9. How to calculate Energy from Stream?
How to account for seasonal water level change?
How to select the appropriate turbine?
What should the system physically look like? (Design)
How to deal with winter freezing?
Considerations
10. 1. Develop a procedure for calculating instantaneous
power from measurement data.
2. Using historical data from representative waterways,
develop a model for Annual Energy available from
the stream.
3. Determine which turbine and system design is best.
4. Develop an Excel spreadsheet that tabulates financial
return based on available annual energy and
equipment costs.
Method
11. 1. Develop a procedure for calculating instantaneous
power from measurement data.
2. Using historical data from representative waterways,
develop a model for Annual Energy available from
the stream.
3. Determine which turbine and system design is best.
4. Develop an Excel spreadsheet that tabulates financial
return based on available annual energy and
equipment costs.
MethodNext 12 slides.
12. Three measurements required:
a) Water Speed
b) Cross-sectional Area of Water
c) Available Head (Δ High Water, Low Water)
1 – Instantaneous Power
13. Measure distance.
Drop stick in water.
Time how long it takes to travel distance.
Correct for friction loss.
1 – Instantaneous Power
a) Water Speed
Answer: * ft/s
14. Water travels slower at stream-bed and
shores due to friction.
The “Average” water speed is
approximately 80% of the “Surface” water
speed.
1 – Instantaneous Power
a) Water Speed
Friction Loss
16. 1 – Instantaneous Power
b) Cross-Sectional Area of Water
Breakup stream into
“subsection” rectangles.
Measure Width and
Depth of each rectangle.
W x D = Area.
Add up all Areas to get
“Total Cross-sectional
Area” of stream.
22. 1 – Instantaneous Power
Bringing it all Together
Instantaneous Power =
Water Speed * Cross-sectional Area * Head * Water Density * Acceleration
Instantaneous Power (kW) =
0.197 (m/s)* 1.651 (m²) * 2.311 (m) * 1000 (kg/m³) * 9.81 (m/s²) / 1000 (W/kW)
= 7.37 kW
23. 1 – Instantaneous Power
Therefore:
On the day of our Site Visit, we measured the
instantaneous power of the Stream to be 7.37 kW’s.
24. 1. Develop a procedure for calculating instantaneous
power from measurement data.
2. Using historical data from representative waterways,
develop a model for Annual Energy available from
the stream.
3. Determine which turbine and system design is best.
4. Develop an Excel spreadsheet that tabulates financial
return based on available annual energy and
equipment costs.
MethodNext 9 slides.
25. 2 – Annual Energy of the Stream
The Stream will not ALWAYS be producing 7.37 kW’s of power;
Only on the days with the exact conditions of our site visit...
•Water level Varies.
•Water Speed Varies.
•Flow Varies.
•Head Varies.
Day-by-Day;
Month-by-Month;
Season-to-Season.
26. 2 – Annual Energy of the Stream
To get accurate idea of annual energy of the stream, need
to measure instantaneous power at minimum once per
month for a year.
(Jan Power * Jan Hours)
+ (Feb Power * Feb Hours)
+ (Mar Power * Mar Hours) …
= Total Annual Energy of the Stream (kWh).
28. 2 – Annual Energy of the Stream
We now have:
•A procedure for calculating instantaneous power;
•An Excel Tool to calculate annual energy from power.
That’s fine BUT….
29. 2 – Annual Energy of the Stream
•No Data on the 11 other months!
•Cannot offer financial analysis from just October measurements!
We need to estimate what data we should expect from missing months.
30. 2 – Annual Energy of the Stream
Government of Canada Historical
Hydrometric Database
•Over 7600 stations.
•Flow and Water Level Data
From here, we can acquire data from
waterways representative of our stream!
31. 2 – Annual Energy of the Stream
By matching our October
measured flow rate (0.33 m³/s) to
the October flow rate of a
representative waterway, we can
estimate what the flow rate for the
other 11 months might be!
33. 2 – Annual Energy of the Stream
A reasonable estimate for
potential energy
generation for the
missing 11 months.
34. 1. Develop a procedure for calculating instantaneous
power from measurement data.
2. Using historical data from representative waterways,
develop a model for Annual Energy available from
the stream.
3. Determine which turbine and system design is best.
4. Develop an Excel spreadsheet that tabulates financial
return based on available annual energy and
equipment costs.
MethodNext 15 slides.
50. 1. Develop a procedure for calculating instantaneous
power from measurement data.
2. Using historical data from representative waterways,
develop a model for Annual Energy available from
the stream.
3. Determine which turbine and system design is best.
4. Develop an Excel spreadsheet that tabulates financial
return based on available annual energy and
equipment costs.
MethodOpen Spreadsheet
