ECOENTREPRENEURS DEVELOP HYDROPOWER TECHNOLOGIES

In Business, May-June, 2005, Vol. 27, No. 3, p. 13

Pioneering firms harness power of waves, tides, currents and flowing water to generate electricity - without the negative environmental impacts of building dams.

Diane Greer

FOR THOUSANDS of years, civilizations have employed the energy in flowing water. The ancient Greeks used water wheels to grind wheat into flour. Americans in the 1700s operated milling and pumping stations powered by moving water. In the early 1880s, Michigan was the site of the first U.S. hydroelectric power station. By 1940, 1,500 hydroelectric stations were producing one-third of the nation's electrical energy.
Today hydroelectric power is the country's largest source of renewable energy. Over 70,000 dams impound our nation's rivers producing 90,000 MW of power, representing approximately ten percent of the country's electrical generating capacity. Unfortunately, this clean, renewable source of electricity has developed a bad reputation due to environmental impacts.
Development of a new breed of hydropower technologies extracts energy from free-flowing sources such as streams, ocean currents and tidal waters as well as manmade facilities like irrigation channels, municipal water systems and effluent streams. The technologies promise to create a renewable source of electricity without adversely affecting the environment. Given sufficient experience and scale, the new devices are also expected to be competitive with traditional sources of electricity.
These new sources of distributed power are known by a variety of names including free-flow, instream generation, tidal power and wave power. Although the devices generally produce less than one MW of power, they can be grouped into “farms” to produce power equivalent to small electrical generation facilities. One strategic research firm, Douglas-Westwood Ltd., estimates wave power farms have the potential of producing up to 50 MW of power.

CLEAN POWER FROM FREE-FLOW TECHNOLOGIES
So how much energy could be derived from the various free-flow technologies? The short answer is we still do not know. Government, university and private research groups are just starting to examine the potential for the technology.
Mike Bahleda of the Electric Power Research Institute (EPRI) references a 1998 Department of Energy (DOE) study estimating undeveloped instream capacity at 70,000 MW. “Assuming you throwing out half the sites because they cannot be developed, you are still left with 35,000 to 40,000 MW,” says Bahleda. “My guess is that maybe half of these sites could be developed, so say it is 20,000 MW. That is still a lot of capacity! If a megawatt of power supports 700-800 families, we are talking about a huge potential.” He also indicates the estimates did not include the projections for free-flow sources producing power from the discharge streams of conventional hydroelectric sources or power plants.
A recent New York University study estimated U.S. free-flow turbines could produce 12,500 MW of power. Verdant Power, a developer of a free-flow turbine system, projects at least 120 North American tidal locations, many with multiple sites, suitable for deploying its technology. They have also identified 75,000 preexisting dams and 9,000 power plants where their technology could be employed to generate electricity from flowing water leaving the facilities.
Estimates for wave power potential are much higher. Wave energy represents the most concentrated form of renewable energy available today. Energy analysts project ocean waves could produce up to two terawatts (trillion watts) of electricity.
“Ocean energy has the potential to produce a virtually limitless supply of pollution free electricity,” says Tom Denniss, the Chief Executive of Energetech, a developer of wave energy devices. “The challenge is capturing it in an economical and esthetically acceptable way.” Denniss believes “within 10 to 15 years there may be up to five percent of the world's energy produced by waves.”
Despite the promise and potential, the technologies face significant challenges to prove themselves in the market. Many of the devices are progressing from the laboratory to demonstration projects designed to prove their viability. The final step will be the commercialization of the technology. Along the way, companies need to secure financing and navigate a minefield of regulations.
Three companies, Verdant Power, Energetech and Rentricity illustrate the innovative nature of the technologies. All three are undertaking demonstration projects in the U.S. To help them succeed, they have partnered with state renewable energy agencies, universities and local utilities in an effort to secure funding, obtain technical assistance and navigate the regulatory maze. Their stories highlight the potential of a new source of renewable energy and the difficulties of bringing emerging technologies to the market.

VERDANT POWER - GOING WITH THE FLOW
If all goes according to plan, Verdant Power will install several hundred underwater turbines beneath New York City's East River in a one-mile stretch adjacent to Roosevelt Island. The 15 foot tall turbines, looking like pint-sized windmills, are expect to generate 10 MW of electricity saving the City the equivalent of 65,000 barrels of oil each year and reducing CO2 emissions by 33,000 tons. “This is not just clean energy, it is local energy,” explains Trey Taylor, President of Verdant Power.
At the heart of Verdant's technology are axial-flow rotor turbines that convert the kinetic energy from free flowing rivers or tidal currents to mechanical energy that drives an electrical generator. Units can be deployed in water flowing as slowly as three knots (five feet/second) and in water depths as shallow as 20 feet. Depending upon water velocity and turbine size, power output from a turbine ranges from 25 kW to 250 kW.
Verdant's technology - Instream Energy Generation Technology (IEGT) or Free-Flow Hydropower - works similarly to the way wind power drives wind turbines. The important difference is that water is much denser than air, 832 times denser to be exact. Higher density allows free-flow hydropower projects to operate effectively and economically utilizing smaller turbines at slower water velocities. “Because you have a denser medium, you can extract more energy,” adds Bahleda of EPRI.
The east channel of the East River was selected as a demonstration site due to the strength of the current, flowing at speeds up to four knots, and the short slack time of the tide. “The site not only has good currents but it is also away from commercial boat and deep-draft vessel traffic which uses the west channel of the river,” says Taylor. The turbines will be mounted on pivots so that they can turn to face the tide. Taylor estimates that the turbines will generate power 16 hours a day.
Implementation of the project is occurring in three stages. The first demonstration stage, successfully completed in January 2003, consisted of a single turbine suspended under a barge anchored in the channel. Verdant received a $500,000 grant from The New York State Energy Research and Development Authority (NYSERDA) to help fund the testing. “In February of 2005, we will deploy a six pack (six turbines) for further testing,” adds Taylor. The turbines will be anchored to the pilings on the bottom of the river. “The six turbines will generate between 150 kW to 200 kW of electricity depending on water currents and velocities.” Power generated by the turbines will be used by facilities on Roosevelt Island including the Gristedes Supermarket and the Motorgate garage.
Testing and monitoring during the pilot project will assess environmental impacts and help Verdant to optimize issues related to turbine spacing and power production. Upon the successful completion of the second phase, the company will begin the installation of the larger turbine farm. The final stage of the process is expected to take four years and cost $20 million. “Our goals are to be able to install these systems for $1,500 per kW yielding a .05 cents kWh production costs,” he predicts. “Right now, we are at a $3,000 per kW to install and 10 cents per kWh production costs. We want to be competitive with wind.”
So far, navigating the regulatory environment has been the biggest challenge of the project. “People say we picked the hardest place in the world to start in terms of regulatory approvals - So many entities have to weigh in. We had initially budgeted about $750,000 for fish studies but the number is now up to 1 million dollars.” Taylor does not expect the testing to uncover any environmental impacts. “The turbines have blunt edges and turn slowly, at 30 rpm. We do not expect to have any problem with the fish in the river.” The turbines are also far enough under the water not to interfere with birds diving for fish.
Beyond producing a renewable source of electricity, the systems can be employed in a number of applications including irrigation, desalinization, water purification and aeration of anoxic waters. The units could also be utilized at the water discharge flumes of power plants and dams. In the future, Taylor sees the technology deployed as part of a sustainable development strategy. “Modular systems could be designed that are easily deployed to generate electric, clean water and irrigate fields in developing countries.”
Taylor's enthusiasm for the technology is infectious. “This is the right technology and it will work” said Taylor. “Lots of little distributed electrical sources can add up to a lot of power. The onus is now on us to show this is a viable technology.”
ENERGETECH - CATCHING THE WAVES
Tom Denniss, the Chief Executive of Energetech, grew up near the Kiama blowhole on Sydney, Australia's south coast. He was awed by the force of the waves entering the Kiama sea cave propelling columns of compressed air and spray up to 80 feet into the air through the top of the blowhole. Years later, Denniss drew inspiration from the display, harnessing the concept to design the Energetech wave energy device.
The Energetech design starts with a standard oscillating water column (OWC). An OWC is a partially submerged hollow structure open to the sea below the water column and to the air at the top of the column. Waves entering the column cause the water level to rise, compressing the air in the chamber and forcing it to rise through the column. The chamber design narrows at the top, accelerating the rising airflow to drive a turbine located at the end of the column. As waves recede, the process is reversed. Falling water levels within the column decompressed air in the chamber, pulling air back through the turbine and down into the chamber.
Two innovations improve the performance and efficiency of the Energetech device over standard OWC wave devices. The first feature increases the energy output of the chamber. Ocean waves contain a great deal of energy, but the energy is spread out along the crest of the wave. Energetech employs two curved walls radiating from the sides of the OWC, akin to the walls of a cave, to concentrate the force of the incoming waves, maximizing the height and pressure exerted on the air column. “We are able to have four times more energy in the chamber than has been the case,” notes Denniss.
The second innovation incorporates a new turbine design that is four to five times more efficient than conventional technology, the Wells Turbine. Traditional turbine blades are designed at fixed angles. This proves to be an inefficient configuration for oscillating air flows. In the Denniss-Auld turbine, “the turbine blades pitch back and forth,” explains Denniss. “The angle of attack of the airflow on the blades is optimal at all times.” The turbine also operates at a slower rotational speed with higher torque. Testing of the devices has not identified any environmental impacts. “It is a totally static structure. There are no moving parts in the water. Anything swimming into the chamber will feel the same effects as swimming into a cave.” He believes that the device could have a positive impact on wildlife. “It acts like a artificial reef, actually attracting marine life.”
“Quite frankly, we do not feel this technology has much negative environmental impact,” adds Nancy Selman of Energy & Environmental Ventures who is consulting on the project. “Water does not go through any blades. The most serious impact is visual, but the device has a low profile compared to a wind turbine.”
The wave device's low profile, measuring 100 ft long by 120 feet wide by 40 feet high above the water line, minimizes potential visual impacts. When placed a mile or more from the shoreline, the device is barely visible. The facility is also quiet and will not be audible from shore or by marine life. Testing has shown the noise level at a distance of three feet is equivalent to the sound of a vacuum cleaner.
“One very specific benefit of the technology is to help with coastal erosion,” says Denniss. The Energetech wave devices “takes the destructive energy of the waves and turns it into a constructive form. Protection against erosion is paid for with the electricity generation.” The Army Corps of Engineers is interested in learning how the technology might mitigate coastal erosion and is exploring partnering with Energetech to quantify the effectiveness of the technology.
The four-legged wave device sits on the ocean floor, moored by cables to the seabed. “Optimally we look for locations with a fairly even bottom in water 10-20 meters deep as close to the shore as possible.” Placement close to the shore minimizes cabling costs. Denniss was quick to point out that cabling costs are not an issue when multiple devices are placed in a wave farm.
Wave energy, like wind and solar, is an intermittent power source. Waves change in power and size throughout the day, but unlike wind and solar, continue throughout the day. There is also a great deal of data on waves from harbor wave and rider buoys. This data helps with siting the devices.
Energetech is still working on optimal placement of the devices in a farm. “When placed in a farm, they will be staggered like a sawtooth or a v-shape,” continues Denniss. “This will insure a smooth delivery of power - like the way pistons are timed in a car.” Current research calls for the devices to be separated by a distance of about 50 meters. “They may be placed closer together in instances where we are trying to protect the coast.”
The first United States Energetech pilot project will be installed one mile off the coast of Rhode Island at Pt. Judith and generate a peak of 500 kW of electricity. The project, dubbed GreenWave Rhode Island, will be set up as a not-for-profit. Greenwave is currently undergoing a state and federal permitting process expected to be completed by the middle of 2005. The installation is slated to begin in 2006. Energetech believes their device is not only technologically but also economically viable. Moderately good wave climates are expected to produce power with the current technology designs at a cost of approximately 10 cents per kWh, with ideal sites costing around five cents. As the technology is refined and capital costs fall, the cost of moderately good sites are projected at four cents kWh.
RENTRICITY - TAPPING THE POWER OF WATER MAINS
The idea for Rentricity was spawned by the aftermath of September 11th. The tragedy forced Frank Zammataro to relocate his office from Wall Street to a conference room on the upper floors of a midtown Manhattan office tower. The new location offered a bird's-eye view of a large water tower on an adjacent building. Zammataro recalls gazing out of the window and speculating on the force generated by the water as it traveled from the top of the tower to the lower floors of the building. “Wouldn't it be interesting if you could create a device that could fit in the pipes and capture the power of the water?” asked Zammataro.
Zammataro's initial speculation led to the formation of Rentricity in May of 2003. The company's Flow-to-Wire technology recovers surplus energy from water utility pipes and converts it into electricity. The concept is applicable across a wide range of piped systems where gases, liquids or solids exert excess pressure. Gravity fed water systems employ pressure release valves to reduce water pressure resulting from elevation differences between the source of the water and the customer. The Flow-to-Wire system places a microhydroturbine onto pressure release valves in municipal water systems to harness the inherent energy. “The turbine mimics the pressure reduction valve, but does not eliminate the valve,” explains Zammataro. “We are simply taking advantage of a recovery situation. Energy that would be lost when it is dissipated through the friction of the valves is instead recovered by the turbines.”
Turbines can be scaled to operate in water utility vaults with flow rates as low as one million gallons per day up to 30 million gallons per day. “We believe we can easily get one to two MW of power out of a large water utility.” In addition to creating a clean, renewable source of power, the technology provides both a monitoring and security service for water utilities. Pressure and flow sensors can be used to identify leaks and optimize operational efficiencies. “The system could also include contamination sensors.” Data collected by the system is relayed back to Rentricity and the water utility via wireless technology.
The technology will allow water utilities to work with electric utilities to solve peak demand issues. Unlike solar or wind power, the electrical output generated from a Rentricity turbine would be predictable and controllable. “There is a high degree of knowledge on what is going through these vaults.” This knowledge will enable installations to manage flow and pressure, thereby targeting peak demand periods when electricity pricing is at the highest.
Rentricity is launching a pilot project with Aquarion Water Company of Connecticut to test the technology. Installation of the first turbine is expected to generate 40 kWh of electricity. The turnkey system includes an interconnection package, allowing electricity to be sold back into the grid. The Connecticut Clean Energy Fund is helping to finance the pilot. The first pilot system will handle between one to four million gallons per day and require a capital investment of $70,000, recoverable in two to three years. Zammataro compares the investment in the company's Flow-to-Wire system to an annuity. “We are looking at a predictable cash flow from these vaults,” said Zammataro. “A typical installation can generate $25,000 to $26,000/year over a 40 year life.”
Selman of Energy and Environmental Ventures likes the economics of the technology. “Rentricity out of the box will be cost competitive,” she says. “They are using commercially available standard technology. When you have a situation like that, the risk profile is much lower which makes everything easier.”
The economics of the technology will improve as Rentricity scales the business. “There is no doubt that as we order multiple units, we will get the per unit installation cost down dramatically,” stresses Zammataro. Selman agrees. “I think their costs will come down when they produce units in bulk. At the same time, we are going to see wholesale power prices go up. For various reasons, this will be very economical. That is what is so exciting about the technology.”
Zammataro envisions great potential for the technology. “We think we are just scratching the surface with potable water.” He believes the market is about 25,000 potable water units worldwide. He points to additional application of the technology in irrigation systems, waste water systems, industrial steam and other pressurized gas or fluid flows in pipes - such as natural gas and oil. “We believe this form of energy recovery from inflow power systems should be getting more attention and notice.” Zammataro speculates that inflow power systems could produce thousands of megawatts of power worldwide.

Diane Greer is an environmental consultant and researcher, specializing in the area of green technologies.

SPEED BUMPS ON THE ROAD TO COMMERCIALIZATION
WHILE hydropower technologies show great promise, they still face significant hurdles on the road to commercialization. Free-flow hydropower and wave power demonstration projects are essential to moving the industry towards commercialization. There is still very little experience with the technologies in the field. Issues regarding efficiency, power delivery, longevity in underwater environments and environmental impacts are yet to be proven. “Deployment is the big challenge; all technologies have to prove their concepts,” says Mike Bahleda of the Electric Power Research Institute. “Every time you get a unit in the water you are closing the information gap.”
Deployment is also a critical step in validating the economic case for the technologies. “Economically, most of these technologies are more than doable,” observes Bahleda. “But you do need to be careful about looking at the current financial numbers. None of these technologies have been deployed in the field.” Bahleda believes getting some field experience is the only way to design robust structures and understand real operating costs. Tom Denniss, Chief Executive of Energetech, agrees: “All technologies need to go through a learning process. We just need the chance to get some projects out there. The sooner we get projects, the sooner the costs will fall.”
Navigating the complicated and cumbersome regulatory terrain is another challenge companies must face when testing devices in public waterways. “Regulations could be the demise of this part of the industry,” notes Bahleda. “All the existing FERC and Clean Water Act regulations deal with issues as they relate to traditional hydro facilities. There is no history in the field so regulators will be skeptical. The capital and time required to comply with regulations makes it almost impossible for a fledgling company to put a unit into the water.”
The licensing and permitting process for the Greenwave Rhode
Island project will involve the Army Corps of Engineers, Rhode Island Coastal Resource Management and the Federal Energy Regulatory Commission (FERC). All have jurisdiction. “Regulatory issues and getting each project permitted is not insignificant,” points out consultant Nancy Selman
of Energy & Environmental Ventures.” She and others involved in the Energetech project are talking to regulators, trying to figure out ways to shorten the process.
Verdant Power is engaging the major players, such as FERC, to find effective solutions to ease the industry's regulatory burden. “We are exploring flexible and modular designs that will allow all projects to be reversible,” says Taylor. “We want to work in a collaborative process, not an adversarial process.”
“Regulators have a charge they are trying to protect,” Bahleda explains. “But if promising new technologies are going to emerge, we are going to need a mechanism to take some risk. Regulations need to be produced in a way that make practical and economic sense. What are the real environmental impacts of these technologies? You can not make these assessments unless you put them in the water.”
Another significant challenge facing the industry is funding. Substantial investment and financial support will be required to complete demonstration projects and deploy the first commercialization installations. Government support and financing from outside investors will be essential. To date, state governments have been leading the way, helping to fund demonstration projects. “States have a longer perspective,” notes Bahleda. “States are interested because they see the potential for infrastructure development in terms of manufacturing and jobs.”
NYSERDA will be providing up to $500,000 for the second stage of the Verdant Power demonstration project in the East River. The Connecticut Clean Energy Fund has made a $1 million investment in Energetech. Energetech has also received a $100,000 grant from the state of Rhode Island and Massachusetts has pledged $660,000 toward the GreenWave demonstration project. Rentricity received a $50,000 grant from the Connecticut Clean Energy Fund to help support the Aquarion pilot project.
In addition to grants, 13 states have employed a market-based mechanism called a Renewable Portfolio Standard (RPS), providing an additional source of funding for renewable energy projects. The RPS requires a certain proportion of the state's electricity to be derived from renewable sources of generation. Utilities can meet the requirements by either generating the renewable electricity themselves; purchasing it from someone else; or purchase renewable energy credits (REC) in lieu of capacity.
RECs are created when certified producers of renewable energy generate power. In essence, RECs represent the monetary value of the environmental and social benefits derived from producing power at renewable facilities. Rentricity's current business model calls for receiving RECs by selling electricity generated by their system back into the grid. “We qualify under the Connecticut RPS as a Class 1 renewable energy source,” says Zammataro. “The RECs are critical; they are very, very important.”
State and federal financial incentives and grants for renewable energy projects will only provide a small percentage of the money needed for commercial installations. The bulk of the funding will need to come from private sources. “These technologies are not developed enough for the typical utilities to make an investment; the technologies do not meet their performance standards for return,” said Bahleda. “We are starting to see people looking at some of these technologies and envisioning the role that they can play.” He cautions that private funding will not come in any large amounts until the technologies complete successful demonstration projects.
The good news is that venture capital investments in so-called “Clean Tech” is growing. In 2003, venture investment in the sector rose 6.4 percent, up from four percent in 2002. The Clean Tech sector, which includes renewable energy, is defined as companies producing products and services that drastically reduce or eliminate environmental impact. The market, previously the domain of smaller venture firms, is also starting to attract the attention of larger venture capital companies.
Without the proper incentives and investment, the development of the domestic free-flow and wave power industries could follow the pattern of wind and solar. In both the wind and solar industries, the UK and Europe were more supportive of the technologies. Consequently, the U.S. has lost out on manufacturing, industrial infrastructure opportunities and jobs.
“There is tremendous potential,” sums up Mike Bahleda of the Electric Power Research Institute. “This is a source of renewable energy with a low environmental impact. We need to find ways to work cooperatively to move the technology forward. If we do, we will have more renewable power at lower costs.”

Copyright 2007, The JG Press, Inc.