Many people don’t consider boilers to be a “green” technology. However, the truth is, steam is the ideal medium for moving heat around, and nothing else comes close. The bottom line is, steam is far greener than most people realize.
An institution
The first thing to think about in regard to boilers and green technology is just how widespread its use is. Right now, boilers are a key part of the infrastructure to many of the world’s most important industries, which include about 80% of all products we use. A substantial number of manufacturing facilities rely on steam to create the machinery that keeps assembly lines running. Hospitals rely on steam for heat and, more importantly, for the sterilization of surgical instruments. Schools and universities rely on steam to keep classrooms warm.
That can’t all be replaced overnight. Furthermore, replacing a steam system would require a lot of heavy lifting and some demolition and rebuilding. That would all take additional energy to accomplish. Then, there’s the matter of what you’re replacing the system that produces steam with. A lot of so-called “green” technologies, especially electricity, has a much higher back-end cost than people realize.
Electricity doesn’t just flow out of the wall by magic. It has to be generated. Right now, that means using fossil fuels, like coal and natural gas. When it comes to wind and solar, there’s the matter of storing the electricity. As demand for batteries increases so does the demand for the toxic materials used to make them. In addition to being hazardous to mine, they also generate a lot of hazardous waste while processing
So, for the time being, boilers are the most viable alternative for steam.
As heat technology advances, though, additional fuel sources, like solar energy, bio-gas, hydrogen, and even ammonia, may become an even more viable way to fire a boiler to provide steam. The bottom line: Steam is not going away.
Physics
Another reason boilers are green has to do with heat transfer. Right now, there is no more efficient way to transfer low-pressure heat through a wide distribution network than steam. Hot air and water have temperature limitations. Steam, however, can be delivered at temperatures exceeding 1,250°F.
Whether you’re heating a classroom, manufacturing materials, processing textiles, or sterilizing the equipment in 10 operating rooms throughout a hospital, there’s no better way to move heat from the point of generation to the point of use than steam.
Reclamation
Boiler technology has come a long way in the past 70 years, and a lot of its major advancements have been in the area of efficiency. For example, optimized burners can get more out of every fuel dollar through more complete combustion.
Furthermore, economizers let a boiler system reclaim a tremendous amount of usable heat from the stack that can be used to preheat feedwater or process water to reduce the load on the furnace.
Public perception
There’s another reason steam isn’t seen as a green technology by some people, and that has to do with the steam they see. When you drive by a manufacturing plant and see it belching white vapor into the air, what you’re actually seeing is clean steam venting into the atmosphere.
Steam that is being used to scrub harmful waste materials out of exhaust gasses and actually make air cleaner.
So, the notion that steam-powered facilities are pouring particulates into the air, like so many old-time locomotives, just isn’t true.
With the advancements of burners being able to burn at 9-ppm NOx or using a selective catalytic reduction (SCR) system, the steam we produce today is actually produced with cleaner stack emissions than ever and will be around for many, many years.
