A new book from green building expert Jerry Yudelson provides the first large-scale study comparing building performance data worldwide from the highest-rated large green buildings of the past 10 years. The World’s Greenest Buildings: Promise vs. Performance in Sustainable Design relies on actual energy and water operating data from 57 projects in 18 countries, and offers architects, engineers, and builders new ways of designing and constructing high-performance buildings.

Below, Yudelson talks with ECOHOME about his research and its implications for American builders.

Your new book talks about the greenest buildings in the world. How did you choose which buildings to feature?
We decided to focus on a subset of buildings that met the following criteria: LEED Platinum or equivalent; nonresidential typologies; 50,000 square feet or larger; built after 2003; and willing to share a year's worth of energy data (and water where available). With these criteria, we wanted to illustrate that you can have super-green contemporary buildings, with architectural merit, that meet all major green attributes but which are very energy and water efficient.

Some great buildings in North America are Manitoba Hydro Place in Winnipeg, Canada; Genzyme Center in Cambridge, Mass.; Twelve West in Portland, Ore.; and the NREL Research Support Facility in Golden, Colo.

What makes a building green? What are the most important factors?
If you ask me, LEED certification makes a building green, as do similar rating systems such as Green Star in Australia, DGNB in Germany, BREEAM in the UK, and CASBEE in Japan. However, the key is that a building is rated by an independent third party using consensus-based systems such as LEED. The fact that LEED is now used on projects in almost 150 countries makes it the de facto international standard. Certainly for LEED Platinum buildings, scoring high on energy and water efficiency is a key element of certification.

Why is building performance so important?
We have all signed on to major reductions in carbon emissions from buildings, with a goal of zero emissions by 2030. It's important to identify buildings that are on the right path, i.e., meeting the 2010 requirements of the 2030 Challenge, as well as those that are already doing much better; our goal is to show design teams how to get there. Without performance data, we're all just flying blind.

Why is performance information on buildings so hard to come by?
Most people are not accustomed to asking for or sharing performance data with the world. In addition, on many campuses, individual buildings are not even metered, as there's just a central campus chilled water, steam, and electric power system. In the private sector, it's even more closely guarded information, especially for corporate real estate. Bottom line, architects and engineers are not asking for it and owners are not volunteering it, especially for publication. (While LEED does require performance data, it's treated as confidential and reported as anonymous, something that absolutely has to change.)

In writing the book, did you come across new information that surprised you?
Biggest surprise: there are plenty of examples of buildings with EUI (Energy Use Intensity) well below the United States’ "good" practice of 40,000 Btu per square foot per year. Second big surprise: energy use in high-level green buildings is almost always independent of climate. This is easy to understand in a way: once you get a good building envelope, more than half of the energy use is lights and plug or process loads, whereas space heating and cooling tend to be below 20 percent of the total, so the climate impact on energy use is not that significant. Heating-dominated climates such as Canada and northern and central Europe tend to have naturally ventilated buildings and cooling-dominated climates, such as the tropics, have no heating load at all.

You researched green building rating systems across the world. How do they compare to U.S. rating systems?
In the book we have buildings certified to LEED, BREEAM (UK), DGNB (Germany), Green Star (Australia), Green Mark (Singapore), HQE (France) and CASBEE (Japan), plus a few other standards. The fact is that most major rating systems (CASBEE excepted) are converging on the same approaches, with similar attributes and similar relative weightings of environmental attributes, giving me confidence that we'll see nearly identical (and therefore comparable) rating systems around the world in the next five years, but LEED will remain the dominant global system.

What do you see for the industry in the next 15 years?
We will get on a "glide path" to meet the 2030 Challenge in terms of building energy performance. In addition, I think we'll see virtually all new buildings built to LEED standards by 2020 and perhaps up to 75 percent of (currently) existing buildings will be LEED certified by 2025.

Building on its successful launch in 2012, ECOHOME’s Vision 2020 program continues in 2013, focusing on eight critical areas in sustainability. Track our progress all year as our panel of visionary focus-area chairs, our editors, and leading researchers, practitioners, and advocates share their perspectives on initiating, tracking, and ensuring progress toward sustainable priorities and goals in residential construction between now and 2020. The program will culminate in an exclusive Vision 2020 Forum in Washington, D.C., in September 2013, and with a special edition of ECOHOME in Winter 2013. Click here to see the 2012 Wrap-Up.