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More support for merit order effect

by Jerome a Paris Wed Mar 2nd, 2011 at 10:46:52 AM EST

I've discussed the merit order effect and its economics before (see also here, here or this article for the New Scientist), but it's good to get - again - confirmation from the real world that it's real:

Irish wind generation costs analysed
Wind generation in Ireland does not increase wholesale electricity prices and in fact, the trend is that it lowers them. This is according to a study by Eirgird, the Irish grid operator and the Sustainable Energy Authority of Ireland (SEAI).

(...) The report found that although wind generators have high capital costs, they have no short-term costs as they do not consume fuel.

By displacing higher cost fossil fuel generation, wind energy tends to reduce the wholesale cost of producing electricity.

When balanced against other costs, the overall cost impact of wind is less than half of one percent, which is within the study's margin of error.

It concludes that the increased use of wind energy on the Irish electricity system increases Ireland's security of supply and ensures a more diverse fuel supply in the long-term.

Ireland is one of the countries with the highest penetration of wind in its electrical system (more than 10% of total production as of end 2008, and increasing), and as an island, it has to deal with the supposed problem of wind intermittency on its own, something that its grid company, which prepared this report, appears perfectly able to do...

Part of the Wind power series...

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More support for merit order effect | 28 comments (28 topical, 0 editorial, 0 hidden)
Speaking of costs (none / 1)
This EER article on the UK energy market has this graph:

For some reason, Europe has managed to build 80 GW of wind on the basis of feed-in tariffs which are typically in the 8c/kWh range (80 EUR/MWh), so you wonder how the lower bound of the wind price in that graph can be at the equivalent of 100 EUR/MWh and projects not be bankrupt across Europe...

Wind power

by Jerome a Paris (etg@eurotrib.com) on Wed Mar 2nd, 2011 at 11:28:06 AM EST
Re: Speaking of costs (none / 0)
Wind power could be much cheaper?
A new 2000W vacuum cleaner costs 50e. If we couple a vacuum cleaner in reverse, it works as a generator.

Let's assume that this generator lasts 1 year. It produces 2kW*8600h = 17 MWh. So the costs are 50e/17MWh = 3 e/MWh.

by kjr63 on Wed Mar 2nd, 2011 at 01:35:34 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
forgot to mention the €3060 for the year's continuous electricity.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin
by Crazy Horse on Wed Mar 2nd, 2011 at 01:44:35 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Electricity for what?
by kjr63 on Thu Mar 3rd, 2011 at 07:53:59 AM EST
[ Parent ]
Re: Speaking of costs (none / 0)
I'm sure you realise this, but you would need a might big funnel in the wind to make a vacuum cleaner run in reverse.
by njh on Wed Mar 2nd, 2011 at 10:06:22 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
You mean the rotation speed of a wind mill is slower than a vacuum cleaner?
by kjr63 on Thu Mar 3rd, 2011 at 08:02:51 AM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Uh, yes. This should not come as an unbearable surprise to anybody who is even casually acquainted with the physics involved.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Thu Mar 3rd, 2011 at 12:09:42 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Wow. Such an "obvious" knowledge? Please elaborate. Is the wind speed so much higher in a vacuum cleaner? I have seen pretty fast rotating wind mills. What about a gearbox? That would take out as much rotation speed as needed.
by kjr63 on Thu Mar 3rd, 2011 at 12:45:26 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Is the wind speed so much higher in a vacuum cleaner?

The pressure gradient is a lot steeper (on the order of a tenth of an atmosphere per meter, while the pressure gradients generating winds are less than a hundredth of an atmosphere per kilometer). How that translates to wind speeds is a bit out of my field, but I guarantee you that you will not get a kW out of a vacuum cleaner fan if you stick it in even a gale-force wind.

What about a gearbox? That would take out as much rotation speed as needed.

Yeah. That's what windmills do. Large blades, big gearboxes. That's what makes them expensive. The generators themselves aren't, AFAIK, the main cost.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Thu Mar 3rd, 2011 at 01:59:09 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
From wikipedia:
http://en.wikipedia.org/wiki/Airwatt


Airwatt

An airwatt or air watt is a unit of power very close to the watt which is used for various vacuum cleaning systems, such as vacuum cleaners. The airwatt is derived from English units. ASTM International defines the airwatt as 0.117354 * F * S, where F is the rate of air flow in ft3/m and S is the pressure in inches of water. This makes one airwatt equal to 0.9983 watts.

The airwatt is useful measurement of vacuum power, since the power carried by a fluid flow (in the case of a typical house vacuum the fluid is air) is equal to pressure times volumetric flow rate. This could be a more useful figure than the electrical power drawn by the vacuum system's motor, since the efficiency of motor and vacuum systems varies.

If i understand correctly, this means that electric power is directly related to air flow = air speed. So if, you put a relevant rotor in the vacuum cleaner, you get 2000W. Should not be too difficult.


That's what windmills do. Large blades, big gearboxes. That's what makes them expensive. The generators themselves aren't, AFAIK, the main cost.

Hard to believe. Can a rotor and couple of gears rise price from 3e/MW to 80e/MW? I believe generator manufacturers are being screwed.

by kjr63 on Thu Mar 3rd, 2011 at 02:30:01 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
If i understand correctly, this means that electric power is directly related to air flow = air speed. So if, you put a relevant rotor in the vacuum cleaner, you get 2000W. Should not be too difficult.

No you won't. With a pressure gradient on the order of tenths of atmosphere per meter, you get a considerable loss from friction. You'd be lucky to recover 200 W from a setup like that.

Hard to believe. Can a rotor and couple of gears rise price from 3e/MW to 80e/MW?

And a tower. And grid connection. And transformers. And installation. And output governors. And you're converting a pressure gradient into electricity, which is a lot harder than converting electricity into a pressure gradient.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Thu Mar 3rd, 2011 at 04:11:19 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Similarly, you assumed that your generator would survive 8600 hours of continuous operation. Assuming that your average household vacuum cleaner is used for three hours every week, that translates to a lifespan of something like fifty years.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Thu Mar 3rd, 2011 at 04:16:55 PM EST
[ Parent ]
Re: Speaking of costs (none / 1)
The rotation of the blade tips is limited in absolute terms by the speed of sound.

Divide the speed of sound by three times the diameter of the blade to get the maximum RPM allowed (of the order of tens thousand for a vacuum cleaner, of the order of a hundred for a wind turbine).

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11

by Carrie (migeru at eurotrib dot com) on Thu Mar 3rd, 2011 at 12:42:31 PM EST
[ Parent ]
There are earlier limits (none / 1)
I think that speed close to 80-100m/s (Crazy Horse can confirm), so only a third of the speed of sound, are already a pretty hard limit, for reasons of acoustics as well as damage to the tips of the blades. So in practice, large wind turbines rotate at something like 20-30rpm or so.

Wind power
by Jerome a Paris (etg@eurotrib.com) on Thu Mar 3rd, 2011 at 12:53:51 PM EST
[ Parent ]
Re: There are earlier limits (none / 0)
Okay, if the blades were made of unobtainium the limit would be the speed of sound.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11
by Carrie (migeru at eurotrib dot com) on Thu Mar 3rd, 2011 at 05:15:16 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Sure. But naturally the same laws work in a vacuum cleaner. 2000W motor creates a certain wind speed related to the physical dimensions. And the generator speed is not limited to the rotor speed.

I'm just curious about the difference in costs between these two "machines."

by kjr63 on Thu Mar 3rd, 2011 at 12:57:48 PM EST
[ Parent ]
Re: Speaking of costs (none / 1)
A vacuum cleaner is not a reversible transducer, due to turbulence or something.  I think it's similar to the feynmann story about sprinklers in swimming pools.

Oh, and vacuum cleaner motors are universal motors, which don't make very good generators.  You generally want either an externally excited motor, a permanent magnet motor, or a synchronous AC motor for good generation capacity.  These are more expensive.

And then there is synchonisation with the grid, stability, remote control, self protection in high winds, abrasion (the vacuum cleaner turbine is in a dust free environment - I once tried to use my mum's vacuum cleaner without the bag, with a second pipe from the blow hole out the window.  It lasted about 5 minutes before it seized up.)

by njh on Thu Mar 3rd, 2011 at 06:49:45 PM EST
[ Parent ]
Re: Speaking of costs (none / 0)
Obviously generator and vacuum cleaner motor have a somewhat different construction. However, motors and generators are so similar by design that it is hard to believe significant cost difference between them. And naturally there are other costs than just motor. But so has a simple vacuum cleaner.

Anyway, Jerome's graph includes transfer price? That's half of the overall price, so the actual (end) production cost is in fact about 40e/MWh.

by kjr63 on Fri Mar 4th, 2011 at 02:09:18 PM EST
[ Parent ]
Re: Speaking of costs (none / 1)
Cheap motors are cheap.  But they don't make good generators.
by njh on Tue Mar 8th, 2011 at 05:02:43 PM EST
[ Parent ]
It might have something to do with... (none / 1)
... the assumption of double-digit return on investment.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Wed Mar 2nd, 2011 at 02:04:47 PM EST
[ Parent ]
indeed (4.00 / 3)
10% discount rate is already a "commercial" rate rather than a "social" one and, as such, is an ideological choice on what kind of energy infrastructure we want (cheap infrastructure, variable running costs expected to be low thanks to low fuel prices, rather than high infrastructure costs, low running costs) - and more generally, if we care about "me, now" or "us, later"

Wind power
by Jerome a Paris (etg@eurotrib.com) on Thu Mar 3rd, 2011 at 12:56:13 PM EST
[ Parent ]
And some concern trolling in the NYT (4.00 / 3)

Rush to Renewable Energy Generates 'Enormous' Financial Questions in Europe

LONDON -- The spectacular growth in recent years in the number and size of renewable energy sources across the European Union -- particularly wind and solar power -- driven by high subsidies and government rhetoric on climate change has left the national electricity grids scrambling to cope.

"Basically, governments have allowed the buildup of wind without thinking through the grid consequences," Oxford University economist Dieter Helm told ClimateWire. "There are two responses: Stop wasting so much on the rapid development of wind and its questionable economics, or plough on regardless, in which case enormous grid investments are urgently needed."

Estimated costs of strengthening, upgrading and smartening the grids are put at up to €100 billion ($138 billion) over the next decade alone at a time when budgets remain extremely tight and as governments either impose or contemplate cutting their generous subsidy schemes.

As usual, solar and wind are mixed, subsidy regimes and grid issues are conflated, and costs over many years are thrown in without any perspective on what these numbers mean and how they compare to what would be done without renewables. But hey, it's in the NYT, so it must be true.

Wind power

by Jerome a Paris (etg@eurotrib.com) on Wed Mar 2nd, 2011 at 11:35:15 AM EST
Re: And some concern trolling in the NYT (4.00 / 2)
The NYT is beyond reproach.  Why do you hate freedom?

Also, for all the Brits on ET, when are you people going to stop Oxford from doing economics?  Oxford does economics like Billy Joel drives.

Be nice to America. Or we'll bring democracy to your country.

by Drew J Jones (pedobear@pennstatefootball.com) on Wed Mar 2nd, 2011 at 12:10:50 PM EST
[ Parent ]
Re: And some concern trolling in the NYT (none / 1)
From the train to Bremen:

Perhaps we could write an ET Op-Ed? No reason there isn't room for some actual true experience regarding renewables in Yurp.

PS. on the way to Varel i saw fields of very old, small Enercons enjoying the fresh spring winds, long after they've paid for themselves. Still producing electricity of course.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin

by Crazy Horse on Wed Mar 2nd, 2011 at 12:38:40 PM EST
[ Parent ]
Re: And some concern trolling in the NYT (none / 1)
Dieter Helms and the usual talking points:

Interview: Dieter Helm : article : Nature Reports Climate Change

What we have learnt is that politicians tend to choose the most expensive options first. Faced with climate change, what's our solution? In Europe, it's to devote most of our energies to a rapid build-out of wind power. This is the sort of thing that makes nuclear power look cheap.

And the real enemy is coal and wind is wimpy against it and it's time to grow up and nuclear is the only way. Oh, and CCS.

Professor of Energy Policy at Oxford. Probably pulls in some nice sponsorship for the poor, struggling place.

by afew (afew(a in a circle)eurotrib_dot_com) on Wed Mar 2nd, 2011 at 04:47:34 PM EST
[ Parent ]
Re: And some concern trolling in the NYT (none / 0)
It is beyond the pale, I suppose, to explain to the "Professor" the difference between "affording" an investment that will pay for itself and an "investment" in saving big banks.

"It is not necessary to have hope in order to persevere."
by ARGeezer (ARGeezer a in a circle eurotrib daught com) on Thu Mar 17th, 2011 at 11:18:54 PM EST
[ Parent ]
Re: More support for merit order effect (none / 1)
There is a recent article in Wind Power Monthly that  is much more informative than the troll based stuff:

http://www.windpowermonthly.com/news/1057892/Wind-energy-deliver-€100-million-savings-ireland-2 020/

And since Ireland is so darn windy, why stop at 45%. Why not go for the whole glass of that fabled stout instead of leaving it 45% full on the table (isn't that against natural law?). What we haven't heard much about is pumped hydro storage in Ireland, possibly utilizing ocean water and those decent sized cliffs, such as the Cliffs of Moher:

http://www.cliffs-moher.com/

Sufficient pumped hydro should allow pretty much all of the electricity to be supplied with wind energy, though for Ireland, tides and waves could also play a part.

It's so analogous to where I used to live, on Michigan's north coast, which is, believe it or not, rockier than that part of Ireland, and just about as windy and with humongous pumped hydro energy storage capability.... And since both places have had most everything of value not impressively welded in place (bolts would just get unscrewed) long since stolen/swindled/bargained away... well, there is that point in common, too.

Nb41

by nb41 on Thu Mar 3rd, 2011 at 12:04:54 PM EST
Re: More support for merit order effect (none / 1)
Or just use continental europe as the storage.
by njh on Thu Mar 3rd, 2011 at 06:51:55 PM EST
[ Parent ]
More support for merit order effect | 28 comments (28 topical, 0 editorial, 0 hidden)


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