October 5, 2014
By Carl Smith
The non-profit New Buildings Institute (NBI) works with governments, utilities, energy efficiency advocates and building professionals to improve the energy performance of commercial buildings. Its funders and project partners include the Energy Foundation, U.S. Green Building Council, American Institute of Architects, U.S. Department of Energy, Environmental Protection Agency, electric utilities and public benefits administrators.
ZNE Research Director Cathy Higgins talks about the evolution of this new building type, and the prospects for Zero Net Energy school facilities.
What is the mission of the New Buildings Institute?
NBI is a National non-profit. We have been around since the end of the 1990s, and we work in 4 “corners” of building activity, like a foundation to a building.
The first corner is Zero Net Energy buildings where we do national research on the characteristics and trends of ZNE buildings and verify their energy performance. The second is advanced design practices, identifying and then developing guides of the best design practices for architects and engineers. Corner number three is measured energy performance of both buildings and emerging technologies; I lead a lot of that in tracking, documenting and promoting actual measured energy performance of buildings. The fourth corner is policies and programs–leading and developing drivers for deep efficiency though energy codes and policy mechanisms.
Those four pieces make up NBI’s work to accelerate deep efficiency in commercial buildings. We only work in commercial buildings, not residential, and our job is to make buildings use less energy and move the market towards that goal.
What kinds of things do you do to pursue this goal?
In the last couple of years, working on zero net energy buildings and deep efficiency has been prominent, coupled with our policy work. An example is our “Getting to Zero” research study, the largest study on the trends, the technologies and the practices used to get to zero energy across North America. We did that in 2012 and 2014, and documented the buildings because it is not just the data, it’s showing some of the individuals and the firms that are moving toward these leading-edge practices that we think are really valuable to helping the market.
We also do design guidelines for new construction that get adopted as voluntary or reach practices through utilities or cities. Those migrate, becoming the next generation of code. We integrate our activities a lot in this continuum of pulling the market forward from standard practice to what becomes code and then to best practice, which is leading edge or the top-of-the-game efficiency in commercial buildings.
Probably the most widely published thing we ever did was the largest study of LEED commercial buildings’ actual energy performance. That was a number of years ago, but that’s still a widely referenced study on the outcome vs. the intention of good practice design.
How did NBI get involved in advocating for ZNE buildings?
It’s the natural edge of long-term work in deep efficiency and best practices. Historically, we had worked to cut energy use in commercial buildings by 50 percent. That was our previous leading-edge work, again being out at the edge so we can back-cast and pull other practices toward that example. That “Getting to 50” has now migrated to our ‘Getting to Zero’ work. It is really just a natural migration of policy trends that are in place on carbon reduction, efforts by a number of firms and the AIA and cities and governments to reduce carbon emissions and to have a more aggressive goal, combined with examples that were already in place documenting that really low energy buildings are possible. We need to leverage these factors to build a lot more of them.
What is the most broadly accepted definition of a “Zero Net Energy” building?
I’m on a national committee that is answering that very question. They are going to publish their best effort at consensus in late calendar year. The answer that is most widely used right now is that first, it is a very low energy building. The energy use is very low, such that over the course of the year it can meet all of its energy use with on-site renewable energy. There are probably 4 or 5 variations, but that is the answer to your question as to what is most widely accepted.
If a homeowner really prefers gas for cooking, but is also passionate about the environment, could they have a gas stove and still have a ZNE building?
Absolutely, in my opinion. The exception would be a program that is zero carbon, and so that is a different issue. With zero net energy, the word is energy, and it can and needs to be calculated across all fuels. Many of our ZNE buildings have gas. You can use gas and electricity – it’s just a math problem to take gas and electricity used and convert them to Btus and compare them to the Btus generated by renewables. It is just a formula–does generation exceed energy use, total energy use? You could even have steam, as another example. Someone on a central plant might not want to change to electricity when their central steam plant would be better so you take the fuels add them up and subtract the total generation and that is your ‘net’ energy.
So, yes, they can be zero net energy buildings. They may not meet other targets that are zero carbon, but that would also involve checking the fuel source. An all-electric building is not necessarily zero carbon either, because the electricity might be generated by natural gas.
Do we already have all the technology we need to create ZNE buildings, or are there still some things it would be nice to have to speed progress?
Well, yes and yes. The technologies are definitely readily available. We have lots of building owners who designed and accomplished ZNE, so we know that it can be done with things that are off the shelf and standard designs available today. Especially if they are starting with the passive strategies that have been in place for eons essentially, going back to incorporate practices that were in place before the advent of electricity and other mechanical systems that reduce the base loads.
Given that there are a couple hundred buildings you can point to, of all sizes and shapes and types that have accomplished ZNE, that answers the question whether it is technically attainable and easily accomplished by firms with the knowhow.
Your second question, whether there are technical challenges remaining, the answer to that is also yes. One of the priorities is to get integration of renewables at the grid. That is still pretty new. You can get the building energy down, but the ability to trade energy in two directions is still, technically, somewhat immature. The other big technical area is continued commissioning and the system monitoring. The aspects that happen after the occupants go into the building are the biggest challenge. It isn’t necessarily on the design side, it tends to be on the occupancy and operators’ side with things like plug loads and IT and how the controls are operating. Technologies that control plug loads and central IT and control settings are the most absent parts in the picture of ZNE. They are technologies that are a part of a ZNE building, but they are still evolving, really.
California has climate zones where air conditioning would seem to be essential. Is this the biggest challenge for designers? Are there strategies that are especially promising?
Air conditioning, and thermal comfort in general, is a big piece of the challenge to get to zero net energy. You have to start with a good shell, they do use passive technologies, they include natural ventilation, fresh outdoor air, daylighting. Almost all of the ZNE buildings I documented have air conditioning, have HVAC systems that are both cooling and heating and some of them are in the hotter, dryer climates. In those climates, and in more modest climates as well, the trends unique to ZNE buildings are that they are moving away from traditional rooftop units and VAV systems, which is what you will find in 80 percent of the buildings in California. They are moving away from those because they have high fan power, and that is going to hurt you in a ZNE building on your energy use.
We move away from that to separate ventilation air, through a dedicated outdoor air system, or “DOAS.” Then we move the thermal comfort into its own system, which is perhaps a radiant system with radiant floor or slabs, or radiant panels or chilled beams. Using water to provide your thermal comfort is a lot more efficient than using air to move heat and to cool. They get great energy efficiency and thermal comfort through these radiant systems. The source for these systems tends to be ground source heat pumps, high efficiency chillers or thermal energy storage. You have a highly efficient system creating the heating and cooling, but the distribution system has a huge energy savings if you do it with radiant and separate ventilation. Another trend is indirect evaporative cooling, which is also highly efficient.
That was a somewhat technical answer, but yes ZNE buildings have air conditioning and the way they get it super-low energy is through those types of systems that reduce forced air.
A number of studies in recent years have demonstrated that it’s possible to build green at essentially the same cost as “conventional” construction. Is this true for ZNE?
Yes, and it has been – but more research is needed. Last year a study from Integral Engineering stated that the cost to get to green or zero was not distinguishable in a total building’s budget. ARUP and Davis Energy Group did a study for PG&E in California with similar findings and a wide range of costs, but definitely showing there were buildings where they did track, and didn’t spend more. The builders had a fixed budget and got a ZNE within that same budget. The number one money saver is design firm experience.
If the costs are greater, how convincing is the case that the ROI justifies the investment?
I would say as a professional in this field that the project owners would have a greater or higher return on investment than from a standard building. Studies have found the ROI has been improved by things like higher occupancy rates and higher rental rates in green buildings. B CB Richard Ellis, for instance, did some studies on their portfolio showing higher rents, lower costs and greater value. There is a huge trend for information workers and the young professionals to want new, green and progressive designs and workspace. The market is really strong for these kinds of buildings, and they have a big visible profile due to the PV – when you go zero vs low energy you also have this external attractant to go on the building that is an asset.
Lastly, even using traditional asset value analysis based on income and operating costs, in a ZNE building they are going to value the building higher due to its lower operating costs.
The CPUC’s Long Term Energy Efficiency Strategic Plan aims to have residential construction meet ZNE standards by 2020 and commercial buildings by 2030. The CEC is working toward gradually tightening the Energy Code to meet these targets. What’s your sense of how developers and the design and construction communities will respond to this shift? Can it be fairly smooth, or might there need to be some “reality adjustments” along the way?
The code cycles have long been in place in California and the building industry and the construction community know this cycle so it’s not some new approach. It’s not going to have much impact to those firms that are already doing low and zero energy buildings.
Will it be smooth? The majority are not ZNE builders and for them to get there, probably not. It’s the nature in any shift, to have rocky times and I’m sure there will be builders and people in the construction industry that will have to struggle to be at this next shift. I just don’t think a major shift is inherently smooth in its very nature. It’s bumpy and that’s how we get change in our market and in our world. There are enough examples and data to support the transition. There are colleagues you can turn to, to share their experiences.
It’s not just out of the gate; we’ve got a lot of momentum in front of it. The state and local levels are doing some workforce training to get practitioners up to speed with designing and building to zero–your event for example, and workshops. There is a lot of support for a transition from having just a handful of practitioners to having everyone there in the next 15 years.
I wanted to mention what I have heard in talking with ZNE firms. In 15 years from now, when this is required, I predict that the design and construction industries are going to be saying that they never been more proud of the structures they are creating, or having more fun with the engagement and outcome of the work and with their clients. I say that because I hear that again and again from the people that are already in this area. After they did a couple of ZNE buildings, one firm said, “Why would we build anything else? This has been the most fun I’ve ever had in 25 years of building buildings.”
Even if it’s not smooth, people are going to have a sense of pleasure in their work, pride in their work and accomplishment that is going to be a whole different game than just building to code.
There seems to be some consensus that progress toward ZNE might be somewhat easier with school facilities than in other sectors. Why might that be true?
The health factor, care for the next generation and the emotional aspect at schools is really in our favor. Schools are 36 percent of our data set. A lot of the reason for that is the pull to make a good learning environment for the community, and individual concerns about the environment the students are in–and that is despite a pretty complicated financing and approval processes. There are also champions and really great advocates at the school level. That’s a fundamental piece of getting any item forward through process-intensive entities.
This is tied together with the building type for schools, a low rise and large roof area–a building type that is really well understood. Schools often have firms that are completely dedicated to doing educational facilities and they are often already into advanced practices. Back to your point earlier, that can help lower the cost when the proposal is put together for schools.
When parents come to events at the school, or a school board member, they may go back to their company and say “I saw this at my school and I want to do it in my building.” It is such a ubiquitous platform for ZNE to get into the market place.
NBI is organizing a ZNE workshop at the upcoming Green California Schools Summit. What will you be covering, and who should attend?
I would hope that folks attending your summit add this pre-event as part of their attendance. It’s really for anyone involved in schools and energy use. It would be for the design firms that work in school sector. We would love to have facility folks that are engaged in operating and managing school energy use, or people who are involved in school in policy and areas where the decision making might come through them. We could also have some students and teachers; that would be great as well because ZNE schools often use the building as a teaching tool and have related courses that are really interesting.
At the workshop we will be focusing on the strategies and processes used in existing schools that got to ZNE. The process is equally important. How did they advocate internally at the school, how did they get that decision approved? We’ll be talking about the process and strategies for ZNE buildings to get approved, designed and built. We will also be sharing and introducing education and case study resources that are available to help move schools in California out front.
What would you say to a facility professional or business officer who isn’t quite sure ZNE is a “today” sort of topic–that it might be a nice thing for the future, but not a priority today?
I’d say it’s more expensive to chase the train then to be on the train. It’s ride now or run later. I would share specific examples of leading business and property owners that are already adopting ZNE. I would provide some examples of other folks that are on this pathway and why.
I would have them look at the industry or urban planning news, commercial real-estate news and the regulatory requirements that are already adopted–not being considered, already adopted.
Those definitely make it a “today” topic. Waiting is just a costly alternative.