverts to a safe condition in the event of trips etc. key factor The choice between rotary gas exhausters and in determining the required extent of these safe- steam ejectors was made in favour of the former on guards was the power station location at the top of the basis of pure economics when relatively high a hill overlooking a number of environmentally percentages of gas have to be removed. sensitive areas along the Waikato River. The possibility of a large scale overflow into the Waikato River had to be minimised. FIG.l Simplified CW System Diagram 57 D P Brown, N R Hall This was achieved by two means. Firstly the Water supply to the first three sections of hotwell, as the lowest point in the system, in- the condenser is controlled by the butterfly cludes a substantial overflow chamber which can condenser control valves, with a separately con- collect all the water discharged from the condenser trolled supply used for the gas cooler .section. barometric legs following an emergency trip caused This reflects the findings of the pilot plant work by a major electrical power loss. In the unlikely and will allow for the possibility of some control event that there is insufficient capacity in the of CW chemistry. A second control valve is in- overflow chamber, the excess water will flow over a stalled in parallel to the main ones to be used weir in the hotwell wall into a large bunded whilst they are out of service for maintenance etc. overflow Both the condenser control valves and their Secondly, vital valves have been duplicated isolation valves are fitted with nitrogen powered with a second valve in series and/or provided with pneumatic motors for emergency use. a stored energy system nitrogen gas or hydraulic accumulator) to provide operation in the The barometric leg discharge from the con- event of power failure. denser leaves from below the counter-current section. CONDENSERS. GAS COOLERS AND INTERCOOLERS An intercooler is fitted between stages of each gas exhauster in the gas extraction system. Condenser design is critical to both the power These direct contact heat exchangers are used to output of the power station and the resultant water reduce the gas temperature part way through the gas chemistry in the CW system itself. Poor control of compression cycle of the gas exhausters thereby the CW chemistry may lead to corrosion or slime reducing power requirements and water vapour problems. A pilot plant was used at Ohaaki to carry-over. flow into the intercoolers is investigate the best method of controlling the controlled by butterfly valves and is discharged to of and into the CW within the the hotwell via separate barometric legs. condenser and gas cooler. The results of these pilot studies were made available to the - condenser designers for use in the con- LEVEL CONTROL SYSTEM denser design. The hotwell level control system bypasses CW The condenser itself is divided into four from the CW culvert directly into the hotwell.
Load more

Recommended publications
  • Renewable Energy - Industry Status Report (Year Ending March 2006)
    Prepared for The Energy Efficiency and Conservation Authority Renewable Energy - Industry Status Report (year ending March 2006) By East Harbour Management Services EAST HARBOUR MANAGEMENT SERVICES P O BOX 11 595 WELLINGTON Tel: 64 4 385 3398 Fax: 64 4 385 3397 www.eastharbour.co.nz www.energyinfonz.com June 2006 East Harbour Project # EH243 Field Code Changed - Third Edition This study has been commissioned by the Energy Efficiency and Conservation Authority (EECA). EECA welcome any feedback this report. For further information contact: EECA Phone 04 470 2200 PO Box 388 Wellington New Zealand http://www.eeca.govt.nz/ [email protected] EECA disclaimer: ―It will be noted that the authorship of this document has been attributed to a number of individuals and organisations involved in its production. While all sections have been subject to review and final editing, the opinions expressed remain those of the authors and do not necessarily reflect the views of the Energy Efficiency and Conservation Authority. Recommendations need to be interpreted with care and judgement.‖ Notes: 1. The report focuses on useable energy at source from renewable energy resources, because this is what is pragmatically measurable. Hydro, wave, tidal and wind useable energy is measured as direct output from the electricity generator. Solar primary energy is measured as direct output from the collector. Geothermal primary energy is measured at the well head. Bioenergy is measured as direct output from the heat plant. Solar space heating is not measured. 2. To allow comparison with other studies the following methodologies are followed: Electricity Primary energy for electricity generation (excluding PV) is useable energy at source plus generator losses.
    [Show full text]
  • Pollution of the Aquatic Biosphere by Arsenic and Other Elements in the Taupo Volcanic Zone
    Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author. ~.. University IVlassey Library . & Pacific Collection New Z eaI an d Pollution of the Aquatic Biosphere by Arsenic and other Elements in the Taupo Volcanic Zone A thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biology at Massey University Brett Harvey Robinson 1994 MASSEY UNIVERSITY 11111111111111111111111111111 1095010577 Massey University Library New Zealand & Pacific Collection Abstract An introduction to the Tau po Volcanic Zone and probable sources of polluting elements entering the aquatic environment is followed by a description of collection and treatment of samples used in this study. The construction of a hydride generation apparatus for use with an atomic absorption spectrophotometer for the determination of arsenic and other hydride forming elements is described. Flame emission, flame atomic absorption and inductively coupled plasma emission spectroscopy (I.C.P.-E.S.) were used for the determination of other elements. Determinations of arsenic and other elements were made on some geothermal waters of the area. It was found that these waters contribute large (relative to background levels) amounts of arsenic, boron and alkali metals to the aquatic environment. Some terrestrial vegetation surrounding hot pools at Lake Rotokawa and the Champagne Pool at Waiotapu was found to have high arsenic concentrations. Arsenic determinations made on the waters of the Waikato River and some lakes of the Taupo Volcanic Zone revealed that water from the Waikato River between Lake Aratiatia and Whakamaru as well as Lakes Rotokawa, Rotomahana and Rotoehu was above the World Health Organisation limit for arsenic in drinking water (0.05 µglmL) at the time of sampling.
    [Show full text]
  • Plan Change 3 Snas Summary Of
    RDC - 950566 Plan Change 3 - Significant Natural Areas - Summary of Submissions Consider Joint Submitter Address for Service Support / Wish to be Topic Submitter Name Address for Service (Email) Presentation Decision Sought Reasons # (Postal) Oppose heard (Y/N) (Y/N) Site 659 - 1 1.01 Aislabie, V & B 52 Dudley Road [email protected] S N N Supports not to include their property as SNA The area identified for further protection in your maps predominantly exists across the property boundary at 62 Dudley Mervyn Street Kaharoa m [at 52 Dudley Road] that is already Road. We agree that providing further protection to these types of areas, which are already protected could cause covenanted. confusion in the future. f) Sites with 2 2.01 Bay of Plenty Regional Council [email protected] O Y (Regarding new and expanded SNAs) - Regarding considering of new and expanded SNAs - BOPRC retain concerns about the exclusion of some sites assessed as alternative Toi Moana (BOPRC) Include all sites that meet significance meeting the RPS Appendix F Set 3 criteria and/or provided protection under other means. We consider areas covenanted legal criteria. Ensure completeness of the SNA or protected by other mechanisms should still be added where these sites meet SNA assessment criteria. Generally these protection layer, District Plan schedule and maps. covenants seek to protect indigenous vegetation/ecological values which aligns with the purpose of SNAs. Our main (general concern is occasionally covenants are removed to enable subdivision and development inconsistent with the purpose of points) PC3. Excluding such areas poses a risk that their private protection status may be removed leaving them with no protection under the District Plan.
    [Show full text]
  • Ohaaki West Bank Production Fluid Compositions
    OHAAKI WEST BANK PRODUCTION FLUID COMPOSITIONS Ed MROCZEK1, Sang Goo LEE2, Ruth SMITH2 and Brian CAREY1 1GNS Science, PB 2000, Taupo 2Contact Energy Ltd, PB 2001, Taupo Keywords: Ohaaki, Composition, Chemistry SUMMARY - During 2006 and 2007 Contact Energy undertook a successful well drilling programme to increase the resource capacity and power production from the Ohaaki Geothermal Field with eight new wells drilled on the West Bank. This enabled a doubling of nett generation from about 30 to 60 MWe. A conservative production management approach has been taken seeking to avoid deleterious calcite scaling and drawdown of cooler surficial fluids. Of the eight new wells, two discharge fluid similar in terms of TQZ, ClQZ and SO4QZ, to the fluid initially produced (in 1995) and presently discharging from BR48; that is relatively cool at o o ~260 C and dilute. Three of the remaining six new wells discharge aquifer fluids at TQZ ~290 C which is hotter than any of the presently discharging wells, indeed hotter than wells at the commencement of production in 1988. The last three wells discharge fluid with reservoir TQZ temperatures of ~280oC which was similar to those observed at the commencement of production. That six of the new wells discharge reservoir fluids which have been minimally affected by both dilution as well as boiling as a consequence of previous production is a good outcome for the future generation from Ohaaki. 1 INTRODUCTION The Ohaaki Geothermal Resource, which is bisected on the surface by the Waikato River into the East and West Banks, is located some 27 km north east of Taupo on the Eastern Margin of the Taupo Volcanic Zone (Bibby et al., 1995).
    [Show full text]
  • Resolution of the Environmental Factors Influencing the Development of Ohaaki Power Project P
    Roc. 1 lth New Zealand Geothermal Workshop 1989 RESOLUTION OF THE ENVIRONMENTAL FACTORS INFLUENCING THE DEVELOPMENT OF OHAAKI POWER PROJECT P. A. Canvin DesignPower New Zealand Ltd, Wellington Utilisation of geothermal energy resources Description of the Process posed several environmental problems which were identified during investigations preceding the . Geothermal fluid will be taken from the ground preparation of an Environmental Impact Report. An via approximately 2 5 production wells located in the audit of the Environmental Impact Report was carried two connected steamfields on the east and west banks out by the Commission for the Environment and the of the Waikato River. The geothermal fluid will be recommendations of the audit were accepted and taken fed to five separation plants where steam and water into account during the planning and design of the fractions are separated, with the water being station. returned to the ground via reinjection wells. The steam will be passed to the power station via a Environmental Considerations f\ piping system. Some of the steam will condense during this process due to heat loss from, the pipeline and this will be removed from the pipe l his Environmental requirements for Ohaaki have 1 necessitated features in the design which were not by steam traps discharging to drains leading to the used at Wairakei. Requirements which considerably \.^ river. In the power station, the steam will pass through the turbines, generating electricity, and increased the capital cost of the station were:- t will be finally condensed (Note: HP steam after i) the reinjection of separated geothermal water; passing through the HP turbines is added to the IP ii) the disposal of much larger quantities of steam and passes through the IP turbine for non-condensible gases from the geothermal steam condensing) .
    [Show full text]
  • BEFORE the ENVIRONMENT COURT Decision
    BEFORE THE ENVIRONMENT COURT Decision No. [2011] NZEnvC 380 IN THE MATTER of appeals under Clause 14(1) of Schedule One of the Resource Management Act 1991 (the Act) BETWEEN CARTER HOLT HARVEY LIMITED (ENV-2009-AKL-000132) WAIHOU IRRIGATORS INCORPORATED & UPPER WAIKATO IRRIGATORS SOCIETY INCORPORATED (ENV-2009-AKL-000133) HAMILTON CITY COUNCIL (ENV-2009-AKL-000134) WAIPA DISTRICT COUNCIL (ENV-2009-AKL-000136) WAIKATO DISTRICT COUNCIL (ENV-2009-AKL-000137) WATERCARE SERVICES LIMITED (ENV-2009-AKL-000138) HORTICULTURE NEW ZEALAND (ENV-2009-AKL-000139) RAUKAWA CHARITABLE TRUST (ENV-2009-AKL-000149) TE RUNANGA 0 NGATI TAHU (NGATI WHAOA) (ENV-2009-AKL-000 ISO) WAIKATO-TAINUI TE KAUHANGANUI INCORPORATED (Successor to Waikato Raupatu Trustees Company Limited) (ENV-2009-AKL-000151) TUWHARETOA MAORI TRUST BOARD (ENV-2009-AKL-000153) DEPARTMENT OF CORRECTIONS (ENV-2009-AKL-000055) NEWMONT WAlHI GOLD LIMITED (ENV-2009-AKL-000092) MIGHTY RIVER POWER LIMITED (ENV-2009-AKL-000I07) (ENV-2009-AKL-000I08) (ENV-2009-AKL-000I09) (ENV-2009-AKL-00011O) (ENV-2009-AKL-000III) (ENV-2009-AKL-000112) (ENV-2009-AKL-000 113) (ENV-2009-AKL-000114) (ENV-2009-AKL-000115) (ENV-2009-AKL-000116) (ENV-2009-AKL-000117) (ENV-2009-AKL-000118) SOLID ENERGY NEW ZEALAND LIMITED (ENV-2009-AKL-000119) HAURAKI DISTRICT COUNCIL (ENV-2009-AKL-000120) WAIRAKEI PASTORAL LIMITED (ENV-2009-AKL-000123) WAIRARAPA MOANA INCORPORATION­ WAIRARAPA MOANA FARMS (ENV-2009-AKL-000124) TRUSTPOWER LIMITED (ENV-2009-AKL-000125) GENESIS ENERGY LIMITED (ENV-2009-AKL-000126) 2 CONTACT ENERGY LIMITED
    [Show full text]
  • Energy Information Handbook
    New Zealand Energy Information Handbook Third Edition New Zealand Energy Information Handbook Third Edition Gary Eng Ian Bywater Charles Hendtlass Editors CAENZ 2008 New Zealand Energy Information Handbook – Third Edition ISBN 978-0-908993-44-4 Printing History First published 1984; Second Edition published 1993; this Edition published April 2008. Copyright © 2008 New Zealand Centre for Advanced Engineering Publisher New Zealand Centre for Advanced Engineering University of Canterbury Campus Private Bag 4800 Christchurch 8140, New Zealand e-mail: [email protected] Editorial Services, Graphics and Book Design Charles Hendtlass, New Zealand Centre for Advanced Engineering. Cover photo by Scott Caldwell, CAENZ. Printing Toltech Print, Christchurch Disclaimer Every attempt has been made to ensure that data in this publication are accurate. However, the New Zealand Centre for Advanced Engineering accepts no liability for any loss or damage however caused arising from reliance on or use of that information or arising from the absence of information or any particular information in this Handbook. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, transmitted, or otherwise disseminated, in any form or by any means, except for the purposes of research or private study, criticism or review, without the prior permission of the New Zealand Centre for Advanced Engineering. Preface This Energy Information Handbook brings Climate Change and the depletion rate of together in a single, concise, ready- fossil energy resources, more widely reference format basic technical informa- recognised now than when the second tion describing the country’s energy edition was published, add to the resources and current energy commodi- pressure of finding and using energy ties.
    [Show full text]
  • Annual Report 2014
    Full steam ahead Annual Report 2014 Te Mihi geothermal power station Investment decision – February 2011 Commissioned – May 2014 Officially opened – August 2014 Contact 2014 Contact 2014 2 Geothermal Resource Geothermal Resource 3 Contents We are… 04 Geothermal Resource One of New Zealand’s largest listed companies but we operate with the same genuine concern for our customers 10 New Customer System and communities as the smallest. We are integral to our customers’ lives – and our customers are integral to us. 14 At a Glance 16 Our Business Model 18 Where We Operate 20 KPIs 22 Q&A 28 Our Board 30 Our Leadership Team This Annual Report is dated 5 September 2014 and is signed on behalf of the Board by: 32 Case Studies 40 Our People Governance 46 Financial Statements 59 Grant King Sue Sheldon Remuneration Report 52 Independent Auditor’s Report 87 Chairman Director Statutory Disclosures 55 Corporate Directory 88 Contact 2014 Geothermal Resource 5 Another milestone in the journey Contact is a company committed to the development and use This investment programme has dramatically grown the breadth of geothermal energy. Why? It’s renewable, it’s clean, it’s fi nancially of expertise within our organisation. With Te Mihi, we have proven secure, and it’s always available to power Kiwi homes and our ability to develop and operate large, world-class geothermal OUR businesses – today and into the future. power stations. Our combined gross geothermal generation output is now 431 megawatts (MW) and is globally signifi cant in Our Taupō steamfi eld operation is large by international standards.
    [Show full text]
  • Contact, Geo40 Partner with Maori on World-Leading Energy Project
    Contact, Geo40 partner with Maori on world-leading energy project (19 July 2018) - Geo40, in cooperation with Contact Energy and the Ngati Tahu Tribal Lands Trust, is this month set to start commercially extracting silica from geothermal fluid as part of a world- leading sustainable energy partnership. The operation will see Geo40 use its technology to extract silica from geothermal fluid used at Contact’s Ohaaki power station. Once extracted, the silica will be sold to manufacturers for use in everyday consumer goods, such as paint, providing an environmentally-sound source of silica that would otherwise require amounts of carbon-intensive energy to make. The potential volume of high grade silica that will be sourced from Ohaaki is up to 10,500 tonnes a year, most of which will be exported overseas. “Geothermal energy is a proven source of renewable energy and this partnership builds on geothermal’s already impressive environmental credentials,” said James Kilty, Chief Generation Officer at Contact Energy. “It’s part of our de-carbonisation strategy. Our focus is on using innovative ways to support customers to shift off carbon-intensive inputs by maximising the benefits of the abundant renewable resources in New Zealand.” The partnership offers clear benefits to all parties. For Contact, the operational benefits are significant. Silica builds up in the geothermal pipes over time, and removing the silica significantly reduces equipment maintenance costs and increases the overall life-span of the plant. Removing silica also allows the plant to extract more heat from the geothermal fluid, making it more efficient to run. The deal provides financial and social benefits to Ngati Tahu Tribal Lands Trust.
    [Show full text]
  • AN UPDATE on GEOTHERMAL ENERGY in NEW ZEALAND Brian
    Proceedings of the 7th Asian Geothermal Symposium, July 25-26, 2006 AN UPDATE ON GEOTHERMAL ENERGY IN NEW ZEALAND Brian WHITE New Zealand Geothermal Association, PO Box 11-595, Wellington, New Zealand E-mail: [email protected] ABSTRACT The New Zealand geothermal scene is currently very active. There has been recent installation of new generation, with more generation being planned and prepared for. While direct heat use has been relatively static, some market leaders are now installing geothermal heat pumps, and this looks like an area for considerable growth. Various regional and district councils have been, or are in the process of clarifying the rules and policies related to takes of water. Central Government remains philosophically dedicated to the greater use of renewable low-emission energy forms (including geothermal energy), but is now trying to clarify its wider energy strategies and means of encouraging further uptake of renewables. Key Words: policy, geothermal energy, New Zealand, electricity generation, direct heat use, geothermal heat pumps, consents. 1. INTRODUCTION Geothermal energy can be found in high temperature fields in the Taupo Volcanic Zone and Northland (suitable for both power generation and direct use); medium/low temperature fields mainly located in the upper North Island or throughout the Southern Alps (potential heating applications); or low temperature resources at shallow depths anywhere in the country (suitable for ground-source heat pump applications). Among the various renewable resources available to New Zealand, geothermal energy is the only resource that can directly supply both heat and electricity, and has become increasingly competitive, especially as thermal fuels have increased in price and exchange rate improved.
    [Show full text]
  • OHAAKI = a POINTER to the FUTURE Johnw
    Pmc. 1Ith New Zealand Geothermal Workshop 1989 OHAAKI = A POINTER TO THE FUTURE JohnW. Malcolmson Eiectricorp Production, Eiectridty Corporation of New Zealand Ltd ABSTRACT But the Minister's statement to Parliament in 1947 This paper briefly outlines the history of the really marks the beginning of the geothermal power development of the Ohaaki geothermal field and story. Conventional steam plant was virtually discusses some of the more recent legislative and damned for anything but standby purposes on the environmental issues that would now have to be grounds of high capital cost, long delivery and taken into account if a similar power station were cost and availability of fuel. Imported oil, even built today. These legislative and environmental then, was considered prohibitively expensive, and issues will make it more difficult to build future New Zealand Coal was seen as a very limited geothermal power stations in New Zealand. There resource. But the statement contains these are also a number of design concepts that may be significant words: approached differently If the project were comnenced today. These are briefly outlined and "There is one possibility which must not be discussed. overlooked and that i s the use of natural steam for power generation. It is proposed to investigate this matter without delay..." INTRODUCTION From that time on geothermal development was a reality. The DSIR began on the trail which made Electricorp will never build another Ohaaki! New Zealand the world leader in the investigation and application of geothermal power. By 1950 During this address I will cover the reasons why investigation had concentrated along a three and a Electricorp will never build another Ohaaki.
    [Show full text]
  • Subsidence of Cover Sequences at Kawerau Geothermal Field, Taupo Volcanic Zone
    Subsidence of cover sequences at Kawerau Geothermal Field, Taupo Volcanic Zone, New Zealand A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Hazard and Disaster Management at the University of Canterbury by Scott David Kelly Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand 2015 i Table of Contents Table of Contents ...................................................................................................................... i List of Figures .......................................................................................................................... iv List of Tables .......................................................................................................................... vii Abstract .................................................................................................................................... ix Acknowledgements ................................................................................................................. xi 1 Introduction ...................................................................................................................... 1 1.1 Regional Geological Setting........................................................................................ 2 1.2 Kawerau Geothermal Field ......................................................................................... 5 1.2.1 Wells and KGL Power Station ............................................................................
    [Show full text]