Carbon-optimized building design

Construct buildings that use cleaner electricity.


Net zero energy is not net zero carbon. Historically, building designers have designed to use less electricity, but treated all kilowatt-hours of electricity as if they were equal. But especially as more variable renewable generation is integrated into grids around the world, kilowatt-hours at certain times are becoming far more pollution-intensive than the same energy consumed at other times. It is increasingly important to consider not only how much electricity a building consumes, but also when it consumes that electricity.   


WattTime helps designers of green buildings wring more GHG emissions savings out of their designs by providing them with a typical hourly carbon profile specific to the project location. This typical hourly carbon profile can be matched to the energy model that is usually created when a new building is designed. Based on the anticipated hourly energy consumption of all of the building’s systems, the emissions implications of different decisions can be accurately assessed. This allows designers to more accurately account for the GHG savings of various design alternatives, and empowers them to choose lower-carbon designs.   


The choices made during design echo for decades. New buildings today will eventually be part of a carbon neutral economy. Every decision to save more carbon helps carbon neutrality arrive that much sooner.


Mechanical Engineers
Energy Modelers
Sustainability Consultants

Case Study 1: Atelier Ten

Reducing GHG emissions is a priority for California College of the Arts and it was a driver for their campus unification and expansion. The new building prioritizes energy efficiency, electrification of both new and existing natural gas equipment, and on-site renewable energy and storage. To achieve low-carbon operations for the campus, especially with newly electrified loads, a thoughtful and intentional approach to electricity demand was needed.


Atelier Ten used granular emissions data to inform the team’s design process and to assess the carbon impacts of various system choices and design options. Atelier Ten also used the emissions data to look beyond efficiency to quantify the extent to which enhanced controls and storage could be leveraged to further reduce GHG emissions.

Are you interested in using typical carbon year profiles along with your energy models to assess building carbon performance? Let us know and we’ll help you get access.


How do you calculate typical profiles?

WattTime translates our database of historical marginal emissions rates, usually for the prior three years, into typical emissions profiles for each grid location. Our procedure expands on the methodology described in the appendix of this whitepaper.

How do I access the data?

A typical emissions profile for a given location can be requested as a CSV file by using WattTime’s API. Here are the instructions. Please contact us to get access to the data.

Can I hear Henry explain it?

Henry explains how you can integrate grid emissions factors into building design in this video.