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Comment by regularfry | Hacker News Reader

From the press release:

    Amazon today announced “Amazon Wind Farm Texas,” a new
    253-megawatt (MW) wind farm in Scurry County, Texas,
    that will generate 1,000,000 megawatt hours (MWh) of 
    wind energy annually

Seems optimistic. Rule of thumb is that onshore wind generates 30% of its plate rating. That's 660GHw, not 1000, for a 253MW plant. Still a nice, impressive number, just seems over-cooked.

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New (taller) turbines do significantly better than 30% capacity factors. The weighted average for 2014 vintage projects was above 40% with individual projects exceeding 50%.

https://dqbasmyouzti2.cloudfront.net/content/images/articles...

We've made a ton of progress in siting and engineering of wind turbines.

Some areas of TX have a capacity factor of 50% !

Underrated comment. Texas can't build transmission lines fast enough to export their wind power, and some utilities are giving power away for free at night because of it.

Living in Texas, while almost every provider has a free nights plan now most won't give you very aggressive daytime rates that make them worth it compared to other averaging plans (Unless you have on premis solar). Air-conditioning during the day still drives the bulk of residential consumption. I'm waiting on energy storage like zinc-bromide to mature and drop in price or something better to come along.

There is a datacenter in AZ that takes advantage of low cost night power. They have giant underground tanks full of a proprietary solution that they cool down at night, and then during the day the use it to keep the DC cool. My guess is it's just antifreeze and water, mineral oil, or something similarly boring.

It turns out this is pretty cost effective.

It should be almost trivial for a refrigeration mechanic to build a home scale system like what you have described to take advantage of free / cheap night time electricity.

It's just a heat pump with the cooling side heat exchanger immersed in glycol & water,storwge tank and a pump. Maybe some insulation. Add a heat a set of heat exchanges fir a secondary loop in to the house.

I know absolutely nothing of cooling and refrigeration, but it is an area I've been thinking of transitioning my career towards (burned out SysAdmin) and learning as a trade.

What you just described is something I actually overheard a couple of guys talking about at a neighborhood pub. A/C and Energy efficiency are bit topics in Central Texas as other posts mentioned.

Do you have any articles you'd recommend for someone with a passive interest in renewables that may cover residential projects like this?

One of my previous jobs was infrastructure maintenance in a data centre, I've worked closely with refrigeration mechanics quite a bit.

I'm at work at the moment, let me get back to you when I'm home.

Cheers!

What about the controller? Also, why not use ammonia? I can imagine that condos could also use this in places like SF.

Industrial refrigeration components are very modular, controllers capable of handling this sort of set up are available off the shelf.

The whol set up is pretty much identical to a chilled water data centre cooling set up but with a smaller chiller and a larger chilled water reservoir.

Ammonia would probably be better, I was just thinking on terms of something a fregierstion mechanic could hack together as a proof of concept in a couple of weekends.

It perhaps Texas better than average? 30% seems too round to really be across all areas of the country.

Yeah, that's not altogether unlikely. Kinda hoping someone more locally-versed will chime in.

Not sure of the exact figures, but whether or not the wind farm is in a constrained area or not generally determines if they can generate full out or if they will be capped at a lower level to keep from overloading the transmission grid.

We are seeing capacity factors well over 45% in Panhandle now. ERCOT rated the various windy areas of the state back in 2006. Scurry Co. was 10th or 14th if I remember correctly. Not as high cap fac as Amarillo and other areas north of Lubbock. But CREZ Panhandle is already constrained due to the nature of putting lines in the middle of nowhere with no load and no inertia. Scurry Co is on the other side of the constraint, so good move on Amazon's part. Great location with respect to wind resource and transmission access and deliverability.

For 2015 the average across the country was 32.5% for wind. [1] Texas appears to be several percentage points above the average, and newer plants often are better than old plants (if they have similar sites).

Here is state data from 2011-2012 [2], with a handy map [3]. It looks like Scurry County might be in a good part of Texas. In principle, the data for 2015 is available here [4], although one would have to process it.

[1] https://www.eia.gov/electricity/monthly/epm_table_grapher.cf...

[2] http://www.windaction.org/posts/37255-u-s-average-annual-cap...

[3] http://s3.amazonaws.com/windaction/attachments/1962/US-WINDm...

[4] http://www.eia.gov/electricity/data/eia923/

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