Sealed beneath 30 acres of a Minnesota landfill closed for more than three decades, 8,700 solar panels began feeding the grid in September, and the buried waste below is the reason the panels track the sky differently
The grass at Ramsey, Minnesota stretches flat and undisturbed over ground sealed for more than three decades.
Nothing goes into the earth here, and nothing comes out without a permit.
So when crews arrived to build a solar farm, they could not drive a single steel pile into the soil.
Each of the remaining landfills in Minnesota has a different cap age, a different slope, a different bond structure and a different distance to grid infrastructure.
The answer was to let the landfill’s rules shape every engineering choice on the site.
How exactly those rules rewired a standard solar build is the part worth following.
Why the buried waste changes everything above it
A closed landfill sits under an engineered cap, a carefully graded membrane of clay and soil that seals off the decomposing material below and keeps groundwater clean. Driving steel foundations through that cap is not permitted, because any puncture risks releasing leachate into the surrounding soil and water. That single rule determined what kind of solar installation was physically possible here.
Because the cap could not be penetrated, every tracker assembly was anchored with ballast and surface mounted hardware rather than driven piles. The panels rest on terrain following single axis trackers that tilt with the sun from east to west, wringing more output from each panel than a fixed tilt system would.
The panels themselves are bifacial, meaning they generate electricity from both faces. The cap’s grass surface reflects usable light back up into the underside of each panel, and in a Minnesota winter, snow on the ground adds a second reflective surface, pushing output higher during the months when sunlight is scarce.
The landfill that took ten years to unlock
The Anoka-Ramsey landfill closed more than 33 years ago and passed into the hands of the state’s pollution control agency, which manages more than 100 legacy landfill sites across Minnesota. Those sites carry bond restrictions designed to ensure long term environmental monitoring, and for decades those same restrictions made solar development legally and financially impossible.
In 2019, the state legislature directed an environmental board to evaluate closed landfills for possible solar development, and the Anoka-Ramsey site ranked among the five strongest candidates out of 111 properties studied. Lawmakers then approved legislation in 2021 that removed the bonding restrictions blocking solar development at the property.
Even after the legal path cleared, construction did not begin quickly. The electric cooperative now leases the land from the state, with payments supporting a state account that could fund future solar development on other closed landfill sites. The whole process, from first concept to first kilowatt hour delivered, took more than ten years.
What the meters recorded when the array switched on
The array, called the Ramsey II Renewable Station, began commercial operation on September 2. Spread across nearly 30 acres, the 4.125 MW array features 8,700 bifacial panels and is expected to produce roughly 7,900 MWh per year, enough to power approximately 750 to 790 homes.
A private energy developer financed and owns the project under a 30 year sublease, while the cooperative purchases the electricity, capacity and renewable energy attributes under a matching 30 year power purchase agreement. That structure kept upfront capital off the cooperative’s books while locking in a supply price for three decades.
“This project has been more than 10 years in the making, and we’re proud to see Ramsey II Renewable Station now serving our members,” the cooperative’s chief executive said when operation was announced.
The complications the grass and the cold actually create
The terrain following trackers solve the no penetration rule, but they introduce a maintenance picture that flat field solar operators rarely face. The landfill cap must be inspected regularly for erosion and membrane integrity, and tracker foundations that shift with freeze-thaw cycles need annual checks to confirm they have not migrated in ways that concentrate load in the wrong place.
Vegetation management adds another layer. Native pollinator friendly vegetation was planted beneath the panels, a practice the cooperative has used at its solar sites since 2014. But on a landfill cap, mowing equipment must stay light enough not to stress the membrane, and root depths are restricted so aggressive plants do not threaten the seal.
Snow accumulating at tracker bases can slow the soil warming the cap relies on to prevent gas pressure buildup below, and operators will be watching the first full winter closely for exactly that effect.
What Ramsey unlocks for the hundred landfills still waiting
Minnesota’s pollution control agency oversees more than 100 closed landfill sites, and Ramsey is the first solar array constructed on any of them. Lease payments flow to a dedicated state account that may encourage development at other closed landfills, so the first project is effectively seeding the financing mechanism for the next ones.
The pattern is not unique to Minnesota. Similar projects have gone up in Virginia, and as grid batteries have shown in Australia, pairing storage with distributed solar makes smaller arrays more valuable to a cooperative. The question of what unusual ground does to panel performance has surfaced in unexpected places too, including a floating array in Arkansas where migrating ducks will provide the first real performance review.
Each of the remaining landfills in Minnesota has a different cap age, a different slope, a different bond structure and a different distance to grid infrastructure. But Ramsey proved that the legal and physical obstacles can be worked through, one site specific law at a time. For communities sitting next to sealed landfills mowed and monitored for decades, that is the number that matters most: not the 4.125 megawatts, but the more than 100 sites now watching what comes next.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
