Perspective  | 

Net Zero is bigger than any one building, but every building can help us get there

by Amanda D. Smith, Ph.D.
Building with rainbow in sky in the distance
Credit: Anastasiya Dalenka | Unsplash

It’s Net Zero Buildings Week! Time to celebrate the progress we’ve made in making buildings better for people and for the rest of life on this planet. And time to get real about where the net zero concept is useful and where it’s not.

At Project Drawdown, we count net zero practices among our proven solutions in the buildings sector. We advocate moving toward a future where buildings support human communities and the communities of life outside of them—and where everyone has a building they can call home. So it might seem like an odd time to tell you that pushing for every individual building to be net zero is not how we get there.

Net zero is a story about what we want for the world—and in particular the atmosphere that wraps around the Earth. We want an atmosphere to support both people and all of the flora, fauna, and funga that make up the web of life. To protect and preserve life on Earth, we have to quit dumping heat-trapping gases into the atmosphere so quickly that they hang around and cause havoc.

The global net zero concept is simple: We’re currently emitting greenhouse gases much faster than nature or humans are able to take them out of the atmosphere. We’ll reach net zero when natural and manmade systems remove greenhouse gases from the atmosphere as fast as we emit them. That means the current sources of emissions shrink down until they’re no bigger than the existing sinks. Project Drawdown illustrates this system with the rainbow graph below. (Happy Pride Month!)


On this graphic we see greenhouse gas emissions on the left, divided into six big sectors that contribute to the problem. On the right, we see that our lands—from forests to prairies—and oceans are “sinks,” removing carbon dioxide (the primary greenhouse gas produced by human activities). Unfortunately, these sinks remove less than half of what we emit, and may not be able to keep it up as our emissions pile up in the atmosphere.

On the left hand side of the rainbow, we see that buildings account for about 6 percent of greenhouse gas emissions. Global emissions get assigned to sectors based on where those gases enter the atmosphere. For buildings, that means we’re counting only direct emissions that happen when a greenhouse gas is released at a building site. Those emissions predominantly come from burning fossil fuels to heat things up inside, such as air, water, and food. Not burning fossil fuels inside or next to our buildings is the best place to start in reducing buildings’ contribution to climate change.

But buildings have a much larger role to play in our journey to global net zero. Decisions we make about buildings will increase or reduce emissions in every one of these sectors.

So buildings are a critical piece of the puzzle if we’re going to reach global net zero. Should we advocate for making every building “do its part” by becoming net zero on its own?

While definitions vary, a net zero energy building will be energy-efficient and will produce renewable energy, preferably on site. The renewable energy produced, added up over a year, must be at least as much as the energy that the building uses over the same year. Zero energy buildings point our efforts toward energy efficiency and on-site use of renewable energy—a much-needed but limited set of the solutions available in the buildings and electricity sectors.

Similarly, a net zero carbon or net zero emissions building will balance the emissions it adds to the atmosphere with the emissions it removes from the atmosphere. That reflects our global net zero goal. Zero carbon buildings point our efforts toward material efficiency in design and non-polluting operations—critical advances that push us in the right direction.

So what’s the problem? There are several potential pitfalls. First, a net zero standard can create the temptation to “balance out” emissions with offsets. An emissions offset is supposed to incentivize someone else to cut emissions, but all too often this becomes a carbon shell game. We’re kidding ourselves if we believe that there’s always someone else to make the deep emissions cuts we need on a global scale.

Instead of making every individual building net zero, we should be focused on how we can use the buildings sector to achieve the deep cuts in greenhouse gas emissions we know are necessary.

Second, a net zero standard that balances out energy or emissions over the year can mask variations that matter to the larger system made up of buildings plus the electrical grid. For example, a building with its own solar panels can still have days where it needs a lot of power from the grid. Grid operators have to balance the power demands from lots of buildings with the power supply coming from lots of generators, and they have to maintain this balance  instantaneously. Energy-efficient net zero buildings will have smaller power demands, which make the grid operator’s job easier. But focusing on the annual net zero metric means we don’t see all the variations that matter.

Third, a focus on individual buildings can mask opportunities for leveraging economies of scale. The best scale for reducing energy demands might not be the same as the best scale for meeting energy needs with renewables. For example, buildings within a neighborhood or campus might cut their emissions together with a group program deploying energy efficiency retrofits and then pool their savings to purchase clean energy provided by a local utility.

And finally, applying the same net zero metric to every building glosses over buildings’ individuality. Just like us, each building brings something unique to the world and each requires something different to fulfill its role. Hospitals need to consume a lot of energy to function even when they’re as efficient as possible, and that’s OK whether they have access to renewable energy or not. Instead of making every individual building net zero, we should be focused on how we can use the buildings sector to achieve the deep cuts in greenhouse gas emissions we know are necessary.

Every decision we make about a building’s design, operation, and demolition drives us closer to an equitable future with a habitable planet—or further from it. Net zero practices are specialized tools in our climate solutions toolbox. We will also need other tools to complete big jobs like eliminating fossil fuel combustion altogether in buildings, electricity generation, and industry.

So what is the value of making your individual building meet a net zero standard? If the process of achieving that standard pushes you to take actions that cut emissions—wherever they occur—then go for it! But make sure you’re not duped into using more energy and resources than you need just because you can afford “enough” solar panels to make up for it or because you think you can buy your way out of taking responsibility for your project’s emissions. Don’t shy away from the bigger, thornier questions:  Does making my individual building net zero energy necessarily help with net zero emissions? If my annual energy use is net zero, are my energy use patterns during the year making it easier or harder for everyone else to go net zero?

As you work with any net zero standard, keep the big picture in mind. Your choices affect the emissions tied to an individual building, and they also have the potential to influence the collective. Let’s consider how to give each building what it needs to function well while remembering what matters. Net zero buildings are great, but we need a net zero planet.