Just for thought, but why?
 

Capturing and Distributing Waste Heat From Power Generation | GreenBuildingAdvisor.com

I have long wondered why powerplants don't distribute hot water to surrounding houses and businesses.

And yes I am aware of the 1% in New York and Philly but lets ignore that for a moment.

In Weston WI, there are 4 coal fired plants, the general rule of thumb is if it can provide electricity for a house, that same energy can also heat the same house, meaning the power plant throws away about half its energy (at best)

Any thoughts why large scale co-generation is so unpopular?

I can think of one really big reason. Liability

One reason is that, at least hereabouts, thermal (fossil fuel and nuclear) power plants tend to be located quite a long ways - hundreds of miles, sometimes - from any significant number of houses.

Our society's record of maintaining and protecting infrastructure doesn't inspire much confidence in a widespread network of hot water pipes.

I work for a major power company. Many of our power plants have installed secondary heat recovery generators to use the cooler discharge water. They really are trying to be efficient.

Makes sense. If you can sell the heat, stands to reason you can also use it in-house.

It can be done, if there is the will to do it. CHP is very common in this part of the world. As of 2011 (the latest detailed figures I have seen) there were 169 towns in Finland with district heating networks, totalling 13100 km of district heating pipelines. (Source)

An example I have visited is Naantali, where district heating production for 2011 was 1 315.6 GWh of which losses were 2.4 GWh. Not bad losses considering their output includes steam delivered to industry some of which is over 10 km away and some of the heat distribution network is above ground in a harsh climate and some, if I remember correctly, is even under the sea.

Another nice example is in Stockholm where they have a district heating network and also the world's largest district cooling network. So they can extract heat from places that need to be cooled or refrigerated and move it to places that need to be heated. Now that is cool, if you will pardon the pun.

Weston 1-4 are located within 5 miles of 10,000 dwellings

Well, that's not "hereabouts" for me. The local utility's fossil plants are located roughly 20-200 miles from large numbers of houses. And that's straight-line distance: there are a number of mountain ranges &c between.

I think it comes down to economics. How much would it cost to build a network of distribution pipes? And you'd have to have a return system too, since you wouldn't want to just dump the water in a sewer (in most places, which are rather drier than Wisconsin). Then you have to figure the cost of pumping water through the system...

There are better ways to use the waste heat. Secondary recovery is one, of course, but there are others. Back when I worked for the power company (a couple of decades ago) they used the heat for dehydrating potatos, looked at raising tilapia fish in the cooling ponds, and a number of other uses I don't recall offhand. There was even a guy who wanted to start an alligator farm, though I don't think it ever got off the ground.

I don't know but we are constantly building systems that include 2 water pipes coupled with 1 "gas" pipe all underground to every house in our area.

One could assume the mission critical gas pipe would be omitted on homes with the extra pipe and it would be a differential of how much the cost difference is between a gas pipe that can't leak and a water pipe that has to be insulated.

Another more radical thought, why not just use the existing pipes, the powerplant complex makes enough heat to heat 500,000 homes, more than are even in the area, why not just run all municipal water as hot through existing lines, the heat sync affect would eventually allow the water to be hot in most areas and to get cold water you would need a heat sync.