Arup Thoughts: Resilience through district thermal energy
District thermal energy can improve resilience – it’s a robust and efficient, yet locally sourced and delivered, form of thermal energy.
There's plenty of discussion about resilience in the context of power and microgrids but you don't hear much about how district thermal energy can improve resilience. Well, I believe it can - because it's a robust and efficient, yet locally sourced and delivered, source of thermal energy.
Why can't district thermal energy do for thermal energy what microgrids have done for electrical energy? Traditional power infrastructure placed generation so far from end-users that non-local earthquakes, hurricanes, terrorist attacks and similar threats could, and have, disrupted local power supply. Microgrids overcome the problems of this 'too-large' model by bringing generation and storage closer to end-users. This makes the system more efficient and robust.
It's common sense to mirror this approach for thermal energy. Yet I hear plenty of people arguing against district thermal energy. Two arguments in particular confuse me. The first is that 'it is like putting all your eggs in one basket'. The second is that it is an operational risk as buildings give up control of their own heating and cooling systems.
The first argument is only true if the district is so large that non-local threats can affect buildings. And the second argument - in my mind - is simply a matter of perspective.
Most of our non-mission-critical clients would agree that if a local event were to damage and disrupt building operations, their employees would not keep working, as they'd have bigger concerns than air-conditioning. So to forego district thermal energy systems and all the efficiency, maintenance and operations, acoustic, aesthetic, and real estate benefits they unlock on the back of the 'eggs-in-one-basket argument' is ill-informed.
Then there's the argument about giving up control. While building owners have traditionally been more than happy to outsource their power needs and pay at the meter, the norm for thermal systems has been to generate heating and cooling on-site. So they see connecting to a district thermal system as giving up control. But I think they should see it as an outsourcing decision which means they need fewer operating and maintenance staff, fewer permits and approvals, and less space for plant in their building and on their rooftop.
District thermal energy can deliver thermal energy more efficiently and with far fewer resources than is achievable at the individual-building scale. Yet it can achieve the same level of uptime that has come to be expected from electrical utilities.
Systems can be designed to achieve the same level of redundancy that each individual building requires, but with less overall kit. The economies of scale achieved unlock the ability to switch to renewable fuels, which is a lot harder for individual buildings.
So if you hear someone arguing that district thermal energy means giving up control, my recommendation is to respond by saying that it is actually a lower risk option. It allows individual building owners to focus on their core business without being distracted by generating chilled and hot water, much like they already do with power.
- Afaan Naqvi is a mechanical and energy engineer. This article originally appeared on Arup Thoughts. Arup is a CFE Media content partner.