Heating Cities Is the Hard Problem

A crematorium in Redditch, England, has heated the town swimming pool since 2013. Aberdeen will pipe crematorium heat to a new school, and a Finnish town will connect its new crematorium to the district heat network that warms more than 6,500 homes, Wired reported.

Macabre, but also admirable in its way.

Strip out the grim part and the story is about district heating: one central source, a network of insulated pipes, heat delivered to buildings as hot water or steam. Northern Europe runs on it.

The problem is what feeds the network. Many systems still burn fossil fuels, and fuel prices and supplies swing with every war and cold snap. Finland is hunting for every spare unit of heat it can find, in part because Russia cut off its gas in 2022. That is how you end up warming a school with a crematorium.

America has one network at European scale. Con Edison's Manhattan steam system has run since 1882 and serves more than 1,500 customers through about 105 miles of pipe, and natural gas fuels nearly all of it. Stockholm's network is more than ten times as long.

It is not a coastal curiosity either. In Indianapolis, more than 250 commercial buildings, Lucas Oil Stadium among them, depend on steam, about half of it from a plant that burns the city's trash. Nashville's downtown system warms the Tennessee State Capitol and the Music City Center. Every one of them faces the same question Finland does.

The real answer is cleaner and bigger than waste heat. Electrify district heating. Run large heat pumps and thermal storage off wind, solar, and hydro, store the heat when power is cheap, and deliver it in the coldest hours when power is not. I worked on this earlier in my career, and good friends are still at it.

Heating cities through a northern winter without fossil fuels is one of the hardest problems in the energy transition and one of the least discussed. Crematorium heat is a footnote. The chapter still needs writing.