An iconic image of winter in Detroit is the columns of smoke spewing from sidewalks. Steaming streets are part of the landscape, but few know the answers that lie beneath this mystery in plain sight.
Below our sidewalks, there’s a vast infrastructure that includes electricity, water, sewer, and fiber optics. In a portion of the city, there’s also a network for what’s known as superheated “district steam.”
Most buildings and homes have their own furnace or boiler, but properties on the district steam system connect to a grid that delivers steam directly to their pipes. It’s not so different from the way that most buildings receive electricity from a utility grid rather than having their own internal generator.
District steam is common in dense urban areas with large buildings because a central plant can be more efficient than individual boilers. The current system serves more than 100 buildings in greater downtown, including the GM Renaissance Center, Cobo Hall, the Fox Theater, and Ford Field.
But this type of system is limited for a reason: Heat escapes rapidly as the steam pipes pass by cold external air, so it is not suited for long distances.
Detroit’s system is notable because it is so extensive — with over 50 miles of steam mains — and because it is so old. The system dates to 1903, when it was opened by Detroit Edison Electric Company. It’s also very leaky, as evidenced by all the steam seen rising from city sidewalks and streets.
The leaks are more than a systemic inefficiency. They also bring their own quirky hazards. The thick columns of steam can create blind spots that are dangerous to both drivers and pedestrians. And apparently, enough passers-by have burned themselves on scalding steam, that one local law firm has a dedicated website for personal injury suits from “Detroit manhole cover steam burns.”
Minor perils aside, the steam itself is not all that scary. It is just hot water — not swampy sewer gas or exhaust from the forgotten Detroit salt mines.
But upon solving that riddle, another one emerges: What powers the steam? And how can a system with these inefficiencies survive?
The short answer is waste. One source of fuel for the steam loop was the largest municipal incinerator in the world, which created electricity and steam from an abundant resource we like to call “garbage.”
The steam loop originally ran on coal until it was converted to natural gas in the 1970s.
When Detroit’s incinerator was built in 1986, garbage became the "fuel du jour". It killed two birds with one stone by saving money on landfill tipping fees and generating fuel.
The District system includes more than 50 miles of steam mains and serves more than 100 buildings in greater downtown Detroit.
The incinerator was based on the calculation that landfills would become more expensive over time, and that the ability to make trash disappear would generate revenue for the city. But as Detroit’s economy spiraled, the city lost residents.
The incinerator eventually became a financial and environmental burden for the City. According to some sources, city residents paid more than $1.2 billion in expenses for the incinerator, which was sold in 1991 to private investors. In 2010, it was purchased by an LLC, which runs the steam side of the business as an independent subsidy.
According to provided data, the incinerator facility was converting up to 3,300 tons of municipal solid waste per day. The combustion generated electricity and steam, which is delivered to the thermal supply system.
The incinerator ceased operation due to local environmental concerns and the steam system continues to operate the best it can.
Sources: www.hourdetroit.com; www.google.com