Making the Transition From Zero Energy to Zero Carbon Building Policies

As the building industry transitions into a new era — one focused on delivering carbon-neutral buildings — building codes will continue to play a critical role. This is the third in a series of blog posts about the transformation occurring within the building industry away from programs and policies that deliver energy savings toward programs and policies that deliver carbon neutrality and overall carbon reductions.

The first blog (Efficiency and Carbon Reduction Goals Converge at the Built Environment) focuses on the forces driving the building industry to look beyond kilowatt-hour (kWh) savings to a carbon metric, and examines some of the big questions around how we define zero carbon buildings. The second blog (Decarbonizing Buildings: A Changing Lexicon) focuses on the emerging lexicon of low-energy buildings and why it’s important to get clarity around the terms as well as defining metrics associated with decarbonization. In this current post, we’ll share some of the tools available to jurisdictions that want to pursue carbon neutral building policies and programs as a way to achieve climate goals.

Five Foundations of Zero Carbon Building Policies

For new construction and major retrofits, achieving climate policy goals in the built environment relies on developing policies that are soundly built on five foundations, or fundamentals.

Foundation 1: Energy Efficiency

Energy efficiency still offers many of the least-cost actions to achieve carbon reductions in buildings. By ensuring that policies capture energy efficiency savings, each of the other three foundations becomes easier to meet. And many jurisdictions have decades of experience writing codes that lead to energy savings, including zero energy building codes. Seattle’s commercial and residential energy codes are some of the most advanced in the country. In 2015, Seattle aligned with the Washington State Energy Code, which under state law:

  • Residential and Nonresidential construction permitted under the 2031 state energy code must achieve a 70% reduction in annual net energy consumption (compared to the 2006 state energy code) (RCW 19.27A.160), and
  • Construct increasingly efficient homes and buildings that help achieve the broader goal of building zero fossil‐fuel greenhouse gas emission homes and buildings by the year 2031 (RCW 19.27A.020)

Foundation 2: Renewable Energy Resources

Promoting zero carbon and zero carbon-ready buildings requires the understanding that not all building types and locations will have access to enough onsite renewable energy to achieve an annual zero energy balance. Building owners are turning to purchase renewable energy from off-site locations as a way to meet their renewable energy requirement.

Code writers must be mindful of this and write code in a way that ensures appropriate and verifiable crediting of off-site renewable energy sources. Programs such as community solar, power purchase agreements, and offsite shared corporate facilities are all viable options. A leading example is the California Department of General Services (DGS), which manages a portfolio of 69 state-owned buildings totaling 18.5 million square feet across the state. DGS entered into two 20-year community solar agreements with the Sacramento Municipal Utility District (SMUD), the city’s community-owned nonprofit electric service, to generate 39 megawatts of renewable energy at an offsite solar farm. This agreement is the largest community solar project of its kind in the nation—creating enough energy to power about 8,200 homes per year (about 74 gigawatt hours), according to SMUD.

Foundation 3: Building-Grid Integration + Storage + Electric Vehicles

Codes that encourage buildings to generate enough energy to offset their entire annual energy consumption can create new challenges by putting extra burdens on the grid. How? When a building’s demand for electricity during a day, week or year differs from the time when energy is being supplied by onsite or grid-supplied renewable energy, the misalignment of electricity demand and renewable generation can contribute to distribution grid stress. This in turn can lead to higher systems costs, indirect GHG emissions, and reliability issues. Codes should encourage building designs that address the variable patterns of generation and consumption on the electricity grid (as in Title T24-2019 residential). Codes should enable or require one or more of the following: smart building controls that can communicate with the grid, electric vehicle (EV) charging systems or behind-the-meter battery and thermal energy storage.

Foundation 4: Building Electrification

Onsite combustion of fossil fuels contributes to local pollution, GHG emissions, and indoor air quality issues. Building electrification policies aim to eliminate most, if not all, onsite combustion of fossil fuels by replacing traditional natural gas applications in buildings with electric options.
As the electricity grid decarbonizes and the emissions impacts of electricity usage shrink, the emissions impacts of onsite combustion will remain, and the emissions benefits of building electrification will grow. In cases where remaining combustion is unavoidable, policies should:

  • Emphasize the use of qualifying renewable fuels with strict standards.
  • Require that onsite combustion appliances be electrification-ready: install all wiring, power supply, outlets, physical space, etc. needed to electrify the appliance in the future.
  • Ensure that onsite combustion for buildings is not permitted to exacerbate local air pollution and indoor air quality problems.

Foundation 5: Life-Cycle Impacts

Building materials and construction accounts for fully 11% of global energy-related carbon emissions (UNEP 2017). As buildings increasingly target high-efficiency levels and low/zero carbon operations, the embodied carbon in the materials used to construct buildings constitutes a growing share of life cycle carbon impact. Buildings can be required to be constructed with lower embodied carbon materials and with components intended to be reusable or recyclable at the end of their application in the building.

As we approach a Presidential election year, climate change is surfacing as a key issue. All Democrats in the race support recommitting to the Paris Climate Agreement. And most Democratic candidates view achieving net-zero carbon emissions as the pathway to meeting the goals of the Paris Climate Agreement.

Many local and state jurisdictions have already committed to meeting the goals of the Paris Climate Agreement. NBI is working with many of them to incorporate these five foundations into their zero carbon building policies. However, these forward-thinking policies typically address new construction only. In the fourth and final blog in this series about decarbonizing the built environment, we’ll focus on policies that address zero carbon existing buildings.

by Jim Edelson, NBI Director of Codes and Policy