Comment & Debate
Euan C. Blauvelt, research director of ABS Energy Research, an independent market research firm in London. – “The environmental benefits of wind are not as great as its champions claim. You’ve still got to have backup sources of power, like coal-fired plants.”[1]
“The pros and cons of wind power debated again”. Orangeville Citizen. 10 Aug. 2006 – wind energy’s achilles’ heel its intermittency limits its capacity value and its impact on emissions. As an intermittent/variable
electricity source, wind energy has not and cannot replace conventional sources (coal, nuclear power and natural gas) of base-load electricity generation. These sources must continue to be maintained and built as our electricity demand grows regardless of the amount of wind energy facilities constructed.
Furthermore, as an intermittent/ variable electricity source, wind energy must be backed up by standby dispatchable generation (usually natural gas) for other than modest amounts of production.
As wind energy penetration grows, the need for backup
and the associated emissions largely offset the purported emissions savings.
In short, modest wind energy production doesn’t make much of a difference in reducing emissions, and meaningful levels of production have, at best, a negligible positive impact.
Eric Rosenbloom. “The Low Benefit of Industrial Wind”. 20 Jan. 2006 – Even the most cautious of advocates do not doubt, for example, that “every kilowatt-hour generated by wind is a kilowatt-hour not generated by a dirty fuel.” That may be true for a small home turbine with substantial battery storage, but such a formula is, at best, overly simplistic for large turbines meant to supply the grid. The evidence from countries that already have a large proportion of wind power suggests that it has very little, if any, effect on the use of other sources. This is not surprising when one learns how the grid works: A rise in wind power most likely just causes a thermal plant to switch from generation to standby, in which mode it continues to burn fuel.
“Impact ofWind Power Generation in Ireland on the Operation of Conventional Plant and the Economic Implications”. ESB National Grid. February 2004 – This section summarises the broad conclusions of the study. Diversity of siting of wind farms has been confirmed to be effective in reducing the intermittency of wind powered generation (WPG). In this regard locating relatively small on-shore wind farms in the south and south-east of the country would be beneficial in reducing the intermittency of wind power as seen by system generation. The opposite effect would result from the construction of a very large wind farm on a single site, whether on-shore or off-shore.
The capacity credit of WPG capacity has been confirmed to be considerably less than that of conventional thermal plant, and declines incrementally to saturation. Therefore as WPG increases additional or ‘surplus’ generation capacity is required if security of supply is to be maintained. There are significant costs associated with having ‘excess’ capacity on the system. Therefore the capacity surplus that results from WPG adds to the total generation costs.
The effect of WPG on the thermal plant on the system has been quantified. Mid-merit and high-merit plant are the categories most affected. Low-merit plant (OCGTs) is minimally affected. If high levels of WPG are to be accommodated in the future, existing
plant may need to be modified and new plant selected so that they can cope with this type of operation.
The adverse effect of wind on thermal plant increases as the wind energy penetration rises. Plant operates less efficiently and with increasing volatility. There is a financial premium to be paid for WPG. We estimate that for a system with a peak of 6,500MW, and a generation portfolio comprising of combined and open cycle gas turbines, and no WPG, that the total annual generation costs would be €1.28bn. When WPG is increased to 1,500MW the total generation costs increases by €196m per annum
to €1.48bn. For a system with a peak demand of 6,500 MW, 1500 MW of WPG represents a wind energy penetration level of 11.7%. The EU target for Ireland, from all renewable sources, is 13.2%. Therefore it can be estimated that, in the long term, using WPG to comply with the EU target will increase electricity generation costs by 15% (€196m as a percentage of €1.28bn). This translates to a CO2 abatement cost in excess of €120/tonne.
The cost of CO2 abatement arising from using large levels of wind energy penetration appears high relative to other alternatives.