You’re going to learn most by doing

Developed from an idea that came from an office move after the events of 9/11, Rentricity has come up with a solution to utilise the waste water flowing through the pipes of the US every single day – to generate electricity. Total World Energy speaks to co-founder and CEO, Frank Zammataro who explains why in-pipe hydropower is such an innovative concept…

With a goal to harness clean and renewable energy from excess water found within the water mains system, Rentricity (an amalgamation of renewable and electricity), established in 2003, is pioneering a new wave of reliable and renewable hydro-kinetic energy in the US.

With the continual flow of water through underground pipelines – 24 hours a day, 365 days a year – inevitably allows the generation of renewable energy all year round too. Co-founders, Frank Zammataro, Al Spinell and Jason Scharfspitz originally set up the company as a side-line project to help utilise this excess flowing water through the pipelines of New York City.

Zammataro, an ex-Wall St. Executive, spending 21 years at Merrill Lynch, always had a flair for innovation and entrepreneurship. Leaving in 2000, he explains after the events of 9/11 in New York, he moved offices in his then current job to mid-town Manhattan – “It just so happened that when we set up this temporary space, below the conference window there was a water tower on top of a 30 storey building. We stared at that water tower for weeks on end after 9/11 and at one point, my co-founder turned to me and said: ‘Can we use the water in the tower to create power?’ As it was going from the 30th floor down to the ground floor.

“We envisioned an emergency evacuation system that could be powered by water on top of tall buildings. At the time I had zero mechanical or electrical background, but luckily I had a contact at Rensselaer Polytechnic Institute in Troy, New York,” Zammataro explains.

From the initial idea, the co-founders took their concept to academic professors to see if it was a viable one. Although the concept had potential, the professors pointed out that, inevitably, water tanks have a limited supply of water as opposed to the prospect and opportunity found in water systems and water distribution networks with artificial pressure regulation.

So in the summer of 2002, Zammataro explains the Rentricity team began cold calling some of the largest water utilities in the US. By the autumn, they were out in the field looking at water infrastructure and the potential it held – “Large pressure reduction valves were just dissipating pressure through friction, essentially wasting energy. So from this, we derived the conceptual framework for Rentricity.”

With a business plan in place, Rentricity tried to get government funding before receiving US$200,000 from the state of Rhode Island and the state of Connecticut to research and build a pilot in a real live water system.

Taking five years to complete this pilot, initially working on a part time basis, Zammataro explains Rentricity went commercial in July 2009, joining New York City’s very first Cleantech incubator called ACRE (Accelerator for a Clean and Renewable Economy.)


In the US, on a daily basis, an estimated 400 billion gallons of water moves through its water pipes. 200 billion of this is for the energy industry, 100 billion is for irrigation and agriculture with 50 billion for consumption and 50 billion for industries (food processing, chemical plants, oil and gas etc.)

Rentricity made the initial decision to focus on the 200 billion gallons that is the drinking, industrial and irrigation water – “That’s our focus and it’s a huge market”, Zammataro explains. “At a domestic level in the US, it’s approaching a $4 billion market and globally, it’s a $17 billion market.

“There is so much wasted processed water and energy just there waiting to be integrated back into the electricity grids, or into buildings where the water is flowing.

“I visited a turkey processor in Pennsylvania which processes 20,000 birds every day for packaging and delivery to supermarkets. They use 400,000 gallons of water a day in the different cycles – the aggregate level in the US is that we process between eight and nine billion birds a year for consumption and that’s just in the US. We found we could reduce their energy costs by roughly 10%,” Zammataro explains.


So, how does this energy generating concept work? Rentricity’s technology makes use of the highly pressured water that flows through pipes to be delivered to neighbourhoods and businesses. After leaving the treatment plant, water typically goes through the water utility where the pressure and flow are reduced as the water gets ready to enter the smaller pipes to its end users.

“We can monitor, control and optimize the pressure in the system so that we can get the most electricity potential out of the system,” explains Zammataro.

The design and installation of its highly unique energy recovery system, Flow-to-Wire™, will help to harness the recurrent high volumes of excess energy, using it to generate clean electric power. A single Flow-to-Wire™ system is able to produce between 30-350 kW of clean, renewable, electricity which can then be sold back to the grid.

Rentricity is also developing a suite of Sustainable Energy & Monitoring Systems (SEMS™) – a set of pre-packaged, pre-engineered, skid mounted energy recovery systems, equipped with an integrated set of water quality sensors that will extend the Flow-to-Wire line to between 5-30 kW.

Working in partnership with water pump and treatment equipment maker, Xylem, both companies are demonstrating the new technology in a Pennsylvania site.

Rentricity can also install flow and pressure sensors that collect data and detect leakage for water utilities, particularly if the water treatment systems are located in remote areas.

Because in-pipe water power is very dense, Zammataro explains that the economics of Rentricity’s projects are more appealing than many other renewables due to the consistency and predictability of water flows, as oppose to weather dependent renewable solutions.

Rentricity’s equipment currently has a 40-year life span with energy savings covering the cost in three to 16 years, depending on the size of the installation and the clean energy incentives that have been put in place.


Nearly a decade on since its inception and Rentricity is nearing the completion of its largest project to date: a 325 kW installation at a water transfer station in Palos Verdes, California, for the largest investor-owned water utility in the state, California Water Services Company.

And additionally, with the potential to generate up to 100 kW, Zammataro explains: “We have created the very first energy neutral water treatment plant in the city of Keene, New Hampshire, which is powered by its inflow of pressurized water – so that plant is completely energy neutral.

“We have now exploited every possible area for energy recovery within drinking water and 2015 is a big irrigation water year for us,” explains Zammataro. “We have two irrigation projects underway in Idaho and Utah and next year, we will be focusing on generation from industrial water.”

It is often said that the best ideas come completely out of the blue, perhaps when you least expect it or are busy planning something else – but from a series of events back in 2001, these helped to encourage three co-founders into creating, developing and establishing Rentricity. So, what’s next?

“We have received many enquiries from international engineering companies and renewable energy developers,” Zammataro explains. “We are actively pursuing our first project in central and South America, where energy costs are very high. In Mexico, the electrical grid is being deregulated, so the electric companies are looking for ways of fostering cleaner energy.

“So it’s very exciting, we remain opportunistic and I think the future is very bright for us.”


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