The Solar Resource The Hydro Resource and Micro Hydroelectricity Systems

Overview Review of the Hydrologic Cycle System components Measuring head and flow Generating power from water (examples) 6/22/2009http://retc.morrisville.edu2

Hydrologic Cycle 6/22/2009http://retc.morrisville.edu3 Key terminology »Insolation »Evaporation »Transpiration »Evapotranspiration »Sublimation »Condensation »Precipitation »Infiltration »Sub-surface flow »Ground water discharge »Overland (surficial) flow »Freshwater storage »Oceanic storage

Hydrologic Cycle 6/22/2009http://retc.morrisville.edu4 condensation sublimation Insolation Precipitation Surficial flow Freshwater storage Transpiration Evaporation Infiltration Subsurface flow Oceanic storage Groundwater discharge

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 6/22/2009http://retc.morrisville.edu5

Measuring the hydro resource 6/22/2009http://retc.morrisville.edu6 In central New York, when do we get most of our precipitation? 28 inches per year

Measuring the hydro resource 6/22/2009http://retc.morrisville.edu7

6/22/2009http://retc.morrisville.edu8

System components: Intake 6/22/2009http://retc.morrisville.edu9 Water enters penstock through the intake Remove debris High maintenance Accessible

System components: Penstock PVC »Cheap, light, and rigid »Low pressure systems »Easily available at hardware stores »Low losses (in straight sections) »Freezing issues 6/22/2009http://retc.morrisville.edu10

System components: Penstock Polyethylene tube »Flexible »Longer lengths »Lower losses in sweeping bends »Freeze resistant »Expensive components »Difficult to purchase 6/22/2009http://retc.morrisville.edu11

System components: Turbine 6/22/2009http://retc.morrisville.edu12 High head, low flow 1, 2, and 4 nozzle designs 12, 24, 48, VDC options 120 VAC options Pelton wheel with bronze runner

System components: Batteries 6/22/2009http://retc.morrisville.edu13 Lead-acid Deep cycle Generally 2 to 6V Wet cell or sealed (gel)

System components: Charge controller 6/22/2009http://retc.morrisville.edu14 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!)

System components: Diversion Load 6/22/2009http://retc.morrisville.edu15 Waste electrons as quickly as possible Resistance heating elements Protect the battery bank

System components: Inverter 6/22/2009http://retc.morrisville.edu16 Converts direct current (DC) to alternating current (AC) Can match the utility signal (voltage, shape and frequency)

Generating power Now that you understand the system components, how does one actually generate power with a micro hydro system? 6/22/2009http://retc.morrisville.edu17

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/m 3 ) »Acceleration of gravity (g, 9.81 m/s 2 ) »Quantity of water flow (Q, in m 3 /s) »Vertical distance (head, H, in meters) 6/22/2009http://retc.morrisville.edu18

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 = m 3 /s 6/22/2009http://retc.morrisville.edu19

Measuring flow 6/22/2009http://retc.morrisville.edu20

Measuring the hydro resource - head 6/22/2009http://retc.morrisville.edu21 Head (H) Head is the vertical distance of the hydro system (from intake to turbine) Relationship of head and pressure 2.31 feet 1 psi

Measuring head 6/22/2009http://retc.morrisville.edu22

Stream profile diagram 6/22/2009http://retc.morrisville.edu23 1,110 feet of penstock

Hydro power - example 6/22/2009http://retc.morrisville.edu24 Small stream: » 20 GPM flow, 140 feet of head, 85% turbine efficiency Pressure: Flow: Head:

Hydro power: example 6/22/2009http://retc.morrisville.edu25 P= η ρ g Q H »Power = 0.85*1000 kg/m 3 *9.81 m/s 2 * m 3 /s * 42.7 m »Power = watts Yearly energy in kWh? »448.6 W *24 hrs/day * days/yr = 3,932 kWh/yr My house uses about 4,000 kWh/yr

Hydro power: what if? 6/22/2009http://retc.morrisville.edu26 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= η ρ g Q H »Power = 0.85*1000 kg/m 3 *9.81 m/s 2 * m 3 /s * 6.1 m »Power = watts

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 6/22/2009http://retc.morrisville.edu27

Hydro power: a comparison 6/22/2009http://retc.morrisville.edu28 20 GPM and 140 ft of Head Yearly energy in kWh? »448.6 W *24 hrs/day * days/yr = 3,932 kWh/yr My house uses about 4,000 kWh/yr

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…to wind! 6/22/2009http://retc.morrisville.edu30 Class 3 site (7 m/s average; 15 mph) Turbine at 30% efficiency P=0.5* η ρ A V W = 0.5*0.3*1.2 kg/m 3 *(3.14*r 2 )*(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!

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 6/22/2009http://retc.morrisville.edu31

Phil Hofmeyer, Ph.D. Assistant Professor Ph: Web: Ben Ballard, Ph.D. Director, RETC Assistant Professor Ph: Web: Contact Information