Powering Your House with Flowing Water: There’s Beauty in that Silver Singin’ River
Here’s a video suggesting that hydrokinetic energy can power your house. Of course it can, but the video is misleading on a couple of levels:
1) It suggests that this technology for converting the kinetic energy in moving water to electrical energy is superior to what’s currently available; it isn’t.
2) It implies that many houses can take advantage of water flowing through or near to their properties; they can’t. Here’s why:
The energy released by a mass falling due to gravity = (mass * height * gravitational acceleration)
The average American home uses 30 kWhs/day = ~100 million Joules/day. If you have a creek in your backyard that falls one meter between your property lines, across, let’s calculate the flow of water required.
10 million = X (mass in kilograms of water) * ~10 (gravitational acceleration in meters/sec²) * 1 (meter height). Solving for X, we get 10 million Kg, or 2.5 million gallons/day or 250 gallons/second, or about one bathtub full of water /second. (Add more to account for efficiency losses of at least 20%.) That’s not Niagara Falls, but it’s not a little creek.
For extra points: Who wrote this:
There’s beauty in that silver singin’ river?
There’s beauty in that rainbow in the sky
But none of these and nothin’ else can know the beauty
That I remember in my true love’s eye
Yikes!!! 30kWh/day??? That’s the problem right there. I don’t think I got above 13kWh/day so far this year and usually hover around 10 and have seen less than 9 last year and am trying for less than 8 at some point this year.
Really though you only need to harvest 1250 watts (4.2ish million joules) or so to make this work.
I can’t play that video again on my phone to see how much power this makes. Have to wait until I get home.
That your electricity consumption is incredibly far below the national average surprises no one, given you penchant for efficiency. 🙂
It says it can generate 20 MW, “enough for a (very) small city.” Of course it can, given enough water and enough fall. The Grand Coulee Dam has a nameplate capacity of 6.8 GW.
Home energy efficiency has always been key to moving toward sustainability. From the aging CFL’s to newer LED’s and beyond, household efficiency measures of all sorts yield cost savings and make distributed generation more viable.
And yet somehow I can’t get people seriously interested in the simple yet very functional products which I represent that stop people from literally throwing money and energy down the drain.
Craig,
Um, er, hung on I’ll get back to you when I stop daydreaming about the accompanying photo,..you have excelled yourself ! 🙂