If we are going to keep the global temperature rise below 1.5°C, we need to fix our buildings. They are the largest end-users of energy, generating nearly 40 percent of annual global greenhouse gas emissions. However, addressing energy efficiency and renewable energy one building at a time will not be enough. To make real change, we must also work at a district level.
In 2016, Rocky Mountain Institute (RMI) worked with the National Renewable Energy Laboratory (NREL) and US Department of Energy (DOE) to launch the Zero Energy District Accelerator. The goal of the Accelerator was to share best practices and provide technical support to groups wanting to implement high-performance building strategies on a district scale. The three-year-long process led to many emerging high-performance districts, as well as the recently released report, A Guide to Energy Master Planning of High-Performance Districts and Communities.
District Heating and Cooling
Heating and cooling buildings on a district level provides great benefits including higher efficiency, lower costs, and more reliable and resilient energy. Instead of each building having its own heating and cooling sources, a district energy system exchanges heat between a central plant and a group of buildings.
A key advantage of a district thermal approach is that the diversity of thermal loads across buildings (e.g., time of day, days of week, months of year) can lead to additional savings by creating opportunities for waste heat recovery and energy sharing. One way to do this is to include diverse building types. For example, residential and commercial buildings are often used at different times of the day, and thus can have complementary heating and cooling load profiles. They may even benefit from waste heat produced in other building types with higher energy densities (e.g., high-rise office buildings or manufacturing plants).