Electrical transmission systems are roughly 85% efficient to the consumer; together with boring old resistive electric radiators which are 100% efficient. So is there any reason to subscribe to the steam system for new construction?
But they're only about 33% (old tech) to 45% (best-case new tech) efficient when it comes to thermal potential. Burning coal or natural gas produces lots of heat, and while some of that heat turns the turbine, there's still a lot left that gets lost to the condenser or to the exhaust flue and atmosphere.
However, that's where steam distribution is awesome: It enables cogeneration, where some of the waste heat from electricity production can be efficiently used by heating industries. The electrical plant requires supercritical steam at 1000F and 1000 PSI, but the steam network only needs steam at ~150 PSI and 350F, which still has a lot of energy in it from the burners but is of comparatively little use to the turbine.
The water isn't quite as hot as it needs to be when it arrives, so it's heated additionally in the building itself.
The article mentions a similar approach, with steam instead of water:
> They also purchase additional steam from a 322 megawatt plant in Brooklyn
In modern co-generation you can for example burn gas in a gas turbine & produce electricity. Then heat water to steam with the gas turbine exhaust & power a steam turbine to get more electricity. And then the steam is condensed by the district heating water loop.
So in theory you will get more electricity & almost all the "waste" heat is used to heat houses.
Almost all electricity run through computers are basically resistance losses at the end of the day, so data centers and crypto miners on the other hand...
> Typically, high-voltage transmission lines are designed to operate at temperatures of around 75 to 100°C (167 to 212°F). However, under heavy loads, they can sometimes reach up to 150°C (302°F), but this is usually the upper limit for safe operation.
If that's a core temperature then the insulation might not make it significant, but if the outside leaks this much... I might not mind paying myself for a plastic tube and a fan to use around the line if I lived near one. Okay okay, it'll be more complicated than that, but still: free energy? And you're doing the power company a favor by decreasing the resistance in the case of most metals (https://www.engineeringtoolbox.com/resistivity-conductivity-...) including copper which https://en.wikipedia.org/wiki/High-voltage_cable says they're made of
Beyond that, you're likely also decreasing the maximal electrical current the wires can carry, as they won't be able to dissipate the heat as effectively with the additionally insulation.
- insulating high voltage lines isn't trivial
- the conductor will be hot inside the insulation...
- service cost of either system will be increased (by rather a lot, I'd guess)
So using electricity for heating would be just throwing free heat away. Heat distribution networks are of course not free though.
Electric heating would be an economical win if the electricity could be harvested by solar and wind generators, and stored. Storing solar heat directly is much trickier.
Steam with <1112 BTUs per pound vs room temperature will condense, so the heat value of a megapound of steam is at least 325,895 kWh. That's a marginal cost of 1 cent to 3 cents per MMBtu or 3.5 cents to 11 cents per MWh. The hookup cost ($3,555) is much smaller than the cost of the steam ($13k-$44k per the article).
For comparison natural gas costs a couple dollars per MMBtu and wholesale electricity costs $40-$60 per MWh. *The steam is orders of magnitude cheaper.*
If the article's quoted prices are accurate (note: Lincoln Towers seems to pay $2.43 per megapound, significantly less than the $11.35 usage fee the article gives immediately before. Not sure what's up.) then steam is practically free. I'm not really sure how that's possible; maybe there are subsidies or regulations enforcing production. A significant amount of the steam is from cogeneration, where steam is a byproduct of pollution-reducing processes- it makes sense that would reduce the cost, almost all steam would need to be a byproduct to explain the price.
Also either need very expensive oversizing or backup heat sources to compensate reduced heat output, even if you get occasional cold spikes.
Unfortunately nothing in life is as simple as it first seems.
I won't try to make his case here, but he is pretty convincing that a reasonably sized heat pump system can be sufficient even in very cold climates (by US standards).
I would reccommend keeping backup heat source when installing heat pumps into older homes. A simple wood stove, used during cold spikes, could be enough.
My country has subsidies for heat pump installations into older homes and it had requirement to get rid of chimneys to get that. After the whole europe energy crisis thing, this requirement is gone now. Turns out having alternatives is a good thing :)
Out two tonne heat pump works just fine even at -25C this past winter.
We still have a natural gas furnace but our gas usage is down 65% despite this winter being colder than last year’s.
Tell me again how heat pumps don’t work in colder climates?
It is easy to see the loss of something old. However the opportunity cost from not building new is something that is very hard to get people to understand.
This is actually terrible and supports their point. Heat pumps are not sized as if they were running at a mere 100% or less, they are sized for the btus they normally produce, and aim to run close to 100% of the time, meaning they will be too small and not be able to do the job when they drop below 200-300% efficiency, unless they are grossly oversized. That leads to short cycles which makes condensation and moisture in the summer and wear and tear all year and less electrical efficiency because starting a pump and blower costs more than running it.
Current inverter types that can run slow do allow them to be oversized but it's still not great. Those are more expensive and have more failure points in electronics too.
Sure, you can still find good weather heat pump that crap their pants near or under freezing. However, the majority sold here in Europe still stay well of 200% down to -15C, some even -25C.
What does this mean? Are you imagining a future where individual houses have their own nuclear plants? Or where nuclear plant workers live on-site?
I'm get the argument that we should have more nuclear power, and that some future reactors may be small, but I don't understand the expectation that they would be close enough to residences to pipe steam.
- https://newatlas.com/energy/oklo-aurora-nuclear-microreactor... - https://www.popularmechanics.com/science/a33896110/tiny-nucl... - https://www.nuscalepower.com/products/nuscale-power-module
They target from home to residential scale. I hope they are eventually a thing.
In such tighter conditions, you can easily have enough inhabitants per km² that it would justify building small mobile nuclear reactors.
Who would like to live next to a reactor if it can melt down? Well, you have reactors using fuel pellets locked in marbles that due to their diameter can never meltdown.
https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generato...
> Most electricity is generated by using steam to turn turbines
That is true. It is also true that renewables usually do not use steam. But they don't answer for "most electricity". That's natural gas, coal and other types of thermal plants, including nuclear.
Gas combined cycle power plants get part of their power from gas in the turbine directly, and part of it from steam cycles. I can't figure out what % over of power comes from which part, and not all gas power plants are combined cycled.
It seems reasonable to say that most electricity is not generated by steam turbines. However I'm not sure how to find the real data to verify this. (and pedantically the gas in a gas turbine is mostly steam)
There's zero opportunity cost of "you could use it for some other purpose instead".
Wikipedia says "Approximately 30% of the ConEd steam system's installed capacity and 50% of the annual steam generated comes from cogeneration" i.e waste steam, which is .. half good, I suppose.
It also gives https://web.archive.org/web/20101207021857/http://coned.com/... which I guess has the rest of the details in.
I'm wary of attempting comparisons of end to end efficiency, just because these aren't apple to apple comparisons. Solar panels are 20% efficient. Nuclear power can be anywhere between 60 and 90% efficient. Coal plants can be between 35 and 50% efficient. Each of these can have an economic rationale despite these differences in efficiency.. A Dyson sphere with 0.001% efficiency could be a winning value proposition. Granted, these are energy sources rather than transmission infrastructure, but the point is the same.
I would want to know about the efficiency loss from whatever primary source of energy was generated before it gets transmitted across the electrical transmission infrastructure, and I would want to know how it compares to a steam source, which could plausibly be such a thing as waste heat. If your steam is cheap or potentially even free it could conceivably win out in the final assessment, even if it has higher relative transmission losses.
All that matters is the actual power generation since there's no marginal utility of "what else we would use that space for" (unless you're consuming farmland etc for the solar panels)
If the purposes are mixed, of course a photovoltaic panel can generate electricity for many purposes, while sunlight shining on a garden hose can only heat water. So it might be a more useful system, even more cost-effective, despite being much less thermally efficient.
It's the same with burning things to make heat, versus burning them for electricity and then using electric heaters.
Electrical generation itself isn't a 100% efficient. For example a gas powered electricity plant is about 60% efficient for generating electricity. Generating heat from gas is far more efficient.
Then again if you use the electricity not for direct heating but for example to power a heatpump on the other end (i.e. you use the electricity to extract heat from the air) then it could be more efficient.
I am not sure about "always". Does it not depend on the temperature difference?
The use cases for steam seem to be where you need more than room heating though: the first paragraph mentions sterilising medical equipment, humidity control, and washing.
My understanding: A heat pump is always better than resistive electric heating. Sometimes a outside air using heat pump needs to use extra energy to defrost the outside unit (with resistive electric heating). The defrosting is driven by sensors, but rarely happens more than e.g. once an hour for 5 minutes at a time. Heat pumps really do win over resistive electric heating on everything except initial cost, and that's not even hard -- resistive electric heating is very wasteful.
I don't know of any of the customers of the steam system in downtown Vancouver that use it for sterilization purposes, it connects almost exclusively large office towers. There's no hospital or medical facilities connected to it.
That said, I think most of this applies to heated water, not steam.