“Greater good” of widely distributed wind farms is minimal 

I would like to add to the discussion raised by Mr Steven Cooper’s article “Wind farm noise – An ethical dilemma for the Australian Acoustical Society?”, Acoustics Australia 40(2), 139-142 (2012).

Letters from Kym Burgemeister and Marshall Day Acoustics (both in Acoustics Australia 40(3), December 2012), each make the important point that there is a need to balance the impacts from any given technology on local residents against its benefits to the wider community. It is the latter – the supposed benefits or, “the greater good“, provided by wind farms – that I wish to address here.

The wind industry and its academic supporters tell us that, while individual wind farms produce an electricity output that is variable, that by spreading a number of wind farms across a wider region, their combined output becomes sufficiently smoothed so that, with a little balancing from gas turbine generation, the combination can readily replace coal-fired powerstations. See, for example, Diesendorf [1]. Thus, we are told, wind farms provide a direct benefit to the wider community by reducing the CO₂ emissions from fossil-fuelled generation. This, I understand, has become a generally accepted view among the government policymakers involved in the wind farm approval process.

I am an electrical engineer. I thought to test this smoothing hypothesis [2]. The operator of the eastern Australian grid, the Australian Energy Market Operator (AEMO) publishes, on a daily basis, the previous day’s operational data for all registered generators. The data is published as the output at each 5-minute data point for all such times in the 24-hour period, that is, 288 data points for each of more than 300 generators on that grid. There is now a total of some 2700 MW of installed wind farm capacity spread across the eastern Australian grid, the most far-flung grid on earth, over a region that is 1200 km in its east-west extent, and some 500 km over a north-south extent, making this network of wind farms one of the most widely dispersed in the world. I thought to analyse the performance of this network of wind farms for the full calendar year 2010. At that time, the total installed wind capacity totalled a little over 2500 MW, incidentally making it a larger capacity than that of a single coal-fired powerstation.

In light of the generally accepted view stated above, the results were little short of astonishing. Not only is there no appreciable smoothing of the wind farm output, but there occur very frequently through the course of a year what can only be termed common-mode failures of the entire wind farm fleet. I chose a figure of 2% of installed capacity as the minimum acceptable level of output. (I am advised by other electrical engineers that this figure is “kind” to the wind industry: those others would have chosen a figure of 5% as the minimum acceptable figure, a figure that would have resulted in an even worse result.) Using my 2% minimum figure as the failure criterion, the wind farm fleet failed on some 109 occasions in 2010. To provide some perspective, the unscheduled outage of one major conventional powerstation once a year would be deemed unacceptable. This is a direct comparison, in terms of presently installed wind farm capacity, but, in addition, the failure of the entire conventional generation fleet – for this is also a direct comparison – on any single occasion, would be regarded as catastrophic, and would result in a national inquiry.

In addition to the common-mode failure, there were numerous occasions through the calendar year where wind output dropped rapidly from high values, requiring the rapid response of fast-acting gas turbine generation to fill the gap. The rapid response requirement results in inefficient operation of such plant, resulting in excessive CO₂ emissions at such times. Inhaber [3] determined, using a conservative approach, that as a result of this excessive fuel consumption, that where wind installed capacity approaches 20 percent of total installed generation capacity (the Federal government’s renewable energy target), any resulting CO₂ emissions saving is completely nullified by the inefficiencies resulting from the frequent, rapid ramping.

This result is due entirely to the prevailing meteorology: the frequent passage of large high-pressure systems cause occasions where the wind is not blowing anywhere across the entire grid [2]. As a result, increasing the wind farm fleet is no solution to the common-mode failure problem. Indeed, continued increase in installed capacity would merely result in the increased risk of catastrophic grid collapse, as a consequence of the increased absolute magnitude of the swings in wind farm output. Miskelly and Quirk [4] also address the impact of these wind-caused sudden variations in demand.

These findings concur with the empirical observations being made in both the UK and Germany, for example, where there is a new understanding, based on operational experience, that wind energy is both not decreasing CO₂ emissions to any appreciable extent, but is also placing the continued operational security and reliability of those countries’ respective grids under increasing strain.

I respectfully suggest to members of the AAS that, in the light of these findings, it is time to give serious consideration to the possibility that the “greater good” to be had from grid-connected wind farms is not only minimal, but that it is indeed likely to be non-existent. Therefore, any noise impacts on nearby residents resulting from the operation of wind farms are totally unacceptable.

As a result of these findings the ethical issue raised by Steven Cooper takes on a new importance: given that it is clear from these findings that wind energy technology on the eastern Australian grid is a colossal failure in terms of meeting its stated objective, I suggest that currently-misguided policy strategies by governments require a robust response from AAS members. For example, in NSW, as a first such response, the present exemption of wind farms from the stringent requirements of the NSW INP now require, I suggest, that AAS members practising in that jurisdiction lodge objection regarding that exemption as a matter of urgency with the relevant departmental Directors-General.

Paul Miskelly, BE, MEngSc (both degrees in Electrical Engineering)
Mittagong, NSW

Acoustics Australia, Vol. 41, No. 2, August 2013, pp. 139-140

REFERENCES

1. M. Diesendorf, The base-load myth, The Drum, ABC, 2011 www.abc.net.au/unleashed/97696.html (last accessed July 2013)
2. P. Miskelly, “Wind Farms in Eastern Australia – Recent Lessons”, Energy & Environment 23(8), 1233-1260 (2012)
3. H. Inhaber, “Why wind power does not deliver the expected emissions reductions”, Renewable and Sustainable Energy Reviews 15(6), 2557-2562 (2012)
4. A. Miskelly and T. Quirk, “Wind Farming in South Eastern Australia”, Energy & Environment 20(8)-21(1), 1249-1256 (2009-2010)

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