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Village children help carry conduit from the boat. |
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BlueEnergy’s Nicaragua director Guillaume Craig (center) works with community members to attach blades to the turbine. |
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Preparing to lower the tower. |
Mathias Craig remembers the night last summer when the lights came on in Monkey Point, Nicaragua. “I was in awe,” the 29-year-old blueEnergy cofounder says, recalling the laughter and excited chatter that rang throughout the crowded school building after the community’s hybrid wind- and solar-electric system was up and running.
For the 300 residents of Monkey Point, a remote village roughly 30 miles south of Bluefields on Nicaragua’s south-central Caribbean coast, the moment marked the first step toward freedom from generators and lanterns fueled by expensive, imported diesel fuel. The hybrid wind–PV system, the community’s first renewable power source, provides about 150 kilowatt-hours (KWH) of electricity per month—enough to power lights for the school and a community radio, and to charge batteries for the health clinic and eight homes.
Configuring Components
A blueEnergy team member flew to Managua to purchase the PV modules, batteries, and other electrical components. This equipment arrived days later after first traveling by bus and, then, by supply boat on the Río Escondido. Meanwhile, back in Bluefields, the crew got to work constructing the wind turbine and tower. Here’s a look inside their process:
Electrical. The electrical assembly is key to transforming the wind into electricity. The wind generator’s stator, a metal plate embedded with twelve copper coils and sealed with resin, is precisely positioned between two metal plates (“magnet rotors”) embedded with powerful neodymium magnets. As the blades of the turbine spin, the magnetic flux created between the magnet rotors cuts through the copper coils, inducing the flow of electricity. The wild alternating current (AC) produced by the turbine has variable voltage and variable frequency, which is rectified into direct current (DC). In the power shed, the DC goes through a charge controller to a battery bank that stores the wind-generated electricity. An inverter converts the DC into AC needed for common appliances.
Mechanical. The turbine’s three blades start out as thick, rectangular blocks of locally harvested caoba hardwood. Over three days, woodworkers use a mix of saws, drawknives, planes, chisels, and sandpaper to shape the each block into a sleek airfoil—6 feet in length to match the size and power of the alternator. To protect the wood from the elements, the blades are then painted with multiple coats of fiberglass resin. The blades, magnet rotors, and stator are bolted to a metal frame that workers fashion from welded angle iron. Layers of plywood, fiberglass, and resin form the tail vane that is attached to the back of the turbine body on an angled hinge. Together, the tail and hinge make a passive furling system that turns the turbine out of high winds to protect itself.
Tower. BlueEnergy’s metal workers assemble the tilt-up tower from domestically available 20-foot sections of steel tubing, about 4 inches in diameter. At the shop, the 5/16-inch steel cables used to anchor the tower at the site are cut and then painted to protect the cables from corrosion.
At the Site
Monkey Point is only accessible by a five-hour boat ride across often-rough waters, and crew and equipment were transported in traditional open-top wooden boats. Torrential rains and wicked winds plagued several of the voyages, leaving blueEnergy’s crew members scrambling for refuge beneath garbage-bagged gear and any covered nook or cranny in the boat’s well.
After hours of bailing water from the bottom of the boat, crews arrived to face the greatest challenge of the installation: carrying 30 bags of cement, an 80-foot tower, hundreds of feet of cable, and all the other components and tools up the muddy, steep path to the top of the hill.
Several of blueEnergy’s most industrious members had helped the locals prepare the site weeks before the equipment and rest of the crew arrived. For six days straight, this team worked through unforgiving heat and humidity, digging five holes—about 6 feet deep, 6 feet long, and 3 feet wide—for the anchors and the tower’s foundation.
Four anchors for the guy cables were fashioned out of 10-foot lengths of 3/4-inch rebar, which were bent at the workshop to form a hook at one end. The hooked end was connected to a rebar grate at the bottom of each hole and surrounded by about 100 pounds of concrete. After the holes were backfilled with dirt, only the top piece of each anchor protruded from the ground. Pre-drilled, triangular-shaped metal pieces were welded to the rebar to serve as the connection point for the guy wires that support the tower.
A few weeks after the anchors had been placed, the full blueEnergy crew, about 12 people, arrived back at the site. Over several days, the system was assembled on the hilltop, which offered another challenge: stringing the power transmission cable safely through 150 feet of thick jungle. The method of choice: tying a rock to one end of a string and launching it through Y-shaped branches along the path, then pulling the wire with the string. Four machete-wielding volunteers braved spiders and lizards to clear the way for the wire, while launching lines through the forest canopy.
Since the villagers had already constructed a storage shed for the balance of system components, mounting the PV modules on the roof and making the final connections was fairly straightforward. The highlight of the installation came on the last day in one glorious moment, when more than 20 volunteers and community members secured the guy wires to their respective anchors, and raised the tower and wind gennie into the air.
Powerful Potential
With some wind, a little sunshine, and the flick of a switch, life in Monkey Point is changing. A school building that once sat vacant after sundown now serves as a community center for meetings, celebrations, and late-night church services. Families that once relied on jars of diesel fuel with burning rags for light now read by electric fluorescent lights or listen to worldwide events on the community radio. “We are living in an historical time,” says Pearl Watson, a resident and nurse in the community. “Having electricity in Monkey Point is truly something great for our development.”
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In the shop, blueEnergy team members test the stator. |
In the shop, blueEnergy team members set rotor magnets in resin. |
Children proudly gather around a wind turbine that provides pollution-free electricity for their community center. |
