Greening the grid: Which is how Bates characterizes its most up-to-date initiative in the effort and hard work to stay sustainable.
The higher education is partnering with ReVision Vitality, a primary photo voltaic services company in Maine, to build a photovoltaic array on a lot more than 20 acres of countryside in the town of Skowhegan. The array will comprise nearly 18,500 panels and feed into the regional grid 7.131 megawatts of immediate current, or DC, which will be transformed to alternating recent, or AC, for grid distribution to enterprises and residences.
That’s about a few-quarters of the college’s electrical use, states Tom Twist, Bates’ sustainability supervisor. The array by itself will be the premier ReVision has designed to day, while it is operating on some others of comparable dimension.
The undertaking is scheduled to start out technology this summertime, barring a recurrence of source chain problems that have influenced electrical components in distinct.
To be very clear, Bates has met its electrical requirements with renewable energy given that 2005, when the university began sourcing its juice in the form of Renewable Vitality Certificates, or RECs, from Maryland-centered Constellation Strength. In effect, RECs are documents affirming that a sure total of electrical power has been produced sustainably. (The school will keep on to buy RECs for the approximately 25 p.c of its electrical utilization not made by the solar array.)
What the Skowhegan job will alter, while, is that Bates, in partnership with ReVision, will acquire direct duty for developing its own environmentally friendly electrical power.
Leased for the solar task by landowner Jim Henshaw, a farmer, the design web site is open land some length back again from Eaton Mountain Road.
“It’s kind of hidden and tucked absent in there, surrounded by forest,” states Brian Byrne, the ReVision task supervisor overseeing the development. (The employees land developer for ReVision who assisted put the lease arrangement collectively is Holly Noyes ’10, who is also a farmer.)
In some techniques, the website was a solar installer’s dream. “It’s a nice, stunning, extensive-open up industry. We did not have to apparent any trees,” Byrne describes. It is heavily vegetated and quite properly-drained, meaning that there are no wetlands, no areas susceptible to erosion, and no threat of stormwater runoff or sediment washing off the website. “From a Division of Environmental Safety standpoint, this has been the greatest site we’ve at any time dealt with.”
Sullying the desire, though, were disorders a few or 4 toes underneath the soil surface. Common for a ground-degree PV array, the Bates task consists of very long rows of solar panels, aka modules, attached to “racks” — horizontal rails mounted on steel piles that are driven into the earth. So pile driving was the very first get of business enterprise when development began previous summer months. And cue the stress-constructing tunes:
“We imagined this was just likely to be a very deep soil, like a sandy loam,” claims Byrne, “but it’s really exceptionally compact, dense clay when you strike about 3 feet” underneath the surface area, punctuated with boulders. (Maritime clay strikes yet again!)
As is its wont, the clay all but stalled development. “This web-site appeared to be a dream from the surface area,” says Byrne, “but the moment we started off driving these steel piles, which assist the racking, we could not travel them in.” Amongst the clay and the underground boulders, entirely half of the 2,500 piles could not be pushed to the depth vital — down below the frost line, much more than 6 toes below.
“To make matters even worse, we could not pull them again out mainly because it was these kinds of compacted clay. The sum of pressure [necessary] was unbelievable. It just appeared to defy physics,” Byrne claims. “So we experienced to dig them out.”
In the close, Gardiner-centered Maine Drilling & Blasting arrived in to pre-drill holes for the undrivable half of the piles, which are 16-foot metal I-beams.
“In our ideal entire world, we required all of the modules to be mounted to the racking by the close of December, and that did not take place due to the fact the racking was so delayed.”
For the sake of context, the organization fabricating and placing the racks, RBI Solar of Cincinnati, “was anticipating 12 to 14 weeks to finish this job.” Now completing closing punch listing merchandise, “they’re on 7 days 26.”
“This was the best delay we’ve at any time encountered for setting up racking,” Byrne suggests.
Which is not to say that the trials of the piles stalled the challenge outright. “If there’s an obstacle, we transfer close to it and keep pushing forward,” says Byrne. “While we have been delayed with racking, there had been other items to do.” In conjunction with a typical small business companion, Gifford Electrical of Brewer, Maine, the undertaking crew set up utility poles, equipment racks, DC combiners and transformers dug trenches for electric lines and pulled conduits.
As this was created, about 60 p.c of the 18,486 modules were being in location. Two styles of solar modules, one a bit extra effective than the other, are becoming utilized. Rated at 395 watts is a design made by the German business Qcells: 7,098 of these will be set up. REC Photo voltaic generates the other module: 11,388 of all those at the Bates website will every single generate 380 watts.
(In brief, here’s much more about AC/DC, and we’re not discussing Angus Young’s phase apparel: Daylight on solar panels generates DC, which is transformed to AC for lengthy-distance distribution. The Skowhegan photo voltaic plant will inject about 5 MW of AC current into the grid.)
Each and every kind weighs just above 50 pounds apiece and steps about 80 by 40 inches. Byrne clarifies that set up is a succession of actions executed in waves by just a handful of men and women — pre-positioning elements, attaching some components, placing the lessen row of modules, attaching more hardware, positioning the higher row of modules.
On normal, in benign disorders, a helpful rule of thumb is that throughout a nine-hour working day, just one installer can mount roughly 75 lessen-rack modules or 50 on the higher area.
“Everything is prepared ahead of the crew does the endeavor, and that’s how we can sustain performance. It stays very structured, very thoroughly clean. There is no garbage blowing all-around the discipline.” In actuality, Byrne provides, “Solar is my favorite building undertaking. It’s not a typical building site. As soon as the excavation’s done and you pound the posts, these are the only silent building sites there are, and it is superb.
“If you can hear the birds, and look at the leaves blow and the grass bend, that’s quite ideal.”
Not to mention listening to the munching of sheep on the grass that will proceed to develop at the undertaking website. Historically utilized for hay reducing and on-site grazing, Henshaw’s land will proceed to support haying twice a calendar year, as prescribed by a land-use allow, and grazing any outdated time.
Bates and ReVision have labored alongside one another for many years, a single large-profile consequence getting the set up, over two decades, of rooftop photo voltaic at the Bates Coastal Center at Shortridge.
The latest (no pun supposed, but it’s not lousy) collaboration dates to the decades just prior to the pandemic. Pushed in element by robust scholar fascination in sourcing Bates electricity from big-scale photo voltaic, the college or university undertook a rigorous exploration of its selections.
In 2019, the point out of Maine enacted laws that in a variety of means state-of-the-art the cause of renewable power. One of these costs, L.D. 1711, created financial outcomes “much extra fair for huge solar electrical energy clients,” clarifies Tom Twist, Bates’ sustainability supervisor.
“As quickly as that was handed, we were capable to strike the floor running” in building a workable design for involvement in a solar farm. That contrasts with a selection of other large photo voltaic initiatives in Maine that are nonetheless hanging fireplace, Twist suggests. “We feel really blessed that this is going as a result of.”
As a member of the Bates EcoReps, college students who undertake a wide range of campus sustainability tasks, economics key Kyung Phil “KP” Ko ’22 was a single of numerous involved with that modeling procedure. “We dug into the proposals sent over by a several events, ReVision currently being 1 of them, to definitely comprehend what the positive aspects to Bates would be,” points out Ko, who now analyzes U.S. utilities and power troubles for Scotiabank.
“Once the advantages were being recognized, we worked this up the determination-maker chain. To be precise, the arrangement was a monetary PPA, where Bates could hedge versus the volatility of electrical power expenses thus bringing us value savings and monetizable renewable electrical power credits.”
“Reaching design is a humongous milestone worthy of hoots and holler.”
KP Ko ’22
“I cannot inform you how joyful I am that the project has arrived at the development phase,” Ko provides. “Working in the renewable energy expense banking place, I can notify you that the marketplace has faced extraordinary uphill battles above the past year with provide chain concerns, inflation, bloated interconnection queues, and what pretty much was the conclusion of solar financial investment tax credits.
“Reaching construction is a humongous milestone deserving of hoots and holler. I hope to go to Maine sometime before long and see the arrays for myself.”
The function of Ko, his classmate Tamsin Stringer, and other students was priceless to the undertaking. “To determine out the expenses, figure out the internet benefit of solar electrical power a number of decades into the long run — all those people factors have been difficult, and the college students did a seriously nice job,” suggests Twist. “Really skilled-level.”
He adds, ReVision “knows the ins and outs of the photo voltaic current market close to Maine, and they had been truly equipped to aid us. I think if we went with someone who was not common with Maine, we’d nonetheless be caught.”
In sum, when Bates saw the prospect to go photo voltaic in a huge way, “we had been completely ready for it,” claims Geoff Swift, the college’s vice president for finance and administration and treasurer. “There were being issues that experienced to come about just before other matters could transpire, so it took a lengthy time to get to in which we are these days.
“But it is thrilling to have the array in method and going up in Skowhegan.”
Can we chat? Campus Building Update wishes to listen to from you. You should send out your comments and concerns about construction at Bates, as effectively as your thoughts about maritime clay, to dhubley@bates.edu, with “Campus Construction” or “What do sheep rely when they can not rest?” in the issue line.
