Buildings that consume no outside energy are being developed today using existing technology. This is the last of a two part series. Read part one here.
Residents also play a key role, and are being given access to a web-based tool that enables energy use monitoring by unit. And a smartphone app lets residents turn off lamps and plugged-in electronics remotely.
A little more than a year into the project and about halfway toward its target population of 3,000, West Village appears to be on track to achieve zero net energy use in 2013. The preliminary data is promising but not definitive, according to developer Carmel Partners of San Francisco. The solar panels are performing as expected and residents are using the anticipated amount of electricity. Efforts are underway to educate those residents whose energy use is higher than average on ways to reduce consumption.
All of this comes at a cost, however. In addition to $300 million invested by West Village Community Partnership, a joint venture of Carmel Partners of San Francisco and Urban Villages of Denver, the project received nearly $7.5 million in federal and state energy research grants. And apartment rents are said to be at the high end of the Davis market.
But then, West Village is a demonstration project intended to test and refine ideas that can be replicated elsewhere at market rates. Other projects around the country are also developing concepts and tools that can help make net-zero communities a reality, including the following:
- One challenge to planning such communities, especially in existing neighborhoods and cities, is figuring out which retrofits make the most sense and where. Simulation models exist for single buildings, but using these to try to make sense of large groups of buildings is nearly impossible, says Ali Malkawi, a Penn architecture professor and the director of the T.C. Chan Center for Building Simulation and Energy Studies. As part of his work at the US Department of Energy's Energy Efficient Buildings Hub (EEB Hub) at the Philadelphia Navy Yard, Malkawi's team has come up with "computational tools that enable us to simulate a large number of buildings of varying types and to test interventions in neighborhoods and cities." This allows architects and engineers to test ideas at scale before making decisions, and it allows developers and investors to evaluate, ahead of time, which interventions will be most cost-effective.
- Cassidy Turley, a leading commercial real estate services provider, takes a different approach. The company was recently recognized by the EPA as a 2013 Energy Star Partner of the Year for its centralization of more than 350 buildings into one Energy Star Portfolio Manager account — creating a virtual community of sorts. This aggregation of buildings, notes CEO Joseph Stettinius, allows the firm to set benchmarks, and quickly identify and deal with anomalies that pop up any of the buildings. As a result, says Stettinius: "We can more effectively manage where we want to focus our remediation efforts." The portfolio approach also allows the company to replicate what they learn in one building throughout the portfolio.
- The National Renewable Energy Laboratory (NREL) estimates that 62% of commercial buildings could reach net zero by 2025, but "it is rarely cost-effective to upgrade all buildings and equipment at once to get to net zero energy," notes Managan. She recommends developing an optimal sequencing of steps — delaying upgrades to HVAC systems, for instance, until load-reducing steps have been taken, or taking advantage of "compelling events," such as tenant vacancies or the end-of-life replacement of building systems to make needed upgrades.
- Energy storage is even more important at the community level than it is in single-family homes, both for backup in the event of disruptions to the grid and for load balancing. Riley notes a promising pilot program involving several hundred homes and a nearby wind farm. Wind power is notoriously variable: Sometimes the wind farm generates not only more energy than the community can use, but even more than the grid can safely absorb. At such times, the water heaters in all the homes are turned on, acting essentially as batteries by storing the energy for use later on.
The American headquarters of German software giant SAP points the way toward net-zero commercial buildings: Of the 21 commercial building identified as net zero by the New Buildings Institute (15 measured as net zero, plus six "credibly modeled"), 15 are less than 10,000 square feet and only one is at the same scale as the SAP facility in Newtown Square, Pa, near Philadelphia. (The building is also built to a high standard, and is certified LEED Platinum. The airy structure features a green roof, rainwater collection and geothermal energy.)
The relatively small scale of these buildings points to the difficulty of creating a large net zero energy building. As Malkawi notes: "As you get into larger and more complex structures, it is very difficult to figure out how the building is going to perform," which is why the T.C. Chan Center and other research institutions are working to develop sophisticated simulation models for larger buildings.
But thanks to the pioneering work of SAP and others — including the National Renewable Energy Lab (NREL) in Golden, Colo., which built the one net-zero building of comparable scale, the $64 million, 220,000 square-foot Research Support Facility (RSF) — a few strategies have been identified that will support the design and construction of large-scale commercial net-zero buildings.
Hermetically sealed high-rises won't get you to zero: Until recently, most large commercial structures have been sealed off from the natural world. But future energy-efficient buildings will undoubtedly take the opposite approach, responding continually to what is happening outside. The SAP facility, for example, has a lighting system that "harvests daylight" by using sensors to dim the lighting levels and raise or lower window shades based on the level of sunlight coming through the triple-glazed glass exterior wall. The NREL facility combines a similar window-shading technology with light-bending window louvers that cast rays up into the interior office spaces. And lower-than-average cubicle partitions allow the daylight to penetrate deep into the building.
The same openness to nature characterizes both buildings' approach to heating and cooling. The SAP building uses geothermal wells to both heat and cool areas of the building whenever the temperature inside rises above or falls below the constant temperature of the earth tapped by the wells. The NREL building uses both a massive concrete heat sink in the sub-basement to store radiant heat and windows that open automatically or manually to use outside air whenever it's efficient to do so.
Design and construction are a team sport: In order to ensure that all the various systems and features of a building work well together, everyone involved in the design, construction and maintenance of the building also needs to work together from the very beginning. At a recent conference in San Francisco, speakers from NREL made this point, discussing how the architects, engineers, contractors and operations/maintenance company involved in the RSF communicated with each other to ensure that their individual efforts would support the goal of net-zero energy. The result of this kind of teamwork is a building that functions as the SAP facility does. Brian Barrett, SAP's manager of capital projects, who coordinated construction of the Newtown Square building, notes how systems throughout the facility "are interconnected and are part of a holistic system."
Occupants are central to the success of net-zero buildings: "There has been a lot of work done related to human behavior in relation to energy reduction," says Malkawi. "It is very well understood from a psychology perspective." (He points out, however, that developing computational models that can incorporate this information is a work in progress.)
People use less energy, for instance, when they are made aware of how much they are using and how they can cut back. At the RSF, an icon pops up on occupants' computer screens whenever it makes sense for them open a nearby window (windows that are out of reach are operated automatically).
At SAP, says Barrett: "Education was provided to each employee who was moved into the building so they would understand key features. Informing the people who will actually use the building is important. There were notes on the waterless urinals and explanation of the light sensors at the desk outlets and the lights above, which turn off after a selected period of time. A great deal of time was spent with literature and tours at the onset of the move-in process for the employees."
The result of all these efforts is that the SAP facility is performing even better than expected, consuming 49% to 51% less energy than a conventionally built and managed building. And both SAP and NREL are continuing to make improvements and help nudge the commercial building sector toward net zero.
*[This article was originally published by Knowledge@Wharton.]
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