Transcript 12.4 Wind Hybrid Systems Frank R. Leslie, B. S. E. E., M.

12.4 Wind Hybrid Systems
Frank R. Leslie,
B. S. E. E., M. S. Space Technology, LS IEEE
3/15/2010, Rev. 2.1
fleslie @fit.edu; (321) 674-7377
www.fit.edu/~fleslie
In Other News . . .
 Wind Turbines in Chicago Tribune 3/14/10
http://www.istockanalyst.com/article/viewiStockNews/articleid/3946002
 (Source: Chicago Tribune) By Julie Wernau, Chicago Tribune
 “Mar. 14--Months have passed since anyone has waved hello to one
another in Waterman or Shabbona in rural DeKalb County. Some people
claim they've even stopped going to church to avoid having to talk to
former friends.
 "It's gone. The country way of living is gone," declares Susan Flex, who
lives in Waterman with her husband and their nine children.
 The animosity stems from the greenest of energy sources: a wind farm.
“
 Complaints of noise and light flicker
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12.4 Overview: Wind/Solar Hybrid Systems
 Erratic energy sources like wind and solar are not
dispatchable, that is, available on command of utility
dispatchers
 Sometimes or often, the wind blows when it is cloudy, or
the sun shines when the wind is calm
 A system that combines various energy sources is called
a “hybrid” system
 Diesel generators are often used for “reliable” power,
and wind or solar are used to decrease the fuel costs
 Studies of a site can indicate the optimal combination of
wind, solar, and diesel (or gasoline) to provide power at
the lowest overall annual cost
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12.4 About This Presentation
 12.4.1 Energy Mixture Availability
 12.4.2 Hybrid Mixes
 12.4.3 Economics of System Combination
 12.4.4 Hybrid System Design
 12.4.5 Balance of System (BOS)
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12.4.6 Power Control
12.4.7 Power Availability
12.4.8 Hybrid System Examples
12.4 Conclusion
12.4.1 Energy Source Mixture Availability
 Assessment of wind vs. solar for a specific site uses a small
representative turbine or anemometer and a PV module
 The energy ratio plotted throughout a year indicates the
relative energies available, which can then be compared
with system cost ($/kWh)
 The actual energies available can then be compared with
longer-term climate data to estimate annual variations
 Life-cycle costs of the two systems must be included to get a
comprehensive determination of an optimal system design
 One of the systems might be omitted if the energy
contribution is less than ~5% of the total
 Why bother if $/kWh is too high?
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12.4.1 Energy Source Cost Choices
Hypothetical
Cost Line
100% $ 0%
http://dna-view.com/triangle.htm
$
50% $
0%S, 100% F
50%
33.3%S, 33.3%W, 33.3% F
$
Solar
0%
Wind
$
100%
$
50%
Fuel
100%
0%
100%W, 0% F
 Assess cost of various mixes of energy, enter total costs, sketch contours to
seek lowest cost region
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12.4.2.1 Wind/Diesel
 Wind/diesel systems work well
where sunlight is limited, as
above the Arctic Circle or below
the Antarctic Circle
 Wind turbines have worked well
at the South Pole Station, but
diesel generators are also hard
at work there
 Gasoline engines also can be
used, but may lack the life of a
heavy diesel engine
 Diesel fuel costs $2.90; gasoline
$2.77 as of 3/15/2010
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www.renewableenergyaccess.com
12.4.2.1 Wind/Diesel
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 3/15/2010
diesel prices
12.4.2.1 Wind/Diesel
 1970-2009 crude oil $ vs. production million barrels per day
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12.4.2.2 Solar/Diesel Hybrids
 Solar power has a much more stable short term output
than wind power; the solar energy is less “volatile” than
wind to use an economics term
 As the insolation rises in the morning, the diesel engine
might be shut down until late afternoon or when clouds
reduce solar power for a certain number of minutes
 The controller could run the diesel engine only when the
battery voltage drops below a very low set point, such as
10.5 volts
The diesel would be stopped when the battery
voltage rose to approximately 13.9 volts
 A battery-charging procedure minimizes the number of
engine starts and ensures full-load engine operation
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12.4.2.3 Diesel Engines
 A 9.2 kVA diesel
package plant from
Genasys Systems in a
quieting package (top)
 Multiple large diesel
sets (bottom)
 A small diesel might
require 2.5 L/hr at idle
and 7.5 L/hr at 14 kW
changing somewhat
linearly from idle to full
load
http://www.eere.energy.gov/windpoweringamerica/
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12.4.2.4 Propane Engine Generator
 Liquefied petroleum gas (LPG) in the United States is
primarily propane, but also contains propylene, butane,
and butylene
 Gasoline-carbureted generators may be converted to
propane; often done in pickup trucks in Western US
 The Onan (Cummins) generator shown below produces
5.5 kW and costs ~$2970 (~$540/kW)
 One gallon/hour of liquid propane will produce ~10kW
http://www.merequipment.com/Frequently%20Asked%20Questions/Powergard_Elliott_faq.htm
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http://www.emnrd.state.nm.us/ecmd/html/propane.htm
12.4.2.5 Tripartite Systems
 A wind/solar/diesel system is only somewhat more
complex than the wind/solar type
 The system balance between wind and solar is
determined as in a conventional system, adjusting the
costs of each to match the available energy
If the sun rarely shines, the solar equipment would
not be cost-effective
If the wind rarely blows, the wind equipment would
not be cost-effective
Each of these sources offsets the need for diesel
consumption, yet including some diesel capacity
improves the availability and reliability of power
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12.4.2.6 Fuel Consumption
 The rate of diesel fuel consumption is critical to the
analysis
Diesel fuel costs ~20% more than gasoline
Biodiesel is even more costly
Fuel transportation raises the actual fuel cost and
must be included in the total price
 The engine speed must be matched to the
generator/alternator to optimize efficiency
 When the generator runs, it should do so at full load,
charging batteries as necessary, then shutting down
completely to save fuel
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12.4.3 Economics of Plant Combination
 The location is the prime driver of the costanalysis
 When the remoteness and lack of roads makes
fuel-hauling or helicopter transport too costly,
the wind or solar components must be
increased to ensure reliable power
 Mountain-top radio repeaters exemplify the
inaccessible site, and access may be limited to
hiking or horseback (pack trains)
 The handset radio has 5W to reach the
repeater, the repeater receiver audio is
patched to the 50W transmitter on another
frequency, and the high power signal
reaches other receivers farther away
 Matching of the load times to the energy times
determines the need for storage capacity
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Scottish Moor
http://www.windsund.com
12.4.4 Hybrid Installation Design
 Some rules from Manwell, et al.:
Without storage, the load limits what energy may be
used or extracted
Load matching for time of day limits output as well
Diesel engines must be sized for highest load to carry
the loads in normal operation
The savings is never greater than the fuel savings
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Manwell, et al., 2002
12.4.5 Balance of Systems (BOS)
 The balance of system must include the necessary fuel
tanks, piping, transportation support, etc.
 Local shops may be needed to perform engine overhaul,
since the distance to civilization may be great
 BOS must include means of transporting fuel to the
engine
If a truck is normally used to travel to a location that
has fuel, there might not be an extra trip or expense
With dual truck tanks, one might be used just for
hauling fuel for the generator
The labor (driver) cost is increased slightly for getting
fuel, but increased greatly if the trip would not have
been otherwise made
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12.4.5.1 Balance of Systems (Wiring)
 An
installation
in China
 Please
don’t do
this!
 Wiring
should be
neat and
well
secured to
prevent
fires!
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http://www.nrel.gov/international/china/pdfs/vp_workshop_2002/wallace_undp.pdf
12.4.5.2 Balance of Systems (Diesel)
 Fueled systems will require tanks, lines, and possibly
pumps
 In cold weather, diesel oil thickens, and insulation or
heating of the lines may be required
Hot water tubes can be run parallel to the fuel lines
 Small car engines may use 3 liters per 100 km (78 mpg)
If at 78 mph, that would be 3 L/hr, or to avoid mixed
units systems, approximately 3/4 gallon/hour
 A typical 500 gallon tank would hold ~500 hours of fuel,
so replacement fuel must be obtained faster than that to
keep the tank filled so the generator doesn’t stop
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12.4.5.3 Battery Storage
 Batteries provide an “inexpensive” form of storage
 They are required for wind and solar energy, but diesel
(gasoline) generators could run to carry the load
 For reliability, some diesel service might expensively be
kept online at all times to avoid starting delays
 Large battery systems require some maintenance checks
but usually last for many years (7-20)
 A large Uninterruptible Power Supply (UPS) can carry
the load for minutes to hours or longer depending upon
the amount of battery ampere-hours that supports it
 Adding storage means that the energy available is
“leveled” and unnecessary engine starts are avoided
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12.4.5.3.1 Battery Storage (Australia)
http://www.solarshop.com.au
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 This shipping container contains the controller and a very large
battery
12.4.6 Power Control
 System monitoring by computer allows programming of
automated supervisory monitoring and determines
actions to take in response
 The system functions in software might include
Start an engine
Control battery charging
Control energy load dumping for wind turbine
Change loads to match available power
Engage engine clutch
Report alarms to a distant operator
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12.4.6.1 Power Control for Backup Engine-Generator
 The engine-generator starting sequence automatically begins when
the line voltage sags (drops) below perhaps 105 volts
 A transfer switch changes the load from the wind/solar inverter
output to the engine-generator output
 The battery is connected to the starter motor and the engine is
cranked to start under a solenoid-controlled choke fuel
enrichment
 As the starter turns over the engine-generator, the speed is
sufficient to provide voltage to the load
 Once the engine is running, the choke is opened to provide a
normal fuel mixture
 The entire sequence is so fast that lights on the load side don’t
noticeably flicker
 When inverter power returns for thirty seconds, the load is
switched to the inverter (after a delay) and the engine is
stopped
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12.4.6.2 Power Control for Continuous Hybrid System
 In a full hybrid system, the engine runs continuously
and the wind/solar sources subsidize (add to) the
available energy, saving fuel by shutting down the
engine whenever possible
 The inverter is synchronously matched to the power
frequency and voltage, providing more or less power as
is available
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12.4.7 System Availability
 As long as the engine works and the diesel fuel lasts,
system availability is high
 If the renewable sources are low, the fuel will be used
faster (and require replenishment more often)
 If the engine fails and there is no storage (battery), the
system will only have the varying renewable energy and
might not function at all due to voltage variations
 Solar energy might carry the load until mid-afternoon,
but the wind system would be too variable in many
locations
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12.4.8 Example: Alaskan Hybrid Site
 Coast Guard Station in
Alaska
 Wind and solar energy
seem to be augmented by
five large propane tanks
near the base of the turbine
If so, a propane-fueled
generator would be used
instead of diesel
There is likely a really
long fill hose on the
supply boat that can
connect to the tanks
http://www.uaf.edu/energyin/webpage/pages/other_important_topics/hybrid.htm
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12.4.8.1 Example: San Clemente Island, CA
 US Navy turbine installation to reduce diesel fuel use by
a navigation light
 NREL determined that cost of energy (COE) was
$0.193/kWh vs. $0.45/kWh baseline with all diesel
power
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12.4.8.2 PV Installation in Australia
Diesel generator supplies backup
power
 See www.solarshop.com.au for
details
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http://www.solarshop.com.au/
12.4 Conclusion: Wind Hybrid
 Combinations of energy sources will provide more reliable
power than any one source alone --- energy diversity
 Diesel, propane, or gasoline engine-generators produce
power on demand, and can self-start when the power
line voltage is dropping
 Natural gas can be piped to some areas
 When wind or solar energy is available, the fueled
generator will shut down, saving its fuel cost
 Although overall costs are higher, the power is more
reliable
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Olin Engineering Complex 4.7 kW Solar PV Roof Array
Questions?
080116
References: Books
 Boyle, Godfrey. Renewable Energy, Second Edition. Oxford: Oxford University Press,
2004, ISBN 0-19-26178-4. (my preferred text)
 Brower, Michael. Cool Energy. Cambridge MA: The MIT Press, 1992. 0-262-02349-0,
TJ807.9.U6B76, 333.79’4’0973.
 Duffie, John and William A. Beckman. Solar Engineering of Thermal Processes. NY:
John Wiley & Sons, Inc., 920 pp., 1991
 Gipe, Paul. Wind Energy for Home & Business. White River Junction, VT: Chelsea
Green Pub. Co., 1993. 0-930031-64-4, TJ820.G57, 621.4’5
 Patel, Mukund R. Wind and Solar Power Systems. Boca Raton: CRC Press, 1999, 351
pp. ISBN 0-8493-1605-7, TK1541.P38 1999, 621.31’2136
 Sørensen, Bent. Renewable Energy, Second Edition. San Diego: Academic Press,
2000, 911 pp. ISBN 0-12-656152-4.
 Texter,
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References: Websites, etc.
http://www.uaf.edu/energyin/webpage/pages/other_important_topics/hybrid.htm
http://www.sandia.gov/wind/
http://gttserv.lth.rwth-aachen.de/~sp/tt/gtt-news/gttn_13.html triangle plotting of proportions
http://www.nrel.gov/international/china/pdfs/vp_workshop_2002/wallace_undp.pdf RE systems
http://alaska.bp.com/alaska/beyond_petroleum/limevillage/limevillage.htm Lime Village, Alaska by BP
http://www.eere.energy.gov/windpoweringamerica/pdfs/workshops/2002_wind_diesel/san_clemente_california.pdf
____________________________________________________________________________
[email protected]. Wind Energy elist
[email protected]. Wind energy home powersite elist
mailto:[email protected]
rredc.nrel.gov/wind/pubs/atlas/maps/chap2/2-01m.html PNNL wind energy map of CONUS [email protected]. Elist
for wind energy experimenters
telosnet.com/wind/20th.html
www.google.com/search?q=%22renewable+energy+course%22
solstice.crest.org/
dataweb.usbr.gov/html/powerplant_selection.html
http://tonto.eia.doe.gov/oog/info/gdu/gasdiesel.asp
http://www.pruftechnik.com/fileadmin/user_upload/COM/Condition_Monitoring/Products/Online_Systems/VIBROWEB_XP/Brochure/PRUFTEC
HNIK_WindBrochure2010_en.pdf
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Notes hybrid
 Sorenson p. 851
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