In the fight against climate change, buildings have some weight to pull. They’re responsible for an estimated 74% of electricity consumption in the U.S. and about a third of the country’s greenhouse gas emissions. Bringing those figures down—whether by reducing electricity usage or improving energy efficiency—would have a measurable impact.

A year-old company called nZero has a way for buildings, and many other energy users, to do both of those things. The solution, according to the company, is all about managing the time of day energy gets used.

Carbon emissions from the electricity use in a building tie back to the production of that electricity, explains nZero CEO Adam Kramer, and electricity produced at different times of the day produces different amounts of carbon dioxide. Depending on the energy mix—coal, natural gas, a combination of solar and wind—electricity production can have wildly different carbon intensities. Times of day when coal is the main source have high intensities compared to times when renewable-fueled batteries are the power source for a utility’s customers, for example.

Using data from across the energy grid, nZero helps companies accurately track their carbon emissions by monitoring the carbon intensity of the electricity they use on an hourly basis. “Whether you flip on the light at 7 a.m. or 7 p.m., the carbon intensity is dramatically different,” Kramer says. But most carbon emissions tracking available today relies on daily averages of carbon intensity. “The average is very much a blunt tool.”

The company’s clients have been found to be over-and under-reporting their emissions by between 5% and 40%. “That accuracy matters,” Kramer says. More accurately tracking emissions 24/7, Kramer says, can enable building owners or companies to adjust when and how they use electricity in order to achieve the largest reductions in carbon emissions.

The company began operations in April 2021, and is already tracking about 35 million square feet of real estate in 3,500 buildings across North America. Kramer says it took three years to develop the algorithm that allows nZero to so closely track the carbon intensity of energy production and use across the U.S., from federal data to regional load-balancing information to local utility production and customer usage stats. In total, the company parses around 200 million data points.

The analysis nZero provides is increasingly demanded by the owners and users of buildings, Kramer says, even in the U.S., where carbon emissions reporting at the building level is still mostly voluntary. Building tenants want to be able to tout their environmental standards and building owners want to have emissions data to show potential tenants. Some buildings are even required by their financiers to do so. “A lot of these buildings are owned by funds, whether they’re public pension funds or private equity funds, that are now requiring them to report this emission data,” Kramer says. “They have constituents on both sides that are requiring this.”

Companies across the U.S. are using nZero’s data to better understand when and where their emissions are coming from, and adjusting their practices and building infrastructure in response.

Though he can’t name the company, Kramer points to a large hospitality client whose buildings total 13 million square feet. At its headquarters in the desert southwest, the company was using daily averages to estimate its carbon emissions. The daytime carbon intensity—particularly high in the desert—was used to estimate the entire 24-hour day of emissions, despite emissions dropping sharply at night. They ended up overestimating the headquarters’ carbon emissions by 35%.

Another client in the aviation industry used nZero’s data to learn that, aside from jet fuel, their largest source of emissions came from heating their jet hangars with natural gas. That knowledge was used to drive investments in heat pumps and geothermal wells that will produce far less carbon emissions.

The city of Reno, Nevada, also used nZero’s granular data to trim emissions. The hourly tracking showed that a significant amount of emissions were being caused by the overnight charging of the city’s electric vehicle fleet. By switching to daytime charging, when the local utility is able to produce more of its electricity from renewable sources, the city was able to cut down their car-charging emissions by 30%.

Kramer says it’s all just a matter of knowing more granular details about how electricity is being used. “It opens up a whole host of solutions greater than, ‘We just need more green energy,’ or ‘We just need to change our lightbulbs,’” he says. “It is allowing you to be precise on the actions you can take and should take to reduce your environmental impact based on where, when, and how you’re producing emissions.”

Carbon emissions reporting is still relatively rare in the U.S. the Environmental Protection Agency only requires it from large emitters—those producing 25,000 metric tons or more per year. California has its own law, with a threshold of 10,000 metric tons per year. These amounts tend to only apply to large industrial sites, like cement plants, oil and gas production, and transportation fuel suppliers. New York City recently passed its own emissions reporting law, which is based on the size of a building, starting at 25,000 square feet, about the size of a grocery store.

Kramer is hoping to convince lawmakers to make this more common. His company is actively engaged with both lawmakers and regulators on rethinking what responsibilities building owners and operators need to have in reducing their environmental impact.

The first step is gathering the data to better understand the problem. Daily averages of carbon intensity are no longer good enough, Kramer says. “When the problem is something that’s being measured in inches and you have a ruler that only measures in feet, you’re going to be dramatically off in understanding where your impact is coming from and therefore being able to address it.”