© Civic Mapper, LLC 2018
This tool uses a basic formula for estimating power generation potential; it is suitable for planning purposes only. The underlying elevation data driving the calculations is provided by the US Geological Survey through web service hosted by ESRI. Where available, head calculations rely on high resolution elevation data services hosted by the NY State GIS Program Office.
Current Hydro provides an overview of microhydropower technology on their website.
A= area of the watershed upstream of the microhydropower installation, in
square miles. This helps determine the volume of water that could pass through the turbine. This tool automatically determines this value from geospatial data (you have the option to override that).
H= head (elevation change) for the microhydropower installation in
feet; the drop in elevation helps determine how much energy the turbine will be able to generate. This tool automatically determines this value from geospatial data (you have the option to override that).
Y= watershed yield, as
cubic feet per second per square mile(
cfs/sqmi). We use 1.6 cfs/sqmi as a constant as a general estimate of the amount of water per square mile a watershed will yield, which is good enough for planning purposes.
F= an environmental flow constant, typically between 0.1 and 0.5
cfs/sqmi. Our default is 0.3.
E= a power generation efficiency constant. Our default is 70%.
R= electricity value per kilowatt-hour, in dollars
P= power generated, in kilowatt-hours
V= annual value of power generated, in dollars
Qt = A * YThis is how much water theoretically comes down the stream (cubic feet per second).
Qe = A * FThis is how much water is needed to maintain basic ecosystem function (cubic feet per second).
Qu = Qt - QeUseable yield from the watershed (cubic feet per second).
P = (Qu * H / 11.8) x epower generated, in kilowatt-hours
V = R * 8766 * Pannual value of power generated, in dollars
Interested in running the calculator programmatically? You can access the formula through our Calculator API.
This calculator relies on publicly-available, map-based data to generate estimates of electrical power
potential. Default values are provided, but users may manually override the default and map generated values.
It's important to understand that not 100% of the available water may pass through the generator, and that
generators are not 100% efficient.
This calculator is not a precise tool and is not intended to replace field measurements or surveys. Dam owners should discuss their options with a micro hydropower design professional as individual circumstances may vary.
While Bard College has endeavored to ensure that the supplied calculations and information are based on valid assumptions and approaches, outputs from the calculator are meant to guide only. Users should verify the information obtained through the calculator independently. Bard College takes no responsibility for any error or defect therein. Bard College shall not be liable for any loss or damage arising from the use or reliance of any data supplied by the calculator.
This calculator will guide you through these steps:
Use the map to the right, its search tool, and available layers to find locations suitable for microhydro installation. Dam locations (New York State only), along with hydrography from USGS, are available as map layers. A layer indicating the coverage of high-resolution LiDAR elevation data is also available. Switch the basemap between several available imagery and topographic styles to get a better sense of the terrain.
Use the draw tool to draw a line from a point downstream (lower elevation) to a point upstream (higher elevation) to indicate the potential location of a microhydropower installation's outlets and inlets, respectively. You don't need to trace the exact path; start and end points are sufficient!