Comments on: Co-Locating Wind & Concentrated Solar Power Can Improve Total Capacity Factor

By: Hans

Hans — Sun, 05 Oct 2014 09:33:00 +0000

Seems to be a confusion of definitions here:

Capacity factor is the same thing as the performance ratio. It is the actual output over a year (Eout) divided by the output if the system would have operated at nominal power (Pnom):

CF=PR=Eout/(Pnom*year)

What is meant in the article is capacity credit. This is the amount of conventional baseload power that can be replaced by the renewable power plant.

End of autistic “get your definitions right you sloppy non-specialist writer person” outbreak.

More general:
For people in the know this is old news, but it is good that it gets public attention again.

Regarding the smoothing discussion by other commenters:
Geographic smoothing is important too, and for the overall system reliability you should look at the whole grid. However, smoothing locally means that you can use transmission lines more efficiently, which saves grid costs.

By: Zachary Shahan

Zachary Shahan — Tue, 05 Jun 2012 00:39:00 +0000

” How likely is it that the wind stops blowing, the sun stops shining, the tides stop flowing, the waves stop breaking, the crops stop growing the rivers stop flowing and the earths heat expires all at the same time in every location? ”

And if that happens, i think we’re screwed no matter what.

By: RobS

RobS — Sun, 27 May 2012 06:03:00 +0000

I’m not suggesting geographical distribution solves the whole issue its just one of the stronger mitigators of intermittent output. Which is exactly why additional mitigating factors like co-located complementary technologies are being discussed. Having sailed extensively using only wind and solar for well over 95% of my power needs I can tell you first hand that wind and solar are a highly complementary pairing, they naturally play off each other in that there tends to be more wind at times with less sun and vice versa so the size of the battery storage needed and the need to run a generator were both significantly reduced by combining these two technologies.

By: Bill_Woods

Bill_Woods — Sun, 27 May 2012 04:57:00 +0000

Some days that works, and some days it doesn’t.
E.g. see http://windfarmperformance.info/?date=2012-05-20
Or the UK’s wind power from 20 to 24 May 2012
http://www.geog.ox.ac.uk/~dcurtis/NETA.html

By: RobS

RobS — Sat, 26 May 2012 05:12:00 +0000

If you want to see what geographical distribution is capable of even within one technology group check out the Australian wind power output for yesterday, 25/5/12, here http://windfarmperformance.info/ if checking this later than 26/5/12 make sure to set the date in the top right corener to 25/5/12

By: RobS

RobS — Sat, 26 May 2012 04:26:00 +0000

That is true Matt but the smoother you can make the output the smaller the storage system needs to be to shave the peaks and fill the valleys in output, turning intermittent into highly valuable base load. Battery and other grid storage techniques are in their infancy and are still very expensive. Using techniques such as co-located sources and geographical distribution to reduce the degree of intermittency means the storage capacity and therefore cost is minimised. Ive always felt one of the big mitigating factors of renewable intermittency is the variety of technologies and the way they complement each other. How likely is it that the wind stops blowing, the sun stops shining, the tides stop flowing, the waves stop breaking, the crops stop growing the rivers stop flowing and the earths heat expires all at the same time in every location? Using the benefits of a diverse catalogue of renewables smoothed with a small amount of storage is the end game in my opinion.

By: jburt56

jburt56 — Fri, 25 May 2012 17:05:00 +0000

As the grid builds out the balancing act gets easier. Eurasia has some interesting possibilities as it spans so many time zones.

By: Matt

Matt — Fri, 25 May 2012 15:29:00 +0000

Would have seen the “same” effect if you placed a large battery on the wind farm. Of course transmittion utilization 24/7 might not be what you want to maximize. In fact having the storage close to where it is used to load level as needed it likely a better solution. When cost come down there will be storage of wind on the farm, for when too much wind means I can’t send it down the line yet (line cap limit) and storage closer to use for load balance.