Tidal Energy Idea

[Pal]

http://www.energeticforum.com/renewable-energy/13479-gravity-energy-source.html

[Ein~+ein]

I see you're back to the idea of using decommissioned barges (or oil rigs) but if they're decommissioned due to corrosion, you're no further ahead. Did you notice corrosion as one issue with tidal generation although it can be reduced (to what extent?) through ionization and if you're generating electricity, that's not a problem.

The ideas we discussed on that previous thread may be worth looking into. You may wish to contact university or gov't departments, environmental NGOs, etc to get an idea as to how feasible these ideas are. The next step then is to initiate public discussion about going ahead with them:

a) inserting micro-hydroelectric generators into canal lock inlet/outlet ports

Let's assume we have a 5 metre x 25 metre lock with a 5 meter drop that takes 5 minutes to fill or empty. That's 2.08 cubic meters/second falling an average of 2.5 metres producing 20 to 35 kWs. That's not much but how does it compare with small-scale solar or wind for initial cost and return on investment? The only question is about 'system efficiency' which is said to range from 40 to 70% in these micro-generators. Does it drop exponentially when water levels approach equilibrium due to backflow?

Gross Head x Flow x System Efficiency x C (a constant) = Power (kW)
2.5 m drop x 2.08 m3/s x from 40-70% x 9.81 = 20 to 35 kWs

Recommendations:
1. contact micro-hydroelectric generator manufacturers/distributors to discuss the feasibility, system efficiency.
2: Contact canal operations staff for specifics: lock capacity, water throughput.

b) Surface-based wave generating platforms (possibly coupled with some underwater current capture mechanism) to take over the functionality of protective breakwaters near harbours or coastal regions threatened by by erosion.

Recommendations: same as tidal--see below

c) Tidal power: here's what the the Canadian Encyclopedia says:

"... estimates of hydroelectric potential do not include the long-recognized but still undeveloped TIDAL power potential of the Bay of Fundy in NS, a major source of low-head hydro power adjacent to populated areas of NS and NB. Like river-based hydro, tidal power is a natural hydraulic source that can be converted directly to mechanical and electrical energy by means of a turbine. However, tidal power is very expensive to develop, and the cyclical nature of the energy makes it less useful than river-based hydro."

Without having looked into the mechanics of tidal generating, that last comment intrigues me. One would think, as with wind turbines, any reversal of water flow wouldn't affect the ability to harness the energy. Furthermore, river-based hydro would seem even more cyclical, dependent as it is on seasonal and weather conditions? How many rivers and streams only capture a fractional amount, particularly in spring?

Recommendations:
1. Get the facts the figures behind the assertion that: "...tidal power is very expensive to develop."
2. Compare them with current state-of-the-art technology and costs

[Pal]

[Ein~+ein]

a. Corrosion is a factor. Prebuilt empty hulls could be made of corrosion resistant metals (oil rigs stand in salt water for a long time).

Corrosion-resistant metal isn't cheap. Now you know why it isn't feasible.

Micro hydro generators have a low output but using several locks in a canal would increase the total output.

The value in this is is that it tests and helps focus a jurisdiction's commitment to renewables. As I recommended, we'd need to consult with micro-generator suppliers/canal operators to verify the feasibility. Shall I do this or do you want to take this on and report back?

Probably? We won't know unless we fact-check that encyclopedia entry--it could be merely conjectural based on past energy projections? As for the Annapolis tidal station, that same link provides its MW capacity--a tiny fraction of the entire proposal. How about you check up on this and report back and I'll do the same for canal lock micro-hydrogeneration?

[Pal]

Yes go ahead and investigate the micro-hydro generation proposal, basically it is your idea, but be careful an eager salesman might want to sell you a turbine.
In the meantime I will look into the cost factors etc. of tidal power plants and will report to you shortly.

[Ein~+ein]

I've emailed 2 Canadian micro-hydro generator distributors and also got a dozen hits on microhydropower.net for 'canal' one of which reads:

HydroVolts Big Canal Turbine installed in Washington

Working with the U.S. Bureau of Reclamation, the company this month deployed its "Big Canal Turbine" in Washington state.
The turbine was 'plunked' carefully into the Roza Canal, which moves water east from the Yakima River to irrigate crops in one of Washington's most important agricultural regions.

Hydrovolts said the device, capable of putting out up to 10 kilowatts (kW), was expected to produce 5 kilowatts (kW) in a flow of 2 meters per second. But with the water flow exceeding that speed, the turbine was steadily cranking out at least 6 kW, the company said.

This actually isn't the first time Hydrovolts has dropped a turbine into the Roza Canal; it did so last spring and summer with smaller turbines, demonstrating ... (read the rest)

So, not only is it feasible, but more efficiency than anticipated!!! As with any other 'claim', now all we've got to do is replicate it!

So, the next step would be to promote the idea among canal operators elsewhere. There are at least 2 canal systems in Ontario, Canada with locks. Any others?

[Pal]

[Pal]

[Pal]

I managed to locate a lock in England which is producing hydro power. Although it required a lot more construction work than simply placing a turbine in the water. (The first in England)
I googled: Manchester locks hydropower
The first item: Hydro-electric generating station built within a canal lock system.

[Ein~+ein]

Here's one of the 2 replies I got. It's from microhydropower.com:

Whether doing what you suggest is feasible or not is mostly a financial question. Since this would be intermittent power, it is much less likely to make sense compared to using the usual sources or hydropower which are largely underutilized on a small scale.

Regards,
Paul Cunningham, CEO
Energy Systems and Design
Email: [email protected]

By 'intermittent' is he suggesting the natural water throughput in (most?) locks is insufficient to make this worthwhile? At least we know there are locks with installed generators so the question is what throughput would make this economically viable given a jurisdiction's overall (and peak-load) electricity costs (whether from generating or from grid purchases).

I'm still looking at this from an accountant's perspective given that it's doable, but from an engineer's, I imagine it would be a single generator turbine, submerged at the base of each lock, rather than 2 separate ones for efficiency reasons but I don't know.

Thanks for listing those canal systems in Canada. I'll research water throughput when I get a chance?

[Pal]

[Ein~+ein]

But the overall contribution of micro hydro is so minute in the context of the total renewable energy picture (ethanol and wind take the lead) it can be very easily overlooked.

Solar, wind and tidal are also minute but I'd love to see a cost comparison between solar and micro-hydro (in a canal, river or creek). My brother's installed solar panels on his Ottawa bungalow rooftop--I'll ask him for details.

When I get the time, I'll find out about canal (lock) water throughput.

[Ein~+ein]

Regarding Canal Hydro-electric potential:
At least in Ontario, Canada,the Trent-Severn system currently produces nearly 100 Mws with an added potential of 50 Mws. With hydro everywhere, there's a lot of unused potential, especially in spring.