The Center for Sustainable Infrastructure Blog

by Donna Albert – Energy Engineer
Washington State Department of Enterprise Services

It can be notoriously difficult to predict the future. Fifty years ago we imagined flying cars, but no one envisioned we would be sending cat videos to each other on tiny cell phones that would be as powerful as computers!  We are likely to do just as badly predicting what the world will be like fifty years from today. Yet we are designing buildings now that will be used for even longer than that. So get out your crystal ball and imagine how green buildings will function in the year 2066!

The Climate Imperative

Our energy sources have remained mostly the same over the past 50 years, but that may be changing rapidly.  We’ll need to design for the changes we know to expect, for instance those resulting from climate change.  We can incorporate changing weather patterns into our designs, and plan for infrastructure that will better serve us under these new conditions We can also anticipate that the energy source that buildings will be using 50 years in the future is likely to be fossil-fuel-free electricity. My predictions in this article assume we will heed the warnings of scientists, and make a rapid transition to very low CO2 emissions energy sources. I’ll focus on principles for new building design which are aligned with our future fossil-fuel-free energy infrastructure.

Before thinking about design, we need to make assumptions about what energy sources will be available during the lifespan of our new buildings.  Most new commercial building designs today assume that the same energy sources that are common now will still be in use 30 to 50 years from now.  Is that a good assumption?

Source: thesolutionproject.org

At COP21, the countries of the world agreed in principle to avoid exceeding 1.5 degrees Celsius of global warming.  Some argue this goal is still within reach if the world stops burning fossil fuels by 2050 (although some disagree). In this article, I’ll use 2050 as the deadline to complete the transition off of fossil fuels, and I’ll assume that developed countries will complete the transition away from fossil fuels about 10 years before developing countries.  In that case, the United States will be fossil fuel free by 2040.  Some states, like Washington, may be ahead of others in the transition, since we have a healthy economy, green industries, and hydropower.  In that scenario, Washington will be fossil fuel free by 2035 – less than 20 years from now.

There are credible plans for nearly fossil fuel free energy infrastructure, one of which is by Mark Jacobson of Stanford University.  Key features of these energy infrastructure transition plans are (1) electricity generated using energy sources that do not emit CO2, (2) an electrified transportation system, and (3) energy efficiency improvements to building stock and transportation systems that reduce the amount of electricity generated.  We could argue about whether nuclear qualifies as zero greenhouse gas emissions, and whether the public would allow it.  We could argue about whether carbon capture and storage is actually feasible.  But neither of those details would affect our new building design.  The bottom line is that if one of these plans for fossil-fuel-free energy infrastructure is implemented, the electricity serving our building will generate near zero greenhouse gas emissions.

Phasing Out Natural Gas

Although the future is hard to predict (remember the flying cars and tiny cell phones!), it seems highly unlikely that a miracle technology will be invented in the next 20 years that will pull CO2 out of the air faster and cheaper than trees do.  Since engineers do not plan on miracles, we will expect to stop burning natural gas in buildings for heat within the lifespan of our new building’s HVAC system. It’s also unlikely that natural gas fueled combined heat and power (CHP) plants will be in use in 2035.  The bottom line is that our new building will not be burning natural gas 15 to 20 years from now, so it is not logical to specify new natural gas systems in a building today.

Could the architect designing a new building specify a natural gas system for heat or CHP, and plan to abandon it in 2035?  Maybe the annual greenhouse gas emissions of a building design using natural gas for heat or CHP is comparable to the greenhouse gas emissions of an energy efficient all-electric design at the time the building is occupied. However, if the greenhouse gas emissions of our electricity infrastructure is reduced each year until it reaches zero greenhouse gas emissions in 2035, the all-electric design may emit about half as much greenhouse gas emissions as the natural gas design, between the year it is built and 2035.  If the true social cost of greenhouse gas emissions over the life of the systems is considered, the all-electric design should be more economical.

Zero Net Energy

How much energy should the ideal new building use? Remember the third key feature of a credible fossil fuel free energy infrastructure plan is energy efficient building stock and transportation systems.  Renewable electricity is more affordable if we don’t need as much of it.  The ideal building of the future is a Zero Net Energy (ZNE) building, which makes as much energy as it uses each year.  If the budget is tight, we can consider a Zero Net Energy Capable (ZNE-C) building, which is designed to accommodate sufficient solar photovoltaic panels on the roof to power the building, but the solar panels are installed later.

Above all, our new building should have a very tight, well-insulated and durable building envelope, and a dedicated outside air ventilation system with heat recovery.  The window to wall ratio should be as small as practical while providing daylighting and views. Window placement should control heat gain.  Space for solar panels on the roof should be maximized.  These features are inexpensive in a new building, but very expensive to retrofit.

The Bullitt Center in Seattle is an example of a Zero Net Energy building. Image sourced from Joe Wolf, Flickr (CC BY-ND 2.0)

Government agencies, colleges, and school districts with greenhouse gas emissions or energy reduction goals should use ZNE or ZNE-C designs for new construction, since a new building that uses energy takes them further from their emissions reduction goals.  Every renovation is an opportunity to reduce energy use.  Government agency, college, and school district major renovations should pursue ZNE or ZNE-C goals.  Set the energy use goal for a new building or major renovation before the architect is selected.

The construction cost premium for a ZNE-C building is about 10%, if the ZNE-C goal is set prior to project scope, if the design team is experienced in ZNE-C construction, and if the owner is willing to let go of building features that are not compatible with the ZNE-C goal.  The extra cost, if any, will be recovered in reduced operational costs.  The key to funding a ZNE-C building is to overcome the artificial barriers that separate the initial capital construction cost and operational costs.  The ZNE-C building is a better financial decision.

Is a new building even needed?  Functions such as offices and classrooms may require a fraction of the physical space they once needed, because some classes and work are done on the internet.  Are there opportunities to share existing building space which is not always fully occupied?  Is it possible to renovate an existing building instead of creating a new one?  If we do add building space, we must make sure it does not add to future energy use.

Conclusion

In summary, we cannot hope to avoid climate catastrophe unless we stop burning fossil fuels.  The plans for transitioning off of fossil fuels which appear to be viable include fossil fuel free electricity, an electrified transportation system, and energy efficient buildings and transportation systems.  The buildings served by this fossil fuel free electricity should be very energy efficient, and will not burn fossil fuel on site.  We are building those buildings today, whether we are aware of it or not.

Architects and engineers designing new buildings may not be able to guarantee that we will have zero greenhouse gas emissions electricity by 2035, but we can design buildings that are ready for it, and we can advocate for fossil fuel free electricity. Doing anything less is accepting that our children have no future.

Donna Albert is a licensed Civil Engineer with a Master’s Degree in Civil Engineering from Saint Martin’s University, a LEED Accredited Professional, and a Certified Energy Manager.  She has 22 years of experience managing the design and construction of new buildings, renovations and building energy retrofits for the State of Washington.  She currently works as an Energy Engineer for the Washington State Department of Enterprise Services.