Comments on: London Array Wind Farm, Soon World’s Largest Wind Farm, Begins Generating Power

By: Jonathan_Justice

Jonathan_Justice — Fri, 05 Jul 2013 19:03:00 +0000

This discussion of metrics suggests that there needs to be a ‘box score’ on pieces like this that can be quickly compared to other projects box scores. It would also suggest that there ought to be a link to more detailed discussions of how the outcomes can be understood.

In a somewhat different direction, Links to publicly compiled performance data would also engage some of us. I might prefer live data about today’s performance, but even summaries of the months since installation was completed would be something.

By: Zachary Shahan

Zachary Shahan — Mon, 21 Jan 2013 08:47:00 +0000

Agreed.

By: Kompulsa

Kompulsa — Mon, 14 Jan 2013 15:13:00 +0000

Very few people know the size of any power plants, this is nowhere near a useful comparison for the average person to understand.

They don’t even know what average power plant sizes are, this is why the number of houses comparison is much more relevant.

By: Zachary Shahan

Zachary Shahan — Fri, 02 Nov 2012 01:58:00 +0000

To someone well versed in this field, as you are, this may be irritating, but i think it really does help to convey the size of the project to a common person (which many of our readers are). The # will never be perfect, but i think it is done well enough and a useful enough note for most readers that it is worth making such notes.

By: Bob_Wallace

Bob_Wallace — Thu, 01 Nov 2012 20:05:00 +0000

Equally meaningless to the average person on the street. I think it more likely people have a rough idea of how much electricity their house uses than what a “620-MW Vermont Yankee plant” means.

By: Bill_Woods

Bill_Woods — Thu, 01 Nov 2012 19:30:00 +0000

It’s a UK wind farm so I used UK referents. Wales is a common standard (though usually for area). http://en.wikipedia.org/wiki/List_of_unusual_units_of_measurement#Wales

For an article intended for US readers, use, e.g.,
‘almost half as much as the 620-MW Vermont Yankee plant’, or
‘almost 40% of the electricity consumption of Vermont’.

The EIA’s figures show what a lousy unit the ‘household’ is. It’s as if gallons in TN were more than twice as big as the gallons in ME. And this case also shows it: the London Array is using a figure of 4478 kW-h per household — quite different from the 3300 kW-h figure Anne found.

By: Bob_Wallace

Bob_Wallace — Thu, 01 Nov 2012 17:45:00 +0000

A “useful specific comparison” is what I’m after.

”about 1/4 as much as the 1200-MW Sizewell B nuclear plant” does not mean jack to the ordinary person. The typical American has no idea how many people live in Wales (most couldn’t find Wales on a map).

From the EIA –

“In 2010, the average annual electricity consumption for a U.S. residential utility customer was 11,496 kWh, an average of 958 kilowatthours (kWh) per month. Tennessee had the highest annual consumption at 16,716 kWh and Maine the lowest at 6,252 kWh.”

Most people do understand what a US house is.

By: Bill_Woods

Bill_Woods — Thu, 01 Nov 2012 17:08:00 +0000

First give the actual number, then give some useful specific comparison. Apparently it’s expected to generate about 2.1 TW-h per year. http://www.londonarray.com/downloads/london_array_brochure.pdf

That’s ‘an average power of 240 MW’,
or ‘about 1/4 as much as the 1200-MW Sizewell B nuclear plant’,
or ‘more than 10% of the electricity consumption of Wales’.

By: PatLogan2

PatLogan2 — Thu, 01 Nov 2012 11:58:00 +0000

2.2TWh from a nominal capacity of 630 MW is a capacity factor of 40%.
According to the 2010-11 Renewables Obligation Annual report, the average capacity factor for UK offshore wind is considerably lower than that.
At the end of that period, approximately 1,500MW of offshore wind was accedited. Of that approximately 570MW was accredited during the year – so we can assume an average of roughly 1215MW through the year.
total issuance of ROC for offshore wind through the year was 5.1 million.
The 570 MW of newly acredited sites received 2ROCs/MWh, and the older units 1.5 ROCs.
So, on that same averaging basis, we’ll have seen 930MW of the capacity getting 1.5 ROCs, and 285Mw (averaged over the year) getting 2 ROCs. That gives a weighted average of 1.61 ROCs/MWh.
SO, the 5.1 million ROCs equates to 3.17 million MWh.
3.17 million MWh from 1215MW of capacity gives an average capacity factor of 29.7%.
If anything, a better assumption would have been about 1.65TW.

By: Bob_Wallace

Bob_Wallace — Wed, 31 Oct 2012 21:29:00 +0000

What metric do the two of you suggest for communicating the size of whatever to people who don’t know what MWhs mean?

By: Bill_Woods

Bill_Woods — Wed, 31 Oct 2012 21:08:00 +0000

The other one is 'equivalent to taking y number of cars off the road'.

By: Anne

Anne — Wed, 31 Oct 2012 12:34:00 +0000

The more is read this ‘x number of households’ metric, the more I am starting to hate it. It is about as useful as a rubber yardstick.

A big problem is that most electricity is not used in households, but in factories and office buildings. The ‘households’ metric silently inflates the impact of this wind farm. 470,000 households is about 1.5 percent. But 630 MW of offshore wind power generates ~2.2 TWh anually, which is 0.6% of the 365.3 TWh electricity generated in the UK in 2011. But yeah, what sounds more attractive: ‘470,000 households’ or ‘0.6% of electricity’?

According to Ofgem, the typical British household consumes 3300 kWh annually. That would mean this first phase is good enough for ~670,000 households, not 470,000. My guess is that the author of the article used the capacity factor of onshore wind to determine annual output.

By: Neil Blanchard

Neil Blanchard — Tue, 30 Oct 2012 19:29:00 +0000

Will the windmills be ugly or pretty ones?

Neil