Passenger vehicles driven for one year
Homes electricity use for one year
Number of smartphones charged
Tree seedlings grown for 10 years
Ground-mount Array Gives New Life to a Milwaukee Landfill.
Brownfield solar conversion leverages unique technical capability.
SunVest partners with We Energies to complete.
Solar installations on landﬁlls have been a growing trend nationwide – which is no surprise to the solar experts at SunVest. Open, unused land with limited shade is always a great opportunity to produce clean, renewable energy for a community. But solar installations on landﬁlls can be tricky.
These projects require extra engineering and a diﬀerent installation technique for a few reasons. First, landﬁlls are capped with a cover that isolates landﬁll waste and contaminated soils to prevent the spread of toxins. Solar developers need to guarantee that installations will not puncture this protective cap. Second, landﬁlls are shaped like a dome or a large mound, far from the ﬂat surface solar installations were designed for.
SunVest partnered with the We Energies Solar Now Program to design and develop a ballasted ground mount system at the City of Milwaukee College Avenue Landﬁll. The site is next to Mitchell International Airport, abutting the 128th Air Force Refueling Wing. In addition to the unique requirements of a landﬁll site, SunVest needed to obtain approval and documentation from the Federal Aviation Administration (FAA). We also had to pay extra attention to scheduling and site access.
SunVest has designed, developed, operated and maintained over 100 MW of solar power projects since 2009. The opportunity with We Energies was a challenge we gladly accepted. SunVest designed and installed a ballasted ground mount system, which uses concrete blocks to secure the array instead of penetrating the ground. Once all of the landﬁll considerations are solved, a ballast system is actually one of the easiest and cost-eﬀective systems to install.
Extra ﬁll and gravel were distributed and compacted over the top of the existing landﬁll cap on the north and west sides of the solar ﬁeld to level out the surface. The back of the landﬁll had the most slope, so we added landscaping timbers to keep the gravel in place.
The system used 776 ballast anchor blocks – each measuring 20” x 114” and weighing 4,000 pounds – with embedded attachment points for solar racking. The racking involved angled panel supports bolted to vertical steel columns.
Once racking was in place, 7,200 Trina Solar 400-watt panels were installed and wired together using messenger wire. Messenger wire electrically grounds the entire array and supports CAB Solar hangers where solar conductors can be secured, routed, and organized.
DC power ﬂows from panels to combiner boxes within the installation, then to 18 SMA Sunny Highpower 125 kW inverters at the north end of the array. AC power is routed to a switchboard and disconnect, then to a transformer provided by the utility.
The result is a once-abandoned brownﬁeld site transformed into a solar ﬁeld that will produce clean, renewable energy for decades.