New Hydropower Under Construction in Rhode Island

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New Hydropower Under Construction in Rhode Island

DATE:

May 17, 2021

BY:

Dennis Cakert, Senior Manager of Regulatory Affairs and State Policy, NHA

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New Hydropower Under Construction in Rhode Island

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The New England Hydropower Company (NEHC) officially broke ground the week of May 10, 2021, on its second new hydro project in the northeastern U.S. The new project revitalizes the 19th century historical Albion Dam on the Blackstone River using an even older technology – the Archimedes screw.  

Nearly two thousand years ago, Archimedes and his screw pumped water up from lakes and rivers into the famed Roman aqueducts. Now, the NEHC team is calling Archimedes out of retirement: NEHC installs the screw at existing non-powered dams to convert previously wasted flow into carbon-free electricity.   

HOW IT WORKS 

The screw is a 50-ton piece of steel with three grooves spiraling down a central shaft. The weight of the water flowing into the grooves forces the screw to turn, which is then converted into electricity through a system of gears, motors, and other state-of-the-art electrical equipment. 

The Archimedes Screw is an attractive option to developers for a few reasons: 

  • Operates over a wide range of flows; 
  • Has very few moving parts; 
  • Easily passes fish downstream; 
  • Can withstand heavy debris; and 
  • Is efficient at a variety of angles and lengths. 

The Archimedes Screw is featured as one of the 1,000 solutions in the Solar Impulse Foundation’s “1,000 Solutions release. 

Proven Success 

NEHC installed its first Archimedes Screw in the U.S. at Hanover Pond in Connecticut in 2017. The pond is human-made, or rather, re-human-made: the dam was repaired around 2012 to impound water for recreational purposes. The new dam features a fishway built by the state of Connecticut which passes eels, lamprey, herring, and shad. 

The 96-square-mile watershed upstream from Hanover Pond sends anywhere from 10 to 200 cubic feet per second over the dam or through the screw. Given the screw’s wide operating range, it runs nearly 24 hours, 7 days a week for 365 days a year, only stopping for extreme low flows. It produces 1,000 megawatt-hours of carbon-free electricity per year, enough to power more than 125 homes. 

The project was financed through the Connecticut Green Bank, an innovative source of public funds dedicated to the development of new renewable energy technologies. The project received “low impact” certification from the Low Impact Hydropower Institute (LIHI) in 2019. 

THE NEW PROJECT AT ALBION DAM  

Standing a proud 9 feet tall, the Albion Dam on the Blackstone River spills as much as 800 cubic feet per second. But soon enough, most of this flow will be redirected through two Archimedes Screws with a capacity of 420-kW of carbon-free electricity.

In May 2021, NEHC finished building a road which will be used construct the powerhouse, drop in the two screws, and allow National Grid to build new poles and wires for interconnection.  

Though the project qualified for an exemption from the Federal Energy Regulatory Commission, the NEHC staff was not liberated from paperwork – a seemingly endless paper trail to figure out who owned what property around the dam caused a fair share of headaches throughout the development process. 

AND THEY’RE NOT DONE YET  

Next up for NEHC is the Ashton Mills Dam, just downstream from Albion. This project will boast the second Voith Stream Diver in the United States (See Notre Dame University for the first Streamdiver, a project championed by then Mayor Pete Buttigieg, now serving as U.S. Secretary of Transportation).  

The Stream Diver features a powerhouse built within the turbine itself, reducing the costs associated with building a conventional powerhouse above the 100-year flood line, a necessity at Ashton Mills given the existing infrastructure and topography.

Once all three projects are complete, NEHC’s staff of eight will provide carbon-free electricity to more than 1,200 households and reduce U.S. carbon emissions by 7,000 metric tons per year.  

The United States is home to 90,000 dams, of which only 2,500 are used to produce electricity. As companies like NEHC prove, retrofitting these 90,000 dams is an essential pillar of the United States climate response.