new zealand wind energy association www.windenergy.org.nz Practical constraints National Policy Statement associated with developing for Renewable Electricity a wind farm Generation Activities Policy C1 of the NPSREG requires The merits of any wind farm site, design, considerations for assessing the wind decision makers to have particular and overall feasibility will be driven by the resource at any particular site: regard to the practical constraints associated with the development developer’s own assessment of various ›› average hub height wind speed commercial, technical, and environmental of wind farms. Policy C1 lists the ›› turbulence considerations. For each of these following constraints associated considerations a number of practical ›› extreme wind speeds with renewable electricity generation activities: constraints will apply regardless of the ›› wind shear location or scale of the project. ›› flow conditions. a) the need to locate the renewable Practical constraints associated with electricity generation activity The wind turbine selected for a particular developing and operating a wind farm have where the renewable energy wind farm will depend on these key been summarised by the New Zealand resource is available; considerations plus the availability Energy Efficiency and Conservation Authority of turbine technology and various b) logistical or technical (EECA) in The National Policy Statement for commercial considerations, both of practicalities associated with Renewable Electricity Generation Technical which are highly time dependent. developing, upgrading, operating Guide1. These practical constraints all relate to the ability to physically harness the wind or maintaining the renewable energy resource to generate electricity electricity generation activity; and then export the electricity to the local It is not always practical for a developer c) the location of existing structures distribution network or the national grid. to stipulate the exact turbine and infrastructure including, but characteristics prior to seeking consent not limited to, roads, navigation approval. This is largely because and telecommunication Physically harnessing the different-sized turbines require structures and facilities, the wind energy resource to different spacing to avoid “wake” generate electricity effects that can influence the utilization distribution network and the of the available and suitable land area. national grid in relation to the Practical constraints associated with physically A thorough commercial evaluation and renewable electricity generation harnessing the wind energy resource to tender process is required to examine activity, and the need to connect generate electricity relate to the suitability of: the above issues and identify the final renewable electricity generation 1. wind speeds model after all the necessary regulatory activity to the national grid; consents are obtained. Accordingly, 2. available equipment d) designing measures which allow a developer might seek flexibility in operational requirements to 3. land and access. the turbine design and location and complement and provide for might identify a number of potentially mitigation opportunities; and Wind speeds suitable wind turbine models. In such e) adaptive management Wind farms typically require a consistent cases, the “worst case scenarios” of and good average wind speed. The following the environmental effects would measures. characteristics are often key technical need to be assessed. Some technical assessments, for example, noise in accordance with NZS6808:2010, require actual turbine models to be 1 Refer pages 48-49 in The National Policy Statement stipulated to allow accurate modelling. for Renewable Electricity Generation Technical Guide, 2013. Available from EECA’s website: www.eeca.govt. nz/resource/national-policy-statement-renewable- electricity-generation NEW ZEALAND WIND ENERGY ASSOCIATION: Practical constraints associated with developing A wind farm PAGE 2 Available equipment modate the turbines, and the construc- ›› the ability of the electricity generator to tion of low grade roads required to secure legal and physical access rights Wind turbine technology is advancing at a transport wind farm components and for the transmission very high rate. Developers need to ensure heavy construction vehicles (e.g. cranes, that resource consents enable the newer ›› the capacity of the electricity more efficient technologies to be used rather concreting trucks) transmission network to accommodate than being tied in to older technology that ›› accessibility to existing transport the additional generation may have been considered initially. infrastructure, such as ports or wharves ›› the ability of the electricity generator to Most wind turbines are manufactured for receiving shipped components and sell electricity over a long term. overseas and developers compete in an public roads suitable for transporting These practical constraints are often heavily international market when purchasing heavy overload vehicles, is another influenced by the distance between the wind turbines. This means the international consideration wind farm and the point of connection to exchange rate has a significant influence on ›› environmental considerations, including the national grid and/or distribution network the cost and availability of wind turbines. the logistics associated with assessing and in relation to the demand centre. For Importing wind farm components from managing environmental effects associ- example, a high transmission cost close to overseas can introduce additional logistical ated with each component of a proposal a demand centre may be more acceptable compared to a low transmission cost hurdles. For example components for a ›› securing legal access to use the land, and single wind turbine may be manufactured located away from a demand centre. a determination from the Civil Aviation in numerous factories in different countries. Authority, including all necessary In some cases ancillary equipment may also resource consents. need to be imported. For example a 600 Wind farm developers and electricity tonne crane was shipped to New Zealand generators that do not have an from Denmark especially to construct the The ability to export the existing retail function need to enter Te Uku wind farm. electricity to where it may into a long term power purchase be used agreement with an electricity retailer or sell on the spot market. Land and access Once harnessed, electricity generated from Securing an off-take/power purchase Access to land is a critical component of a wind farm needs to be connected to the agreement can be a significant accessing the wind resource. Land access national grid or the local distribution network determinant as to whether or not a constraints can include: so that it can be transported to end users. wind farm project will proceed. ›› compatibility of the project with existing Electricity from a wind farm can be sold: land uses and securing legal access to ›› on the spot electricity market; the land and access routes More Information ›› as part of an electricity retailer’s portfolio; or ›› understanding the suitability of the Find out more about wind energy ›› directly to a consumer. ground conditions and civil engineering and wind farms in New Zealand at requirements including the size of the Practical constraints associated with www.windenergy.org.nz. land area and topography to accom- transmitting and selling the electricity revolve around: NZ Wind Energy Association PO Box 553, Wellington 6140, New Zealand The New Zealand Wind Energy Association (NZWEA) is an industry association that works towards the development of wind as a reliable, sustainable, clean and commercially viable energy source. We aim to fairly represent wind energy to the public, government and the energy sector. Our members include 80 companies involved in New Zealand’s wind energy sector, including electricity generators, wind farm developers, lines companies, turbine manufacturers, consulting firms, researchers and law firms. Te Uku JUNE 2013.