Micro Hydroelectricity BIG energy from SMALL power systems

Transcription

1 Micro Hydroelectricity: Benefits and Applications Micro Hydroelectricity BIG energy from SMALL power systems June 29, 2011 Phil Hofmeyer, Ph.D. Morrisville State College

2 Overview Basic Electricity» Ohm s Law, Power Law, power to energy Hydro Resource System Overview Turbines Civil Works Electrical Systems Permitting 6/29/

3 How I got here 6/29/

4 How I got here Annual Stemwood Volume Increment (dm 3 ) Cored Trees Stem-analyzed Trees [6] Power [7] Weibull Projected Leaf Area (m 2 ) Two nonlinear models fit: β1 VINC1 = β0 + PLA, R 2 = 0.75 β3 PLA VINC 2 = β 1 1 EXP β2 R 2 = /29/

5 The Training Center Location 6/29/

6 6/29/

7 Primary Energy 6/29/

8 What we really want 6/29/

9 Basic Electricity Electricity is a form of secondary energy An energy carrier of converted primary energy to our desired end use» Thermal energy» Mechanical energy» Sound energy» Light energy» Chemical energy 6/29/

10 Basic Electricity Electrical circuit - a network with a closed loop, giving a return path for the current. Conventional flow notation A simple electric circuit made up of a voltage source (V) pushing an electric current (I) through a resistor (R). 6/29/

11 Ohm s Law Effect = Cause Opposition I = E Current = Voltage R Resistance 6/29/

12 Ohm s Law and Power Law Volts = Amps * Ohms Watts = Volts * Amps (volts) (power in Watts) (amps) (ohms) (Volts) (current In amps) 6/29/

13 Power and Energy Energy is the capacity to do work (cumulative)» Common units: kwh, Joules, BTU, therms Power is the rate at which work is done (instantaneous)» Common units: Watts, kw, HP, BTU/hr Power Energy 6/29/

14 Power and Energy (quick example) To convert from power to energy, we must know time of operation Assume we have a 1 kw hydro system operating at maximum power and functioning perfectly for 365 days per year 24 hours 365 days 1 kw = day yr 8760 kwh/yr 6/29/

15 The Hydrologic Cycle sublimation condensation Insolation Surficial flow Precipitation Transpiration Evaporation Freshwater storage Oceanic storage Infiltration Subsurface flow Groundwater discharge 6/29/

16 Local Precipitation Resource 5 Long-term data from NOAA.GOV Average Precipitation for Allentown, PA Precipitation (inches) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 6/29/

17 Local Discharge 300 Long-term data from waterwatch.usgs.gov Jordan Creek Discharge ( ) Cubic Feet per Second avg cfs 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 6/29/

18 Local Discharge Long-term data from waterwatch.usgs.gov 300 Jordan Creek Discharge ( ) Cubic Feet per Second avg cfs Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 6/29/

19 Hydrograph Jordan Creek Long-term data from waterwatch.usgs.gov Base Flow? 6/29/

20 Micro Hydroelectricity System Overview What is micro hydro I don t know.» Many, many definitions and break-downs Small wind refers to on-site energy consumption (up to ~100 kw) Let s go with on-site consumption (up to perhaps 5 kw) 6/29/

21 Simple DC micro hydro system 3/30/

22 Hydro system power output Hydro system power output really has only two resource variables to measure Head» Vertical Distance between intake and turbine Flow» Volume of water per unit time Streams tend to be either high head and low flow or low head and high flow 6/29/

23 Measuring Flow Weir Wall 6/29/

24 Measuring Flow Float method 6/29/

25 Measuring Flow Flow meter 6/29/

26 Measuring head tube and gauge Great for short penstock runs 41.6 ft 2.31 feet 18 psi 1 psi 6/29/

27 Measuring head Clinometer and tape X 154 ft 16 Sin(16)=X/154 X=42.4 6/29/

28 6/29/

29 Measuring head - Altimeter 1052 ft 978 ft 1052 ft = 74 ft 32 psi 978 ft Great for very high head systems * how accurate is the altimeter? 6/29/

30 Hydro power (geek math version) E potential = mgh A Power (watts) = ρqgh» ρ is water density (1000 kg/m 3 )» Q is flow (m 3 /s)» g is acceleration due to gravity (9.81 m/s 2 )» h is head in meters V ρ t 6/29/

31 Hydro System efficiency Power extraction = ηρgqh» η is system efficiency» Penstock (0.9), turbine (0.9), generator (0.8), wiring (0.95), and electrical conversion (0.95) efficiency» 0.8*0.9*0.8*0.95*0.95 = 52% water-to-wire efficiency» What is residential wind system efficiency? 6/29/

32 Hydro power example A hydro system has 135 feet (41.2 m) of head and 85 GPM ( m 3 /s) of useable flow. Assuming typical efficiency, what is the annual energy output expected? P = ηρgqh P = 0.52*1000*9.81*0.0054*41.2 P = 1135 Watts 1135 Watts 24 hours Day 365 days yr = 9942 kwh/yr 6/29/ kWh 1000 Wh

33 Hydro power (napkin math version) To avoid the geek math used thus far, we have an option for quick power estimation» This is used universally in micro hydro installations P (Watts) = Q (GPM) x H (feet) 10 From the previous example P = 85 * 135 / 10 = 1147 Watts 6/29/

34 Flow examples 115 GPM (18 culvert) 475 GPM 6/29/

35 Benefits of hydro power If system is sized appropriately, nearly constant power production year-round» More predictable than wind» Much higher site specificity» Downtime for maintenance? High system efficiency is possible Low power systems that generate a lot of energy 6/29/

36 Turbine selection Remember, most systems are either: OR High head, low flow Low head, high flow 6/29/

37 Two broad categories of designs Impulse Efficient over a wide range of conditions (most common at high head) Nozzles convert potential energy to kinetic energy Reaction Designed for medium to low head sites Requires high flow rate Pressure drop occurs with a draft tube at the runner More site specific than Impulse designs 6/29/

38 Impulse designs Turgo Pelton 6/29/

39 Reaction Designs Francis Kaplan Propellor 6/29/

40 Other turbine designs Aquair (zero head) Darius Turbine 6/29/

41 Civil Works 6/29/

42 Intake schemes Storage Uses a dam to stop flow Builds up reservoir More stable year-round flow Siltation Complex Expensive Environmentally difficult Run-of-River Diverts part of the stream flow into a pipe Little to no flow regulation throughout the year Simple Reliable Inexpensive Environmentally friendly 6/29/

43 Run-of-River Intake Placement Choose a site with a stable stream bed The inside of bends accumulate sediment The outside of bends are subject to erosion and flood damage Place the intake along a straight section 6/29/

44 Run-of-River Intake Types Coanda screen Screened box 6/29/

45 Settling Basin (Silt Basin) Located near the diversion or the intake Reduction in water velocity A drain is required for periodic flushing Turbulence must be avoided 6/29/

46 Penstock Accessories Vacuum relief, gate valve, pressure gauge and cleanout 6/29/

47 Penstock types Most common for small systems is PVC or high density polyethylene (HDPE) PVC is cheap, rigid, widely available, and has a low friction coefficient HDPE is more flexible, comes in long rolls, more freeze resistant, with slightly higher friction losses 6/29/

48 Watch for Freezing! 6/29/

49 Joining HDPE penstock sections Compression Fitting Heat Fusion 6/29/

50 Head Loss Charts Flow US GPM Pipe Diameter, Inches Values are feet of head lost per 100 linear feet of penstock (PVC).

51 Hydro Electrical Systems Unlike solar PV and small wind systems, there is no specific section in the National Electrical Code Most Codes Enforcement Officers will not be familiar with these systems» Refer to Article 690 (Solar PV), 694 (Small Wind), and 705 (Interconnected Generators) 6/29/

52 Off-grid micro hydro system 52

53 Grid-tied micro hydro system 6/29/

54 Grid-Tied Electrical Components 1. Energy System and Design Stream Engine 4-nozzle Turgo hydro turbine at 120 VDC (600 Watts, 5 Amps). Earthing equipment ground (6 AWG bare copper). 2. Outgoing source conductors: #12 AWG stranded copper THWN in 1/2 liquid-tight flexible metal conduit. Positive black, negative white, and ground green. 3. Non-fused DC disconnect (250 VDC, 30 Amp) for diversion control isolation. Positive conductor broken. 4. Hi-Powered Hydro rectifier and voltage clamp (maximum outgoing voltage 600 VDC) Watt diversion load (NEC requires diversion load to be sized for at least 150% of maximum turbine output). 6. PV Powered 2000 W inverter with integrated DC and AC disconnects. UL 98 and 1741 listed for grid interconnection, NEMA 3R for use outdoors. Input 120 to 500 VDC, output 120/240 VAC, split phase, power factor > Outgoing conductors: #10 AWG stranded copper USE-2. Line 1 black, Line 2 black, Neutral white, and ground green. Conductors sized for 1.5% voltage drop over length of run and ampacity of 4 amps. 8. Easy Read #6 AC kwh meter. GE I /240 VAC. 9. Non-fused AC double pole disconnect (250 VAC, 30 Amp). Hot (line) conductors broken. 10. Easy Read #6 AC kwh meter. GE I /240 VAC. 11. Main distribution panel (200 Amp) in client s basement. A new double pole (240 VAC, 15 Amp) breaker is inserted along the bus bar at the furthest point from supply terminals (NEC 694). Maximum allowable renewable energy source breakers total 40 Amps (120% of bus bar rating, NEC 694). 6/29/

55 Permitting One of the more difficult portions of micro hydro system installation» And for good reason! A bit about New York State» I am unfamiliar with PA regulations 6/29/

56 Interconnection 6/29/

57 Net Metering New York 6/29/

58 Net Metering - PA 6/29/

59 Department of Environmental Conservation 6/29/

60 Environmental Permitting Water resources are usually closely watched and often protected» As they should be! Be sure to check local regulations BEFORE starting a micro hydro system Work with the agency, rather than attempting a clandestine hydro system 6/29/

61 Questions? Thank you! Courses at: 6/29/