>Dr. Tony Jones
>
>August 5
>
>Tidal Power for San Francisco?
>
>
>San Francisco is uniquely situated to take advantage of a tremendous
>tidal resource in its backyard. The City is committed to developing
>a 1 MW tidal power station within three years. A major proponent
>of this project is HydroVenturi Ltd. Their new technology, developed
>at Imperial College, has no moving parts underwater. The technology
>takes advantage of a venturi created by design of the subsea tidal
>station. All mechanical moving parts for the system are on land
>including conventional air-driven turbines used to generate
>electricity from the venturi suction.
>
>Tony Jones holds a doctorate in oceanography from the University of
>Hawaii and has worked on environmental issues related to commercial
>development of Ocean Thermal Energy Conversion (OTEC) at Lawrence
>Berkeley Laboratory.
>
> Currently, Dr. Jones consults on environmental and regulatory aspects
>of desalination and development of renewable ocean energy technology
>through oceanUS consulting, and is a Director of a non-profit group
>that serves as a clearinghouse for exchange of ideas to accelerate the
>commercially viable use of ocean-based sustainable energy systems.
>(www.poemsinc.org)
>
>Dr. Jones will describe the state-of-the-art in renewable ocean
>energy systems and the potential for use of this technology in the
>Bay.
>
Dr. Jones began his talk by explaining that there are a variety of ways to get energy out of the ocean. You can get wind power by using the same windmill technology that is used over land, and some people have proposed using this technology in places like Cape Cod, MA. You can mine the heat difference between surface and deep ocean waters. Hawaii was very interested in that in the late '70s, but the large startup investment has meant that no significant projects have been built. You can mine the salinity difference between fresh and salt water at the mouths of rivers, and that is being tried a couple of places, but nobody has gotten a commercial scale system going yet. The same is true for harnessing the power of waves. The big opportunity is tidal power, which has the power (at least theoretically) to supply San Francisco with all the green power it can absorb.
Dr. Jones then showed us pictures of a variety of systems that have been designed to capture this power as electricity. One of them was a four mile bridge between two islands in the Philippines, under which a large number of large "egg beaters" catch energy in water currents to turn generators. Another had fan blades that look a lot like the windmills that you see on land. Most of these machines were much bigger than people, probably at least thirty or forty feet tall.
One of the good places to put a tidal power generating system is the mouth of San Francisco Bay, under the Golden Gate Bridge. Dr. Jones explained that the water is deep enough there that there is plenty of room under the shipping channel for it. Also, the actual generator could be put in a location to be determined around the Presidio, Ft. Mason, or Seacliff areas. The City has expressed some interest in doing such a project, and he expects them to put out a Request For Proposal (RFP) this fall sometime. The proposed project would be about one megawatt in size, cost about $4 to $6 million to build. The project would be financed with private money from European sources.
During the Q&A period, a number of interesting things came up:
At this point the longest running venturi tidal power generator has been in operation for about two and a half years. As of right now, it has not had any serious maintenance issues.
The Europeans are very interested in tidal power because they are looking at ways to power their modern lifestyles and honor the Kyoto Protocols. The Russians are not doing much in the area because their economy is so messed up they haven't the resources to invest.
The current administration in the Philippines is not interested in building that four mile causeway and tidal power generator, mainly because the previous government looked favorably on the idea.
The biggest unknown that could be a gotcha is how going through the turbulent water zone of a tidal generator affects tiny marine life. Dr. Jones thinks adult fish will have no problems, but jellyfish and the like could be damaged by the experience. Nobody has investigated the issue yet.
Tian Harter
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