
Apple building 171 acre solar panel farm to power NC data center - shawndumas
http://arstechnica.com/apple/news/2011/10/apple-building-171-acre-solar-panel-farm-to-power-nc-data-center.ars
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0x12
> No details about the planned solar panel array or its potential power output
> are known at this time

Taking the 171 acre figure we can compute at least the limits of what it could
do.

171 acres is about 700,000 square meters. At a solar incidence of about 1 KW /
square meter and an efficiency of 23% that's 161 MW peak power and an average
of 4.7 sun hours per day will give about 750 MWh of usable electricity every
day.

This calculation ignores shading effects and assumes that the panels will be
stationary rather than tracking, you could probably easily deduct another 50%
to account for those effects, so say 375 MWh give or take and 80 MW peak.
Likely these figures are _still_ very high, think of it as the maximum amount
of solar power that you could extract at that location from incident sunlight
without further accounting for conversion losses (solar panels produce DC,
you'll need inverters if you want AC power, some data center equipment can run
on 48V DC but you'd still need a conversion step for that) and so on.

I wonder how big a chunk of the total power requirements for a datacenter that
size will be covered by this PV system, to be 100% effective it would have to
be sized _at least_ 6 times larger than the total power consumption of the DC,
using the grid as a storage system.

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maxerickson
I think you dropped 1,000.

(I would expect 161 nominal megawatts to produce more than 1 megawatt-hour in
an hour)

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0x12
Ah, yes, apologies. KWh should have been MWh, I'll edit the comment above.
Thanks for the correction.

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gallamine
For the curious, here's a link to the Google Maps satellite view of the plant:
<http://g.co/maps/sk9vn>

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juiceandjuice
>
> [http://www.greenpeace.org/international/Global/international...](http://www.greenpeace.org/international/Global/international/publications/climate/2011/Cool%20IT/dirty-
> data-report-greenpeace.pdf)

I can't imagine any scenario where Greenpeace would actually be happy besides
companies never using any sort of energy at all.

To replace coal (7PWh) with solar energy, you'd need the entire state of New
Jersey (~22e9 m^2) filled solar panels averaging 20% efficiency and the
equivalent of 4 peak hours of sunlight over the year. With the area of
Pennsylvania you could start to approach the total energy consumption of the
US. Maybe those environmental impacts would be worth it?

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Derbasti
You know, I recently rode my bike through some villages in Germany. Just about
_every_ house had solar panels on their roof. My parents have solar panels on
their roof. They produce more electricity than they use and only need very
little oil and some wood for heating in winter. And they are no exception.

Germany currently produces 20% of its energy using regenerating resources
(water, sun, wind).

It's not like you have to put all the solar panels in huge parks. Just put
them on roofs. My uncle works at a big company and they just put solar panels
on their roofs. That company now produces more energy than they need. Solar
panels are already efficient enough to usually provide more energy per area
than people or businesses consume in the same area.

The next step would be to have batteries in every household, to save on energy
losses during 'transportation'. Also, solar panels are getting more efficient
and cheap every year.

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goodweeds
This would be a great trend, datacenters becoming their own utilities. It
would help them better control opex and reliability. I wonder if utilities
will try and prevent this sort of self-sufficiency from otherwise potentially
lucrative customers.

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hugh3
Sunlight is one of the _least_ reliable forms of power out there. If the grid
goes down then... well, you're screwed unless it just happens to be daytime
and sunny.

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jayfuerstenberg
Knowing Apple's recent interest in glass and materials science I can't help
but wonder if even their solar farm will be awe inspiring and functionally
ahead of the curve in some way.

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cwe
Don't know enough about this project, but are the putting them on the roof of
this datacenter as well? Seems like a no-brainer.

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nobody3141
Comparing it to the installed Sarnia plant at roughly the same latitude.

That is 96.6 ha (239acres of cells) 80MW capacity and (estimated) 120,000 MWh
over a year.

So this plant should achieve around 70% of that, so 85,000 MWh /year or
235MWh/day

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goodweeds
I actually drove through Sarnia a couple of months ago trying to find the
site, but couldn't find it. Has it been completed yet?

