Sunday, 21 June 2015

What will happen if Europe enters a cold period ?

The winter of 2010 was characterized by low temperatures and low wind speeds. It was considered a 1 in 10 year i.e. a year like this comes around roughly once in ten years. But there are long term cycles which determine temperature in Europe. The North Atlantic Oscillation (NAO) is the dominant mode of winter climate variability in the North Atlantic region. A negative NAO results in low temperatures and weaker storms and a positive, vice versa. The NAO oscillates between positive and negative every few decades and there are hints of a transition to a negative NAO at the present time. This could mean that we are entering a cold and calm period in the coming decade with weather much like the winter of 2010.

So what will this mean for Ireland's energy strategy ?

Along with the amount of installed wind capacity (currently 2,200MW which needs to be at least doubled by 2020 but may well be trebled) there are two main factors which determine whether or not Ireland meets its renewable targets :

  1. The strength and frequency of the wind blowing during the year (I will use the term capacity factor¹) and 
  2. Annual demand for electricity (total electricity consumption over the year).

Capacity Factor  

In 2010, according to Eirgrid, average capacity factors for wind was 24% (see page 33 here) well below the average of 31%. Long cold periods usually bring calm weather and this would be a disaster for the wind industry and Ireland's energy policy. The wind farms would receive less income from the market and some would go bankrupt.

So could they increase the PSO Levy to save them from bankruptcy ? Well the simple answer is no. The PSO Levy exists to bring the income they receive from the market (about € 50 per MWh) up to the subsidized REFIT level (€ 80MWh). So the less power a wind farm produces, the less it receives from the market and the less it receives from the PSO Levy. Payments from the PSO Levy are directly linked to the power a generator produces. It cannot be used to generate additional income over and above what a generator produces. 

Electricity Demand 

Eirgrid explain :
The actual amount of renewable energy this requires will depend on the demand in future years, the forecast of which has decreased due to the economic downturn. 
(Eirgrid Capacity Statement 2015)
The renewable targets essentially depend on the outcome of a simple equation - total wind output divided by total electricity consumption or demand. The higher the demand the smaller the renewable generation percentage and vice versa.

A long cold period will create higher demand for electricity (peak demand hit 5,100MW during the winter of 2010) :

Temperature has a more significant effect on electricity demand, as was particularly evident over the two severe winters of 2010 and 2011, when temperatures plunged and demand rose (Eirgrid Capacity Statement 2015)

So extended periods of cold temperature will increase the bottom figure in our equation (demand) reducing the percentage of wind in our energy mix and eroding the bottom line for many wind companies.

So basically, if the NAO becomes negative for a prolonged period, wind output goes down, demand goes up, and the percentage of wind relative to our electricity needs goes down, meaning our renewable energy targets will be next to impossible to meet regardless of how much wind capacity we install.

There will be alot of head scratching should this happen. Perhaps we shouldnt have put all our eggs in one basket we will most likely be told by journalists who will have suddenly become experts but refused to listen to anything other than the official line at the time².

¹Capacity factor gives the amount of energy actually produced in a year relative to the maximum that could have been produced, had a generator been generating at full capacity all year.
²There have been notable exceptions - economist Colm McCarthy for example


  1. Eirgrid published very high capacity factors during the early naughties, 2004 being 34.5%. I decided to carry out an analysis on high ground at Kingscourt, East County Cavan for 2008 and 2009. I measured it every day for 2 years coming up with an adjusted factor of 24.1% at turbine height. I excluded wind speeds below cut in speed. The British published factors averaging 24.1% for the same period. I then obtained the Met Eireann 30 year wind speed record for 1971 to 2001 which when adjusted to turbine performance co-related with my findings. Eirgrid CEO Dermot Byrne acknowledged actual factors were not meeting published ones. Professor Gordon Hughes of Edinburgh University found recent factors of 24% for Britain. I believe the factors were being overstated to seduce investors and to fit the model of most big renewable energy companies to build and sell on as soon as possible. Overstatement is large, 30.5% - 24.1% = 6.4% and 6.4/30.5 x 100 =21.3%. Very few companies can break even and have a 21.3% profit. In my humble opinion is that it was all to build, sell and get out before the poor performance was noticed and Eirgrid, a semi state outfit were implicit in misleading investors. Preliminary results for the Mount Lucas wind farm in Offaly is 15.45%. This is owned by Bord Na Mona who are holding a monster auction of machinery from their peat harvesting operations. Could there be a connection?

  2. Two small points to add to above. 1) The Australian Prime Minister Tony Abbott is totally against the idea of wind energy. 2) Irish wind farms are sometimes giving out energy when it is completely calm, Bear in mind that cut in speed for a turbine is about 12.5 MPH wind speed. In Spain they were caught using diesel generators to boost output and gain the subsidies.