Grid-Tied Microhydro in New York State

Intermediate

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About half of the system’s total head comes from a waterfall just below the house. Access for building the powerhouse and maintaining the system was a challenge.
Flow fluctuates significantly throughout the seasons, and depends on rain events and temperatures.
The retention pond, built for the project, holds approximately 520,000 gallons and helps temper runoff to a usable, steady flow. The perforated intake is visible near the overflow drain.
There’s a valve and vacuum break at the top of the 4-inch penstock where it enters the dam, next to the overflow culvert. The pipe had not yet been connected to the elbow.
Students weld 20-foot sections of 4-inch HDPE pipe into the 800-foot-long penstock.
The gauge at the power shed shows 43 psi of static pressure. At maximum flow, pressure loss due to friction will reduce net pressure to about 30 psi.
A Morrisville State College student with the (L to R) DC disconnect; SMA Sunny Boy 2.5 kW batteryless grid-tied inverter; hydro production kWh meter; and AC disconnect. From there, the input backfeeds a 15 A breaker in the main distribution panel.
The turbine includes a 4-inch turgo runner and four nozzles.
A HiPower 300 VDC hydro controller and disconnect.
A view into the power shed shows the component layout, including diversion resistor and 2 kW HiPower turbine and tailrace in operation. The fourth nozzle was not yet connected.
Bernie, with the microhydro system in full operation. By closely monitoring flow and adjusting nozzles appropriately, the system will product about 70% of his homestead’s energy annually.

In 2014, Morrisville State College students in the Renewable Energy Technology program installed a grid-tied, net-metered 2 kW residential microhydro system at a 44-acre homestead near Oneida, New York. This system produces an average of 8,500 kWh each year—covering approximately 70% of the homestead’s needs in a typical year.

n 2012, I gave a presentation about microhydro-electric systems at a small conference on renewable energy and efficiency options for local farms. At the end of the seminar, a tall man with a rough farm-built handshake asked me about the process of installing a net-metered microhydro system at his homestead. This is how I met Bernie Wootten, and how we came to install his hydroelectric system.

When I first pulled down his long driveway, I was greeted by guinea fowl, chickens, sheep, and Scottish Highland cattle. His homestead sprawls across 44 acres outside of Oneida, and his hand-built house is perched at the brink of a 40-foot waterfall on a small, unnamed stream. Bernie has long had a love of water; he has paddled whitewater with the best boaters in the world and holds several records for flatwater kayaking time trials. He works on weekends as a rescue kayaker for a whitewater-rafting outfitter on the Black River in Watertown, New York. While he always dreamed of using water to create electricity for his home, he was unsure how to go about it.

Permitting, Contracting & Incentives

If you’re interested in a grid-tied PV system in New York state, companies will show up within 48 hours to give you a free assessment, can have the permitting paperwork submitted within a week, and your system can be installed within a month. Though small wind has permitting challenges in this part of the state, companies are at the ready for a client with a promising wind site. But microhydro specialists are few and far between—Bernie had been trying, unsuccessfully, to find a company who would take on his project.

I had been working on and teaching about residential and farm-scale hydro projects since 2008 through SUNY-Morrisville, a small agriculture and technical college in upstate New York. Though most of the courses I teach are about solar electricity, solar water heating, and small wind systems, I have had a strong interest in residential hydro systems. We have abundant rainfall (approximately 36 inches) that’s well-distributed throughout the year, and topography amenable to hydro (rolling, forested ridges with 100 to 200 feet of relief). Additionally, I enjoy the challenge of designing and installing hydro systems. These systems require integration of assessment, analysis, electrical, mechanical, and on-site fabrication skills. Many lean companies cannot afford to take on hydro systems and stay profitable, so hydro systems are relegated to the few.

In New York, there are excellent state incentives—both tax credits and grant funds—for solar electricity and small wind systems. However, no such incentives exist for microhydro systems—though small hydro can be cost-competitive without incentives. To help offset the expense, I applied for a grant through the Research Foundation of SUNY. I used this grant fund, along with free student labor, to help Bernie get his dream hydro system installed.

Site Assessment

Estimating power from a hydro site is not terribly complex. Since the base physics equation is derived from potential energy, potential hydro system power can be determined as:

Power = Water Density × Acceleration Due to Gravity × Flow ×  Head

Since density and acceleration of gravity can be considered constants at a given site, you need only measure head (the vertical drop between the intake and the turbine) and flow (volume per unit time) to estimate the resource’s power.

Head (ft.) × Flow (gpm) ÷ 12* = Power (W)

*For this system, 12 was used; a range of 8 to 12 is typical.

After our initial meeting, Bernie had a retention pond constructed to raise fish and to water his animals and gardens. At the time the pond was constructed, he sistered a perforated 4-inch-diameter PVC pipe next to the overflow culvert for an intake, and capped the end that punched through the berm.

During the site assessment, we discovered that there was 100 feet of vertical drop between his retention pond and where the turbine could be installed. Water has a relationship between vertical distance and static pressure—there is 1 psi for every 2.3 feet of vertical drop (for every 10 vertical foot of water in a pipe, there are 4.3 psi). Since Bernie’s site had 100 vertical feet, this would give a static pressure of 43 psi. To get the water from the intake to the turbine, it required about 800 linear feet of pipe.

Comments (7)

Jim and Elaine Stack's picture

Some Solar PV and good Lithium storage batteries and he could be Off GRID or make money from the GRID Tied power.
A friend in Skaneateles has solar and National GRID the local power company owes him every month.

mberdan's picture

Great Idea. keep up the good work. together we can all make significant changes.

Todd Cory's picture

48 kWh/ day only does 70% of this home's loads?

yikes... someone needs to do an energy audit and learn how to conserve!

Phil_H's picture

Hi Todd, I'm not quite sure what you mean by this. The equipment is rated at 2 kW, but it is not continuously putting out 2 kW because the resource is intermittent. The system provides an average of 8500 kWh/year, which is about 23 kWh of production per day. It covers about 70% of his home energy consumption, which is about 12,000 kWh/yr. I agree that value is high for a typical residence, but for a homestead that is fully electric with limited load shifting, it's not terrible.

Christphor's picture

What permit challenges did you run into? What agencies did you have to contact ? Are there specific designs for registered trout streams in New York?

Phil_H's picture

We had to file permits with the DEC, the town, and all utility interconnection paperwork. I think there may be a hydro permitting article coming out soon in HP, so hopefully that will help address the many permitting challenges that come with hydro systems.

I have some things very specific to NYS permitting, if that would be helpful as well.

Christphor's picture

Phil,
The New York stuff would be awesome. Could you send that to me Email? Tiletec@frontiernet.net
Thank you, Chris

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