Water in Oregon pipeline is tapped for electricity | Hacker News Reader

Water in Oregon pipeline is tapped for electricity

pennenergy.com

26 pointsjonbaer14 comments

Just had to post this: http://what-if.xkcd.com/91/

California has a similar, but much larger, hydroelectric plant where the California Aqueduct reaches the Los Angeles basin.[1] It's reversible; it can be used either for power generation and pumping. LA Water and Power usually pumps water uphill late at night when power is cheap, then lets it down in midafternoon when power is expensive.

[1] http://en.wikipedia.org/wiki/Castaic_Power_Plant

Wait what ?

If it is what I think it is, that would mean extracting energy from the water's movement, movement that most likely has been created via pumping. So... moving energy from pumping back to energy, with most likely a big loss in the process. Anyone to explain me what I didn't get ?

From the article: "The LucidPipe™ Power System uses the gravity-fed flow of water inside a PWB pipeline to spin four 42” turbines that are now producing electricity for Portland General Electric (PGE) customers under a 20-year power purchase agreement (PPA) with the utility"

No pumping required.

Presumably Portland's reservoirs are located somewhere uphill (in the Cascades even?) so this would be exploiting a natural gradient.

The reservoirs are indeed elevated around here -- washington park, mt tabor, powell butte -- so it's all gravity fed.

Gravity.

They can do this in New York as well, they get 95% of their water from gravity fed sources - so much that they have to install periodic pressure-breaks as the water comes down from mountains to avoid too much pressure in the system.

> "each has an individual output capacity between 20 and 100 kW"

That's a pretty good amount, yeah? Enough for a number of houses.

"The project will generate approximately $2 million worth of renewable energy capacity over the 20-year PPA period, enough electricity for more than 150 homes in Portland."

100kW * 24 * 365.25 * 20 = 17532000 kWh over it's lifetime.

$2,000,000.00/17532000 ~= $0.11/kWh.

Not bad for renewable power, absolutely terrible for hydroelectric ($0.01-0.03 / kWh on average).

And that's assuming full capacity (100kW)... That's too bad.

But I don't quite understand what you're doing with the $. You're taking how much it'll generate in kWh vs how much they say it'll generate in worth of energy and getting a $/kWh. But isn't the $kWh just determined by the market?

Why not: 2,000,000 / .02 (your number) = 66,666,666 kWh over the lifetime of the 'project', not individual units, which has 4 turbines (this is a similar value to yours x4).

You're right, that's not a fair comparison.

(I'd guess the real cost of power from this is >$1.00/kWh btw since it will almost certainly not last 20 years...)

We changed the url from http://phys.org/news/2015-02-oregon-pipeline-electricity.htm..., which points to this. If anyone can suggest a substantive article on the subject that isn't a press release, we can change it again.

The same new was submitted a few days ago from a different source that has a little more of information. https://news.ycombinator.com/item?id=9041249 (2 points, 9 days ago, 0 comments)

Reply on news.ycombinator.com