From the Design Quarterly: Are net zero energy and net zero carbon buildings a must-have?

July 12, 2019

The approaches, markets, and tools for sustainability are evolving—and net zero is an attainable goal

 

By Rachel Bannon-Godfrey and Samantha Lane

A new world of possibilities is opening for design. An expanding tool kit of approaches, materials, and systems is making it possible for designers to respond to a growing buildings market: net zero energy and net zero carbon. What was once a niche for government clients is now emerging as a must-have for many educational institutions, even private developers.

 

What’s driving the push to net zero carbon and net zero energy?

Urgency. Global organizations recognize that energy consumption by the built environment is significant and that it must be addressed to contain and reverse climate change. The urgency is reflected in agenda-setting documents such as the United Nations’ 2030 Agenda for Sustainable Development and the Paris Agreement. New targets by government, public sector institutions and private sector leaders outline goals for reduction of carbon footprint in the built environment.

Simultaneously, new government regulation and codes are pushing the building and development industries toward low carbon intensity. For example, California’s California Energy Efficiency Strategic Plan stipulates that all new commercial construction will be net zero energy (NZE) by 2030.

 

California Military Department Consolidated Headquarters Complex (CHQC) in Rancho Cordova, California, is a large-scale NZE project.

 

The United Kingdom’s Labour Party has a plan to transfer the UK from 9% to 60% renewables by 2030. Canada plans to reduce its greenhouse gas emissions by 30% below 2005 levels by 2030. Stantec has joined in the 2030 Commitment of the AIA, working toward carbon neutral buildings by 2030.

There’s no getting around the fact that government and civic architecture is leading the way when it comes to NZE and net zero carbon (NZC). In Canada, civic projects such as the Varennes Net Zero Library and Parcours Gouin Trail Net-Zero Energy Reception Pavilion have set the pace for buildings to come. While in the United States, NZE projects such as the Sacramento Municipal Utility District East Operations Center, Dearing Elementary School in Texas, and the Denver Water Complex Operations Center (opening in 2019) are setting the tone for responsible development.

_q_tweetable:We are in the midst of a global transition, one in which buildings play a key role._q_The good news is that motivators for clients to pursue net zero energy and net zero carbon are changing. Potential NZC/NZE clients are beginning to see the business case for making these investments, namely lower energy costs for operators, an improved energy resiliency, greater security in energy prices, as well as an attractive “green” story to help market their buildings and attract top talent. Commercial developers who may have missed the boat on the first round of sustainable development with LEED are looking for a new competitive edge. The promise of significantly lower (even zero) utility bills for potential office lessees or condo buyers is a powerful selling point for them in these typically competitive markets. Private developers can also offer prospective lessee spaces that will support their corporate social responsibility mandates.

The education market for NZC and NZE buildings is ripe. Schools want to walk the talk. Schools are teaching about renewable energy, even offering courses in designing for solar energy. Naturally, they want to say they have a building that supports that kind of learning, a living laboratory. In higher education, NZC/NZE buildings aid in achieving energy security and low operating costs.

Due to their large scale, institutional NZC/NZE buildings can require energy offsets to meet their targets. But don’t discount their value as marketing tools. In the war to attract top talent, the story of a low-carbon building can help an institution show that its values align with the student it hopes to attract.

 

Read and download the Design Quarterly Issue 06 | Destination Zero

 

Net zero carbon

In the Paris Agreement, net zero carbon emerged as a significant pathway to mitigating the impact of fossil fuel-based energy consumption. The market is becoming more educated and committed to a zero-carbon future. Mayors from over 20 cities around the world have committed to achieving NZC buildings, with end goals ranging from 2030 for new construction to 2050 for existing buildings. We are amid a global transition, one in which buildings play a key role.

When designed properly, an NZC building prioritizes energy efficiency to minimize loads first, then leverages carbon-free renewable energy (e.g., solar photovoltaics) to offset the remaining fossil-fuel use and hit that net-zero equation.

The cleaner the utility grid serving the building, the fewer renewables are needed to reach zero carbon. However, if the building is served by a grid with a high-carbon content, the relationship between energy efficiency, renewables, the grid, and the zero-carbon goal changes significantly. NZC requires the design, engineering, and analysis team to carefully consider the impact of the local and regional utility infrastructure on the building’s goals.

Commercial zero-carbon buildings are here. The 100,000-square-foot commercial property evolv1, which Stantec designed for the Cora Group in Waterloo, Ontario, is now operational. In 2018, evolv1 won the first-ever Zero Carbon - Design certification and Zero Carbon Award from the Canada Green Building Council. It’s currently being evaluated as a net-positive energy building—delivering more renewable energy to the grid than it consumes.

 

George Mason High School in Falls Church, Virginia. The design-build team of Gilbane, Stantec, and Quinn Evans Architects is targeting a NZE-ready school.

 

Expanding possibilities for reaching NZE and NZC

Beautiful envelopes

As building energy codes become more stringent, the market expands for products and systems that can make NZC and NZE projects a reality. We have more economic tools to design those buildings than ever before. Previously, North American net zero designers were really limited by the range of envelope products available, especially in heating-dominated colder climates, where envelope design is critical for efficiency, human comfort, and survival.

To achieve net zero, our design palette was limited to a monolithic box with few windows and super-insulated walls, or the so-called marshmallow approach. Things have changed significantly, and designers are exploring an array of products from vendors with attractive aesthetics and pricing. With the availability of triple and even quad glazing (which permits daylight harvesting while super insulating a building), designers can create more elegant and nuanced designs that respond to their context and function.

A net zero building doesn’t have to be a bland windowless box. Now, our designers have more freedom to create beauty, fill spaces with natural light, and connect the building to its surrounding community and nature, leveraging the power of biophilia within these buildings. Alongside these envelope-related products, we’re considering the embodied carbon of building materials, the health and wellness of interior materials, and the availability of lower-impact materials such as engineered timber.

 

A bigger toolbox

Building systems are also advancing rapidly. And many of the manufacturers of the latest superefficient and innovative renewable systems are keen to see them demonstrated in the marketplace, as they anticipate a booming market for these systems.

 

Denver Water Complex Operations Center in Denver, Colorado, is pursuing LEED-Platinum certification and NZE.

 

The price of photovoltaic systems has dropped in recent years, and solar panels will only become more affordable. Pushed by the demand for clean energy, battery systems for off-grid storage are making rapid advances—and will only become more important as clients look for energy security and resilience in their new buildings and retrofits. The variety of solutions to mitigating the carbon footprint of our buildings, old and new, is growing—from wind turbines to biogas-fueled heat and power generators to carbon sequestration. Ground source, heat-exchange systems, which can be used almost anywhere, are becoming more popular for heating and cooling.

As we dive deeper into a carbon-neutral future, our toolbox continues to accrue more inventive and surprising options like carbon sequestration using algae or chemical processes that turn emissions into valuable carbonate by-products like soap.

 

Digital modeling

Today’s digital design technology allows designers, architects, planners, and energy consultants to explore numerous, complex interactions between the building, its systems, the climate, budget, and operations over time. These tools enable us to understand and represent with more detail and predictability than we could previously. Digital modeling tools allow us to quantify and visualize complicated dependencies for achieving low-cost sustainable strategies. All these tools provide a platform for design teams to compare different solutions not only for energy, thermal comfort, or daylighting performance but also for cost, capital, operational, and life-cycle cost. Our goal is to reach the optimum solution for each client. These tools are crucial to the process of making net zero buildings a reality.

 

Rachel Bannon-Godfrey has more than 15 years of experience in the design, construction, and analysis of high-performance and net zero energy buildings, along with energy efficient and renewable energy technologies. She is Sustainability Discipline Leader for the Stantec Buildings Group and works from Denver, Colorado.

Building performance engineer Samantha Lane is based in Calgary, Alberta. An energy modeler, Certified Passive House Designer, and experienced sustainability consultant, she’s passionate about inspiring teams toward delivering energy-efficient and sustainable projects.

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