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Wind Generator Case Study
The following case study & pictures are from an Air-X
400 watt wind generator
installation designed & installed by Pioneer Systems for a remote,
wilderness
cottage which is off-grid.
Historical Situation
The owner's cottage is located on Manitoulin
Island, Ontario, Canada. Manitoulin Island is the largest
freshwater island in the world. The public utility wanted $60,000
to
install
hydro poles & string wire for connecting the cottage to the grid;
economically impossible for the owners. Therefore the owners have
generated their own electricity for the past 20 years using a 4 kW,
gasoline powered, 110/220 VAC generator. While the
generator was cheaper than the grid tie, it was still expensive, noisy,
and environmentally unfriendly.
The owners wanted a reliable, scaleable, ecologically
sound, and economically feasible power supply for their cottage lights.
The owners needed to explore alternatives, but didn't have the
expertise to achieve their goal for cost reduction, greener living, and
minimizing their
ecological footprint.
Pioneer Systems Assigned Task
Pioneer Systems was asked to investigate alternatives that were
ecologically and economically sound & feasible for the owners to
have lights in their cottage each evening.
Pioneer Systems Actions
Upon interviewing the owners, and other investigations, Pioneer Systems
learned that the cottage owners were located on the South Shore of
Manitoulin Island. Being on the waterfront of Lake Huron, the
unobstructed wind and solar energy represented two excellent sources of
energy.
Historically, the owners ran a 4 kW gasoline generator to power about
0.4 kW of electrical lighting each evening for about 4 hrs. on
average. At other times, the generator was used to run the well
pump,
and power tools. The electric lights each evening for 4 hrs.
represented over 95% of the historical generator run-time for this
cottage. The 4 kW gasoline generator is estimated to have an operating
cost of $2.00 /hr just for the gasoline. For oil,
maintenance, &
depreciation, the total cost of operating the generator is estimated to
be $4.00 per hour operated. When the generator is only loaded at 10%
load (0.4 kW used when 4 kW generator is operated), this idling is very
hard on the gasoline engine; resulting in engine fouling, higher
maintenance costs, and shorter life expectancy. The owners agreed
that this had occurred numerous times over the past 20 years.
Since the cost of wind power is cheaper that photovoltaics (PV), it was
decided to investigate wind power first. The winds off Lake Huron
are
estimated to be as high as Class 5 (700 kW-hr/yr per sq. meter of swept
area of wind generator's rotor, with an annual average wind speed of 14
mph). The 24 VDC
battery
bank and DC-AC inverter should provide sufficient
electricity to provide 4 hrs. of lighting for the cottage every evening
on a continuous basis. For periods with little or no wind, the
battery
bank will supply up to 3 days of power. This assumed there would
be no input from the wind
generator for 3 days, while discharging the batteries from 100% full to
50% full.
Based on conservative design estimates, conservation, and high
efficiency lighting inside the cottage, the owners were pleased with
Pioneer Systems recommendations for design, cost, reliability, risk,
upkeep/invisibility, and required lifestyle changes (energy efficient
compact fluorescent bulbs
instead of the incandescent bulbs used historically by the owners).
The system design depends on having at least Class 3 winds (605
kW-hr/yr per sq. meter of swept area, with an annual average wind speed
of 12 mph) which should be exceeded over 90% of the time. When
exceptionally calm days occur, the generator can be run for a short
duration during one evening to charge the battery bank while supplying
lights for the cottage.
The beach area at the cottage site was rock & boulder glacial
moraine of 0 ft to 3 ft.
deep
on top of the dolomite-limestone bedrock. This represents a
severe
grounding and lightning protection challenge, as bedrock has a soil
resistivity 10,000 times greater than damp organic loam. A
special
design for grounding, static, and lightning protection was developed by
Pioneer Systems.
Large sheets of ice, up to one foot in thickness can come off the lake
and up over the beach area during winter storms.
Anything
that is close to the beach must be massive (resisting the forces of the
ice), or otherwise protected from the
dangerous ice. Pioneer Systems proposal was cheap &
effective; and
readily accepted by the owners.
Based on the Pioneer Systems' estimate of the owner's installed cost
for
the wind generator, it was estimated that the wind generator will pay
for itself after 312 days of not
operating the generator for 4 hrs. each evening just for cottage lights.
For sites operating year round, this is less than 1 year payback on the
investment in wind power. The generator will still be run for the
heavy electrical loads which occur less frequently, and represent the
other 5% of the generator run time.
Pioneer Systems had the role of doing the needs assessment, survey of
electrical usage patterns, site selection, wind generator selection,
detailed return on investment calculations to economically justify the
system, and detailed system design.
The owners approved the design proposal of Pioneer Systems.
Pioneer Systems proceede to buy the required materials, the wind
generator, tower sections, and equipment; all of which were
delivered on-site. The rock drilling was sub-contracted to a
local
driller for the anchors and ground rods. Installation was done
Pioneer Systems
working
hand-in-hand with the cottage owner over a 4 day period.
Day 1 was
site survey for location of tower base, ground rods, and guy wire
anchor placement; and excavation to the bedrock (where necessary).
Day 2 was rock drilling and installation of anchors, tower base rebar
& cement, and grounding rods.
Day 3 was assembly of tower, guy wires, wind generator, electrical
cabling from the wind generator to the tower base, and lightning
protection. Due to the high winds in the area, it was necessary
to
hoist at either dusk or dawn. To ensure adequate lighting, we
decided
to hoist the tower early the next morning when it would be more calm.
On Day 4 at 07:00 AM, the hoist began. The tower was secured to
the
anchors within the hour. Guy tensioning, grounding, backfill of
holes,
and electrical connections were completed before the end of the
day.
The generator was cycled through its operating modes to ensure it was
operating properly.
Results Achieved
The owners are pleased with the installation overall, how it
looks,
and the power that is generating. Adequacy of the design and the
elimination of excessive & expensive generator run time will only
be proven over time. Pioneer Systems will monitor the
installation
after 1 week, 1 month, 3 months, 6 months, and end of the first year to
ensure all is operating properly, and the owners satisfaction continues. |
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The installed wind generator on the 45 ft. tower, with the proud owner
at the base.
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Looking up the 45 ft tower, we can see the electrical box at the base,
and the two sets of guy wires at 24 ft. and 42 ft elevation
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The tower base showing the electrical junction box and lightning
protection system.
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A close-up view of the top end of the 45 ft. tower, the guy wires,
lightning protection, and the wind generator on top.
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© 2001 Pioneer Systems
Original Version: May 17, 2001
Current version: 27 Sept. 14, 2003 |
