Most people don’t think much about heat except when they are chilly and turn up the thermostat, but an absurd amount of the energy consumed today is for residential, commercial, and industrial heat, or wasted in heating in those spaces. And as with everything else, a lot of silly nonsense is being promoted by people invested in legacy solutions or extensions of them while a lot of other actual solutions quietly expand, often very rapidly.
The sexy and practical quadrant is practically empty, denoting how little attention the space gets in the media. That said, two things edge into it. Let’s start with thermal energy storage (TES), as it does get a few headlines, some deserved, many not. Let’s start with what it is actually good for, which is temporary storage of heat in a specific location where heat has been generated and is required a few hours later. This might be a high thermal capacity building soaking up heat during the day so that it stays warm at night, or might be an industrial site that stores some heat at night when electricity is cheap for use during the day time when electricity costs money. It’s even possible to move the heat short distances from the storage to the consumption point.
The sexy but impractical side of thermal energy storage is when the advocates start talking about storing electricity as heat in order to return it as electricity later. Heat is great where you need heat, but heat has low exergy, which is a nerd’s way of say it doesn’t turn into other forms of energy efficiently, and it’s worse the lower quality the heat is. If you have a store of 1,500° Celsius heat you can run a steam generation process off of it with maybe 40% efficiency, but if you have 120° Celsius heat stored you aren’t going to get much electricity out of it at all. Ditto turning it into kinetic energy for moving things. So if someone is talking about a thermal battery being used to store and return electricity, smile politely, hope they don’t burn their fingers, and keep your wallet closed.
Then there’s the unsexy and frequently impractical stuff. A bunch of the heat storage space, things like Antora, make claims about modular storage as well as electrical generation. It’s not well designed to be integrated with where the heat is required, the modularity increases thermal losses, and the ability to move heat between the storage and the required location is poor in many cases. The higher the quality the heat, the harder it is to move it around, the inverse problem of the poor exergy of low quality heat.
Speaking of moving the heat around, one claim often made about heat storage is its value for district heating. Basically, it doesn’t make a lot of sense compared to waste heat capture and recycling and manufacturing heat for distribution as needed. I put this assertion to Diego Mandelbaum, who designs, builds, and operates district heating systems on 2-3 continents with Creative Energy Canada, the folks who run Vancouver BC’s district heat among several others, and per Diego it comes up in most initial brainstorming for specific deployments and virtually never makes the cut for the final solution. Lots of smoke, little heat, in other words.
Thermal energy storage has some good niches, but also a bunch of claims in the space that make no economic sense. It’s easy to heat things up and there’s precious little intellectual capital or materials blockers to prevent entrepreneurs from hanging out a shingle, so caveat emptor.
The other thing that edges, ever so slightly, into the sexy and practical space is hydrogen. I know, I know. I’m actually agreeing that hydrogen has a use as an energy source. Nuance, it’s not just a perfume.
I’ll get to all of the different ways to get heat to industrial processes that are very, very straightforward, but there are some cases where the chemistry of the process will be more efficient and effective even with very expensive gas energy. Per Paul Martin, cement clinker kilns, those rotating drums that turn quicklime and clay into clinker as an intermediary step in making Portland cement, work best with a jet of flame. He’s the expert on industrial chemical processes, so I’ll defer to him. This doesn’t mean that this specific example will persist with all of the work being done to displace cement, but it does indicate that there will be cases where the most economic source of heat will be to manufacture green hydrogen and burn it either directly (less likely) or as some synthetic gas derivate, perhaps methane in the case of cement as the machinery already uses it.
However, as Martin also has made clear to me, and my own assessments and explorations confirm, virtually all industrial processes can run on electrically supplied heat much more efficiently than going through a power-to-fuel intermediary which will always be more expensive. Everything Martin does when designing and prototyping modular chemical plants uses electricity until the final last economic assessment step is applied where it’s determined where fossil fuels are cheapest. As carbon pricing kicks into gear, fossil fuels stop being cheapest pretty quickly, and then conversion to electricity will happen quickly. As a result, virtually but not quite all claims about hydrogen for industrial heat are impractical.
That’s it for the sexy but practical, so now on to the next quadrant, the overhyped and impractical. We’ve already touched on the bits of thermal energy storage that fit in this quadrant, and industrial heat from hydrogen, but there’s more to look at.
Let’s keep on with hydrogen, which continues to have pride of place in the overhyped and impractical quadrant of these charts. Natural gas utilities, the fossil fuel industry and some governments are really trying hard to push hydrogen into homes and commercial buildings for heating. SGN is pushing the hydrogen community string uphill in Fife, promising free appliances and hydrogen for Scottish people who have poor STEM skills and high risk tolerances. As I and many others have pointed out with detailed economic and safety assessments, hydrogen appliances barely exist, aren’t certified, aren’t zoned for, have no safety regulations associated with them, would require expensive hydrogen detectors, are much more likely to cause explosions and would be vastly more expensive to operate than existing, much lower risk electric alternatives. You really have to be stuck in a paradigm where the only sources of heat are burning gases or be a purveyor of gases to burn to think that this is a remotely good idea. It’s going to go away sooner than some other forms of hydrogen nonsense, one assumes.
Similarly, using hydrogen in stoves for cooking, whether in residential or restaurant kitchens, is an equally poor idea for all of the same reasons as heating spaces is. Much less safe, much more expensive, no appliances or regulations supporting their use. SGN will undoubtedly pour money down into this H2 hole until their business model disappears entirely, as will other gas utilities and fossil fuel companies, but everyone else should stay well away.
Speaking of cooking, let’s talk about cooking with gas. You have to give it to the natural gas industry, they have a flare for marketing that coal and oil must envy, starting with calling methane “natural” gas. The 1930s ad campaign to convince people to pipe explosive, polluting gas into their kitchens and then burn it to create indoor smog instead of using electric stoves was remarkably effective. About 4,200 homes blow up and about 40 people die every year from natural gas fires and explosions every year in the US alone, after close to a century of incrementally reducing the risks of the stuff. And those suckers create indoor pollution whether they are operating or not, harming people’s respiratory health. Like burning coal for electrical generation, if it weren’t grandfathered in, no one would accept it.
Just imagine the pitch: “Hey, let’s take this methane stuff which will explode if it leaks, add stinky stuff to it, pipe it into homes with families and get them to ignite it for heating and cooking! Yeah, I know it will kill a lot of people and make a lot more people sick, but think of the money we could make! Hello? Hello?”
There are faster heat, cheaper, much safer, much lower carbon, much healthier alternatives now, which I’ll talk about later in this article. Cooking with gas has to be a thing of the past, and restaurant chefs who have switched to the alternative swear by it.
Next let’s talk concentrating solar power. This is a bunch of mirrors set up in a parabola that concentrate the sun’s rays on something. It’s easy-ish to do, it has a long history including an Archimedes death ray Myth Busters tested, and it failed fairly miserably in electrical generation, where photovoltaic solar kicked its butt to the curb quite handily. Yet there are still a lot of people who think it’s the bees knees for industrial heat. Prime among these is Heliogen, the SPACed out machine-learning enabled CSP variant that claims to be excellent for industrial heat, ignoring things like requirements for much larger heating areas than a 1 meter disc, heating applied deep inside industrial plants not 150 meters in the sky, the rarity of square kilometers of empty flat land around industrial plants, and the requirement for constant temperatures often for days at a time for industrial processes, not ones that fluctuate with passing clouds and the setting of the sun. Solar photovoltaic electricity generation’s intermittency is easily balanced on a grid with other forms of electrical generation, some storage and a some transmission, but solar as a heat source fails to be a useful and reliable source of high-quality industrial heat.
One of the things I can’t help but notice are articles talking about actually useful solar photovoltaic generation that are decorated with concentrating solar power. Those concentric rings of mirrors around a tower certainly are photogenic, but they barely exist in the real world. I wish people who published stuff would figure that out, because they feed the availability bias of people globally who think this is a useful and viable technology instead of a mostly dead fringe.
Okay, enough about the sexy nonsense, now let’s talk about the boring stuff that is impractical. Yeah, industrial heat from coal and gas and natural gas furnaces for residential, commercial and industrial space heating all exist. And they are a massive part of greenhouse gas emissions. And they are massive sources of air pollution, water pollution and various toxic chemicals too. There are a lot of reasons to get away from burning gas and coal for heat where we do it today. The only question is how fast we can do it, and what displaces coal and gas in different applications. And so, on to unsexy and practical.
Let’s start with the most boring of all practical solutions to heat, insulation. If we look at the residential, commercial, and industrial energy services, the gray flows coming out of them include a lot of heat that would have been better kept inside the buildings or facilities. Just like insulating a home’s attic and closing up drafts makes it easier and cheaper to heat, the same is true for a lot of things. You don’t even need to go nuts, just make it better. It’s low-hanging fruit, and it helps whether you electrify immediately or later. Really, that’s it.
Another boring thing are heat pumps for space heating and water heating. Air source heat pumps work just fine. A UK study of over 700 installations found that they were fit for purpose for every building type in that island archipelago, even over the squawks of the remarkable number of people there who think otherwise because … uh… reasons. And they work for water heaters too. Hot water heaters aren’t high grade heat, they are just moderately hot. Getting most of that heat from hot water that’s flushed down the drains and from the air, and maybe supplementing it a bit with resistance heating is very effective. Heat pumps work in Singapore on the equator and in Scandinavia near the Arctic Circle. I’ve done the math for most provinces in Canada and they are already cheaper and much lower greenhouse gas emitting than natural gas and only getting more economically attractive with the increasing carbon price.
Heat pump sales in Europe grew by 31% in 2021, with 2.18 million units installed, making the EU target of 16% growth leading to 50 million of the things by 2030 seem pretty easy to achieve. When I published my assessment of the EU energy crisis, projecting that it will be short lived and lead to positive outcomes, one of the things I saw was a massive uptick in this basic technology.
Oh, and replacing gas furnaces with heat pumps brings the advantage of air conditioning as well, something more and more necessary with heat waves sweeping through countries.
Remember that cooking with gas thing? Well, gas cooking has one advantage over resistance coil electric stoves, which is rapid heat in the pan. Resistance coils take a bit to heat up. Total first world problem, by the way, outside of commercial kitchens. Well, induction cooking doesn’t have that problem. Faster heat and a lot less waste heat as the pan gets hot while the stove stays cool. And you can get an induction plate if you want to keep using a piece of favored cookware for a while longer. No chance of explosions. No air pollution. No odorants. Professional chefs swear by it. So yeah, when you replace your oven and stove, ask for induction. Much better than all of the alternatives.
Next let’s talk district heating (and cooling). North Americans are more oblivious to this than Europeans where it’s more commonly understood and recognized. But there is district heating and cooling in Toronto and two different approaches in Vancouver that I’m aware of. It’s much more common than is recognized, it’s just a little quiet about it. Not that Enwave in TO doesn’t try to make waves, but most Torontonians are oblivious to the downtown west of Yonge getting lots of HVAC from Lake Ontario’s deep waters.
In Vancouver, Olympic Village on False Creek was built for — wait for it — the 2010 Winter Olympics. Per Scott Hein, the former city planner who I had a bike tour with a couple of years ago, they managed to convince the powers that be that a faux-British nautical theme would suck, and instead did an amazing design job in about three weeks to create a great community, with mid-rises with court yards, interesting design features, public art, a water table that sloped gently to False Creek, and a district heat recovery system that provides approaching 70% of the heat requirements. Yeah, big heat pumps underneath the Cambie Street Bridge suck the heat out of gray water from dish and clothes washing and deliver it back to the Village.
And, of course, Mandelbaum’s firm delivers low-grade heat across the peninsula and is preparing to run it under the bridge to Kitsilano. Low-grade heat, you’ll remember, can be distributed further economically, a few kilometers. And the firm is just upgrading to a bunch of electric heat, so it’s increasingly low carbon too. District heating and cooling is this boring process of getting some infrastructure in place, getting buildings to hook into it when they are being built or retrofitting it, and then having much more efficient heat delivery. It’s increasingly zero or very low carbon. It just sits there and makes people comfortably cheaply.
The second last thing I’ll talk about is geothermal heat sources, which I’ll also sweep water heat sources like Enwave into. Basically this is just using a huge natural heat sink that’s at a constant temperature to run heat pumps against. Instead of pumping heat from or to the atmosphere, you pump it from water that circulates through coils in the ground or pipes running into large bodies of water. It’s more capital intensive, especially ground source, but once the money is spent, heat pumps have an amazing resource to draw on for heating or cooling.
So let’s close with some white hot sparks. How the heck do we deliver very high quality heat for industrial purposes? Like 1,800° to 3,000° Celsius heat? A lot of people with burner boxes on their heads like to pretend that there’s no way to do this without burning gases or liquids. They apparently have never heard of aluminum smelters or electric steel minimills. These both use electric arc furnaces to provide highly controllable, highly efficient, very high temperature heat to melt and purify common metals. Electric arc furnaces are completely fit for purpose for most industrial very high temperature heat requirements, and they run off of high exergy electricity. Resistance coils provide lower quality heat in huge amounts with coefficient of performance around 1, which is just as good as fossil fuels, but without all of the CO2 and pollution.
Remember that Paul Martin’s prototypes of chemical plants were fully electric prior to the last stages, when economics of heat and energy entered the equation. As the world demands decarbonization and penalizes the lack of it monetarily, electricity and technologies that move or create heat with it are already very mature, very prevalent and fit for purpose. Hydrogen need not apply, as supplying heat with green hydrogen will always be multiples, often an order of magnitude, of the cost of supplying heat with the electricity directly instead.
So that’s it. I don’t have any more sexy vs practical quadrant charts waiting in the wings. European energy traders Laurent Segalen and Gerard Reid of the podcast series Redefining Energy might do an electricity and energy market mechanisms cut of this based on an online back and forth I had with them, or might not. Others might take this further, picking some sub-topic and drilling down in more detail. But for now, I put down my keyboard. As always, tell me what you think I got wrong, and what you think I missed.
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