District Energy Systems: The Invisible Giant of Urban Efficiency
District energy systems employ a centralized facility to supply heating, cooling, and sometimes electricity for multiple buildings in an area through a largely underground, mostly unseen network of pipes. When district energy systems are utilized, individual buildings do not need their own boilers, chillers, and cooling towers. This offers a number of benefits to building owners and tenants. Among them are:
Energy Efficiency. Centralized heating/cooling is more efficient than individual building systems, reducing energy use by 30% to 50% in some cases.
Cost Savings. Lower operations and maintenance costs through economies of scale and reduced equipment needs per building.
Reduced Environmental Impacts. Emissions are lessened and renewable energy resources can often be more easily integrated.
Reliability. A more resilient energy supply is often provided, with redundant systems and professional operation.
Space Optimization. Buildings need less mechanical equipment, freeing up valuable space.
The concept is far from new. In fact, Birdsill Holly is credited with deploying the US's first district energy system in Lockport, New York, in 1877, and many other cities incorporated district systems into their infrastructure soon thereafter. While district energy systems are particularly effective in dense urban areas, they're also widely used at hospitals and at other large campuses around the world. “There's over 600 operating district energy systems in the US, and that's in cities, also on college and university campuses, healthcare, military bases, airports, pharma, even our sort of newer industries like Meta, Apple, Google, their campuses are utilizing district energy, because, frankly, there's economies of scale,” Rob Thornton, president and CEO of the International District Energy Association (IDEA), said as a guest on The POWER Podcast . “District energy is actually quite ubiquitous,” said Thornton, noting that systems are common in Canada, throughout Europe, in the Middle East, and many other parts of the world. “But, you know, not that well-known. We're not visible. Basically, the assets are largely underground, and so we don't necessarily have the visibility opportunity of like wind turbines or solar panels,” he said. “So, we quietly do our work. But, I would guess that for the listeners of this podcast, if they went to a college or university in North America, I bet, eight out of 10 lived in a dorm that was supplied by a district heating system. So, it’s really a lot more common than people realize,” said Thornton. The IDEA's mission is to work actively to foster the success of its members “as leaders in providing reliable, economical, efficient, and environmentally sound district heating, district cooling, and combined heat and power.” The organization was founded in 1909 as the National District Heating Association. Today, the IDEA has a membership of about 3,000 industry professionals in 28 countries around the globe. It hosts two conferences: CampusEnergy , which will be held Feb. 3–6, 2025, in Boston, Massachusetts, and the IDEA Annual Conference , which will be held June 2–5, 2025, in Minneapolis, Minnesota. It's not uncommon for unique, locally available resources to be incorporated into district energy systems, which often adds to a system's efficiency, and can provide economic and environmental benefits as well. Thornton offered a number of examples to show how innovative designers can be. For example, Thornton explained that Cornell University in Ithaca, New York, invested a significant amount of money in a deep lake water cooling system back in 2000. “Instead of buying electricity from the grid to run electric chillers, they began to take cold water out of Lake Cayuga,” Thornton said. The cold water from the bottom of the lake was run about a mile to a heat exchanger building, then two miles uphill to the campus. The school “basically traded an electricity bill for a bond payment,” said Thornton. “Cornell, I think within the last two years, did a forensic analysis of that investment, and they found that not only had the plant performed economically more efficiently than designed, but environmentally better than designed,” Thornton reported. “And, the bonds were retired in less than 15 years.” Another example revolved around data centers, a hot topic for many energy observers these days. Servers in data centers are known to produce a lot of heat. Now, rather than the heat being considered a liability, district energy systems are utilizing the resource as an asset. “There's a proliferation of data centers in Dublin, Ireland, and one of the large hyperscalers was actually told they were not going to get a permit for their data center unless and until they were using the heat for district energy,” Thornton said. “So, it's interesting that we're seeing now recognition that this heat has value and that by itself it's a cost center, but when the heat can be utilized with either a heat pump to polish and improve the heat or use it for heat and cooling, district energy really becomes sort of the aggregating, integrating technology that can reduce downstream emissions, generate efficiencies, and provide economic benefit both to the grid and to the local community.” To hear the full interview with Thornton, which contains much more about the benefits of district energy and many other examples of innovative uses, listen to The POWER Podcast . Click on the SoundCloud player below to listen in your browser now or use the following links to reach the show page on your favorite podcast platform:
The POWER Podcast · 179. District Energy Systems: The Invisible Giant of Urban Efficiency
For more power podcasts, visit The POWER Podcast archives . — Aaron Larson is POWER's executive editor (@AaronL_Power, @POWERmagazine).