Saturday, January 3, 2009

Winded Power

What is it about 3rd January? This day last year saw wind speeds drop to near zero across Ireland, with a resultant drop in electricity output from wind generation - as the chart shows. The same thing seems to be happening again, as reported by EirGrid.

At 10.30am this morning, total wind generation had fallen to 63MW - that's just 6.8% of a total installed capacity of 920MW. At 2am on Friday 4th January 2008 last year total wind generation fell to 11MW - so we may not be at the bottom yet.

It doesn't matter of course so long as we have back up generation ('fully dispatchable' to use the jargon) in the form of gas and coal fired power plants. The problem is that we are winding down our fully dispatchable generation capacity whilst winding up our non-fully-dispatchable capacity. The sort that only works when the wind is blowing ...

Here's what EirGrid has to say about wind in its latest Generation Adequacy Report (pdf):
In the last number of years there has been a rapid increase in installed WPG. Installed capacity has grown from 145 MW at the end of 2002 to the 920 MW as of 1 September 2008, with a further 1457 MW committed to connection.

... There remains very significant interest in the development of further WPG. Beyond committed projects, there is a 168 MW tranche of wind capacity being progressed under the Connection Offer Process. There are approximately 7 GW of wind applicants awaiting a connection offer. At the time of writing, the CER had published a proposed direction paper directing the system operator to process 3,900 MW of wind as part of Gate 3. This is in addition to a significant amount of conventional generation that is expected to be part of this Gate process.

... energy supplied from WPG has increased in recent years. In 2002, just 1.6% of Ireland’s electricity needs came from WPG. Despite rapid electricity demand growth in the interim period, at the end of 2007 the share provided by WPG, (of a larger demand figure), had grown to 7.1%. 2007 was considered to be a “poor” wind year in terms of nationwide average wind speeds. From consultation with industry it was found that this below average wind speed is within expected wind speed ranges. Wind conditions seem to be recovering so far in 2008.
These are extraordinary numbers - and paint a worrying picture given the Government's ideological goal of generating 33% of electricity from renewables by 2020. According to EirGrid, current projections estimate that 4371 MW of wind and other renewables would have to be connected by 2020 to meet the 33% target. This would rise to 5405 MW to achieve a 40% target in 2020. Mostly from wind - which tends not to blow a lot this time of year.

Still, there'll be a big market for woolly jumpers - assuming there are any retailers left to sell them ...


  1. Please substantiate your claim that we are winding down our fully dispatchable plant capacity! It would seem to fly in the face of a lot of recent and planned investment in such plant - both with respect to combined-cycle baseload plant and open-cycle peaking plant (which can also be brought on or off the system quickly due to fluctuations in what wind energy can deliver)...

  2. Take a look at Table 4-C on page 37 of the Generation Adequacy Report (pdf version), it shows a net reduction of 209MW of fully dispatchable plant capacity by 2012.

    EirGrid expect there will be more fully dispatchable capacity thereafter - but not before - and a net reduction in the meantime. The completion of a second high capacity cross border transmission link in 2013 show alleviate the shortfall.

  3. Nothing wrong with wooly jumpers. Or wood burning stoves. They are not symbols of the dark ages you know. Still, I'd like to see wave and tidal getting a move on, liking the look of for one, and tidal, well, unless the moon decides to feck off someplace we shouldn't run short on that. Open Hydro are another interesting one on that front.

  4. Another great post Gerard.

    I think the following quote is highly instructive: "Wind power has a separate set of problems, not related to mechanical failure, but rather to the variability of wind itself. In the winter of 2006/7, the median wind supply [in Ireland]
    expected to be 283 MW, but it ranges between 51 MW to 556 MW
    for 80 per cent of the time." This comes from Electricity Shortages in Ireland: Likelihood and Consequence by Richard Tol and Laura Malaguzzi Valeri, ESRI, 2006.

    I'm far from convinced that planned increases in wind capacity will do much to resolve this reliability issue. Ireland is a small enough place, and when the wind isn't blowing in one place it's generally not blowing elsewhere either.

    The only reason the Danes have made such a success of wind is their geographical location. When the wind is blowing they can export electricity to the large German market to their south, or essentially store it by sending it to Norway which can switch off their hydro plants instantaneously.

    What bothers me most is that the debate on this issue in Ireland takes place in the context that no acknowledgment that genuine trade-offs exist between security, value and environmental sustainability in powergen. Nor is any attempt to quantify and compare the economic impacts of the power mix made either. The ban on nuclear (which, quite remarkably, has a legal grounding) is made on a 'just because' basis, as is the blind pursuit of wind, which, as we've seen on calm days like today and yesterday, raises a lot of questions.

    Thriftcriminal: please don't make the glib assumption that open fires are in any way desirable if you're young enough to never have had to live with one as your only source of domestic heating. A quick chat with anyone born before 1940 would sort out any misconceptions you might have on this one!

  5. I think you might find I did not refer to an open fire at any stage. I also did not use the word 'desirable', I did say that their use does not mean a return to the dark ages. I successfully use a wood burning stove (by definition not open) to keep my gas usage to very affordable levels (about 1/4 that of others I have spoken to).

    Glib enough for ya?

  6. And lets be clear about wind and tidal - although they are often lumped together, they are completely different in a very important way.

    Wave energy is just as useless as wind in that it can and does drop to nothing on an irregular and unpredicatable basis.

    Tidal energy on the other hand is like clockwork, as predictable as day and night. Unfortunately it too drops to nothing at slack tide twice every day - but at least we know when that will happen!

  7. That table does not take efficiency or availablity into account, Gerard!

    Old plant that is being retired has an efficiency rate of around 45%, while modern plant is around 55-60%. Accordingly, you could replace 100MW of old plant with 75-80MW of new plant and still have the same output!

    Moreover, you then have the technical availability of the plant. Ageing plant breaks down more frequently. So the differential in megawatts above can be higher again with no loss of output.

    Interpreting the table that you highlight, Whitegate & Aghada come on in 2009/10 and Tarbet & Great Island go off in 2011. The year's differential is to allow for delay in either of the first two reaching completion. As a precautionary step, that makes massive sense.

    You also need to remember that we have brought on Tynagh and the two Huntstown CCGTs in recent years. That +/- table ignores their contribution, as it only starts the clock from 2008 on.

    Finally, that table does not seem to cover new OCGT build, which is also being developped to help bring more wind on stream.


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