The city of Boston now has a powerful new tool for planning its energy future, thanks to the development of a citywide building energy model of unprecedented scale and spatio-temporal detail. Researchers at the MIT Sustainable Design Lab (SDL) and the MIT Lincoln Laboratory, in collaboration with the Boston Redevelopment Authority (BRA), have generated a model that estimates the gas and electricity demand of every building in Boston—nearly 100,000 total—for every hour of every day of the year.

“Nobody has ever modeled a city the size of Boston at this level of detail,” says Christoph Reinhart, associate professor of architecture. “It’s also the first time that these data are being used by a city to guide energy policy decisions.”

The model simulated energy use in a 200-by-200-meter grid for the city of Boston. Image credit: MIT Sustainable Design Lab.The model was announced by the city of Boston and the BRA as an integral part of the Boston Community Energy Study, commissioned by the city to help stakeholders better understand the potential for community energy solutions and to identify specific project opportunities that could lower costs and reduce greenhouse gas emissions.

“Community energy solutions such as targeted energy efficiency, district energy, microgrids, local energy generation and energy storage represent an opportunity to fundamentally change the way our energy system works,” says Austin Blackmon, chief of energy, environment, and open space for Boston. “But to get there we need a better understanding of the existing system and a way to identify the most promising solutions.”

Cities—as well as energy companies, businesses and community groups—can reduce energy use at the building level through efficiency measures such as retrofits or installing rooftop photovoltaics. But in order to identify more holistic solutions, such as combined heat and power (CHP) systems that service multiple buildings, building demand predictions have to be linked to energy supply models.

For the Boston model, SDL partnered with Eric Morgan, of the Energy Systems Group at MIT, to identify dozens of suitable sites across Boston where a combination of CHP, photovoltaics, battery storage and ground source heat pumps could reduce greenhouse gas emissions and offer lower-cost alternatives to current centralized energy supply scenarios.

The city made available its comprehensive geographic information systems dataset, which includes information on building geometry, the various uses of parcels and property tax assessment records. The team spent many hours sorting all 92,000 city buildings into 48 “archetypes” and 12 different use categories (e.g., residential or office), assigning various characteristics to each archetype to account for heating and cooling systems, electricity use, thermostat settings, wall and roof structure, etc.

Since the data were not gathered with energy planning in mind, the researchers had to do some computational legwork to make them usable for their model. Thanks to that work, the resulting tool can simply be adapted, rather than reinvented, by others interested in performing similar analyses across the Northeast.

Reinhart says the new model is designed to help policymakers and planners focus on problem areas—for instance, buildings responsible for driving peak electricity demand on a hot summer afternoon—and conversely on where the best opportunities for energy savings might be found. Another immediate outcome of the work is concrete guidance for city officials on how to document buildings and collect detailed data, relevant to energy planning, going forward.

Reinhart sees a bright future for such urban building energy models, both as an avenue of continued academic research and a resource for those trying to meet climate targets well beyond Boston. The SDL has now developed templates for Boston and Kuwait and is working on new models of Lisbon, Portugal, and Riyadh, Saudi Arabia.

“Ultimately, our goal is for every city in the world to rely on a citywide energy model to meaningfully manage its future energy supply and carbon emissions,” he says.