Generation capability
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The notion of using wind to generate electricity to power the nation is an attractive idea but one that is badly flawed. Wind is intermittent and unreliable, as our sailing forefathers discovered. When the wind dies so does the power.
What this means is that the average output of a wind farm in New Zealand is never more than about 40% of its stated capacity. So for example a wind farm that is rated as 150 Megawatts will on average produce only about 60 Megawatts of power. Consequently very large wind farms need to be constructured to obtain relatively low power outputs. This is expensive and with many adverse impacts on the environment.
When the wind stops blowing power generation ceases. For small scale wind generation, such as on a farm, an array of batteries can be used to store power which will then continue to drive output when the wind dies. For large scale industrial production of electricity there is currently no practical means of storing electricity. The only solution to avoid power cuts when the wind dies is to provide an additional reliable source of electricity that is configured to cut in instantaneously.
For example if 1000 people switch on their 2 Kilowatt electric heaters at 5:30 pm on a cold winters evening the grid needs to be generating 2,000 Kilowatts of power. If the wind happens to be blowing stongly enough at that time then this load could be provided by the output from wind turbines. If the wind dies then some other source of power needs to immediately take over the load. This is not an easy requirement to implement or control
In practice the additional sources of power used to backup wind turbines are fossil fueled power plants, coal, gas, or even diesel. These generators cannot be brought up to speed quickly enough to prevent power cuts when the wind dies unless they are already running in 'standby mode'. In standby mode these generators will be producing approximately 25% of their full output power. They will also be running much less efficiently than at full output with each Megawatt of electricity using more fuel and spewing out more pollutents. The effect of this is to significantly increase the cost of wind generation (by about 30%) and also its pollutent and carbon emmissions, to a point where the business case for large scale wind generation is questionable and driven by direct or indirect subsidisation via carbon credits and a biased electricity market.
There is an idea out there that if a large number of geographically dispersed wind farms are constructed, then they will be able to back up each other. If the wind dies in one place it will most likely pick-up at another, which will smooth out the peaks and troughs. This has been proven not to be the case from a study of 7,000 geographically dispersed wind turbines in Europe, which found that the combined output of these turbines was just as intermittently random.
Backup generation of electricity
Your comments to this overlook one important source of power which is primarily non-carbon related - Hydro Power.
Hydro has the ability to ramp up much more quickly than a fossil fuel powered generator, thus has the ability to provide backup to wind generation. The combination of no wind and a dry summer (and thus empty storage lakes) are of a much lower probability than the probability of simply no wind. Wind will provide enough power to reduce the amount of water required, even in relatively low rainfall periods.
Wind and hydro together can provide a large proportion of our power requirements.
Are YOU prepared to disconnect from the power grid if you get what you want and Puketiro doesn't go ahead?
If you aren't, then consider what you are proposing very carefully....
In answer to your proposal
In answer to your proposal regarding hydro backing-up wind. I'd like to discuss this around a scenario.
Assume that there is a demand for 10,000 KWatts power on a winter's evening. We need to ensure that we have sufficient, guaranteed generation capacity to meet this demand, known as base capacity. Wind cannot be used for such base supply as its availability cannot be guaranteed.
So let's assume, for the sake of argument, that 5,000 KWatts of base can be provided by hydro generation, 2,000 from thermal and 3,000 KWatts from fossil fuel generators. However at the time that the 10,000 KWatts is required, the wind is blowing just strongly enough so that most of the NZ wind farms are producing near to full output, say 2,000 KWatts.
So we switch-off 2,000 KWatts of base hydro and dispatch wind to meet this component of the demand. If the wind dies this hydro can be switched back on instantaneously to take-up the load.
Great, but what advantage does this provide? Hydro doesn't produce CO2 so no direct advantage there. For hydro that is 'run of river', which accounts for much of NZ's hydro supply, there is no water conservation advantage. So the benefit that we might achieve would be to conserve water for those storage hydro generators that were meeting a proportion of the 5,000 KWatts.
Consequently, wind could be used as a 'hedging' mechanism to conserve water usage in hydro storage generation, to effectively increase security of supply of these plants.
As most of the storage hydro is in S Island, this is where most of the wind hedging generation would need to be located, as from a grid perspective, backup through the cook straight link is really not viable (I'll bow to my power engineering colleagues for an explanation of this).
The combined security of stored hydro plus wind could reduce the risk of non-availability but isn't sufficient to guarantee supply (i.e. you can't guarantee sufficient rain and wind), so we would still be reliant on fossil fuel plants for guaranteed base, to avoid situations like the current concern with low lake levels. So, wind cannot reduce our reliance on fossil fuel generation capaciity, it would merely reduce the likelyhood of lakes running out and hence would reduce the likelihood of fossil fuel needing to be dispatched to meet our power demands.
In conclusion, wind generation might usefully be used to hedge the availability of storage hydro schemes in NZ, providing the farms are constructed in locations where they can efficiently be backed-up by storage hydro. Wind would be playing a relatively minor role in the whole supply equation and at very great expense. It is certainly not going to prevent power cuts, and ironically if people continue to misunderstand the role that wind can play, it is likely to result in actions, or perhaps inactions (political, economic, and engineering) that actually increase the likelihood of power cuts.
I also worry that the productivity that we're seeing from the farms that have already been constructed is very poor (hopefully there will be regular publishing of the figures on the web soon so that we'll be able to track this). So even as a hedging mechanism for storage hydro their effectiveness may be questionable.
Consequently, we need to be doing some proper strategic power planning, driven by informed, engineering reality rather rather than political idealism or wishful thinking. Wind farms should be constructed if and where they are effective and efficient, accounting for and compensating for negative impacts on people and the local environment, and no more or less than this. Certainly not be thrust upon us as opportunistic cash cows by those wishing to make a killing on the carbon market (available even if the things don't work) and skewed electricity market pricing.
Personally I think we would be much better to put our resources in NZ into development of thermal and hydro power plants, and serious energy saving schemes, but then there's no get rich quick schemes driving these.