MITs Technology Review has ran a piece on Free Flow Power of Gloucester Massachusetts.  Free Flow’s idea is to set tens of thousands of water flow turbines anchored to the bottom of the Mississippi River that someday could provide more than a gigawatt of renewable energy, enough to power a quarter of a million homes – roughly equivalent to a nuclear power station.

Free Flow has just received preliminary permits from the U.S. Federal Energy Regulatory Commission (FERC) granting it the right to explore energy production at dozens of sites along the lower Mississippi over the next three years.

Free Flow plans to deploy hundreds of 40-kilowatt turbines, each the size and shape of a large jet engine, attached to pylons jutting out from the riverbed at 88 locations along the Mississippi.  This is hydrokinetic power on an unprecedented scale anywhere worldwide.  The plan does illustrate the power the Mississippi offers.

Free Flow uses a “shrouded turbine” design that channels water through the turbine’s blades. Water passes through a rotor with seven blades that are designed for a slow spin rate to minimize fish strikes. The turbines will be sited 10 or more feet off the riverbed. At this depth, water moves, on average, at one to three meters per second.

Free Flow SmarTurbine Images. Image credit: Free Flow.

The Free Flow 3-meter “SmarTurbine” generates 10kW at a 2.25 meter per second water flow 40kW at 3 meters per second flow.

Free Flow’s ambitious Mississippi project relies on relatively unproven technology. So far the only commercial hydrokinetic river-power system operating in the U.S. is a single turbine deployed by Hydro Green Energy close to a conventional hydropower dam on the Mississippi River in Hastings, Minnesota.

Free Flow’s chief financial officer, Henry Dormitzer, points out that river power has distinct advantages. “The water flows in one direction, it doesn’t have salt in it, and, in the case of the Mississippi, people have spent 100 years tracking water flows and velocities.”  It’s a sanguine view; the reality is – it’s a strong motivator.

The catch are the Mississippi is also one of the world’s busiest waterways, the company will have to demonstrate that its turbines will not interfere with commercial shipping, and that it will have no negative impact on the river’s wildlife.

Progress is underway.  Back in July of 2009 Free Flow began a six-month test of a one third size pilot turbine in the Mississippi.  The company is now testing a commercial-scale prototype in the lab. Free Flow’s capital funding is from $7.4 million by investors and the U.S. Department of Energy that will allow it to test its most recent prototype in the Mississippi next year. Free Flow Power is seeking additional funding to test four turbines, each attached to a separate pylon, over a 12-month period, as required by FERC as part of the licensing process.

Funding is critical.  The Technology Review piece quotes Michael Bahleda, an energy consultant with U.K.-based Halcrow Group who observes securing the funding needed to carry out the necessary studies may prove difficult saying, “Until you get through the licensing process, investors aren’t going to commit a lot of money. As it stands now, the permitting and licensing is very time-consuming. It’s hard to attract capital until you are further along in that process.”

Technology Review also talked with Andrea Copping, a senior program manager at Pacific Northwest National Laboratory in Sequim, Washington who said, “There is no question the potential for hydrokinetic river power is huge, but this industry is so young, it’s very hard to say how economically viable it will be.”

Copping says hydrokinetic power needs a strong commitment from commercial and government interests if it’s to take off. “Unless there are public funds to help get this industry off the ground, we are not going to have an industry,” she says. “Right now the early developers are being hit with really expensive studies, because the FERC doesn’t know what the problems are, so they want the individual companies to look at all potential problems.”

The big environmental challenge is preventing direct strikes to fish and other organisms. Even if individual turbines cause only a small number of strikes, the sheer size of Free Flow’s proposed project raises significant concerns, says U.S. Fish and Wildlife Service biologist Joyce Collins, who is working with Free Flow to study strike issues. Collins says the company will have to pay particular attention to an endangered species that lives in the Mississippi called the pallid sturgeon.

On the navigation matter Free Flow Power will have to convince barge operators that their turbines won’t interfere with commercial traffic. “There are times where you can have a low-water period where there is only 10 to 20 feet from the bottom to the top of the water; if you have pylons installed in certain areas, a vessel could run into them,” says Mark Wright, vice president of the American Waterways Operators, a trade group representing the tugboat, towboat, and barge industry.

But Edward Lovelace, Free Flow Power’s vice president of engineering, says all of the sites selected by Free Flow Power will have sufficient clearance above them even during periods of low water. Drawing on historical flow data from the Mississippi, the company selected sites that maintained a depth of at least 40 feet during approximately 100-year lows. Such sites would allow for a minimum of 20 feet of water above the tops of the turbines for barges that draw no more than 14 feet of water.

Chances are that Free Flow can get through the on site tests.  Just how the results will be interpreted isn’t known and we’ll have to wait.  No one wants the wildlife slashed up and its fair to expect that some bit of harm is going to happen.  It does seem that Free Flow has the siting worked out for avoiding a navigation confrontation.

It all looks good.  A 2007 study by the Electric Power Research Institute in Palo Alto, California, predicted that the U.S. could develop three gigawatts of hydrokinetic power from rivers by 2025.  That wouldn’t be all of it.  Each gigawatt approximates a nuclear station – and at today’s cost projections, river flow hydro might turn out to be very low cost.


1 Comment so far

  1. wayne little on December 21, 2012 8:04 AM

    i think someone should take a look at the Double Vortex Water Turbine built in the 1990s surely it can be adapted for modern day use.

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