Great River's new headquarters 'LEEDs' by example

Energy efficiency can be beautiful, as Great River Energy's new headquarters in Maple Grove, Minn., proves. Project leaders are submitting the 166,000-sq. ft. building for LEED platinum certification. (Photo by Great River Energy)

Not satisfied to merely practice the energy-efficiency measures it preaches, Great River Energy aims to inspire its members to go for the platinum—LEED certification, that is.

The generation and transmission (G&T) cooperative will apply this fall to the U.S. Green Building Council's Leadership in Energy-efficient Design program for a platinum rating for its new corporate campus in Maple Grove, Minn. The building is designed to use 50 percent less energy than Minnesota code requires, and to use 90 percent less water than comparable facilities. The builder used locally-manufactured and recycled materials in construction, including fly ash from Great River's Coal Creek Station, and diverted 75 percent of the construction waste from the landfill. The facility will save Great River an estimated $90,000 annually in electricity costs after the seven-year payback.

Loan programs spur efficient building

If that doesn't get the G&T's 28 members motivated, the loan program Great River announced at the building's dedication in April should. The $20 million revolving, zero/low-interest loan fund will help commercial members finance the additional costs of LEED construction. Great River will also finance 100 percent of the costs related to applying for LEED certification.

In a press release, President and CEO David Saggau explained that Great River intended the program to encourage construction of more LEED-qualified buildings in its service territory. "Our headquarters may be the first of its kind in the region, but this program will ensure it's only the first of many."

The utility also introduced an $8 million program to finance the purchase and installation of energy-efficient HVAC equipment in commercial members' facilities.   

That's a lot of effort to promote energy efficiency, but doing less was not an option, said Gary Connett, director of demand side management and member services. "Great River has been pushing energy conservation for years, to end-use consumers as well as to its member cooperatives," he said. "When the time came to build a new headquarters, we had to walk the talk."

Aiming for a LEED platinum rating was a way to take building efficiency to a new level. "Obviously, all new construction won't be trying for LEED certification, let alone platinum," Connett acknowledged. "Our goal for the new headquarters was to show our members and the community how far energy-efficient construction can go."

Systems approach for best results

Minnesota is a pretty green state, he added, so the bar is high. If the high bar posed a challenge in setting a great example, it also ensured that the utility would be able to find LEED-versed architects and builders to help achieve its vision. Great River Energy’s vision was to take the systems approach—to design a building where all the components worked together for maximum energy efficiency.

The utility brought the architect, general contractor and owner's representative together at the beginning of the project. "Usually, the general contractor joins the project later in the process," Connett explained. "You don't get an efficient building by having 10 different contractors, each thinking about one piece of the job. Going for a LEED rating requires consensus."

Creative use of existing technologies

Getting the rating—even a platinum—does not necessarily involve installing a lot of complicated, experimental systems. "Most of our systems used off-the-shelf technology that is available to any builder," said Connett.

What was innovative was the way the building design combined those systems to optimize performance. Geothermal heat pumps and under-floor displaced ventilation systems are widely used to improve energy efficiency. In the Great River Energy building, the systems are teamed up to cut down on the need for fans to push conditioned air around the building. The floor is built 18 to 21 inches above the concrete structure, and floor vents deliver air to each cubicle. "The system increases everyone's comfort, and, as a bonus, moves fewer germs around the office," Connett noted proudly. "I don't know of any building that has that combo."

The site itself plays a significant role in the building's efficiency. The building's longer east-west orientation maximizes daylight harvesting, while fewer windows on the east and west walls reduce solar heat gain. The geoexchange heating and cooling system takes advantage of nearby Arbor Lake. Plastic pipe—35 miles of it—runs under the water which is cool enough to provide free cooling on most summer days, "So we don't have to run the compressors," said Connett.

Dimming ballasts, lighting sensors and motion sensors help reduce artificial lighting needs. The elevators employ a counterbalance mechanism and high-efficiency motors to use 60 percent less energy—and take up less space—than conventional elevators. Every computer in the building has an energy-efficient flat screen CRT (cathode ray tube) monitor. "Basically, we looked at every operation that used electricity and asked, 'How can we make it more efficient?'"

Meeting renewable energy requirement

The less electricity the building used, the easier it would be to meet the LEED platinum requirement that the facility get 12.5 percent of its electricity from renewable energy. That electricity is supplied by a 200-kw wind turbine and a 72-kw solar array mounted on the roof. Solar energy also pre-heats hot water for building use.

The refurbished NEG Micon M700 wind turbine, visible from Interstate 94, reminds passing drivers of Great River Energy’s commitment to renewable energy. The gears in the gearbox were remanufactured and the generator rewound to change the unit from a two-speed to a one-speed to increase efficiency. With those modifications to maximize the lower wind resources in the "urban" area of Maple Grove, the turbine is expected to produce 390,000 kWh/yr. The Maple Grove City Council approved a five-year, conditional use permit for the turbine.

The original building plan called for two wind turbines, but installing two commercial grade units within city limits stirred some concern in the community. "We ended up putting on more PV, and that, combined with the turbine, produces almost 15 percent of the building's electricity needs," said Connett.

Great River Energy’s payback period for all the measures combined is estimated at seven years. The energy-efficiency measures alone will pay for themselves in just four years. "After that," Connett said, "We'll be saving $90 thousand annually."

Outreach to members, public

Throughout the construction process, Great River Energy shared the project costs with its members, including breakouts of incremental costs. "We had to be very transparent, not just for our members," said Connett. "We wanted to make sure that we understood the costs ourselves, so we can share what we've learned."

There has been plenty of opportunity to share since Great River Energy moved into the building. The headquarters is open to the public, and tours come through nearly every day. People will also be able to tour the facility during the Maple Grove Days festival this month. "We've hosted architect and engineering firms, church groups and schools, to name just a few," Connett said. "We are booked up through August, and have had calls from as far away as Boston."

Before touring the building, visitors see a short video presentation on the project that puts energy efficiency in a new light. "A lot of people still equate energy efficiency with doing without," said Connett. "Our headquarters is proof that by applying new thinking to existing technology, you can get the comfort and functionality you want. And you can get it cost effectively."

Resources

Great River Energy

LEED certification

U.S. Green Building Council

People

Gary Connett

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