Currents of Change

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Hydropower

The Snohomish Public Utility District is leading the way in
developing a source of tidal power: turbines that sit on the seabed and make
electricity from subsurface ocean currents.

If you’ve ever watched the ocean during a storm, you know
how powerful it is. Surges can swallow whole chunks of the coast, leaving
disaster in their wake. Yet the real power is deep below the surface, where
tidal currents are strong even on a calm day. Two leaders of a local utility
are working hard to prove that those tides can be a clean, renewable source of energy
for local communities.

As head of Tacoma Power, Steve Klein led efforts in 2005 to
secure tidal power permits for the Tacoma Narrows. Since taking the position of
CEO at the Snohomish County Public Utility District (SnoPUD), the 12th largest
power utility in the country, he has continued to work toward making tidal
energy in the Northwest a reality. Last winter, SnoPUD submitted a preliminary
application for a pilot project in Admiralty Inlet, a channel off the western
shore of Whidbey Island. After approval from the Federal Energy Regulatory
Commission (FERC), the district hopes to file a final permit application next month
and get its license by January 2011.

In the meantime, the district isn’t sitting idle. Research
partners such as the University of Washington, Beam Reach (a marine biology
program based in Seattle that takes college students on 10-week research trips)
and an orca whale advocacy and research group have been collecting data from
sites in Puget Sound for more than a year.
“We’re some of the first to be tapping this [field] from the academic side,”
says University of Washington oceanographer Jim Thomson. With limited funding,
small companies are cautious about sharing discoveries, and most projects keep
their methods and findings strictly private. This approach means that
researchers began work with a mostly blank slate, measuring current speed and
composition, biological activity and human use at various locations.

“It’s breaking a new trail, absolutely,” says Craig Collar,
senior manager for Energy Resource Development at SnoPUD. The university
publishes its data to the web within weeks, and is focused on developing a
methodology that can be standardized and put to use by other organizations.

Tidal power is not widely embraced by energy pioneers. Bill
Gates dismissed it as a secondary option in his speech at the Technology,
Entertainment, Design (TED) conference in February, citing carbon capture,
wind, solar photovoltaic, solar thermal and nuclear as the five best options
for that “necessary miracle”: reducing carbon emissions to zero.

But Thomson believes that tidal power has great potential,
although it will take time, following much the same path as wind energy. He
points out that in the late 1980s, wind was still an unreliable investment.

“It took a long time to get the windmill to the point it is
today, where there’s a refined design that’s used by everyone,” Thomson says.
“I see kind of the same thing happening for tidal.”

Klein and Collar agree that generating power from the ocean
currents is a demanding proposition. Their goal is to succeed in the three
departments they say are absolutely necessary: technology, environment and
economy.

“Every one is a deal killer,” Klein explains. “That’s what
makes tidal such a challenge. You have to hit on all three cylinders in order
for it to work.”

For the district, it’s a challenge worth taking on.

“We have this clean, renewable, predictable power that’s
generated close to where the load is,” Klein says. Puget Sound, because of the
power of its tidal currents, may be one of the best places to exploit this new
technology. According to the Electric Power Research Institute, tidal power
generation in the United States, if fully developed, could produce an average
of 270 megawatts per year, approximately 3.5 percent of the total nationwide
electricity supply in 2004.

One of tidal power’s strengths is its regularity. “The thing
tidal has going in its favor, as opposed to wind, is that it’s predictable. You
can build it into your power system schedule,” says Mark Savory, the vice
president of technical and construction services at Nova Scotia Power.

Unfortunately, as Thomson puts it, “the ocean’s not a very
forgiving place.” Seawater corrodes many building materials, and fast currents
require a solid, resilient design. The turbines SnoPUD plans to use,
manufactured by the Irish company OpenHydro, are rugged, anchored with a
weighted foundation that rests directly on the seabed. Nova Scotia Power is
currently testing OpenHydro’s design in the Bay of Fundy, where the strongest
tides in the world sometimes cause the water level to change by 48 feet in one
cycle.

But many biologists also fear that turbines will injure or
kill marine mammals and fish that migrate through the area or live full time in
the sound.

“There’s no real evidence at all, yet, that they could or
should cause harm,” says Collar of the turbines. They turn slowly (a maximum of
20 rotations per minute) and have no exposed blade ends. A large opening in the
center allows safe passage for animals, and the strongest water flow goes
around the outside of each turbine, Thomson explains, so currents are not pulling
fish toward the blades.

Other installations offer hope that marine life will be safe
from damage. The European Marine Energy Center installed an OpenHydro turbine
near Scotland’s Orkney Islands, a highly productive environment, in 2006. Video
of the turbine’s operation shows no fish or marine mammals getting caught in
the rotor. A large population of endangered seals in Strangford Narrows in
Northern Ireland has stayed clear of two SeaGen turbines installed there in
2007.

On the economic side, Klein believes that tidal power is a
tremendous opportunity for the Puget Sound region. Tidal efforts have drawn
funds and recognition to many of the local organizations involved in the
Admiralty Inlet project. SnoPUD won research support from the Department of Energy,
which has provided a large chunk of the project’s resources. “DOE funding was a
kernel of success,” says Collar.

A major cost of tidal installations is shipping the
turbines. OpenHydro’s 10-meter-diameter apparatus weighs 450 tons, including
the base. Luckily, the equipment is fairly simple to construct.

“If you have a reasonably healthy marine industry in your
area, you can make these things,” Savory says. Local manufacturing, a good
possibility given the Northwest’s strong marine infrastructure, would go a long
way toward keeping capital costs low.

The cost of tidal power is estimated at 20 cents per
kilowatt hour, says Brian Polagye, a research affiliate in the Unviersity of
Washington’s Air-Sea Interaction and Remote Sensing Applied Physics Laboratory.
This price means it’s already ahead of solar power (at 35 to 40 cents per
kilowatt hour) but will have a difficult time competing with traditional
hydropower and onshore wind. Last November, residential electricity in
Washington cost an average of 7.81 cents per kilowatt hour, some of the
cheapest nationwide. But as Klein points out, Snohomish County (and the rest of
western Washington) is growing rapidly, and there’s little to no chance for
further development of cheap hydropower. Heavy taxes on carbon-based fuel could
make tidal power an attractive option, especially as the technology continues
to advance.

Ideally, SnoPUD will put the first turbines in the water in
early 2012. A 10-year permit will give the utility plenty of time to gather
data before expanding any further. Klein and Collar are realistic about their
goals. “We will be informing the science and knowledge base whether we develop
this project or not,” says Klein.

Thomson, too, believes the project has both local impact and
large relevance. He praises the teamwork that has gotten them this far.

“Everyone’s learning,” he says. “It’s been a wonderful
collaboration. I think that’s exactly the way this should work.”

Catching the Green Wave

Catching the Green Wave

Eco-savvy developers incorporate ways to mitigate stormwater pollution.
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Seattle’s 84-year-old Aurora Bridge is built with steel downspouts that dump 3.2 million gallons of untreated rainwater directly into the ship canal between Lake Union and Puget Sound every year, something that bridge designers in the 1930s probably never considered to be a problem.

The CoU Project, named for the Fremont neighborhood that calls itself the Center of the Universe, is tackling the bridge runoff in its design of the Fremont Office Building at 34th Street and Troll Avenue. Situated in the shadow of the Aurora Bridge and two of its downspouts, the project broke ground this spring and is scheduled for completion next year.

Early in their planning discussions, the developer Stephen C. Grey & Associates and the civil engineering firm KPFF decided to catch the water from the downspouts and filter it. Their design includes a stepped system of six bioretention cells, or rain gardens, in the public right of way along Troll Avenue beneath the Aurora Bridge. The roadway’s 15-degree incline poses an engineering challenge, but KPFF designed a system that diverts outflow from the cell above to the cell below. This way, each cell receives enough water to keep the gardens’ plants healthy without irrigation while also filtering rainwater. The last cell sends the filtered water into the ship canal. 

Water runoff from hard surfaces is the largest contributor to pollution in Puget Sound. This isn’t just rain we’re talking about. As it drains from pavement to the sound, the water becomes contaminated with motor oil, gasoline and a variety of heavy metals. 

Striking research by Professor Jenifer McIntyre at Washington State University (WSU) has demonstrated that untreated stormwater runoff from State Route 520 can kill salmon in just a few hours. Salmon are considered an indicator species because their sensitivity to environmental toxins shows how the toxins might affect the health of other species, including humans. Filtering the stormwater through a mixture of sand and compost absorbs the toxins and allows the fish to survive.

The biorentention cells in Fremont will accomplish the same thing in a remarkable example of public/private partnership that has come up with a creative solution despite potential obstacles. The developer and the engineers needed to get cooperation from both the Washington State Department of Transportation and Seattle Public Utilities (SPU) even though they will receive no financial benefit by keeping vast quantities of untreated water out of Lake Union.

“Very few private developers are willing to do this sort of thing,” says Jeremy Febus, KPFF’s civil engineer in charge of the CoU Project. “It’s a big undertaking.”

The COU project will divert about 6,000 gallons of runoff per year, or the equivalent of 16 gallons a day. This isn’t a staggering amount, but Mark Grey, principal and property manager at Stephen C. Grey & Associates, believes it is only the beginning. He says his company has in the pipeline projects that will filter more water and he hopes other developers will be inspired to jump on board to address the issue on a regional level.

The Seattle 2030 District, a public-private collaborative working to create a groundbreaking high-performance building district in downtown Seattle, has developed guidelines to encourage developers to take action on stormwater management, which is becoming a greater issue as climate change leads to more days per year of substantial rainfall. Heavy storms overwhelm existing water-treatment systems, causing untreated water to overflow into local waterways.

District guidelines require newly constructed buildings to keep stormwater discharge 50 percent below the current district average in their designs. Existing buildings must implement retrofits to achieve the 50 percent reduction by 2030. Although the guidelines only affect buildings within the district — 11 neighborhoods in and around downtown Seattle — other communities are taking action as well and coming up with their own site-specific solutions to stormwater management. 

The Sheraton Seattle downtown is finishing the design on a project that will divert rainwater from its roof to a storage tank for filtering, sanitizing and ultimate use in the hotel’s laundry operation. The Sheraton is working with Seattle-based Herrera Environmental Consultants on the filtration and pumping system design and is evaluating bids to find a certified mechanical contractor to complete the work. The goal is to install the system by this fall. 

Rodney Schauf, director of engineering at the Sheraton, believes Starwood Hotels — Sheraton’s parent company — may follow suit with similar efforts to reuse stormwater in its properties nationwide. The result is attractive from financial and environmental standpoints, as it allows the hotel to buy less water from the city. 

Seattle’s little wing Office Building on Sixth Avenue houses the administrative offices of the EMP Museum and demonstrates that creating a green infrastructure doesn’t necessarily cost more money than more established methods and can actually save money. Vulcan Inc., the property owner, is one local developer taking a lead in implementing environmental consideration into its designs.

 The Little Wing design includes a sloping green roof that filters rainwater and also keeps the building cooler in the summer. Runoff from the roof is filtered and either stored in a 9,000-gallon tank for later use or distributed immediately into the building to supply the sewage system.

Theoretically, the system can save up to 89,000 gallons of water per year; actual data show results closer to 60,000 gallons. Installing the green roof and outdoor storage tank for about $180,000 eliminated the need for an underground detention tank and a secondary storm/sewer discharge connection below the street, which would have cost about $250,000. 

The Little Wing building is also Salmon-Safe certified, which means it has met a list of performance requirements that aim to minimize the impact of urban development on the environment and enhance salmon habitat. Standards cover stormwater management, water use, water quality protection and more. Vulcan’s aim is to certify all its properties as salmon safe.

Over in north Bothell, Clearwater Commons, a small, eco-friendly residential development, has a goal of achieving zero discharge. All stormwater is infiltrated on site. The houses stand on pin foundations so rainwater that isn’t sent to cisterns flows underneath the buildings and soaks into the ground, making the houses look more like cabins in the country than suburban homes a quarter-mile from a main road.

None of the houses have basements or garages. The “road” running down the center of the development is made from drivable grass — square bricks with greenery growing between them and sand underneath — and is intended primarily as a pedestrian path with access for emergency vehicles. Residents park their cars in a lot at the front of the development, much of which is covered in permeable pavement.

Permeable pavement absorbs rainfall that would otherwise flow into storm drains, but it suffers from certain drawbacks, such as not being durable enough to be used on heavily traveled roads. Collaboration among the Boeing Company, WSU and the Washington Stormwater Center led to a pilot project using discarded carbon-fiber composites from aircraft production to develop a stronger alternative to existing permeable pavement. Initial testing suggests the material absorbs water efficiently and does a good job of filtering toxic chemicals. More research is needed before such a product reaches the market. 

Meanwhile, projects like Little Wing and the Sheraton that reuse roof runoff have the double benefit of helping Puget Sound while saving on water bills — the green roof of Audi Seattle’s new showroom in the University District recycles water that’s used to wash cars — but local regulations make such recycling impossible in many cases.

The CoU Project, for example, is prohibited from recycling the Aurora Bridge runoff for use inside the building because the runoff falls onto public property and cannot be diverted to private use without first going through the municipal water system. SPU maintains ownership of stormwater that empties onto publicly owned land, including rights of way in front of private buildings.

While some business owners are resistant to change and may not be eager to invest in new technologies to address stormwater management, tighter regulations may force them into action. As stricter national regulations based on the Clean Water Act trickle down to states and cities, local businesses will not have a choice whether to control stormwater discharge. Rather, they will have to decide just how to do so.

The Sheraton’s Schauf offers this advice to building owners: “Start out with an open mind and get creative about what can be done. There are ways that aren’t expensive that both save costs and limit the impact on the environment.”