Today, the stand-alone power system at the Handy Village Institute received a visit from a couple of very distinguished representatives of the Randolph Electric Membership Corporation. Fred Smith, Vice President of Economic Development and Compliance, and Michael Trent, Director of Innovative Energy Solutions, dropped by along with Doc Sydnor and Nick Harper for a late morning tour. Chris Carter began with a tour of his shop, where the March 2017 Homebrew Wind Turbine Workshop participants built another machine just like the one that will be going up at Doc's Braeburn Farm. Doc's turbine was built during the March 2016 Workshop at Handy Village Institute, and Nick Harper, Braeburn Farm Manager, participated in both workshops. Chris showed the visitors this year's turbine and explained in detail how it was fabricated and the advantages of the horizontal-axis, axial-flux, air-gap alternator design.
Chris led the group from the shop down the path to see the two solar photovoltaic (PV) arrays, which are mounted on poles with trackers. One array serves the shop and the other serves the house, each of which also has its own battery set. The Homebrew wind turbine built by the Handy Village Institute team during Dan Bartmann's Midwest Renewable Energy Association workshop in June 2015 proudly spun up with the breezy gusts of a delightfully cool and dry mid-summer day. Days like this often follow atmospheric "cold fronts," one of which had passed through just the day before. When the wind picked up a little more at the height of the turbine on top of its 84-foot tilt-up tower, everyone could hear the quiet hum of power generation. The magnets connected to the hand-carved wooden blades spun past the stationary coils of the nacelle, and the three-phase power flowed through a heavy, buried cable directly to the next component of this stand-alone power system.
The next stop was the shed that stores the batteries for the house and the control center for the integrated solar/wind system for the house. Chris had just added water to all 20 of these 1.5-Volt nickel-iron cells the day before, and he explained the features and requirements of these and other types of batteries, such as the 2-Volt lead-acid ones used to store power for the shop. On the other side of a wall, and accessed through a separate doorway, are the electronics that collect the power from both the photovoltaic (PV) solar panels and the wind turbine and store it in the batteries, and then serve selected loads in the house with either alternating-current (AC) or direct-current (DC) power. For example, the house has a water well- and booster-pump (for its cistern) and a refrigerator, radiant floor circulation pumps for heat, as well as a set of low-power safety lights that run on DC power, but other appliances and outlets use regular household AC power.
These electronics also manage the charging of the battery and situations in which the batteries are full and cannot take in any additional power. In a grid-tied system, this surplus power could potentially be sold, but the stand-alone system must choose whether to cut back on generation, or "dump" the power. Chris explained how the solar PV and the wind generation complement one another well at this homestead scale in our Piedmont region of North Carolina. While we don't have the excellent, industrial-power generation-scale wind of the mountain or coastal regions, we do have frequent winds in the 7- to 20-mile per hour range that is ideal for the smaller turbines, especially in the winter when the days are shorter, the sunlight less intense, and there are many cloudy days. In the summer, there is more sunlight and less wind, but the calm is frequently punctuated by afternoon thunderstorms and continental weather systems moving through, as well as occasional tropical storms. We can manually shut down the turbine during hailstorms and hurricanes, and everything about the system is extremely well grounded to protect it from lightening strikes.
Randolph Electric Membership Corporation is a rural electric cooperative that is very forward-looking and working hard to prepare their system for the future. They polled their membership about its interest in using more renewable power, and found overwhelming support. About 30% of the respondents said they would be willing to pay slightly higher rates for renewable power. The technologies and markets for power generation and storage are changing so rapidly that they have begun exploring new opportunities for balancing loads, energy storage, and power generation using a variety of new and distributed technologies to enhance their system and provide greater benefits to their membership. There are a handful of large solar farms in their territory, now, and they described buying a fuel cell to begin studying its features as a possible component of their system. They are experimenting with time-of-use prices for electric car charging to create incentives to spread out the consumer loads over time, and are very intrigued by the prospect of working with Doc, who is one of their members, to study his planned wind and solar PV hybrid system.
Deborah Amaral joined the group for lunch at the Saxapahaw General Store, where the conversation about the prospects of expanding renewable energy at Randolph Electric Membership Corporation continued. She asked Michael Trent what he thought was the highlight of the tour of the stand-alone system, and he quickly smiled and shared that it was seeing the turbine's blades spinning and generating power in the breeze. Everyone agreed that relative to the wind turbines, solar cells are "boring," with no eye-catching moving parts to see. Having a turbine to watch makes a person more aware of the sky, the wind and the weather. Michael and Fred Smith mused about how great it would be to see small wind generators on Mount Shephard, a high-elevation landmark in their territory surrounding Asheboro, North Carolina.
As the visit was wrapping up, Luther Livermon and Karen Bley, of Quarry Dog Adventures in Mebane, North Carolina, stopped by our table to chat. "Lu" was also in the workshop that fabricated the turbine which will be going up at Doc's farm. He currently has a large tracking solar array, and is interested in setting up wind power on his farm, too. He was very excited to learn of the Randolph cooperative's interest in distributed small wind and PV solar power generation. We were refreshed by the openness to change in the renewable energy market expressed by our guests, and look forward to our continued participation in the project at Braeburn Farm.
Jack Maxwell Barney, Nick Harper, Jeff Barney, Fred Smith, Michael Trent, Doc Sydnor, and Chris Carter celebrating local food and local power at the Saxapahaw General Store, after Randolph Electric Membership Corporation leaders visited the stand-alone hybrid wind and solar PV electricity generating systems at the Handy Village Institute site. Photo by Deborah Amaral.
Doc Sydnor has had a full career in neuro-opthalmology and a lifetime of ranching cattle. He raises his own line of Red Devon cows on grass in the Cane Creek Mountains of the Piedmont region of North Carolina. You can find fine cuts of his Braeburn Farm beef in local restaurants, farmers and cooperative markets, at the local butcher and at a store on the farm. Cindy Sydnor offers training in dressage at the farm. Doc has been discussing renewable energy possibilities at Braeburn Farm with Christopher Carter for about a decade.
It seems that the Sydnor family is situated on an ideal site for small wind power generation. On the hill above their ranch house rises one of the highest peaks in Alamance County. The Cane Creek Mountains are ancient Piedmont hills that have been worn down by erosion over geologic time scales. A series of peaks forms a ridge-line dotted with communications towers and the Three College Observatory. These mountains reach elevations of just under 1,000 feet above sea level, which makes one think about winking as one says “mountains”. Rising as they do above an open plain to the west, they effectively intercept the prevailing winds and the frequent gusts that come with regular changes in the weather, especially cold fronts. In places the terrain here is rugged and steep, offering splendid views and forming headwaters of creeks that flow past former gristmills and into the Haw River.
Nearly one year ago, the Handy Village Institute hosted Dan Bartmann, author of Homebrew Wind Power, for a workshop about building small, made-from-scratch wind turbines to generate electricity. Doc sponsored Braeburn Farm’s operations manager, Nick Harper, who with six other workshop participants worked on three small turbines. They hand wound coils for the stators, cast magnets for the rotors, carved wooden blades, and assembled steel armatures for mounts and tails.
Nick and Doc brought the one of these back to the farm. This turbine is twelve feet in diameter and its copper wire coils were sized and wound to produce 48 volts. After fabrication and assembly, the turbine mount and tail were disassembled and powder-coated a dark green color chosen by Cindy Sydnor, then reassembled with the stator, rotor, and blades, and placed on a short stand where it has been on display during farm tours and community potlucks during the past year. Nick Harper cut out and painted a wooden tail with the Braeburn Farm logo.
Nick Harper and Christopher Carter demonstrate how this small wind turbine has been designed and built to “furl” out the way of strong winds, to protect itself from potential damage.
Even with a good wind resource for power generation, the best flavor of wind will be found above ground level. This is because trees and structures add turbulence to the flow of air, and the best, most efficient transfer of power from the moving air to the turning blades will take place in the smoother, laminar flow of air away from the surface interference. Thus, a turbine needs a tower, and this week, the footings for a small tower at Braeburn Farm have been laid out, dug, and poured.
During his many years installing small, stand-alone renewable energy systems for farms and homesteads, Carter has had a handful of opportunities to place wind turbines on towers near mountaintops in the Piedmont and Appalachian regions. He has installed turbines on Pickards Mountain, near Chapel Hill, Chestnut Mountain, near Mount Mitchell, and for an Inupiak Tribe in Ambler, Alaska. Today, he says he is excited to be “planting the flag of renewable energy on another North Carolina mountain.”
Walking the site with the owner and operator at Braeburn Farm, making careful observations and taking precise measurements, Carter assisted with planning for their tower installation. First came the reconnaissance and string work. Decisions needed to be made for the exact footprint of this new structure on the landscape, taking into account the slope, the relationship to existing vegetation and structures, as well as the animals. An 84-foot tower is being shipped from Lake Michigan Wind & Sun in Sturgeon Bay, Wisconsin, and the parts for its footings have already arrived. Careful drawings and calculations dictated where on the ground holes needed to be dug and at which angles the base and each anchor for the guy cables needed to be placed.
This turbine will be mounted atop a tilt-up tower, and will be raised and lowered by driving a heavy tractor away from or towards it. Make an “L” with your thumb and forefinger. Your forefinger represents the tower, and your thumb represents what is called the “gin pole”. The turbine is attached at the tip of your forefinger the tractor is attached at the tip of your thumb. Point away from yourself with your forefinger, and then pull down on your thumb with your other hand. Your forefinger goes up. Ancient Greeks developed this means of lifting heavy objects, a forerunner to the modern crane.
Digging the holes for the anchor footings, building and installing the forms for the concrete, fitting the anchors and the holes with rebar, and pouring the concrete into the forms all happened very quickly last week. In his younger days, Carter liked to dig his own holes, but was agreeable to working with a team that included a backhoe operator and a couple of trusty shovel hands assisting with the fine work.
James and Sarah pitch in on the fine work of shaping holes for the tower footings at Braeburn Farm.
Doc and Carter during filling of the tower base hole with concrete during yesterday's pour.
Yesterday, the team removed the strings and batter boards to make room for the concrete truck to drive up the hill and access the holes. Carter was a little concerned about the cold and rainy weather, and twice during the day it briefly sleeted, but it wasn’t too muddy or slippery, and the truck arrived, made it successfully up the hill, and quickly filled the five anchor holes. This required a total of 6.5 cubic yards of concrete, which he described as “5-inch slump”. This tells you how wet the consistency is, and the wetter the concrete, the bigger the slump. They thoroughly enjoyed the driver’s stories of visiting schools with his rig, and especially about his visit to a school for blind children, who experienced his vehicle through sound, smell, and touch. He would lift them up to let them feel the rotating drum.
Today, Carter is pulling up the tarps he placed on the fresh concrete to protect it from the cold and rain, taking the forms off the anchors and rounding the corners of the concrete, a bit of a signature for his brand of renewable energy performance art. He expects it will be straightforward to clean up the site with the tractor, moving some of the spoil dirt to fill in any spaces left in the holes.
One remaining concern is the cows, which need to be kept away from the anchors while the concrete is hardening, and which potentially could be harmed by ingesting any stray hardware. A couple of weeks ago, some cows found their way into the hay barn, causing some minor damage, and it is clearly not safe to leave a turbine sitting on the ground with cows around. Plans are to install an electric fence with a solar charger around the tower to keep the cows out and protect the tower from them.
Next steps include setting up a way to monitor the performance of the turbine, assembling the tower, and raising the turbine on the tower, and ultimately, interfacing the wind turbine electricity generation with the utility. Braeburn Farm is a member of the Randolph Electric Corporation, a cooperative that is interested in studying their project and working with them on a scheme for pricing that adjusts for their power generation during peak periods. The Handy Village Institute will host the wind turbine workshop again March 20-25, 2017.
Clancey's Stone Lion is across the highway, tucked in by the railroad tracks. It securely anchors tiny Custer, Wisconsin. In spite of my expectations otherwise, I learned that it was closed on Fish Fry Friday, the second night of the Midwest Renewable Energy Fair. Composed of handsome blocks of stone, its wooden shingles lie upon uniquely curved rooftops. A tiny leprechaun peaks out over the top of a sorry potted plant, his raised arms below the rim reaching up in silhouette over my bar table by the window. A pair of shillelaghs adorn the bar, which is well-provisioned. One Irish whiskey label advises us to destroy the bottle when we are done, lest it should fall into the hands of an imposter.
In a quick dash across the road, I enjoy wild-caught cod with the first fresh green vegetables seen in many days. Then, it's back to the Fair, again, for the evening's speech and concert. Last year, a well-timed Clancey's Facebook post announcing "Fresh Blueberry Pie" lured three of us here, the results of which visit are shown, above.
I have come again for the wind turbines, celebrating our homemade machines that transform the powerful breath of our planet into light and heat in an alchemy of electrons, changing air into fire. Local beer, Midsummer sunsets, a full Moon together with planets Mars and Saturn over the Homebrew turbine at the edge of the fairgrounds lead me to fleeting cosmic thoughts. This quickly mixes with nearby small talk about shared passions and commitments, and whether tonight's band is ever going to play any danceable music. What does it take to live "off-grid"? Why do we do what we do? Will the "geezers" successfully hand this ritual celebration off to younger generations? Another memorial tree has been planted in the Arbor of Activism.