Laurence Payne wrote:

Battersea Power Station used to pipe hot water under the Thames to
provide heating to Dolphin Square and Pimlico.

When the station closed thiis was replaced by a coal-fired boiler house
between the power station and the railway. This was later converted to
'dual', I assume gas and oil, firing according to its sign. Quite
recently this was demolished, does anyone know what has now replaced
it?

But I don't know of
any large-scale steam system. New York has one.

Many New York drains seem to be steaming, whatever the weather. They
also have strange orange and white 'barber's pole' striped chimneys,
for want of a better word, maybe two metres high, which can be seen
sticking up in the middle of the road. They look quite temporary.
I've also seen large, cylinders of liqiid gas, Nitrogen I think, on
street corners, chained to a pole of some sort, with the gas being
piped underground. I think this was being done by Verizon
(telephones), so pipe freezing doesn't seem likely. Any ideas?