Madam, – The case put forward by Aonghus Shortt of the Electricity Research Centre for expansion of the wind energy sector (December 24th) does not stand up to any serious scrutiny.
First, electricity demand in the winter months in Ireland is highest between 4pm and 9pm, with the peak demand occurring after nightfall around 6pm. So even if it is windier during the day, as Mr Shortt claims, it seems disingenuous for him to argue that this “correlates nicely with demand”.
Rather more pertinently, electricity demand is nearly always highest on the coldest days of winter, in other words during anti-cyclonic conditions of little wind. Just as a point of interest, an examination of the Eirgrid website shows that average daily peak electricity demand in the 12-day run-up to Christmas was 4,670 megawatts (MW), while the average wind generation at 6pm on those days was just 245MW (less than one quarter of the theoretical maximum output from Ireland’s wind farms). More tellingly, on December 21st, when peak demand reached a seasonal high of 5,000MW at around 6pm, wind generation was only 90MW – less than 2 per cent of demand.
Although the answer might appear to be in installing five or 10 times as many wind turbines, along with the necessary grid infrastructure (at an estimated total cost of €25-50 billion), this will lead to huge unutilisable surpluses at times when the wind is blowing strongly. The idea that Ireland can suddenly conjure up a nationwide fleet of battery-powered electric cars in order to avail of this surplus is quite ludicrous, more so when one considers that the charging of batteries would always have to take place at times of peak wind output.
With around 1,200MW of installed wind turbines, Ireland is already quite close to the upper limit of useful wind energy capacity. Owing to the inherent inability of conventional power stations to respond to the fluctuating output from intermittent renewables, wind energy surpluses are already occurring, leading to enforced curtailment of wind output and loss of revenue for wind farm operators.
Although the Government has set targets of 6,000MW of installed capacity by 2020, long before this figure (or this date) is reached, there will be massive oversupply in the sector. The outcome will closely follow that of another sector in which there was chronic oversupply, namely residential construction. Abandoned, uncompleted wind farms will litter the skyline, and there will be an unseemly rush among those who have speculatively invested in the sector to get their money out while they still can. In time-honoured tradition, the Government will then blame “external factors that no one could have foreseen”, and proceed to incur further debts of billions of euro on the inevitable bail-out. – Yours, etc,