Tidal Power Options in San Francisco Bay Being Explored

[jpak]

http://www.renewableaccess.com/rea/news/story?id=49018

Pacific Gas and Electric Company (PG&E) signed an agreement with the City and County of San Francisco (CCSF) and the Golden Gate Energy Company to conduct a comprehensive study to assess the possibilities for harnessing the tides in San Francisco Bay.

In addition to being clean and renewable, tidal power offers the advantage of being highly predictable and reliable.

PG&E is committing to provide up to $1.5 million to fund research by third-party experts, dovetailing with up to $346,000 contributed by CCSF for feasibility studies and stakeholder outreach.

"Exploring the potential for harnessing the tides in the Golden Gate to deliver new supplies of clean power to our customers is one of the most exciting renewable energy possibilities being explored anywhere in the world today," said PG&E Chief Executive Officer Tom King.

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[glitch]

1. That would be awesome. K & R nt

[poverlay]

2. Tidal/ wave power is the most reliable, clean, and potentially safe power

technology out there. Recommend for sheer excitement value!

[hunter]

3. -dupe-

...noted here because I have a healthy ego, and liked my reply to the first post...

:P

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=100748&mesg_id=100748

[AndyTiedye]

4. I Like

:kick:

[silverweb]

5. 'bout time.

What took them so long?

[mopinko]

7. it's harder than it looks.

my dad wanted to do this in the 60's. there were people looking at it back them. the hard part is making something that can withstand the pounding of those tides. it's hard.

[diane in sf]

6. Most of the people of the world are near the oceans--this could be great.

They've been working on it awhile here

[hunter]

8. I'm opposed to most tidal power schemes.

They disrupt coastal environments.

It's appalling to me that anyone would suggest one for the bay, but I suspect they will eventually be built as flood control projects as the seas rise.

That, and a peripheral canal to collect fresh water, will be acts of desperation, and are not something to look forward to with any sort of optimism.

[Xithras]

9. Tidal turbines are relatively benign.

When placed in deep water channels with large, low RPM turbines, tidal power schemes can be implemented with little impact on their environment. The SF Bay happens to have a deepwater channel running down its center (the old river valley) which is perfectly suited to this kind of work.

The danger, of course, is that someone will propose a barrage system for the mudflats. Barrage systems are INCREDIBLY destructive to the environment and eliminate shipping and fish habitat. Unfortunatly, they also generate more reliable power and have been the favored design historically. I doubt it would fly in the Bay Area though.

[hunter]

11. Aha! It's like a shooting gallery for all the crap blasting out of there.

Huge logs, ropes, cables, nets, plastic shopping carts, ballot boxes (no, seriously)...

:woohoo:

Just for fun I've sometime watched what they pull up out of the shipping channels.

[LeftCoast]

12. What is a barrage system?

I hope it's not the one I like - Floats out off shore that generate electricity through the up and down wave motion. I've always thought those would be the most environmentally friendly.

[lfairban]

13. No, it isn't.

It is kind of like a small dam.

http://en.wikipedia.org/wiki/Tidal_power

[Xithras]

14. A big dam.

They generate power by exploiting the difference in water level between the inside and outside of the dam. To work, they require that you dam off estuary or mudflats and isolate them from the rest of the bay. As water flows into the dammed area through the turbines, it generates power. When the tide reverses, it generates more power as the water flows back out. The advantage of the system is that you can control outflow to allow power generation throughout the tidal cycle (slow outflow down). The disadvantage is that it destroys the environment inside the dam structure.

Freestanding underwater turbines are more like wind turbines. They don't generate as much power as barrage systems, but they do little to no harm.

People have experimented with systems like you suggest, and the problem is durability. Large floats on the surface would take an incredible pounding in storms, and would be incredibly expensive to install. The concept does work, but the operating costs to replace and repair the floats are through the roof.

[LeftCoast]

15. Ah! Thank you both!

As I understand the plan, they're thinking of putting this right at the Golden Gate, so a barrage system would be out. It would block the shipping channel.

[Xithras]

17. Locks

Barrage systems can be implemented without blocking the shipping channel by implementing locks. The shipping lane doesn't neccesarily wipe it out.

Of course, barrage systems WOULD wipe out the northern California steelhead and salmon runs, which are already endangered. It would also destroy the seal population, thereby erasing the only remaining purpose for Pier 39...which may be a good thing or a bad thing, depending on your perspective. A barrage system would lower the salinity of the Bay too, changing the ecological balance of the saltwater marshes around the bay.

I really doubt that anyone could build a barrage system on the SF Bay. It's technically possible, but you'd have people chaining themselves to bulldozers and protesters by the thousands shutting down the worksites. Bay Area residents seem to be pretty good at mobilizing for important environmental causes, but there are enough exceptions to make me concerned (Bay Area residents ignore the ongoing ecological genocide of the Hetch Hetchy valley because it benefits them. If they'll ignore that, it's theoretically possible they'd ignore this too).

[NNadir]

10. This will differ from the 2005 study in what way?

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9893/32012/01489761.pdf?arnumber=1489761

I do recognize that generating studies is a great way to employ people, but I would guess that this idea has been the subject of "studies" for several decades now.

[GreenPartyVoter]

16. Yah. Time to actually do something