Desalinated water inside of the Kay Bailey Hutchison Desalination Plant
on April 16, 2012. The $87 million facility produces 27.5 million
gallons of water per day, making it the largest inland desalination
plant in the world.
Drilling rigs in the midst of cow pastures are hardly a novelty for
Texans. But on a warm May day at a site about 30 miles south of San
Antonio, a rig was not trying to reach oil or fresh water, but rather
something unconventional: a salty aquifer. After a plant is built and
begins operating in 2016, the site will become one of the state’s
largest water desalination facilities.
“This is another step in
what we’re trying to do to diversify our water supply,” said Anne
Hayden, a spokeswoman for the San Antonio Water System.
More
projects like San Antonio’s could lace the Texas countryside as planners
look to convert water from massive saline aquifers beneath the state’s
surface, as well as seawater from the Gulf of Mexico, into potable
water. The continuing drought has made desalination a buzzword in water
discussions around the state, amid the scramble for new water supplies
to accommodate the rapid population and industry growth anticipated in
Texas. But the technology remains energy-intensive and is already
causing an increase in water rates in some communities.
“If you
look around Texas and you look at the climate situation and the fact
that the reservoirs are being drawn down, there just isn’t much of an
alternative,” said Tom Pankratz, the Houston-based editor of the Water Desalination Report, who also does consulting for the industry.
Across the state, 44 desalination plants — none using seawater — have
been built for public water supplies, according to the Texas Water
Development Board. Ten more, including San Antonio’s, have been approved
for construction by the Texas Commission on Environmental Quality.
Most
projects are small, capable of providing less than three million
gallons per day, often for rural areas. The state’s largest is in El
Paso, where the $91 million Kay Bailey Hutchison Desalination Plant,
completed in 2007, can supply up to 27.5 million gallons of water a day,
though it rarely operates at full capacity because of the high energy
costs associated with forcing water through a membrane resembling
parchment to take out the salts. (Production of desalinated water costs
2.1 times more than fresh groundwater and 70 percent more than surface
water, according to El Paso Water Utilities, which said that the plant's
rate impact amounted to about 4 cents for every 750 gallons of the
utility's overall supply.) Last year, the plant supplied 4 percent of El
Paso’s water.
The Kay Bailey Hutchison desalination plant.
Interest in desalination surged more than a decade ago, when the
technology became more efficient and cost-competitive, according to
Jorge Arroyo, a desalination specialist with the Texas Water Development
Board. But the severe drought of the past two years has triggered extra
calls to his office. Texas holds 2.7 billion acre-feet of brackish
groundwater — which translates to roughly 150 times the amount of water
the state uses annually — in addition to some brackish surface
water. The state water plan finalized this year envisions Texas deriving
3.4 percent of its water supply from desalination in 2060. (It is less
than 1 percent now.)
Environmentalists argue that desalination is
not a silver bullet because it is energy-intensive and requires disposal
of the concentrated salts in a way that avoids contaminating fresh
water. Texas should first focus on conservation and the reuse of
wastewater, said Amy Hardberger, a water specialist with the
Environmental Defense Fund.
“What needs to be avoided is the, ‘Oh, we’ll just get more’ mentality,” she said.
But
getting more is what many Texans want. Odessa, which draws water from
dangerously low surface reservoirs, is considering a desalination plant
that could ultimately become bigger than the one in El Paso. (Odessa’s
deadline for proposals is next week.)
Separately, a planned power
plant near Odessa is studying prices for the technology. John Ragan, the
head of Texas operations for NRG Energy, envisions natural gas power
plants along the coast that desalinate water overnight when they are not
needed for electricity.
Residents near the half-full Highland Lakes in
Central Texas say that desalination could reduce the water-supply burden
on the lakes. Texas Tech University aims to begin wind-powered desalination research later this year, in the West Texas town of Seminole.
The San Antonio project is estimated to cost $145 million in its initial phase, with a daily production capacity of 10 million gallons, and $225 million assuming it is built out to a daily capacity of 25 million gallons (which is possible by 2026). The cost is significantly higher than El Paso’s project, but San Antonio officials say that the figures reflect additional factors like acquiring land — and so far, the project is under budget. Local water rates, along with $59 million in low-interest loans from the Texas Water Development Board, are financing the project.
Desalination means “you’re going to have to spend some money,” said state Rep. Lyle Larson,
R-San Antonio. But it is worthwhile, he added, because “our whole
economic future could be up in the air.” Texans seeking a model, Larson
said, should turn to Australia, where a major drought last decade
spurred billions of dollars of investments in desalination.
Australia’s
focus has been desalinating seawater. That is an option for the Texas
coast, but desalinating seawater generally costs more than twice as much
as desalinating groundwater because seawater is saltier. Energy can
account for 60 to 70 percent of the day-to-day operating costs of a
seawater plant, estimated Pankratz, the Water Desalination Report
editor.
The largest seawater desalination plant in the country,
which is slightly larger than El Paso’s brackish water plant, operates
in Florida. Proposals are inching forward for a seawater plant in Texas.
The Laguna Madre Water District, based in Port Isabel, completed a
pilot seawater desalination project two years ago and is now looking for
property on the north end of South Padre Island to locate a larger
facility, said Carlos Galvan, the water district’s director of
operations. Desalination would reduce the utility’s dependence on the
often-diminished Rio Grande.
The Guadalupe-Blanco River Authority
is also mulling seawater desalination, perhaps in the greater Victoria
area. It has asked companies to submit project proposals by
mid-September, and it may try to locate the water plant with a power
plant, as is done in Saudi Arabia, to boost efficiency and cut costs.
Officials
with both Laguna Madre and Guadalupe-Blanco hope to acquire some
financing from private companies. But government at all levels, from
water agencies on up, will be the key player. In El Paso, the federal
government contributed $26 million in grants — more than a quarter of
the cost — for the desalination plant.
The Texas Water Development
Board has issued $7.1 million in grants for desalination projects since
2000, according to Arroyo, the desalination specialist.
But “we
don’t have any more funds for desalination,” he said. The board asked
the Legislature for $9.5 million in financing for seawater desalination
last session but did not get it.
Gov. Rick Perry
has advocated for desalination in the past, but he has spoken little on
it recently. Expanding the technology “at a cost that is affordable to
consumers will be an important part of any future water plans in the
state,” Lucy Nashed, a spokeswoman for the governor, said in an email.
Officials
at the Texas Desalination Association, a new advocacy group,
acknowledge that requests for money will probably fall on deaf ears. But
they say that the state can help by easing regulations — for example, a
requirement that every desalination project include a lengthy pilot
study — and by doing more extensive mapping of Texas’ brackish water
resources.
“If we eliminate some of the red tape and some of the
permitting issues,” said Paul Choules, the group’s president, “it
reduces a lot of the upfront cost.”
No comments:
Post a Comment