Carbon Offsetting—The Tip of the Iceberg When it Comes to Carbon Neutral Buildings
Carbon neutrality seems to be the new norm. Governments, companies, precincts, buildings—all come with a carbon neutral vision. Forget 2050, 2030—even today consumers can purchase carbon neutral homes, products, and services.
“Does that mean, what didn’t seem possible yesterday is possible today? Does that mean that we are constructing buildings that do not consume any energy or emit any emissions?”
“Not quite? Why not?”
Because carbon neutrality often stands for ‘net’ zero carbon emissions.
“What does that mean?”
It means that buildings can use just as much energy, but the building’s operational energy (energy used to keep the lights and heating on) is sourced from different methods, usually delivering lower emissions overall. Typically, these reduced or even net zero emissions are the result of renewable energy and carbon offset purchases. Carbon offsetting means that carbon credits equivalent to a building’s carbon emissions are purchased. These carbon credits typically reflect initiatives where carbon is being sequestered from the atmosphere, such as planting trees.
Now don’t get me wrong, carbon neutrality is a great initiative, but really, it’s only the tip of the iceberg. Much more important are the energy and associated emission savings associated with:
- Renewable energy
- Operational optimization
- Building performance
Together, these three components are critical when it comes to carbon neutral buildings, with carbon offsetting only making up a very small portion. Like the waste hierarchy which encourages us to reduce and reuse waste before undertaking energy intensive and inefficient recycling processes, these different energy and carbon emission saving initiatives also come with various pros, cons, and wider environmental and social considerations.
Unfortunately, renewable energy does not come without side effects. Its availability varies significantly across time of day, seasons, and location, which creates the need for storage and distribution across a wider network. Often, the sun isn’t shining and the wind isn’t blowing when we need energy the most. Storage solutions, be it batteries or hydro dams, come with significant environmental and social impacts. Dams can destroy otherwise intact ecosystems, and batteries rely on scarce resources typically extracted from a small group of developing countries with poor human rights and create a significant waste problem in the future. Renewable solutions also have their own embodied emissions through the materials required to create these systems.
Having said all the above, renewable energy is a great and necessary alternative to fossil fuels, especially when it can be produced locally and timely to avoid otherwise often significant storage and transport losses.
Operational optimization refers to the ongoing tuning and optimization of a building’s systems—be it the HVAC, sensors and controls, lighting, domestic hot water, or operable external shading. Everything that either actively or passively determines a building’s energy demand should be checked, synchronized, and optimized on a regular basis. Ideally, the question needs to be asked, “Does system X perform to its full potential? Does the actual energy demand align with the original aspiration? And if not, why is that?”
A positive co-benefit of a well-tuned and optimized building is high indoor environment quality. So why do we seldom ask users about their comfort needs and current perception? Perhaps the temperature is comfortable in the morning, but not in the afternoon when the sun has moved. Maybe air quality is at its best during business hours, but significantly drops after 6pm and negatively impacts those working later hours. Maybe light levels are comfortable during the day but are perceived too bright as soon it gets dark outside. Ultimately, regular tuning provides the opportunity to not only reduce energy demand and associated carbon emissions, but also improve occupancy comfort.
Building performance in existing or new buildings should always be the number one priority. Inherent building performance drives the energy with the lowest carbon emission of all—the energy that isn’t even used. Building performance and associated emissions—both embodied and operational—are largely driven by design and construction quality. To provide a carbon neutral future, more than ever before, the construction industry needs to place emphasis on the quality of the building fabric, including its thermal properties and airtightness. The built form, window-to-wall ratio, and shading strategy all need to respond to a building’s unique location and operational profile. Efficient building services are also very important; however, considering their relatively short lifespan of 20-30 years, priority remains to get the building fabric right.
Like operational optimization, improved building performance comes with many social and economic benefits, not only for the building owner and user, but also the wider community. We know that high performing building envelopes lead to increased occupant comfort, but what is often overlooked is that it also leads to greater construction integrity. A well-built façade significantly reduces the risk of interstitial condensation, associated mold growth, and structural corrosion, in-turn reducing risks to occupant health.
Ultimately, positive building performance leads to long term financial savings to a building owner and tenant, especially when coupled with the cost of carbon offsetting, and leads to wider reaching economic growth, fueled by the strong incentive to provide innovative systems and operate in a global market.
So yes, carbon neutrality in buildings is great, but only when their largest part—the one that is most often not seen or known about—is made up of a high performing envelope and systems, is operating as efficiently as possible, and is powered by renewable energy. Otherwise, we are simply relocating but not resolving our environmental footprint. And, we are missing out on the many benefits that high performance buildings typically come with:
- Comfortable indoor environments that seek to optimize occupant wellbeing
- Improved construction integrity
- Long term economic savings
- An innovative and leading building industry ready to operate and compete in a global market
If you’re interested in continuing the conversation about carbon neutrality for new or existing buildings and the iceberg analogy resonates with you, please don’t hesitate to get in touch. Equally, you may have a very different analogy when it comes to the performance of buildings; we are keen to hear about those as well!