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Case Studies: The Green Institute at the Phillips Eco Enterprise Center

GENERAL INFORMATION

Project name: The Green Institute at the Phillips Eco Enterprise Center

Location: Minneapolis, MN

Web site: www.greeninstitute.org

Architect: LHB

Builder: Kraus-Anderson

Building size: 64,000 sf (approximately: office space 24,000 sf, light industrial 40,000 sf)

Building use: Office / light industrial

Completion date: Sept. 1999

Ratings and awards:

  • ENERGY STAR Small Business Award
  • US EPA Award
  • National Award for Environmental Sustainability
  • American Institute of Architects Committee on the Environment
  • 2000 Earth Day Top 10
  • President's Council on Sustainable Development/Renew America
  • Best in Real Estate Magazine 1998 "Cutting Edge Category City Business"

OVERVIEW

The Phillips Eco-Enterprise Center (PEEC) is the result of a cumulative effort to reinvest in the Phillips neighborhood of Minneapolis. After the challenges of EPA superfund cleanup and an incinerator was prevented from being constructed in the area, The Green Institute was formed with community advocates to develop a commercial office space and light industrial facility to house organizations sharing visions for addressing environmental and social justice issues. The building helped pioneer green building and renewable energy approaches in Minnesota. The 34kW solar electric system installed on the building is one of the largest in the state. This solar electric system allows The Green Institute to provide site-generated renewable energy for a portion of the power used by the tenants. Along with several integrated strategies, the PEEC is operated by The Green Institute and has continued to serve as a demonstration site for educating visitors about sustainable practices and clean energy production.

BUILDING PERFORMANCE

Effective energy use solutions:

  • Part of the design approach for the building was the sharing of facilities such as conference rooms and office equipment for the tenants. This reduction in systems and space reduced the energy use for climate control and power, as well space requirements of the building. Zoned systems for heating and cooling allowed for individual offices to maintain climate control isolated from the main corridor and other offices.
  • Placement of a prominent stairway at the entrance with the elevator set further in the building was intended to encourage reduced use of the elevators for energy conserving purposes and to increase the health of occupants and visitors.
  • Shared loading docks and a main corridor in the light industrial section of the building also reduced the number of bay doors opening and closing to the outside providing more controllable interior condition.
  • Other strategies include: low-e glazing, solar-tracking skylights, high-efficiency lighting, geo-thermal heat pump system, energy recovery ventilation, and an energy management system.

Orientation: Main office spaces face north-west, light industrial wing faces south-east

Daylighting strategies:

  • The office spaces have a combined approach for bringing in natural daylight into the building, utilizing windows and white, reflective paints to reduce electric lighting.
  • The front atrium allows light to penetrate into a portion of the open space plan offices through windows in the walls inside the building.
  • Clerestory windows also bring natural light into the other office spaces.
  • In the light industrial section of the building, solar-tracking skylights bring light deeper into the building.
  • The main corridor is almost entirely naturally day-lit.

Shading of structure: Solar array shades rooftop and upper western side windows

Climate control systems: A ground source pump system provides heating/cooling for office space and natural gas powered forced air for the light industrial portion of the building.

Backup power: 48 hour emergency systems battery backup

RENEWABLE ENERGY SYSTEM INFORMATION

Solar system description and size:

  • The 34 kW solar electric three phase system is mounted both on the rooftop with a 30 kW array facing southeast, and with a smaller 4kW array on the upper southwestern wall providing shading on the structure and windows. The net-metered, grid inter-tied system has a 48 volt battery backup. This system allows the Green Institute to sell back power to the utility company on weekends when power use is lower, as well as have an uninterrupted power source with the battery providing 600 amp-hours of backup power to computer, security, and phone systems.
  • System Components: Amorphous (thin film) silicon BP MST 43 watt modules, 696 modules are on the rooftop, with 92 modules on the southwestern wall. 13 Outback charge controllers, 12 Outback inverters, and 48 volt battery make up the balance of systems that convert the DC current energy from the solar collectors to AC current that matches with the needs for selling back power to the utility company.

Solar system cost: $195,000

Financial incentives/donations:

  • MN Department of Commerce provided $68,000 in rebates ($2,000/kW)
  • BP Solar donated 1200 modules (some sold to other community based solar projects to reduce cost)
  • 1,000 hours of volunteer labor contributed during the installation phase for hauling panels to the rooftop, mounting the racks and panels

Payback: 32 years

Date installation was completed: 2005

System Designer/ Installer: Innovative Power Systems (IPS)

Estimated amount of energy delivered by system: 40,000 kWh/yr

Percent of building's total energy use provided by solar: 25%

MOTIVATION FOR INSTALLATION

In addition to the environmental benefits associated with decreasing Minnesota's dependence on coal and other fossil fuels, The Green Institute's motivations for developing its PV system included:

  • Planning an installation that was highly visible to the community, from the ground and by commuters on the Hiawatha Light Rail Transit line.
  • Connecting renewable energy projects with local community revitalization opportunities.
  • Demonstrating how local businesses can utilize renewable energy.
  • Diverting the need for new power stations to cover peak demand periods by selling excess PV electricity back to the utility.
  • Having a system that Minnesota utility companies and state policy makers can use as a successful business model for planning future projects.
  • Jumpstarting the marketing of Green Power to rate payers and invested industries.

(Source Document: PEEC_Solar_Factsheet_2007 courtesy The Green Institute)

LESSONS LEARNED

Part of the process of pioneering new concepts and technologies includes a level of learning what works and what needs further development. At the time of installation, the systems available for balancing the power conversion of such a large solar electric system required the inclusion of a battery backup.

Based on the improvements of today's technology, Carl Nelson, one of the staff interviewed from The Green Institute, suggested that they would exclude batteries if doing the system again. Nelson went further to say that, "batteries require ongoing maintenance and replacement, and are the weak environmental link, having the most environmental impact when utility grid access is available. The lesson here is to not do a battery system if you do not have to in an urban setting."

A different aspect of the solar electric system design that Nelson said would have been included was a monitoring system to get performance data. As The Green Institute passes on its utility costs to its tenants, this system interface would simplify metering and billing, which is challenging when retrofitting the system.

In an effort to incorporate new technologies at the time, solar tracking skylights were included in the original design. Due to climatic conditions they did not perform well. The tracking systems had a built in battery, which got discharged during the winter. The systems were designed originally for California climate. Solar charged batteries were designed for lower latitudes. The Minnesota winters did not provide enough sun to keep the batteries functioning, and so a different system had to be retrofitted.

OTHER INFORMATION

Sustainable features include:

  • native prairie restoration
  • on-site storm-water retention/biofiltration
  • green rooftop
  • Midtown Eco-Yard
  • burnished blocks
  • elimination of dropped ceilings
  • design for disassembly and adaptive reuse
  • pre-cast concrete panels
  • local suppliers
  • construction site recycling
  • low-emissions paints
  • reused materials

See www.greeninstitute.org/buildings for more sustainable features.

Solar Electric Pollution Offsets

  • 30 tons CO2/Yr
  • 180 lbs NOx/Yr
  • 164 lbs SO2/Yr
  • Several lbs of Mercury

IMAGES