While we shouldn’t thank our forefathers for leaving behind landfills and the environmental consequences that accompany them, it is becoming increasingly possible to see some green among those brownfields. In the City of Hutchinson, this green to brown transformation is underway. With a solar field just beginning operations on a former landfill, there is quite a green and golden lining to a brown past.
The 400-kilowatt solar array, which will supply 12 to 15 percent of the power needed to run the adjoining wastewater treatment plant, is the biggest erected thus far on former landfill property in Minnesota, and is the first actually built on top of a closed landfill.
John Paulson, Environmental Specialist, City of Hutchinson
From brownfield to brightfield
Built on the site of a 1970s era city dump, the 400 kilowatt array just hooked up, behind the meter, to the wastewater treatment plant next door, helping offset energy use for the city’s largest municipal energy consumer. There it will be used to transform another brown environmental problem blue.
This Wednesday, elected officials and electricians alike stood atop the snow-covered landfill to celebrate the solar site coming online. Representatives from Xcel Energy, whose Renewable Development Fund grant made the project possible, spoke alongside Hutchinson Mayor Gary Forcier and a number of other City officials. Others represented included Ameresco, who developed the project and will guarantee the performance of the system until it becomes cost neutral, tenKSolar, the Bloomington-based solar company who supplied the hardware and 975 panels, and Hunt Electric, the contractor installing the panels.
Despite the clouds overhead, the theme of the day was bright: This is a big moment in Minnesota’s solar history. The RDF grant was awarded so that the project could be a demonstration of statewide potential for solar brownfield redevelopment projects.
Hutchinson brightfield solar array
Digging into the details
Now that the array is online it’s clear that the ways in which it went above and beyond make it a shining example. For one, to ensure safety and aid replication, extra measures have been included to ensure that the landfill site is handled with proper care during installation, operation, and maintenance. One such measure is developing the project to be “non-penetrating” in regards to disturbing the underlying waste materials in the landfill, thereby limiting health and environmental exposures to such materials.
Because it is non-penetrating, despite being ground mounted, the array more closely resembles a flat roof-mounted system, where the panels are mounted on large concrete ballasts, rather than being stuck into the ground. The site’s efforts to not overturn landfill material even extended as far as the fence encircling the array. There, instead of drilling the posts into the ground as is normal procedure when constructing fences, each post is weighted down by a number of cinder blocks covered with rocks and overlain with dirt.
While the type of construction may limit health exposures from the landfill, no amount of ingenuity can control what goes on below the surface. Most landfills, this one included, have a variety of organic and inorganic materials wasting away below the ground. This can lead to what is referred to as “differential settlement,” meaning even a leveled surface may become uneven over time. You can imagine the troubles this may cause for a solar array—the panels are connected to each other and need to be squared up to ensure proper functioning. If the land beneath the panels were to settle unevenly, there is potential that the dimensions would be thrown off and the array sent into disarray.
Luckily, the dump hasn’t been used since the 1980s. The older a landfill is the less of a problem differential settlement poses. Even so, maintenance parameters are in place to address differential settlement issues that may occur. The system design allows for shims to be placed under the supporting rails if any of the concrete bases settle too much over time.
A shining example for others
As Minnesota’s solar industry blossoms, more and more sites will need to be examined for solar potential. The hope is that Hutchinson’s project will help remove the obstacles and insecurities associated with brownfield development by demonstrating just how feasible it is. All parties win when solar developments make brownfields a little brighter instead of taking up valuable greenspace or other productive land.
Transforming a Brownfield to a Brightfield by John Paulson
If you would like to learn more about the solar project, please contact John Paulson with City of Hutchinson at email@example.com or 320-234-5682. To explore opportunities for your own brownfield solar development, please contact Cameran Bailey with Metropolitan Council at firstname.lastname@example.org or 651-602-1212.
See more photos from the ceremony below:
About the author: Jamie Johnson is a Minnesota GreenCorps member serving with the City of Hutchinson, working on energy issues and efficiency improvements at the local level.
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