Compare to the strategy of locating somewhere that electricity is always cheap and running all the time.
But what a waste of potential to do that! All that overbuilt power generation, simply turned off during summer. Batteries don't help here, it would store it, but then the question of what to do with it is still here.
If society goes the route of massive overbuilding solar/wind, then there's an opportunity to do something with effectively free power during summer. But it's ONLY during summer, so it needs to be something valuable that can also act as a energy storage.
Carbon fuel is perfect for this. Millions of ICE cars exist and are still being produced. Long distance airplanes will be carbon fuel based for a long time. And so many other uses. I think another option is water. Water can also be seen as a valuable resource that acts as energy storage. Use the excess summer power to fill up a near empty dam with desalinated water? Sounds like a perfect fit for regions like southern California or Arizona.
All processes have some waste. In the end, you need estimates done with real numbers to see if it's worth doing. We aren't going to settle it with casual chit-chat.
Pumped storage hydroelectricity is the biggest form of power storage at the moment, and has efficiencies around 70-80%. The losses for desalinization (pumping through media) are ruinous compared to just pumping uphill, and storing desalinized water means you can't use it without spending potential power. There might be good reasons not to mix desalinization and energy storage.
You need elevation difference and fairly stable soil. Everything else is technologically solveable. It's a big civil engineering project but its a profitable one and not particularly challenging.
seawater is also not valuable. You don't care about the water quality in the reservoir, you just let it fall back into the sea. If it evaporates you're losing energy but you aren't losing potable water that you sell, and it doesn't require a connection to a water distribution main.
If it was a reasonable and profitable use of energy we would already be doing it, but we're not because its ruinously expensive. You also run into storage issues (how much of your excess power is being evaporated from the surface of your storage reservoir? The longer you hold your potable water the more you throw away). You also need to consider what you're going to do with the highly saline byproduct of any such process.
There's nothing wrong with purifying water but its very energy intensive and already something we do. Adding more expensive potable water from excess energy generation doesn't make much sense.
It would require dynamic pricing to the consumer to work as off-peak prices would need to be low or very low to encourage all BEV owners to take on the excess power at particular times of the day.
By the way, unfortunately dynamic pricing seems to be a very unpopular idea as far as I can see.
Re water, in addition to filling dams with desalinated drinking water we could also refill aquifers that are being emptied by overconsumption of water (often leading to intrusion of saline water into the water table and associated problems).
> But converting that into carbon fuels that work directly in existing infrastructure and is effectively carbon neutral is a good option too.
This approach seems really underrated, at least for transportation.
Hydrocarbons still have the best energy density of the realistic options. We have a century of experience building ICEs with favorable power/weight ratios. Why throw all that away?
But I want those environmentalists to sit down and think. Yes, climate change is urgent, and that urgency should make you stop asking for perfection. There are 1.4 billion cars in the world. Even a 100% ban today on ICE car production is not going to change that. Cars have an average usable span measured in decades. The projections for 2050 are catastrophic if carbon emissions don't go down.
Green tech has one big overwhelming victory right now, solar/wind. It's annihilating coal and will eventually defeat natural gas as well. We can take that victory and use it to make the existing cars and airplanes carbon neutral. If you care about climate change, why is this not more exciting than EVs?
The first approach of using hydrocarbons as an energy buffer makes perfect ecological and economical sense and is most likely strictly necessary for a carbon neutral energy grid (barring battery breakthroughs), once we reach 60-70% renewable energy in our grids.
The latter approach however makes no sense at all, because we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power. The energy losses, both in the step creating the fuel, and in the step turning fuel to useful work, are just too great to fuel every car or heat every home in the world like that.
I'm not sure if this is the case or not. To give some numbers:
Current global oil consumption is 54225 TWh, or 6.2TW 
Current global solar panel generation capacity is 628 GW (2019) . Median capacity factor maybe 25% 
Current global wind power capacity is 650 GW . Median capacity factor maybe ~37% 
Other renewables are unlikely to achieve the same growth as wind and solar, so can be ignored.
So we need to install 15x current renewables, times whatever the hydrocarbon creation process efficiency is, to produce all our annual oil demand.
Assuming a 50% process efficiency, we'd need to install 30x what we have now. That's a big installation, but it's not outside the realms of possibility. There's a lot of untouched desert in the world.
However, I think 50% process efficiency is too high. High temperature electrolysis is about 60% efficient, but then you only have hot uncompressed hydrogen. There are a number more steps involved to get to a liquid fuel, each of them with considerable losses. I can't find the sources right now but I believe I remember something like 15% end-to-end efficiency for getting to something you can fuel your car with.
Ammonia would be easier (ubiquitous nitrogen everywhere), but isn't a particularly nice fuel either. At least it's easier to store than hydrogen.
99% or what?
The average German needs around 144sqm of solar panels (located in Germany) to meet their primary energy demand of around 48MWh per year (taking into account average production of solar panels in Germany). Germany has a population density of around 4300sqm / person. So in the ideal case with no storage losses you need to cover more than 3% of Germany with solar panels if you want to meet primary energy demand with solar power. (Wind energy is slightly more dense in Germany, but I haven't done the math there).
Realistically you might get something like 1% of the land area without huge resistance of the local population. Probably less, which is why offshore wind is popular. 100% renewable generation is only realistic because you can safely assume that large parts of the primary energy consumption are wasted. For example internal combustion engines are at best 40% efficient. Burning things for heating also only gets you 1J of heating per Joule expended, whereas heat pumps get you 2-3J. You just can't get away with losing another factor two to generate syngas, or even more if you want liquid fuels.
Of course you can justify some inefficiencies if you're willing to transport energy from far away (say solar power from the Sahara), but that is ridiculously expensive compared to more local generation.
Beside that, a transatlantic jet, let alone a Falcon 9, won't ever fly with battery power. You still need highly energetic fuels where power density is at a huge premium.
Sure, it'd be quite a large civil engineering feat, but the speeds would be hard to beat. It'd be just a 12h ride from London to NYC, assuming TGV's top speed of 575 km/h.
A potential alternative could be to use a low-flying plane and deploy a series of HVDC-fed buoys/platforms straight across the Atlantic for fast-charging.
You're right about the Falcon 9 though.
2) Any inefficiency during transit of LNG isn’t leaks, it’s the fuel burnt moving it around.
3) The cost of building high efficiency LNG power plants wherever you need power is another cost that should be considered.
This technology could be retrofitted to coal fired power plants.
No, it can't! The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. It might work for a cement kiln, but not for a power plant.
I'm sure you know that. But the idiot who put a picture of cooling towers into the article clearly doesn't. He probably doesn't know the first law of thermodynamics, either.
Unless you have some way of buffering the CO2. Biologically, this is what CAM photosynthesis does , and i have a vague memory of there being an industrial equivalent. Something like dissolving the CO2 in calcium hydroxide, to make calcium carbonate, then later on sparging it with hydrogen to recover the carbon?
> Something like dissolving the CO2 in calcium hydroxide
That's terrible. Calcium carbonate needs to high heat to release CO2. Unless you want to leave CaCO3 well alone (that's the enhanced weathering concept), this is approximately the last compound you want to make. Simply storing liquid CO2 under pressure (80 bar or so? not nice, but doable) sounds much more appealing. (Ammonia is better in every respect, though.)
Unfortunately, the article does not say how the zinc oxide nanoparticles will help with being able to use solar/wind power to produce syngas.
In fact it is not clear how these nanoparticles could actually be used to make an industrial catalyst. Current catalysts also use nanoparticles - on a substrate with enormous surface area/volume ratio, but these nanoparticles are created on that substrate.
I am curious about what the researchers plan as the next step.
Processes can be refitted to use pure hydrogen or it can just be added in small increments to existing gas burning plants.
Replacing anything that burns fuel with carbon in it with alternatives that dont is a better solution.
And I don't know if you've played the game "Oxygen Not Included", but creating liquid hydrogen is no easy task either.
A more dense energy storage substance (such as a hydrocarbon) would probalby be more efficient in terms of transportation / use / storage.
Not just leaks, hydrogen can destroy the structure of many metals and make them brittle:
And another issue is the very low density - you van see it with hydrolox rockets, how big they are & how their liquid hydrogen tanks are compared to the LOX tanks. This adds up in tank weight, removing some of the energy/density benefits. This is one of the reasons many next gen rockets are opting for liquid methane instead of liquid hydrogen.
Yes, hydrogen is an absolute mess to handle in free form, while hydrocarbons... stable, energy dense, and something we’ve had experience working with for a couple of centuries now.
A nice side effect would be that synthetic hydrocarbons might possibly reduce the dependency on oil for manufacturing plastics, dyes etc. It’s incredibly exciting... I don’t see how this isn’t a huge win.
Where this could make sense is energy storage. Say you are next to a large solar power plant, and you want to store the excess energy produced during the day and release it at night. Batteries are too expensive, pumped water requires some mountains, etc. With this, you store a quantity of CO2 in some tanks. At day you generate syngas and consume electricity, and store it in some other tanks. At night, you burn the syngas, get some of the initial electricity back, and store the CO2 back in its tanks.
Then you can grab the waste CO₂ and turn it into something useful (ultimately liquid fuel, plastics, etc) by using the cheap solar energy, of which we often have a surplus at daytime.
This has the downside of only operating efficiently during sunshine, or needing a power transmission line from somewhere under sunshine currently (e.g. during local night).
Is this a real catalyst? (That is, it doesn't get used up in the process.) Or do they have to keep making more zinc oxide clouds to keep the process going? The paper summary is unclear about the energy inputs to this process.
Costs $10 to read the paper.
I don't think it will have industrial significance any time soon, though. Catalysts and processes for the reverse water-gas shift reaction are better developed. The hope is that electrochemical catalysts like this can combine the electrolysis process for making H2 and the syngas production step into one, with lower equipment costs. It's hard for me to believe that it will overtake better established industrial processes. It's very hard to take a maybe-better process from lab scale to industry when there's already an established pair of processes that get to the same outcome.
My prediction: electrolyzers and catalytic processes will continue to be optimized separately, and combining those modules will continue to be more predictable and affordable than all-in-one electrocatalytic approaches like this.
But for ocean ships and long-range airplanes we are nowhere near ready for that. And hydrogen fuel cells are not nearly good enough. So at least for many years the only way to make some important forms of transportation carbon-neutral will be synfuels
This is an example of 'meh' level work being puffed up.
No reasonable amount of plants will keep a house stable.
If it's just really curiosity, well, people have been scrubbing CO2 since space travel is a thing. Wikipedia was completely unhelpful to me, but I remember there is a mineral with high CO2 selectivity that you can simply push the air though it.
Wikipedia was similarly not useful for me. Scuba divers and the like apparently use a one-time-use non-regenerative mineral that absorbs CO2. The space station has something that regenerates but I haven't been able to figure out what.
You’d have to reduce the CO2 pretty far (I’m betting reducing to CO like in TFA isn’t what you’re looking for.) I think a lot of people underestimate how much energy this takes.
> While cabin air processing, one carbon dioxide removal bed is in the process of regeneration. Regeneration is accomplished using pressure/thermal swing methodology. First, the two-stage pump removes the free air from the adsorbent bed and returns it to the cabin, reducing oxygen ullage. Then Kapton heaters integrated within the adsorbent bed raise the zeolite temperature, and space vacuum creates a low, partial pressure driving the carbon dioxide gas overboard. Daylight and continuous day power cycle is overlapped with the operating cycle. In the daylight power cycle, the carbon dioxide adsorbent bed heaters are only allowed to be powered on during the day portion of the cycle
> The CDRA continuously removes 6 person-equivalents of CO, when operating with both C02 removal beds (dual beds) functioning.
Converting CO2 into CO would be rather counterproductive (absent a reliable and efficient mechanism to remove CO), I suspect an efficient setup will involve "mechanical" filtration not chemical reactions.
1000 ppm is btw. enough to feel uncomfortable. Cognitive impairment will be much more subtle.
Well, that would be problematic sooner or later .
The process of making lime from limestone actually produces CO2, so it's use in CO2 scrubbers are more or less carbone neutral.
The potential alternative, which would not use consumables, would be to just freeze it out. It's not _that_ hard, I believe an ammonia-based single-stage chiller should still suffice. Make sure to use counter-flow heat exchangers to not loose insane amounts of power. Handling the water condensation might not be that trivial, though.
That's a lot of plants.
So you harvest CO2 to into fuel. That fuel is burned and the CO2 is released back into the air. So net difference is zero.
But to harvest the CO2 you needed to generate a high amount of heat. That's extra CO2. So net CO2 is more.
It depends on the cost of harvesting that CO2.
It's a process to turn:
* otherwise-waste carbon dioxide into (taking electricity)
* syngas, which can be turned into
* synthetic diesel, methanol, alcohol or plastics
Plastics could be a carbon sink I guess.
I would much rather to pay more for net zero carbon fuel, then not do anything.
Whether something is net zero depends on what you are adding it to; it's not inherent in that thing.
It's like, if you have a pile of blue things, then the pile is also blue. But other characteristics do not work that way. If you have a pile of things that each weigh 1 lb, then the pile does not weigh 1 lb.
It acts just like a battery.
Look at it this way, do you believe CO2 is basically fungible in the context of global climate change?
It's like moving from a variable rate credit card to a 0% loan. You still have this pile of debt you need to deal with, but you more or less stop the problem from getting any worse.
That depends on where they get their energy from.