Possible desalination plant in Marin County, California. (LOONG!)
- To: clean-water at sculptors dot com
- Subject: Possible desalination plant in Marin County, California. (LOONG!)
- From: Patrick Salsbury <salsbury at sculptors dot com>
- Date: Tue, 31 Dec 2002 18:29:14 -0800
- Cc: salsbury at bootstrap dot sculptors dot com
Saw this in yesterday's paper in San Francisco. It's a pretty good
article, although it underscores a few places where it seems like they
might not have thought things all the way through. (The high ongoing energy
costs and the problem disposing of the highly concentrated brine are two
that jumped right out, as well as $20-$35million in costs just to beef up
the piping systems...)
I'm seriously considering writing up an alternative bid for this
project, and trying to land a contract for Reality Sculptors. I figure if
they've got $100,000,000 to spend, we could take a shot at designing a
different system for them that uses less power, requires less
infrastructure, and is gentler on the environment. And it would probably be
a lot cheaper, too. :-)
The article is at:
...but I'm not sure if they keep them up forever or just for a
I'll put my comments and ideas at the end. Please post any
thoughts. Does this sound like a fun/reasonable project?
SF Gate <http://www.sfgate.com> www.sfgate.com
<http://www.sfgate.com> Return to regular view
* Marin thirsty for desalination
Officials say tapping bay could solve water woes
* Peter Fimrite, Chronicle Staff Writer
<mailto:pfimrite at sfchronicle dot com>
Monday, December 30, 2002
©2002 San Francisco Chronicle </chronicle/info/copyright/> |
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With an uncertain water supply and memories of a near disastrous
drought, Marin County's water lords are looking into an idea as old
as Aristotle -- tapping the sea.
Heeding the pleas of environmentalists, the Marin Municipal Water
District is studying a proposal to desalt the waters of San Pablo
Bay and provide 5 million to 10 million gallons of drinking water a
day, enough to serve as many as 30,000 homes a year.
It would be the first seawater desalination plant in the Bay Area
and the only one in the state to tap into an enclosed bay and estuary.
The idea reflects an ugly reality in California. Even in the absence
of drought, experts say, there soon will not be enough water
available for the number of people crowding into the state.
Meanwhile, the costs for dams and pipelines -- and the concomitant
environmental mitigation -- are shooting skyward, making it
increasingly difficult to tap existing waterways.
The pressure is so intense that water officials are looking
thirstily for alternatives. Desalination is the option that many
California water brokers are considering.
The problem is that desalination -- though not as fantastical a
notion as when the Greek philosopher mused about condensing ocean
vapor -- is still enormously expensive.
Studies have shown that it could cost as much as $100 million to
build a plant in Marin and put in pipelines. And critics say that
even if it could be built for less, the cost of electricity to power
it would be higher than anyone can afford.
"I'm told that about two-thirds of the cost of operating a
desalination plant is power costs," said Dick Hill, one of two
skeptics on the five-member MMWD board of directors. "It uses
substantially more power than conventional means of handling water."
But Jared Huffman, the president of the board, insists desalination
is a viable alternative to pipelines and dams, especially when one
considers the rate at which the technology is improving and costs
"Desal provides us with a very reliable, high-quality water source
that allows us to back off our beleaguered rivers and streams,"
Huffman said. "I would submit it is economically viable as well."
SAME EXPENSE AS IN 1991
In fact, building a plant now would cost about the same amount as it
would have cost in 1991, the last time Marin considered
desalination. That's despite the fact that construction costs in the
Bay Area have gone up 30 percent in that time.
Huffman and other proponents foresee a partnership with the Central
Marin Sanitation District, allowing them to combine the briny
extract with treated wastewater, creating a more natural byproduct
for disposal into the bay.
To date, only two American cities have actually built and operated
full- fledged seawater desalination plants -- Key West, Fla., in the
early 1980s, and Santa Barbara a decade later. The operations were
soon mothballed when cheaper alternatives came along.
Now only a few small, mostly private desalination plants exist in
California. Desalted seawater is really a prominent source of water
only in places like the Arabian Peninsula, where alternatives are
all but nonexistent.
But the tide is turning. The state's ballooning population -- the
current population of 35 million, already 10 million more people
than in 1977, is expected to exceed 50 million by 2020 -- has caused
water officials to take a second look.
"We are already seeing the long awaited but gradual transformation
of need for desalination into the demand for desalination," wrote
James Birkett, an international desalination expert, in a recent
status report on North America. "This transition will slowly
Water brokers from coast to coast are already rushing with siphons
to the salty surf.
Tampa Bay is expected to power up what will be the largest municipal
desal plant this side of Saudi Arabia early in 2003. But that plant
will be only half the size of two planned facilities in Southern
California -- where water officials are facing the possibility of
losing much of the Colorado River water that now comes their way.
The cities of Carlsbad, in San Diego County, and Huntington Beach,
in Orange County, are proposing desal plants capable of producing 50
million gallons of fresh water a day, enough to serve 110,000 homes
Plants capable of producing at least 25 million gallons a day --
about the same size as in Tampa -- are in the works near three other
Southern California cities.
Santa Barbara is ready to dust off its warehoused plant at the first
sign of drought. Last month, Morro Bay started up the much smaller
plant it mothballed seven years ago. The $5.4 million plant, which
produces 430,000 gallons a day, is at this point the only municipal
desalination plant in California.
"I think desal will be a major source of supply for Southern
California in the future," said Ken Weinberg, director of water
resources for the San Diego County Water Authority, which serves 3.5
million people. "Our population is growing in California, and our
water supply is not."
GROWING CONCERNS OVER SUPPLIES
The plant being contemplated in Marin County shows how concern about
the state's future is driving water policy even in comparatively wet
Northern California, which has essentially tapped all the water it
can get from its natural resources. And even though Marin is blessed
with a virtual rain-making machine -- Mount Tamalpais -- and isn't
growing as fast as other counties, it is feeling the pressure.
In an average year, Marin gets more than double the amount of
rainwater than even San Francisco, and that rainwater goes into
seven reservoirs. However, as the district found out during droughts
in the 1970s and again in the early 1990s, there isn't enough during
dry years to sustain both people and the native salmon and trout
populations in West Marin's main tributary, Lagunitas Creek.
So district officials worked out a deal with the Sonoma County Water
allowing the MMWD's 184,510 customers in southern and central Marin
to get 25 percent of their water from the Russian River.
The water is delivered for a fee through a pipeline owned by the
North Marin Water District, which serves Novato. And that is where
the problems start.
As the population grows in Marin County, water use is expected to
increase beyond the capacity of the pipeline to supply both
districts. As it is, the MMWD has to pump during winter months,
forcing the district to guess how much water it will need in the
summer. In wet years, it often ends up with excess water that is
The expected solution for the MMWD was the construction of a $20
million pipeline, which was approved on an as-needed basis by voters
in 1992. But that alternative has since generated intense opposition
from environmental groups.
The primary argument against the pipeline is that the Russian River
and its fishery has been so degraded by gravel mining and other
development schemes that it cannot be relied upon, especially if use
restrictions and costly mitigations are ordered.
"There's a massive amount of financial and environmental baggage
that goes along with being a Russian River contractor, and desal is
everything that that source is not," Huffman said. "It is highly
reliable, potentially has a much smaller environmental footprint,
and it makes us self-sufficient."
Bob Castle, the water quality manager for the Marin water district,
said building a plant to produce 5 million gallons a day would cost
an estimated $34.5 million. A 10 million-gallon plant would cost
about $60.5 million, he said. Another $20 million to $35 million,
depending on the size of the plant, would have to be spent to
upgrade the distribution system.
Castle is confident brine disposal, desal's major environmental
concern, would not be a problem in Marin if the wastewater plant
But the thorniest obstacle is that reverse osmosis technology -- the
process of forcing water through a semi-permeable membrane that
blocks out salt molecules -- is still very expensive.
Pushing water through the membranes takes a huge amount of
electricity, which is why most desalination projects are being built
alongside electric power generation plants.
The Carlsbad plant, for example, would be built by Poseidon
Resources Corp. in collaboration with Cabrillo Power, which owns the
Encina Power Station at the same site. The desal plant would have a
ready supply of electricity and use the existing seawater intake and
cooling water outfall at the power plant.
"Partnerships like this one are real critical to the success of
desalination," Weinberg said.
One plus for Marin is that bay water is warmer and less salty than
the ocean, making it less energy intensive to desalt -- but the
option of pairing up with a power plant doesn't exist there.
Desalination has been a concept since the fourth century B.C., when
Aristotle made his proposal to condense seawater vapor. The first
crude plant was installed in 1862 in Key West, Fla., to support
military personnel at Fort Zachary Taylor.
Talk of harvesting seawater began in earnest in California in 1977,
the worst drought year in the state's recorded history.
Another six-year drought ending in 1993 prompted several counties,
including Marin, to study desalination. In the end, though, most
communities steered clear because of the high cost, usually many
times more than conventional sources like ground aquifers, lakes,
rivers, streams and reservoirs.
The Marin water district is in the early stages of planning, but an
engineering study shows there is reason for optimism. It found that
a 10 million-gallon a day plant would serve all the district's
conceivable future needs if it was combined with the current
allotment of Russian River water.
A 5 million-gallon-a-day plant, combined with the piped river water,
would provide enough water in all but 1977-like conditions,
according to the engineers.
And even though electricity is not exactly cheap or plentiful in
California these days -- its cost has doubled since 1991 -- Huffman
is undeterred, calling the desal plant an investment in the future.
For those concerned about the taste, he said 95 out of 100 people in
a blind taste test of water from a pilot desalination plant built in
1990 preferred the salt-free bay water to tap water.
The evidence supporting desal was convincing enough that early this
month, the water district board agreed to hire a consultant to
conduct a public opinion poll on whether a plant should be built.
It was the first act in a process that could eventually put the
county at the forefront of a national movement.
"If we don't do something, there will be an irresistible push to
build the pipeline," Huffman said. "Desal is the only alternative."
DESALINATION IN THE BAY AREA
COST OF DESALINATION: Between 1980 and 2000, the cost of reverse
osmosis membranes has declined 86 percent. In that same time
productivity has increased 94 percent.
ENVIRONMENTAL ISSUES: the salty extract known as brine is a concern
to environmentalists because such high concentrations of salt can
disrupt natural processes if dumped undiluted into the ocean or bay.
Desalination plants also produce a small amount of solid waste, or
sludge, which must be trucked to landfills.
COST TO BUILD PLANT: Up to $100 million to build a 10 million gallon
a day desal plant in Marin County, including construction of new
pipelines, the same as it would have cost in 1991.
A plant that produces 5 million gallons a day would cost an
estimated $34.5 million to build. A 10 million-gallon plant would
cost $60.5 million. Another $20 million for the 5 mgd plant and $35
million for the 10 mgd plant would have to be spent to upgrade the
In 1991 it would have cost $55 million to build a 5 mgd plant and
upgrade the distribution system, almost the same as today. That's
because the cost of reverse osmosis membranes have gone down about
the same amount as construction costs have gone up since 1991. Once
running, the high cost of electricity in California would also have
to be factored in.
CAPACITY IN GALLONS PER DAY: 5 mgd, 10 mgd or something in between.
WHERE MARIN RESIDENTS GET THEIR WATER NOW: The Marin Municipal Water
District operates seven reservoirs that supply 184,500 customers
over a 147 square mile area with water. The district, through a
contract with the Sonoma County Water Agency, takes another 8,300
acre-feet of water a year, or about 25 percent of its total supply,
from the Russian River.
WHERE THEY PROPOSE TO BUILD IT: On MMWD owned land at the end of
Pelican Way on the north side of the San Quentin peninsula, about a
mile west of the Richmond/San Rafael Bridge.
More info on: www.poseidonhb.com/media/OC_Proj_Brief_2002_08.pdf
/E-mail Peter Fimrite at pfimrite at sfchronicle dot com
<mailto:pfimrite at sfchronicle dot com>./
©2002 San Francisco Chronicle
Page A - 1
First off, you probably know that I'm thinking about atmospheric
condensers/dehumidifiers, right? :-) I'm pleased to note that Aristotle
thought the idea up 2500 years ago, and dismayed to hear a newspaper at the
begining of the 21st Century calling the idea "fantastical".
I did some research yesterday while reading the article, and found
several dozen commercially made dehumidifier units that are available at
retail prices of $150 up to about $1700 for the most expensive industrial
one I located. They produced between 5-75 gallons of fresh water per 24
If you haven't done so, go read the secion on Astmospheric
Condensers about halfway down this page:
It has links to some of the commercially available models, and
retail prices. (Remember that we'd probably get OEM prices if we were to
order them in units of 10,000-30,000.)
According to their numbers in the article above, they are planning
to spend about $100 million on water systems for 30 thousand homes. That
averages out to about $3333.33 spent per home, which doesn't seem so bad.
But about 37% of that cost is just going into rebuilding the pipe network
to handle the increased load.
Also, the amount of water they are alloting to each home (166-332
gallons/day) tells me that they aren't thinking about addressing the issue
of water wastefulness, they're just looking to continue with the way people
currently are: Watering large lawns with fresh, drinkable water. Washing
their big SUVs 1-2 times/week with fresh, drinkable water. Flushing fresh
water down the toilet, etc. If they put together an education program
coupled with these technologies, so that people had enough fresh water for
drinking & cooking, but used greywater systems for their lawns and toilets,
they could probably reduce their water *usage* by quite a bit.
Small, decentralized water systems at the household or neighborhood
level will be more robust and less likely to suffer catastrophic failure
(or terrorist attack! which is the current buzzword...) than the large
systems we commonly build.
And rather than having to devote massive amounts of electricity
(fossil-fuel generated) to run reverse osmosis systems, why not harness the
free energy of the natural systems? The sun is constantly cooking off water
vapor from the oceans, and the wind delivers it all over. Why go to the
trouble and energy expense of separating it outselves and piping it all
over when we could just draw it out of the sky whereever it's needed? (See,
we could even stick with the "desalination" angle, but have most of the
energy-intensive processes done for us, for free! :-) )
They could also just build an Ocean Thermal Energy Conversion
(OTEC) plant and tap into the (rather cold, year round) waters of the Bay
to provide the chilling necessary for condensation, and they could still
pipe it all over if they wanted. I'm still not convinced that reverse
osmosis is the best choice.
All that concentrated brine could harm the environment if dumped
back in the bay, but it could also produce valuable salts if dried
completely. And guess what? There are giant salt-evaporators built all
around the south part of the Bay. And those sea-salt "miners" could be
producing millions of gallons of drinking water per day if they just built
inflated fabric structure vapor-barriers over their salt-pools, then drew
the vapor off and condensed it.
This is what I mean about having only thought the problems through
half-way. These two groups are sitting on opposite sides of the Bay, each
producing a "waste product" that is lifeblood to the other. Why aren't they
So anyway, those are some of my modern twists on Aristotle's 2500
year old idea. :-) I suspect that for probably somewhere around half the
price, maybe less, we could achieve the same result (or water for twice as
many people for the same price), with less impact on the ecosystem, and
with a public education program included so people learn how to use their
water resources sensibly and responsibly.
As it said in the article, all eyes will be on them to see how well
they pull it off. It's a chance for them to be a showcase and role model.
So what do you think? There's enough off-the-shelf technology out
there that we could design and deploy localized systems, or help them make
bigger central plants that use OTEC rather than osmosis. There are lots of
options, and I'm not sure they've really explored them too much, yet. I
think it'd be fun to show them some alternatives, and if we can make a few
million dollars in the process, that leaves us with resources to do other
projects, right? :-)
___________________Think For Yourself____________________
Patrick G. Salsbury - http://reality.sculptors.com/~salsbury/
Check out the Reality Sculptors Project: http://reality.sculptors.com/
"Is it a disaster that one-fourth of the world's population is presently
ill-fed, ill-housed and ill-clothed? Is it a disaster that one-third of all
the people in Asia, South America, and Africa are protein-starved? They are
disasters because they affect the support and recycling of life. Because of
our daily reporting system, we tend to think of a disaster happening in a
shorter period of time rather than something chronic or of long-standing such
as mental illness or slow protein starvation."
-- Harold L. Cohen - The Whole is the Particular (p.60)
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