Environment Waikato has granted consents for taking water, discharge of cooling water, and discharge of contaminants to air from the Huntly power station site.
In a joint hearing with Waikato District Council Genesis Power had applied for the consents to construct and operate a 400 MW combined cycle gas turbine power plant and cooling towers next to the existing Huntly Power Station. Eleven submissions were lodged from the Department of Conservation, Environmental Defence Society, landowners, Huntly Community Board and Primary School, the Land Air Water Association, Maori trustees, Wind Energy Association and Waikato Community Law Association.
The company proposes to install the gas turbine power plant – known as Huntly Energy Efficiency Enhancement Project (‘Huntly E3P’)- at the existing station. The proposed plant is expected to achieve between 55-58 percent efficiency of energy conversion, compared with about 36 percent efficiency for the existing Huntly Power Station.
The plant is expected to take two to three years to construct, with final commissioning in 2005.
Waste gases would be discharged to air, including carbon dioxide, water vapour, carbon monoxide, oxides of nitrogen and sulphur and particulates. There might also be trace levels of unburnt hydrocarbons or other incomplete combustion products.
Cooling water discharges would contain a variety of contaminants, including salts and chemicals to prevent corrosion, scale and biological growths in the cooling tower system.
One submitter said consents for the old station and proposed new station combined should be required.
Environment Waikato resource officer Maree Sanders said the applicant’s argument that there must be good reason to consider anything other than a 35 year duration of consents was incorrect. It was at the discretion of the consent authority, with a maximum of 35 years.
She recommended a 25 year duration for air discharges, with the expectation that when the existing permit expired in 2013, a cumulative assessment would be carried out. It also recognised the beneficial aspects of the project in high energy efficiencies and cleaner technology than the existing station.
The Committee commended the applicant on its comprehensive consultation, which resulted in fewer opposing submissions. The applicant had demonstrated that cumulative adverse effects of the air discharges were minor and could be appropriately managed through conditions. The Committee said the proposal to place a carbon dioxide cap on emissions was commendable and emissions would be less than they would otherwise be, through operation of Huntly E3P.
It had no concerns about the volume of water take applied for, and acknowledged tangata whenua concerns about discharges to the river.
The Committee had intended a 20 year duration for the air discharge but inclusion of the emissions cap and recognition of the higher efficiency of the plant persuaded it to accept a longer term of 25 years. Coinciding expiry dates for water consents would benefit future management of the Waikato River and allow a cumulative assessment, taking into account all environmental effects, it said.