The Solar Resource

1. The Hydro Resource and Micro Hydroelectricity Systems The Solar Resource

2. Overview • Review of the Hydrologic Cycle • System components • Measuring head and flow • Generating power from water (examples) http://retc.morrisville.edu

3. Hydrologic Cycle • Key terminology • Insolation • Evaporation • Transpiration • Evapotranspiration • Sublimation • Condensation • Precipitation • Infiltration • Sub-surface flow • Ground water discharge • Overland (surficial) flow • Freshwater storage • Oceanic storage http://retc.morrisville.edu

4. Hydrologic Cycle condensation Insolation sublimation Precipitation Evaporation Transpiration Surficial flow Freshwater storage Oceanic storage Infiltration Groundwater discharge Subsurface flow http://retc.morrisville.edu

5. Hydro Power • For most hydro systems, we are interested in only certain processes in this cycle • Oceanic storage (wave, tidal, ocean current) • Freshwater storage (wave, pumped storage, dams) • Overland flow (streams and rivers) • Though our systems use these processes, we must keep in mind that it is a cycle • Water is replenished in our systems due to incoming solar energy http://retc.morrisville.edu

6. Measuring the hydro resource 28 inches per year http://retc.morrisville.edu In central New York, when do we get most of our precipitation?

7. Measuring the hydro resource http://waterdata.usgs.gov/nwis/ http://retc.morrisville.edu

8. http://retc.morrisville.edu

9. System components: Intake • Water enters penstock through the intake • Remove debris • High maintenance • Accessible http://retc.morrisville.edu

10. System components: Penstock • PVC • Cheap, light, and rigid • Low pressure systems • Easily available at hardware stores • Low losses (in straight sections) • Freezing issues http://retc.morrisville.edu

11. System components: Penstock • Polyethylene tube • Flexible • Longer lengths • Lower losses in sweeping bends • Freeze resistant • Expensive components • Difficult to purchase http://retc.morrisville.edu

12. System components: Turbine • High head, low flow • 1, 2, and 4 nozzle designs • 12, 24, 48, VDC options • 120 VAC options • Pelton wheel with bronze runner http://retc.morrisville.edu

13. System components: Batteries • Lead-acid • Deep cycle • Generally 2 to 6V • Wet cell or sealed (gel) http://retc.morrisville.edu

14. System components: Charge controller • Monitors battery bank voltage • When the battery bank is “full”, electrons are diverted to a diversion load (a.k.a. dump load) • Can be jumped from 12,24, and 48 VDC depending upon input and battery bank (they must match!) http://retc.morrisville.edu

15. System components: Diversion Load • Waste electrons as quickly as possible • Resistance heating elements • Protect the battery bank http://retc.morrisville.edu

16. System components: Inverter • Converts direct current (DC) to alternating current (AC) • Can match the utility signal (voltage, shape and frequency) http://retc.morrisville.edu

17. Generating power Now that you understand the system components, how does one actually generate power with a micro hydro system? http://retc.morrisville.edu

18. Measuring the hydroelectric resource • Power generation from water is dependent on five variables: • P=ηρgQH • Power in watts (P) • Turbine efficiency (eta, η) • Water density (rho, ρ; usually 1000 kg/m3) • Acceleration of gravity (g, 9.81 m/s2) • Quantity of water flow (Q, in m3/s) • Vertical distance (head, H, in meters) http://retc.morrisville.edu

19. Measuring a stream – flow Flow rate (Q) • Quantity of water passing a given point over a given amount of time • Cubic meters per second • Gallons per minute • 1 GPM = 0.000063 m3/s http://retc.morrisville.edu

20. Measuring flow http://retc.morrisville.edu

21. Measuring the hydro resource - head 2.31 feet 1 psi http://retc.morrisville.edu Head (H) Head is the vertical distance of the hydro system (from intake to turbine) Relationship of head and pressure

22. Measuring head http://retc.morrisville.edu

23. Stream profile diagram 1,110 feet of penstock http://retc.morrisville.edu

24. Hydro power - example http://retc.morrisville.edu • Small stream: • 20 GPM flow, 140 feet of head, 85% turbine efficiency • Pressure: • Flow: • Head:

25. Hydro power: example http://retc.morrisville.edu • P= ηρ g Q H • Power = 0.85*1000 kg/m3*9.81 m/s2*0.00126 m3/s * 42.7 m • Power = 448.6 watts • Yearly energy in kWh? • 448.6 W *24 hrs/day * 365.25 days/yr = 3,932 kWh/yr • My house uses about 4,000 kWh/yr

26. Hydro power: what if? http://retc.morrisville.edu • If we go from 20 GPM flow and 140 ft of head to 140 GPM and 20 ft of head? • What power (watts) should I expect? • P= ηρ g Q H • Power = 0.85*1000 kg/m3*9.81 m/s2*0.00882 m3/s * 6.1 m • Power = 448.6 watts

27. Hydro power • Head and flow have equal importance in determining power (and energy) in a hydro system • What we have just calculated does not take penstock losses into account • This will reduce power output http://retc.morrisville.edu

28. Hydro power: a comparison http://retc.morrisville.edu • 20 GPM and 140 ft of Head • Yearly energy in kWh? • 448.6 W *24 hrs/day * 365.25 days/yr = 3,932 kWh/yr • My house uses about 4,000 kWh/yr

29. http://retc.morrisville.edu

30. …to wind! • Class 3 site (7 m/s average; 15 mph) • Turbine at 30% efficiency • P=0.5* ηρ A V3 • 450 W = 0.5*0.3*1.2 kg/m3*(3.14*r2)*(7 m/s)3 • r = 1.5 meters, diameter = 3 meters This means to get an equivalent amount of energy, I need a 10’ wind turbine rotor! http://retc.morrisville.edu

31. So, what bother with micro hydro? • (Relatively) inexpensive • Constant power production (not intermittent) • Minimal impacts • Turbines have high efficiency (80% to 90+%) Challenges • Not considered “renewable and sustainable” • Permitting process may be required • Highly selective sites • Currently cannot be net metered • Little knowledge of our resource http://retc.morrisville.edu

32. Contact Information Phil Hofmeyer, Ph.D.Assistant ProfessorPh: 315-684-6515 Email: hofmeypv@morrisville.edu Web: http://people.morrisville.edu/~hofmeypv/ Ben Ballard, Ph.D.Director, RETC Assistant ProfessorPh: 315-684-6780 Email: ballarbd@morrisville.edu Web: http://people.morrisville.edu/~ballarbd/ http://retc.morrisville.edu