Iowa university gets high marks for solar/storage system

The Maharishi University of Management's new 1.1-MW solar power plant in Iowa-a cutting-edge facility that incorporates vanadium flow battery energy storage and includes single-axis active tracking-recently powered up for the first time and is now bringin

By Diane Mettler

Universities are known for being at the forefront of technological advancement. So it makes sense that the Maharishi University of Management (MUM) in Fairfield, Iowa, would be breaking new ground installing a cutting-edge design solar array and battery storage system.

In December 2018, MUM began producing renewable energy for the university from a 1.1-megawatt (MW) array designed and built by Ideal Energy Inc.

MUM's goal is to procure at least one-third of its electrical needs from renewable resources-and they are well on their way to meeting that goal.

Ideal Energy was excited to take on the project, since many of the people working for the company are alumni of the university, and the company is based in Fairfield.

"It has been a dream project to move the university more toward net zero," says Amy Van Beek, co-founder of Ideal Energy. "For us, it's been a long-term goal to do something really exciting and innovative for the university right here in our home town."

Ideal Energy spent approximately four years running different conceptual designs for the university. "That evolved as the incentives changed and the utility interconnection rules changed," says Van Beek. "Last year, when batteries became more economically viable, we were actually able to come up with a model that worked. It worked for our sole investor, and it worked for the university."

This solar array is not only the first system of its kind in the Midwest, it is also among the most technologically advanced solar installations in the United States. What makes this installation so advanced is that the design incorporates both single-axis active tracking and battery energy storage, all monitored by artificial intelligence, which guides the array like a field of sunflowers.

"One of the really nice things about the NEXTracker system is that it allows each row to function independently," says Aurelien Windenberger, head of finance and design at Ideal Energy. "Every day the array can tilt up to 60 degrees either to the east or to the west. Over the course of a day, it will start facing east at 60 percent, and then tilt upwards, and then over to the left in the evening." With the use of active-tracking, up to 15 to 20 percent more power can be realized than with a comparably sized fixed-tilt array.

Another unique aspect of the solar array at MUM is that wind, snow, and flood sensors were installed on the edges of the rows, all being controlled by the intelligent tracker control system. Whenever the monitors detect snow, the tracker will move the panels to a 60-degree angle, allowing it to shed the snow as quickly as possible. If there is flooding, the panels can flatten as much as 180 degrees to allow floodwaters to flow underneath the array without damage to the panels.

Of course, the battery storage is a key component of the project. "The whole NEXTracker system has been designed specifically to integrate with an NX Flow battery system," says Van Beek. The system uses Avalon vanadium flow batteries.

The battery energy storage system works in tandem with solar energy to reduce MUM's energy costs. "Peak shaving" is the term for the process of drawing power from either the solar panels or batteries, instead of from the power grid during peak times of the day and year when energy costs are highest.

	With the solar project now complete, the university and Ideal Energy are currently working on the preliminary stages of Phase 2 of the installation, which would generate enough power to cover 100 percent of the university's needs.

The vanadium flow batteries used in the project are ideal for large-scale peak shaving for a variety of reasons. First, the energy storage capacity and performance of vanadium flow batteries does not degrade over time. They can be fully discharged without degradation. And because the batteries are mostly filled with water, they are extremely safe.

"That combination allows you to have a DC-coupled battery system along with the solar," says Windenburger. "In a situation where the solar is putting out more than the AC limit of the inverter, the excess solar can flow into the battery when the battery needs to be restored, to get back up to 100 percent." Ideal Energy used REC TwinPeak series, 350-watt solar modules for the project. "That's the split-cell technology that gets a little bit higher efficiency," says Brandon Neil, Ideal Energy's project manager.

The solar field has 35 rows, each 310 feet long. There are 90 REC modules, one Ideal Power 30C3 inverter, and one NX Flow battery per row.

NEXTracker's NX Horizon System has a short rail mounting system, which worked with a shortlist of approved module frames.

"Our inside sales rep in REC is someone we've been working with since 2013, along with a couple of other manufacturers we have used on our other projects," says Neil. "It has been a long standing and good relationship, and we were able to match the modules with the NX Horizon system and still get the results we were planning on."

Ideal Energy handled the construction of the project. The construction was done in stages, starting in June 2018 with the earthwork preparation. After the excavation, the distribution line went in during August. In late September, the actual building began.

"It was a pretty challenging site to work with," Neil says. "It gets pretty slick in the mud. The construction schedule ran through November and there was snow to contend with. All things considered, we were complete in labor days in about four weeks."

During the process, NEXTracker's in-house engineering worked with Ideal Energy's in-house engineering team to confirm the engineering of the construction plans. NEXTracker engineers also worked with Ideal Energy's project management team on the procurement of all materials, the logistics scheduling, and timing for construction.

"There were a lot of moving parts," Neil says. "Heavy equipment rentals, logistics, the material, a cascade delivery schedule. We had existing partnerships with subcontractors who did some of the specialty work, such as excavation, boring, and foundation pile driving for the piers."

What makes the Maharishi University of Management's installation so advanced is that the design incorporates both single-axis active tracking and battery energy storage, all monitored by artificial intelligence, which guides the array like a field of sunflowers.

Throughout the project, NEXTracker sent field technicians to ensure that Ideal Energy built to their QA requirements, and after installation, they sent out training managers.

"NEXTracker was really great to work with," Neil says. "The field team that came out was tremendous. They were impressed with the level of our quality and execution on our first project with them."

"Being one of the more complex arrays that we've installed, and probably one of the more complex arrays that's been installed so far in the U.S., there were a lot of technologies that went into governing the system, and getting all that up and running has probably been our biggest challenge," says Van Beek.

The project has met the university's goals. "The array is expected to produce about 33 to 35 percent of MUM's total electric usage," says Neil. "There are a couple other smaller arrays on campus, and a 10 kW wind turbine which add up some more. And the utility, Alliant, has some renewable energy in their portfolio as well. When you combine all those sources, the university is currently at about 42 percent renewable energy out of their entire electric usage."

Ideal Energy is currently working on the preliminary stages of Phase 2 of the university installation, which would generate enough power to cover 100 percent of the university's needs.

"Universities have many trustees and donors who are excited about the project, and we're starting to plan," says Van Beek.

"We are looking at probably another 2.5 megawatts of solar," says Neil. "One of the things that we're working on is making sure the finances still make sense in terms of how it all works with the utility tariff to design a system that saves the university money. There is plenty of space where the current array is located, and we sized the distribution line which carries the power from the array to connect with the university's power source to be able to actually triple the size of the array." There is a lot about this innovative project for Ideal Energy to be proud of.

"For me, personally, it was really satisfying being able to match the university's load profile," says Windenberger. "Their daily and yearly load profile actually matches the output from the tracking system much better than it would from just a typical fixed ground-mount."

Windenberger adds, "It was also rewarding to be able to look at the 15-minute public data from the university, and then apply the more advanced tracker technology to fit that curve effectively. Based on modeling, in the summer, the same sized system, a fixed versus the tracker with the same DC size, could see upwards of 30 percent increased production. So we're excited to be watching that as it occurs."

"Ultimately, when our customers are successful, we are successful, and that's how we built our entire business over the last decade," says Van Beek. "I think being able to be a part of a project that is this technologically advanced has been my biggest reward.

"Our whole team really thrives on solving complex energy problems. We like projects that make us roll up our sleeves, that are a lot more challenging than just putting solar on someone's roof. How can we really get in and go after the most expensive energy portion of their bill? How can we use advanced technology in a way that's going to make a big difference for our customers? Designing and building solutions to those questions is what we thrive on."