The New Zealand Energy Strategy calls for a greater emphasis on investing, and exploiting NZ’s abundant renewable energy resources. This comes to no surprise as NZ is a signatory of the Kyoto Protocol. New Zealand’s obligation under Kyoto is to reduce its greenhouse gas emissions to 1990 levels on average between 2008-2012. In accordance with this goal, is the target set by the previous government of achieving 90% of electricity from renewable sources by 2025. These targets and commitments seem desirable; they are made on unrealistic assumptions and expectations of rewnewables, especially wind power. The strategy’s dominate theme is dictated by the idea that NZ should fight climate change with wind power, and it is a very good way to do it. Wind power’s fundamental problem is that it can be intermittent and unpredictable. Thus, wind power operators must have pessimistic views and assume that no wind power will be available over critical periods. In accordance, there needs to be sufficient backup power available to meet peak demand periods.
Output from 184 MW NZ Wind Farm
Figure 1 shows wind powers problems, as the average output is below maximum capacity, and performs poorly during critical hydro dry periods. Further, there is no definite output that can be reliably achieved. To backup wind shortages and meet demand, energy would need to come from NZ’s hydropower reserves. This strategy can be fulfilled during a normal rainfall year and certainly not during a dry year. Dry years, not normal years, dictate the need for new power stations. Wind blows least during the autumn-early winter period when the lakes are low and at a maximum in the springtime when the snow is melting and usually raining. Therefore, wind power generates energy most when it is not needed and least when it is most needed. As a result its contribution is less than it would be if the wind blew hardest in the autumn. Firstly, it is widely accepted that a 20 per cent contribution by wind is about as much as our system can accept without running into excessive costs and serious problems with system operation. Secondly, Wind power is expensive. Wind power’s true cost has investigated as being between 11c and 17c/kWh. This is between 50 per cent and 100 per cent more expensive than energy developed from coal fired power plants. Added to this dilemma is the public backlash as wind power turbine installation, as they produce aesthetic pollution to the countryside. Although the public generally hold positive attitudes towards wind energy, proposals for the construction of new wind farms are often met with strong resistance.
Summarised below are the major problems in wind power investment:
- Very expensive to produce energy,
- The capacity factor is low – 20-30%,
- Energy production is unpredictable,
- The output fluctuates rapidly on a relatively short timescale,
- No more than 5-10% can be relied on when it is needed,
- Wind power is influenced by seasonal weather conditions,
- Needs support from fossil fuel stations,
- Residents close to wind power installations do not want them.
In short, the Government’s energy strategy’s focus on wind power provides the opposite of its intention, resulting in an energy production and supply that is less secure.