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. half mile line running east west near the areas of However, before I do so I want to briefly describe natural activity at Wairakei. The Public Works the history of the development of Ohaaki and Department had six dri11ing rigs in operation. outline some of the aspects that we w i l l have to Steam was already being encountered although the take into account for future developments. light rigs were limited to a depth of about 150 metres. By 1952 two bigger drilling rigs were WHAT LED TO OHAAKI? brought i n and two bores were put down to a depth of 1200 metres. 20 MW of generation was already Ohaaki is the latest chapter in a story which had thought to ba justified and the Minister was its beginnings shortly after the Second World War. expressing "the utmost confidence' in geothermal It is worth casting our minds back to the vastly steam as a significant power source. From then different situation in New Zealand at that time on, driven by a dedicated and enthusiastic when compared with the present i n respect o? partnership of DSIR and the Ministry of Works, electricity generation and demand. Wairakei went from strength to strength. Overseas consultants were appointed, and an initial 40 HW I n 1946 the State Hydro-electric Department, i n development was approved, in conjunction with a its first year of independent existence, already heavy water distillation plant for the UK Atomic faced a chronic power shortage i n the North Energy Authority. In 1956 the heavy water plant Island, with the prospect of 10 percent annual was cancelled and the station output increased to demand growth into the foreseeable future. 69 MW. In parallel with this a coal fired station was in hand at Mercer (Meremere) and with I Water power had, up to then, been the o.nly increasing optimism about Wairakei s future technology considered appropriate and the potential the power planners were beginning to see remaining North Island resource was seen as the light at the end of the tunnel. The merit order Waikato River upstream of Karapiro. This demanded of alternative generation was at that time: a daunting rate of development at a stage when Kaitawa (Waikaremoana) and Karapiso were sti11 'Existing hydro 0.23 pencelkwh under construction. New hydro 0.50 pencelkwh Geotherma1 0.40 pence1kWh Steam 0.75 pence1kWh A few small fuel burning thermal plants were in Coal cost fifty two shillings and sixpence Per ton service. The only two of any significance were Kings Wharf and' Evans Bay but it is of Interest to recall that there was a steam station at Huntly But geothermal generation had some quite which merited a mention i n the General Manager's determined opposition in some quarters. The then Report to the Minister for the year ended 31 March Chief Engineer of the State Hydro Department, 1947. This station had run over the evening peak M G Latta, had published a paper in 1950 on future period for five days a week from June to November power supply to the North Island which had put 1946 forward the possibility of an inter-island link. The proposal was widely criticised at the time as impracticable. Cook Strait was seen as a fearsome stretch of sea with a bottom composed of precipices and canyons. Nevertheless its proponents persisted and i n 1957, backed by overseas experience, the relatively new Combined Comnittee on the NZ Electric Power Supply made a John W Malcolmson strong recomnendation to Government that the resource. Until this question of resource practicality and cost of installing submarine ownership i s resolved no developer i s going to cables across Cook strait be properly venture into an investment over which there i s no investigated. security. The rivalry between the supporters of geothermal Resolution of this question may take some time as power on the one hand and the inter-island link on the Tribunal now has a large backlog of claims to the other was exacerbated by the decision to hear. proceed with a further 53 MU of power at Wairakei and defer by one year the investigation of the DC Present legislation relating to resource use is 1ink. also overshadowed by the Resource Management Law Reform Review and, at the time of writing, the With hindsight the rivalry was unnecessary. The next public part of this process is the country needed both and both were eventually introduction of a Bill into Parliament. However built. Wairakei started generating in 1958 and by an emphasis of the new legislation is likely to be 1963 was developed to its final stage. Its on sustainability of resources. There is also progress and development has been well documented likely to be an emphasis on integrated consents by others, through its peak generation of 169 MU and a regional a1location of resources. down to a plateau of around 145 MU which has been maintained by various field developments to the The question as to who manages the resource must present day. Its record of load factor and be sorted out and it is hoped that this will be availability is impressive, both having remained achieved by this review. The conflict of the not far from 90 percent over long periods. resource allocation responsibilities between the jurisdiction of the Geothermal Energy Act 1953 and It is easy now to criticise the euphoria which in the Water and Soil Conservation Act 1967 needs to the middle to late 1950s led to over-estimating be resolved. the potential of the Wairakei field. But other fields were already being studied. In the early The Corporation is generally supportive uf the 1960s a consultant's report was obtained on a Resource Management Law Reform proposals to possible further geothermal power station at administer geothermal energy resources in the same Te Mihi, west of Uairakei. Although fears of manner as for water resource management. We can adverse effects on Wairakei resulted in this see no reason for additional geothermal licensing project being set aside, it is of interest that as this can be covered under the normal industrial steam fan new wells In the Te Mihi area are now safety legislation. making an increasing contribution to Wairakei. However, a more promising prospect was under study The Crown need no longer play a role as a at- Broadlands to the north. Drilling comnenced geothermal developer and should fulfil only its there in 1965 and by 1970 18 wells had been sunk, roles of policy development, natlonal interest and and the power potential was assessed as 120 MW. oversight and safety inspection. Also with the likely move to a regional allocation of resources, Further field investigations, in particular field most functions can be fully undertaken by the new draw down tests carried out by the Ministry of Regional Councils. Works and Development to determine basellne parameters and engineering studies, continued on a Additlonally, while accepting that ownership of stop-start basis as a response to changing the resource should control access, multiple or electricity demand forecasts, comQeting claims on large scale uses of one geothermal resource are natural gas resources, coal extraction problems not seen as appropriate If sustainable resource and the o i l crises. use is to be achieved without over regulation. More than any other policy or circumstance, thOs It was not until 1982 that Government finally gave will lead to exploitation and degradation of the approval for work to proceed on the design and field to the extent where no one wins on that construction of New Zealand's second geothermal field. power station. This has already become a problem with the recent OTHER GEOTHERMAL FIELDS splitting of the Wairakei field between two major users. The Corporation's assets have been clearly Over the years a number of other geothermal fields devalued by the decision to re-allocate same of have been studied for their electricity generation the geothermal resource to another user.