
The ‘solar canals’ making smart use of India’s space - palo3
https://www.bbc.com/future/article/20200803-the-solar-canals-revolutionising-indias-renewable-energy
======
vishnu_ks
> The running water helps the panels to remain cool, which increases their
> efficiency by at least 2.5-5%

Pretty neat side effect.

------
rblatz
This is an awesome idea that I hope SRP adopts here in Phoenix. We have plenty
of sun, and canals crisscross the whole valley.

~~~
AlotOfReading
Fun fact about those canals: many of them are close to 1,000 years old. The
modern incarnation largely follows the old Hohokam canal system, though some
of the newest, most expensive parts carefully deviate from it.

~~~
m463
That's a fascinating observation.

I guess it makes sense, sort of like roads probably cross mountains where
there used to be animal crossings, then human trails.

------
yaacov
There was a proposal to do this to the California aqueduct, but it turns out
they don’t lose much water from evaporation and it would be cheaper to put
them on land.

[https://green.blogs.nytimes.com/2011/04/20/could-the-
califor...](https://green.blogs.nytimes.com/2011/04/20/could-the-california-
aqueduct-turn-into-a-solar-farm/)

~~~
trackone
A quick google search found this PDF as my first result:
[http://watermanagement.ucdavis.edu/files/4114/3891/2385/A01_...](http://watermanagement.ucdavis.edu/files/4114/3891/2385/A01_Burt_Good_Shachar_Pascual_ESM121_FinalReport.pdf)

According to that paper, 700 miles of canals lose 9300 acre feet of water per
day. They say the price per acre feet (in 2015) was $107. Almost a million
dollars per day is lost according to that paper. And California hasn't been
cooling down since 2015.

It looks like the paper looked at one section of the canal and extrapolated
the evaporation loss to the rest of the canal system in California.

*this paper seems to be from a class at the university. Just using it as an example that it might be more evaporation than stated above

~~~
newyankee
smaller width canals are more suited in terms of the cost of the structure to
support the panels or so i feel ?

------
renewiltord
This is very cool. I love it. These canals are not particularly pretty so I
think the panels are an upside in aesthetics. Look very futuristic.

------
mywacaday
What about the impact to birds insects and animals that access the canal for
water?

~~~
hexagone
These are V-notch canals, made of cement and carry fast moving water. Not many
creatures will try swimming or drinking in it. There are smaller mud canals
that carry water from these to the field. Insects, birds, and animals can be
found there.

------
quaintdev
Offtopic

> The emissions from travel it took to report this story were 0kg CO2. The
> digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page
> view.

Isn't 1.2g per page view huge amount? I wonder if we can have api for this.

~~~
Baeocystin
Some envelope math. From
[https://www.eia.gov/tools/faqs/faq.php?id=74&t=11](https://www.eia.gov/tools/faqs/faq.php?id=74&t=11)
, I get .99 pounds of CO2 per kWh. That converts to 449 grams. Splitting the
difference between 1.2g and 3.6g, we get 2.4g. 2.4/449= 0.00534 or ~0.53% of 1
kWh consumed, or 5.3 watt-hours. Which does strike me as rather high.

~~~
adrianN
The page took 20s to load for me. That's about 1kW to get the ~5Wh. That seems
reasonable. Just my internet equipment consumes about 50W, and there are many
servers involved in loading a BBC page.

~~~
throwaway_pdp09
Loaded in well under 2 secs for me (no JS, all ads blocked, not that there
will be on the bbc)

~~~
Baeocystin
Makes me wonder just how much power/carbon waste goes in to ads vs content on
the modern web.

~~~
throwaway_pdp09
Tell you what, why don't you give it a try? It should take 30 secs to disable
JS on firefox, then see how it feels, re-enable it afterwards. See what a
snappy web can feel like (when it doesn't break, which is ~30% of the time).

I keep saying it, strange that nobody has ever said that they tried it. There
seems to be some weird mental block around trying something new, even if easy
to do and with possible benefits. Why is this?

~~~
throwaway_pdp09
I'm going to ask again if someone would PLEASE give this a try and tell me
what you think. Just 15 minutes, no more, just so we can get an unbiased
opinion (ie not mine).

If it turns out to be tolerable then you've got a trivially easy way of
cutting carbon use, a little.

thanks

~~~
stuaxo
The BBC page didn't seem to load at all, clicking the link above.

BBC is a bad choice as they don't have traditional ads, just ones for their
own content.

Another note: the preference to disable JS is not surfaced in Firefox unless
you go to about: config, so it is a little fiddly.

~~~
throwaway_pdp09
Finally, some feedback! thanks.

The link I see is [https://www.bbc.com/future/article/20200803-the-solar-
canals...](https://www.bbc.com/future/article/20200803-the-solar-canals-
revolutionising-indias-renewable-energy) and it works fine for me. What do you
see?

I'm very surprised about the JS, when I used firefox (I now use palemoon) it
was under preferences. Noted, thanks.

~~~
Baeocystin
Not the person you replied to, but to add to the subject, just uBlock Origin
on Chrome and the page loads in a second or two, with 11 elements blocked. If
I also disable Javascript(1), it loads even faster, but the difference between
the two is on the order of half a second, so minimal in practice.

((1) I use the Quick Javascript Switcher extension
[https://chrome.google.com/webstore/detail/quick-
javascript-s...](https://chrome.google.com/webstore/detail/quick-javascript-
switcher/geddoclleiomckbhadiaipdggiiccfje) )

------
floatrock
A much better example of multi-use space than solar roads.

------
whatshisface
> _To maximise the absorption of energy, the solar panels should face south,
> but the canal’s direction cannot be dictated._

Why does the panel have to be tilted forwards along the row? Can't it be
tilted in any direction relative to the others?

~~~
clomond
For every spot on earth there is an optimal angle of a solar panel / plane to
capture the maximum amount of light (Even at any given moment in time). It is
for this reason that panel for panel, the most efficient way of operating a
given panel are with “duel-axis” trackers. [1]

In the absence of these, and factoring in the complications involved with an
always operating mechanical component, you can have a “fixed axis” which is
the theoretical best point for that place on earth. Most racking systems
assume a rigid NxN rectangular grid, so having something that is commercially
out there that follows the space exactly may be tough.

[1]
[https://en.m.wikipedia.org/wiki/Solar_tracker](https://en.m.wikipedia.org/wiki/Solar_tracker)

~~~
gumby
Trackers are expensive and require maintenance. About 10 years ago The cost of
the trackers exceeded the cost of land and panels almost everywhere, and so
you Don’t see them anymore except in very unusual applications.

------
newyankee
This helps control evaporation losses as well, the water flow in canals is
more predictable which helps. Also there is a great potential for floating
solar especially behind existing hydro as the grid infrastructure almost
exists.

~~~
xaedes
A good point from a dead comment : "I wonder how this would affect the
climate, the rains especially."

Reducing water evaporation should have some kind of effect. Does anybody know
of weather and/or rain effects due to these evaporation preventing floating
black balls on reservoirs?

~~~
usrusr
Less evaporation losses means more water will reach irrigation networks where
it will evaporate anyways (either before or after temporarily becoming part of
a plant)

------
kstenerud
This is great in theory, but if they cover all the canals it will
significantly hamper Knightboat's effectiveness.

[https://www.youtube.com/watch?v=uoV1-fsFCmw](https://www.youtube.com/watch?v=uoV1-fsFCmw)

~~~
dhosek
There's always a canal!

