Developer seeks to use ancient Greek technology to draw energy from R.I. river
BY ALEX KUFFNER, The Providence Journal
WEST WARWICK, R.I. -- On a 127-year-old dam on the Pawtuxet River, Robert Cioe wants to use millennia-old technology to do something new. Cioe, a property developer based in North Kingstown, R.I., plans to build a hydropower project at the Natick Pond Dam that would be the first in the U.S. to use Archimedes’ screws, generators named for the third-century B.C. Greek engineer and scientist who is thought to have popularized the devices to pump water upward for irrigation and drainage.
When used in reverse, Archimedes’ screws have, in recent years in Europe, proven to be an efficient way to harness the downward flow of water to generate electricity. But the generators, which resemble giant corkscrews, have never been installed on this side of the Atlantic.
Cioe hasn’t developed a hydropower project before, so he is working with New England Hydropower, which has partnered with a firm that has installed about 30 Archimedes’ screw generators in the UK.
Representatives of New England Hydropower, based in Beverly, Mass., believe they have found a cost-effective way to build small hydro projects. They say there is potential for hundreds of such projects in New England. And they want to start with the Natick Pond Dam on the Pawtuxet River.
For Cioe, the project has been decades in the making. He bought property adjacent to the dam on the Warwick side of the river in 1968 and built 65 houses there. He sold the homes but hung on to a strip of land on the river, thinking that someday the dam could be used to generate renewable energy.
“I’ve been dreaming about doing this for a long time,” he said on a recent afternoon as he watched water rush over the dam.
Rhode Island has 742 dams, according to the state Department of Environmental Management. Many were built more than a century ago to power textile mills, but they serve little practical purpose these days. Hydropower advocates have long pushed for putting them to use again.
There are only five commercial hydro plants operating in Rhode Island, and they provide less than 0.1% of the state’s energy needs, according to the state Office of Energy Resources. The three largest are on the Blackstone River, with one each in Woonsocket, Central Falls and Pawtucket.
A study released this year by the state Renewable Energy Siting Partnership estimated that Rhode Island could generate as much as 15 MW of power from small hydro facilities on the Pawtuxet, Blackstone, Ten Mile, Wood-Pawcatuck and Woonasquatucket rivers — enough power for 22,000 typical homes.
But small — or low-head — hydropower has been notoriously difficult to develop. Permitting, which requires approvals from state agencies and the Federal Energy Regulatory Commission, can be arduous, and the payoff can be modest.
“The process with FERC treats a 200-MW project out West the same as a 25-KW mill project in Rhode Island,” said Charles Rosenfield, whose company, Putnam Hydropower, operates the plants in Pawtucket and Woonsocket as well as one in Putnam, Conn. “It’s money upfront, and there’s no certainty you can complete the project.”
New England Hydropower has invested a lot of time and effort at the outset to understand permitting, said Chris Conover, the company’s chief marketing officer.
“A lot of renewable energy companies have the technology, but they don’t realize how hard it will be to get it up and running,” he said. “We recognized early that there is a permitting process in this business. If you do what they ask, if you comply, all of these permitting things are doable.”
It might be more expensive now to navigate through the relevant agencies, but those costs will come down once the company has a good process in place, Conover said.
And New England Hydropower believes there are ample opportunities for viable projects. New England has about 10,000 dams, and New York State has another 5,000, Conover said. New England Hydropower has looked at all of them, at least on maps, and has created a list of potentially hundreds of places suitable for Archimedes’ screw generators.
The company is working on other projects in Connecticut and Massachusetts. It also has its eye on other sites in Rhode Island. But the Natick Pond Dam project is furthest along.
Cioe has built hundreds of houses around the state and developed the Metro Center office park in Warwick and the Wickford Junction commuter rail station in North Kingstown, where his company, CO Construction, is based.
But in the 45 years he owned the land near the dam, he was never able to move forward with a hydro project. Others had tried, including one company that received preliminary federal approval to do site work, but nothing came of the plans.
Last October, Cioe attended a meeting of the Environmental Business Council of New England and listened with interest to a presentation by New England Hydropower. He approached Michael Kerr, CEO of the company, afterward.
Kerr gave a personal presentation to Cioe in December, and the two decided to work together. Under their agreement, New England Hydropower will do the installation work, but Cioe will own the project.
In February, they applied to the FERC for a permit to carry out a feasibility study and received approval in May.
At a budget referendum in June, West Warwick voters agreed to sell Cioe land next to the dam. The parcel sits on the opposite side of the river from the land Cioe bought in the 1960s and is more appropriate for development. The land, which had been off the tax rolls, cost about $22,000 and needs remediation for hazardous materials. The dam also needs repairs.
In July, the state Economic Development Corporation approved a $200,000 recoverable loan to Cioe’s company JAL Hydro from the state Renewable Energy Fund.
The money will help pay for site investigation, preliminary design, licensing and permitting, structural engineering and final design. Under terms of the grant, if the project is successful, Cioe will repay the money to the fund.
During a tour of the project site, which sits just below the Providence Street Bridge, Cioe talked about his plans and the history of the area.
The Natick Pond Dam was built in 1886 to store water to power the Natick Mills, where hundreds of workers wove cotton yarn in a complex that dated to 1807, and was expanded over the course of the 19th century.
Water that collected in the 24-acre pond above the dam was channeled into an 8-ft-deep headrace on the West Warwick side of the river that ran 800 ft to the mills, before exiting down a tailrace to rejoin the river.
With the decline of textile manufacturing in the 1920s, the mills closed and, after sitting idle for years, burned to the ground on July 4, 1941.
There are few visible remnants of the mills, but the granite-block dam, which stands 20 ft wide and 166 ft long, is in remarkably good shape, said Cioe.
The 50-ft-wide granite-lined headrace has been filled in over the years. Although parts of the wooden sluice gates that controlled the flow of water from the pond are still visible, it has been a long time since water flowed through the channel.
Cioe plans to open the headrace. Water would flow through it, along the side of the river, into two 11-ft-wide by 60-ft-long Archimedes’ screw generators installed at a downward tilt, and then back into the Pawtuxet River.
The size of an Archimedes’ screw — and its generating capacity — is dictated by two factors: the height of the dam and the volume of water. The generator runs most efficiently at an angle of 22 degrees.
The screws at the Natick Pond Dam would have a combined power output of 296 KW and would generate about 1,500 MW-hr a year, enough electricity for about 250 typical Rhode Island homes.
Hydraulic sluice gates would control the flow of water that enters the screws. The screws would turn slowly enough — 30 to 40 revolutions per min — to allow fish to pass through unharmed, though they would not be able to swim up the dam, according to New England Hydropower.
In the last legislative session, lawmakers expanded the state’s landmark distribution generation program to include small hydropower. The program sets ceiling prices for different types of renewable energy, such as solar and wind power, and requires National Grid to negotiate 15-year power purchase agreements with developers. The contracts are important because they guarantee revenue.
The change was made to give more support to small-scale hydro generators, said state energy commissioner Marion Gold. Legislators also extended the period for contracts to go into effect in recognition of the long time it can take for hydro projects to secure permits.
“That was something concrete we could do to support hydro,” Gold said. “We’re continuing to work with the utility to integrate the growing amount of renewable energy into the grid.”
State regulators have yet to set a final price for small hydro, but Gold said 17 cents a KW hr is being contemplated. That is higher than prices for power from fossil fuel-fired plants, but it’s lower than prices in Rhode Island for power from offshore and onshore wind turbines and solar arrays. The first hydro contracts will go out to bid next year.
Along with the West Warwick project, the state Office of Energy Resources has been in contact with developers with proposals in East Providence and North Smithfield.
If he secures a contract, Cioe expects to make about $250,000 a year selling power. With an estimated project cost of $2 million, he would be able to pay everything off within the 15-year power contract.
Any revenues afterward would be pure profit, he said. Archimedes’ screw generators have an estimated lifespan of 30 years.
As he walked along the West Warwick side of the river, Cioe pointed out the path of the headrace. He clambered over the granite foundation of one of the mill buildings and expressed wonder that an iron crank that once controlled the sluice gates still turns smoothly.
He plans to finalize purchase of the riverfront land in the next few weeks. The project, he said, should move forward quickly afterward.
There are huge challenges. It’s not like the old days when a mill could dam or divert a river with little oversight. These days, permitting can take years.
Cioe, however, is undeterred. He believes that by this time next year his two Archimedes’ screw generators could be up and running.
And then the Natick Pond Dam would be generating power once again.
The Providence Journal