By Max Bloom
In office buildings of the not-too-distant future, temperature sensors embedded in concrete floors cue windows to open automatically at night, cooling the space without the need for power-sucking A/C. Occupants use mobile apps to adjust fans and heaters built into their office chairs, thus minimizing dependence on traditional energy-intensive heating. Software-driven, solar-plus-storage systems produce and manage more energy than the buildings consume.
All of the above innovations – and more – are incorporated into Rocky Mountain Institute’s new 15,610-square-foot Innovation Center in Basalt, Colorado, a living lab that is pushing the boundaries of how built environments can sustainably manage natural resources. With U.S. buildings accounting for 73 percent of the country’s electricity consumption and 38 percent of CO2 emissions, rethinking how buildings are designed and constructed could have a profound impact on our energy future.
The efficiency goals for the Innovation Center were established early on through the rigorous certifications RMI committed to attain. The building has already been LEED Platinum certified, and will soon achieve ILFI Net-Zero Building, IPHA Passive House, and PHIUS+ 2015 Passive Building and Source Net Zero certifications.
RMI also implemented forward-thinking design and construction processes – integrative design and integrated project delivery – that facilitated efforts to maximize energy efficiency. Integrative design encourages an interdisciplinary, holistic approach, with contractors, architects and other stakeholders meeting together in design charrettes from a project’s earliest conception through to completion. Integrated project delivery is a contract mechanism that ties contractor profit to the building’s energy performance.
“Our design team had their budget on the line,” says Craig Schiller, RMI’s LEED AP. “Our general contractor was looking over every subcontractor’s shoulder saying, ‘Nope, you’ve got to tape that again … seal up the envelope even better.’ [Integrated project delivery] got all of the partners to buy in from the onset of the project.” As a result, the building – designed to accommodate a staff of 50 and provide world-class convening space – has achieved a remarkable energy use intensity (EUI) of 17.2 kBtu/sf, making it one of the most energy efficient commercial buildings in the world.
While the Innovation Center incorporates sophisticated solar-plus-storage technology, passive design was the most cost-effective factor in reaching the building’s energy-efficiency benchmarks. “If you want to be net-zero, you are constrained by how much power you can produce on your building,” notes Schiller. “Your entire building load needs to be under that amount.” To that end, the building incorporates a myriad of efficient design features including an airtight building envelope; thermal mass, floor-to-ceiling, quad-paned, Krypton gas-filled, south facing windows; and an automated exterior curtain for shading on hot summer days.
The flip-side of minimizing load is maximizing the building’s power generation. The Innovation Center’s 83kW rooftop PV system – powered by SunPower X21-335 high-efficiency modules – produces enough power for the entire building plus six electric vehicle charging stations. The PV system powers a battery storage solution consisting of a refrigerator-size LG Chem 30kW/45 kWh lithium-ion battery and an Ideal Power inverter, both controlled by a Geli Energy Operating System. With low electricity rates currently available through its local electric coop, RMI opted to remain connected to the grid. In the future, the Innovation Center’s power system will enable microgrid islanding, through which the building could supply its own power totally disconnected from grid.
The “brains” of the solar-plus-storage system, the Geli EOS, determines when to charge the battery (from the PV system or the grid) and when to discharge the battery to power the building. For example, if the Innovation Center draws an average of 50kW or more from the grid in any 15-minute period during a month, the building is pushed into a rate tariff that imposes demand charges. The Geli EOS is programmed to automatically switch the system to battery power before hitting the 50kW threshold.
In RMI’s case, because of low electric rates, exceeding that threshold might not be particularly onerous. But for many commercial buildings, bumping into a higher rate tariff, or being hit with costly demand charges, could be financially painful. As a key component in the Innovation Center’s living lab, the Geli EOS can model various power use cases under a range of rate structures. “We could import the PG&E rate tariff structure into the Geli system and see how this building would respond and lower costs,” says Schiller. “Mimicking what it would be like in California [under that rate structure].”
While solar-plus-storage does enable RMI to achieve its net-zero energy efficiency targets, the system realizes its most significant economic impact as a model for buildings in high-energy-cost rate environments. “This project is groundbreaking in that it is directly transferable to markets where the economics do make sense,” notes Andrew Krulewitz, Geli’s Director of Marketing.
Like a living organism, the Innovation Center’s relative health (i.e. energy efficiency) is demonstrated through extensive monitoring. A publicly-available Lucid dashboard displays metrics compiled from more than 120 sensors and data monitors located throughout the building. A separate Lucid dashboard accessible only to RMI staff can be programmed to monitor the energy consumption of any group of devices or submeters over virtually any time period. Additional dashboards from Geli and Enmetric enable monitoring and control of the building’s energy management systems.
RMI, a self-described environmental “think-and-do-tank,” is dedicated to research and analysis, publication, consulting, and convening gatherings in the general field of sustainability, with a special focus on profitable interventions for energy and resource efficiency. The Innovation Center enables RMI to “walk the walk” in its own backyard, and with 90 percent of commercial buildings in the U.S. under 25,000 sq ft, its impact as a model of energy efficiency could be far reaching.
Historically, humans have sought to achieve physical comfort by “taming” the environment, while expending massive amounts of resources in the process. With the depletion of those resources and the specter of global climate change, it has become clear we can no longer afford to continue in that vein. The Innovation Center was conceived as a 100-year, future-proof building, and was designed to be able to incorporate new efficiency technologies and practices as they develop.
The Innovation Center is already more energy efficient than could have been imagined just a few years ago. “In most buildings, the coldest the building will get will be the morning of the coldest day of the year,” notes Schiller. “In our building, the coldest the building should ever get is the morning of the hottest day of the year in the summer.” It will be exciting to see what possibilities the next iterations of energy efficiency will deliver.
Image credit: Tim Griffith
Max Bloom is a Renewable Energy Marketing Communications Director based in the San Francisco Bay Area.