Ecological, Economic and Employment Benefits:

Ecological Benefits from a 10 or 20 MW Wind Farm

Formula & formatting courtesy EECA, Wind's Up-Planning the Future Now (CO2 = Carbon Dioxide)
A theoretical wind farm with a rated power of 20 Megawatts (MW) is used as an example here.

Background Parameters

  • NZ wind farms have a 40% capacity factor
  • An average NZ household uses 7.8 Megawatt hours of electricity per annum (MWh/annum)
  • Every Megawatt hour of wind produced displaces .6 tonnes of CO2 from NZ coal fired generation
  • A petrol engine car produces 4.33 tonnes of CO2 per annum
  • A model tree can absorb .67 tonnes of CO2
  • There are 8760 hours in a year (hours/annum)
  • NZ total electricity consumption is 36,300,000 MWh per annum (December 2003)
  • A wind farm costs approximately $1.65--$2 M per 1 MW of installed capacity, using turbines from overseas
  • Approximately 40% of the installed cost of a wind turbine is spent within NZ, if towers are made in NZ


Benefits / Equivalents of a 10 and 20 MW WIND FARM

Electricity Generated Per Annum
Rated Power of Wind Farm (MW) x hours/annum x (wind)capacity factor = Wind Farm Output (MWh) of electricity for 1 year

10 MW Wind Farm
10 x 8760 x .4 = 35,040 Megawatt hours

20 MW Wind Farm
20 x 8760 x .4 = 70,080 Megawatt hours

Equivalent Carbon Dioxide Emissions Avoided Per Annum
Wind Farm Output (MWh/annum) x CO2 displaced / MWh (Tons) = Equivalent tons of CO2 avoided per annum

10 MW Wind Farm
35,040 x 0.6 = 21,024 tons of CO2 avoided

20 MW Wind Farm
70,080 x 0.6 = 42,048 tons of CO2 avoided

Equivalent Households Supplied
Wind Farm Output (MWh/annum) ÷ household consumption (MWh/annum) = Equivalent households supplied for one year

10 MW Wind Farm
35,040 ÷ 7.8 = 4,492 households

20 MW Wind Farm
70,080 ÷ 7.8 = 8,985 households

Equivalent Number of Cars Taken off the Road
CO2 avoided equivalent (tons) ÷ annual CO2 produced by a car (tons) = Equivalent # of cars taken off the road for one year

10 MW Wind Farm
21.024 ÷ 4.33 = 4,855 cars

20 MW Wind Farm
42,048 ÷ 4.33 = 9,711 cars

Equivalent Number of Trees That Would Need to Be Planted
CO2 avoided equivalent (tons) ÷ CO2 absorbed by a model tree (tons) = Equivalent trees that would not need to be planted

10 MW Wind Farm
21,024 ÷ 0.67 = 31,379 trees

20 MW Wind Farm
21,024 ÷ 0.67 = 62,758 trees

Proportion of New Zealand's Electricity Consumption
Wind Farm Output (MWh/annum) ÷ electricity consumed in NZ (MWh) x 100--% of NZ annual electricity consumption

10 MW Wind Farm
35,040 ÷ 36,300,000 x 100 = 0.1 % of total NZ consumption (Less than 1/10th of 1%)

20 MW Wind Farm
70,080 ÷ 36,300,000 x 100 = 0.19 % of total NZ consumption (Less than 1/5th of 1%)

Economic Benefits from a 10 or 20 MW Wind Farm

Local (within New Zealand) Expenditure During Construction
Rated Power of Wind Farm (MW) x cost per erected MW ($ Millions) x % spent in New Zealand = $ spent in New Zealand, mainly on Waiheke.

10 MW Wind Farm
10 x $ 2m x .4 = $8 million spent in NZ

20 MW Wind Farm
20 x $ 2m x .4 = $16 million spent in NZ

Employment Benefits of a Wind Farm

The wind industry in 2001 provided more than 50,000 jobs worldwide. A 10-20 MW wind farm on Waiheke would create 30 to 50 local jobs during construction and at least 5 to 9 full time permanent jobs for operation and maintenance.
This number does not take into consideration the increased levels of tourism, tourism expenditure and employment.

The cost of wind energy:

How does the cost of electricity generation from wind compare with other forms of generation?

Costs of generating electricity from the wind are today only about 10 per cent of what they were 20 years ago: This is because of rapid advances in turbine technology over this period. Independent studies have shown that hundreds of MW could be installed in New Zealand today at a cost of around 6c/KWh (read on for more detail and downloads). This figure is supported by comments made on 4 November 2004 by Dr Keith Turner, CEO of Meridian Energy. Current wholesale cost: December 2004: 4-5 Cents.

This means that without any consideration of carbon charges for fossil-fuel powered forms of electricity generation, the domestic wind industry is already directly competitive with fossil fuel-based forms of generation. further technological advances and scale economies: the CEO of Vestas (, one of the largest turbine manufacturers in the world, has publicly stated that he expects turbine costs to be reduced at an annual rate of 3-5% for the foreseeable future.

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