Storm Ophelia

On Monday 16th October, Storm Ophelia raged through Ireland. With lots of reliable wind energy around for a change, one might have expected high levels of wind power. 

As the above graph shows, up to 2,915MW of wind energy was forecast but only 745MW or 25% of available wind power was actually used. This is because there is a cut off point at which wind turbines can no longer safely operate. 

Meentycat Wind Farm

Meentycat wind farm is the largest wind farm in Ireland at 88.5MW. It is owned by Airtricity and located in Donegal about 20 miles from the sea in a hilly area. So it's very well located to take advantage of Ireland's best wind resource.

The following wind maps confirm that it is in one of the best locations in Europe :

It was built in 2004, with an extension in 2009, and consists of 38 2.3MW Siemens wind turbines. According to data from SEMO, it had a capacity factor of 31% in 2015 i.e. it generated on average 31% of its maximum output over the year. It operated for 88% of the time, i.e. roughly 9 hours in 10.

However, as can be seen from the below charts, the wind farm was generating between 0% and 2% for 18% of the time and 10% or less of it's output for around a third of the time. For just 1 hour in 10, it operated at a capacity factor of 75% and above. 

Capacity Factor	Frequency
0% - 2%	18%
10% or less	36%
25% or less	53%
75% or more	10.5%

 Another way of looking at these figures is that for around a third of the time, the wind farm operated at between 26% and 74% of its max output, equivalent to the same amount of time it operated at less than 10% capacity factor. So there is an equal chance that the wind farm will generate mid range amounts of power as it will tiny amounts. There is greater chance (18%) that it will generate none or next to no power as it will very high amounts of power (10.5%).

So we can see that this is wind energy at it's optimum performance. Presumably, results would have been slightly better when it was first installed. Certainly, it's capacity credit was higher then, as there was much less wind farms (capacity credit is it's contribution to generation adequacy and is sometimes referred to the amount of conventional plant that can be decommissioned as a result of the new wind farm without posing a risk to security of supply. Capacity credit tends to decrease with the more wind you add). 

If there is a case for wind farms in Ireland, then it's within that dark blue line only in the map above and should have been restricted to around 1,100MW. The wind industry and government are fond of telling us that "Ireland has the best wind resource in Europe" but actually that only applies to a small portion of the island and is comparative to Scotland and North Denmark.

Impact of Wind Turbines on Birds of Prey in Ireland

An Irish Buzzard

Three years ago (2011) a sea eagle died after colliding with a blade at a wind farm at Sillerthane, near Kilgarvan - Irish Times 2014.

“Shooting is not the biggest problem, poisoning has killed the most and three have flown into wind turbines - White Tailed Eagle reintroduction project manager Dr Allan Mee (2014)”

Evidence for bird of prey collisions with wind turbines is small - about six or seven in the past few years, most notably from tagged eagles that have been re-introduced into Ireland from Norway. This makes it easy to track and record deaths of these birds. However, deaths of native birds of prey e.g. buzzards and falcons are more difficult to track as most, if not all, go unreported. And as any farmer will tell you, a dead bird will be picked up by a scavenger within hours.

There have only been three studies carried out into Wind Turbine bird fatalities in Ireland. They were all carried out at Lisheen Wind Farm and have been obtained under Freedom of Information.

In 2010, two sparrowhawks carcasses were found shortly after operation of the wind turbines. In 2012, a carcass of a kestrel and a buzzard were found beside a wind turbine. Other dead birds were also found such as crows, gulls and pigeons. Only two dead crows were found and no birds of prey during 2013/14 searches. This tends to show that most bird kills occur during the first couple of years of operation. However, many more studies would be required to establish enough evidence to form a proper conclusion.

The Lisheen studies conclude with a very important statement :

"most studies rely on the number of carcasses found, but this can be extremely unreliable, since it is known that carcasses are quickly removed by predators"

So we really do not know the full impact of wind turbines on birds of prey. Green advocates will argue that cars and pets kill more birds. But they fail to discern between birds of prey and common birds. Pets are incapable of killing larger and rarer birds. Cars have been known to kill large birds, in particular low flying owls, but to a much lesser extent buzzards and eagles. The Lisheen study makes this distinction clear :

Species that are long lived and have low productivity (such as many birds of prey) are at higher risk of population level impact through individual losses than short lived and highly productive bird species.

So there is no danger to gull or crow populations from wind turbines but there is a significant threat to birds of prey. A worrying development is that An Bord Pleanala don't seem to consider the threat to protected wild birds much of an issue and have even ignored their own inspectors, for example in the case of a wind farm in Roscommon which was eventually refused permission after a High Court challenge by local man, Ted Kelly:

Mr Kelly also alleged the Board failed to specify exactly why it approved permission for the developments when two of its own inspectors recommended permission be refused after appeal hearings. The inspectors concerns included the visual impact of the developments and their impact on birds and habitats of conservation. He claimed the development of 16 turbines at Croan is likely to impact on ten sites of conservation importance in south Roscommon, including three nature 2000 sites at Lough Croan, Four Road Turlough and the River Suck Callows, with particular concern expressed about the impact on Whooper Swans, Greenland White-Fronted Geese and Golden Plover. The second development would adversely impact on both bird and bat species, it was alleged.

There is also the habitat impact. For example, Carrickaduff wind farm in Donegal requires 121 hectares of deforestation. This impacts other bird species and bats.

The problem for bird of prey numbers is that many wind farms are built in high areas with high winds - the same areas most bird of prey species occupy. The Bird Societies in Ireland seem to think that wind farms and birds of prey are compatible but I see no evidence for how this could be. The wind industry certainly don't care about birds as can be seen in some of their planning applications for wind farms in areas of special interest.  It is left then to local objectors and true bird enthusiasts to defend these majestic animals from this new attack on their existence.

Storm Desmond - the problem with too much wind energy in one graph

Forecasted Wind energy output for 6th December, the day after Storm Desmond, shows a loss in wind generation of 91%

As I write, Storm Desmond is raging outside my window and wind energy output is providing almost 50% of demand. It is coming at a price, however, with ESB Networks reporting that about 12,000 customers had to go without power today due to damaged cables. But electricity is not just required on a Saturday, it is required every day. According to Eirgrid forecasters, wind energy output is forecast to drop by as much as 91% tomorrow, from nearly 2,000MW to 160MW over 16 hours. (a drop in capacity factor from 87% to just 7%)

This explains why wind has such a low capacity credit. Let's look at what Eirgrid had to say in 2009 :

However, the benefits [of wind energy] tends towards saturation as wind penetration levels increase. This is because there is a significant risk of there being very low or very high wind speeds simultaneously across the country. This will result in all wind farms producing practically no output for a number of hours (note that turbines switch off during very high winds for safety reasons). In contrast, the forced outage probabilities for all thermal and hydro units are assumed to be independent of each other. Therefore, the probability of these units failing simultaneously is negligible [Eirgrid 2009].

What they mean is that a gas power plant (CCGT) of 400MW might drop out but will do so independently of another gas plant. So that would be a loss of 400MW which standby reserve would adequately replace. But wind farms do not act independently of each other.  Instead, when one drops out, chances are the rest of them will aswell. So now you have a huge hole in generating output of about 1,900 MW, equivalent to about 50% of tomorrow's demand. So you need to have about 5 large gas plants ready to step in. Starting these type of plant up from "cold" is not a good solution as engineers have stated that this is 20 times more damaging to plant than "warm" starts. It is also very expensive and high emitting in pollutants. So gas plant are kept running on low load behind the wind and will then step in tomorrow to pick up the load as wind slackens off. 

Eirgrid are lucky in that the wind is forecast to decline over a period of 16 hours. What would happen if they are wrong and it falls off at a quicker rate ? Then they may need more fast acting plant like diesel or open gas cycle turbines. These are more polluting than efficient CCGT type plant and will result in higher emissions, thereby negating some of the benefits of having all this wind generation. 

Can we close down any of our power stations and replace it with a huge fleet of wind turbines ? Can we really make a transition to a more sustainable "green" based energy supply ? 

As you can see from the above, the answer is no, not with wind farms.

October 2015 - lowest wind speeds in five to eight years

From Met Eireann :

October 2015: lowest monthly mean wind speeds in five to eight years Monthly mean wind speeds ranged from 4.9 knots (9 km/h) at Fermoy (Moore Park), Co Cork to 12.4 knots (23 km/h) at Mace Head, Co Galway. Generally monthly mean wind speeds were the lowest for five to eight years with Newport, Co Mayo reporting its calmest October since 2005 with a monthly mean speed of 7.8 knots (14 km/h). Gale force winds were reported on the 6th, 21st, 22nd and 26th all in Atlantic coastal areas. Malin Head reported both the month’s highest gust and highest 10-minute mean wind speed on the 22nd with 55 knots (102 km/h) and 40 knots (74km/h), respectively.