The local airport near me has had an experimental remote tower system since 2018. Prior to this there was no tower which limited the types of aircraft which could use the airport and the services which could operate out of it. They were informed in February that SAAB, the provider of the remote tower service, and the FAA were unable to reach an agreement regarding final certification of the system. SAAB has withdrawn their application for final certification. The remote tower system must be shut down June 30th. I believe the air traffic controllers are located in the Kansas City area and the facility there will remain open because the system is certified and in use some places outside the US.
The FAA is going to provide a mobile tower through September after which the town, which owns the airport, must enter a lease for the tower including manning it with controllers at a cost of $720k per year. The town is currently investigating how to fund the mobile tower and a permanent replacement tower. They are seeking grants and/or considering instituting landing fees. The permanent tower must be completed and certified within 5 years.
At least in theory... lower tower construction costs, lower ATC labor costs (especially in high cost-of-living areas), and economies of scale from colocating multiple towers into a single facility (i.g. ability to quickly reallocate controllers between tower sites based on observed traffic, or even having controllers operate two towers simultaneously if traffic is light).
This last one is already done for approach control. Some areas have a consolidated TRACON facility, like NorCal Approach. At night they'll merge all the radio sectors together, and you end up talking to the same controller for half the state.
I looked at the pictures and I predict roughly 4.7x cost overruns when actual construction takes place. Any takers?
Cost is the most important factor in making green tech widespread, as has been proven time and time again.
Building green is mostly solved problem, though we continue to make new advances. This nonsense is an exercise in expenditure. I’m sure if we folded the money trail it’d take us some interesting places.
What? Are there current control towers that run on something besides electricity from the grid? What is this actually talking about, backup generators?
Natural gas heat. It’s keeping in line with administration policy on climate change, electrification, etc. Building energy use is a substantial component of national energy consumption. Proper insulation and high performance building standards means heat pumps should be sufficient (and can run off diesel generators air traffic control infra would run on in a power outage regardless, as it’s critical infrastructure).
Cost savings are there too, the grid gets cleaner and cheaper over time as renewables penetration hockey stick growth curve. Furnaces and boilers burn gas their entire lifetime.
Those are all large airport towers. I imagine most of those are well outside the budget where this design will be used. This new design would be compared against stuff like this.
You can synthesize jet fuel from CO2 and renewable energy. Or biologically derived products.
These are all use cases where consumption won't outstrip capacity, because airline travel is much more efficient then car travel, which is your other alternative unless someone wants to actually build high-speed rail.
I've always thought a carbon credit/tax, or more broadly an externality credit/tax, system, would resolve these issues. Then the users will pay the real cost always, and obviates the need to ponder.
That works until governments realize they have an incentive to maximize environmental damage so they can bring in more tax. There is the risk of the same old game (never solve a problem so that it can be "managed" forever)
> an externality credit/tax, system, would resolve these issues.
This is a good approach to a lot of things, except when said thing also has positive externalites and second order effects associated with it.
Travel is one such example, as it's essential to lubricate the economy. As such, we should encourage as much of it as possible. Business thrives on it.
Without cheap air travel, America is weak. We lack commuter rail infrastructure, and car travel is far too slow. Taxing air travel or increasing its costs are a nonstarter.
If we predicted the era of air travel to be coming to an end, we'd be making rail investments. Air travel is likely to continue growing, however, so there's little rush for domestic rail projects.
Perhaps you'd like to explain some of those considerations rather then just waving at them.
Modern jet turbines are running within a few % of maximum thermodynamic efficiency. So what consequences other then CO2 emissions are worse then anything else?
And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point.
> Modern jet turbines are running within a few % of maximum thermodynamic efficiency.
Indeed they are marvels of engineering. But that doesn't make them "sustainable". It just takes a lot of energy to push something through the air at high speed, no matter how efficient the engines are.
Apart from the CO2 emissions, there's also the issue of the GHG forcing effect of high altitude water vapor emissions. Current estimates are that flight at typical airliner altitudes of ~10 km results in a GHG forcing (over some decades) of roughly 3 times more than burning the same fuel on the ground.
> And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point.
The major issue is due to land use changes. Biodiversity is already in a sharp decline (arguably this is an as big, if not bigger issue than climate change), largely driven by converting nature into cropland. Secondly, converting nature into crops, whether for fuel or food, tends to result in large CO2 emissions due to the carbon that has been stored into the soils being released.
And finally, biofuels just don't scale. There isn't enough arable land on the planet to replace the amount of fossil fuels we use today.
Farming causes environmental damage besides greenhouse emissions. Even discounting all the other forms of environmental damage, a lot of biofuel schemes (e.g. corn ethanol) emit more greenhouse gases than they save.
Thermodynamic efficiency is the wrong way to measure efficiency here. It makes no sense to measure efficiency that way, none at all.
I’m talking about biofuels as they exist today, not as they hypothetically exist in the future. Currently, you burn biofuels, you end up releasing more CO2 into the atmosphere, because the production of biofuels produces CO2. It’s not negligible, either.
All of the analyses I’ve seen of biofuel paint an incredibly dismal picture. As far as I can tell, the main strategy to reduce CO2 emissions is to stop burning fuels altogether, not switch to something like biofuel. Airplanes need power density & energy density in order to work which makes technologies like batteries unsuitable. Way easier to power something on the ground, where you’re not spending tons of energy just to keep it from crashing. Or better yet, on an electrified rail.
When people talk about biofuel as a replacement for oil (which needs to be replaced) I think of the scenes from Horizon Forbidden West where the AI killbot just sucks in all the life around it and leaves the landscape dead.
>Airline travel is only better than cars if you compare it to a 1-passenger car
Why would you compare it with anything else? People don't actually fill their 5-8-person vehicles, almost ever, and certainly not on longer trips. I don't have any sources handy, but I'm pretty sure an airplane is significantly more fuel-efficient (which also means less CO2 output) per person for a NYC-LA trip than a gigantic pickup truck with even 2 people.
Comparing air travel to a fully-occupied Prius is a ridiculous comparison, because Americans just don't ever drive that way. They drive huge trucks and SUVs and they drive them with 1, or at most, 2 people.
> airline travel is much more efficient then car travel
Sure, but for many business travelers, air travel isn’t competing with car travel. It’s competing with a nearly-zero-emissions Teams call or Zoom meeting.
> I doubt a vision of growth is compatible with "sustainability". In fact, I find it highly unlikely.
This is a backwards viewpoint. A future of sustainable is a future of more consumption, but green consumption. Standard of living has a strong correlation with energy use. We'll only use more energy in the future. We're still a ways off from a Type 1 civilization.
> A future of sustainable is a future of more consumption, but green consumption.
This is a common trope among the HN crowd. There's no such thing as green consumption. Consuming resources means pollution, whether it be CO2, toxic substances or other refuse from industrial processes. Manufacturing solar panels and wind turbines still means resource extraction which is polluting by definition. Oh, and by the way, we don't know how to mine for metals without using fossil fuels. What you call "green consumption" simply does not exist.
“Sustainable”: to “sustain”. It means that something is viable over a long period of time.
Current practices in various industries and nations are unsustainable because they depend on conditions which are only possible over the short term. For example, cheap fossil fuels.
Some other practices are unsustainable in the grand scheme of things, because they are partly responsible for an environment which is itself unsustainable. For example, costs externalised to the environment which has a delayed reaction of several decades.
“Polluting” is not unsustainable by itself as long as you have a way to counterbalance it. You can have a sustainable system which extracts resources and exhausts co2.
“Green” is worthless as an environmental adjective because it has whichever definition you want to apply to it. If you say “sustainable consumption”, though, there’s no problem creating that. Nature itself is a closed system of sustainable consumption.
> we don't know how to mine for metals without using fossil fuels.
What magical property of fossil fuels is needed to mine?
Large mining corporations seem to be on the leading edge of decarbonisation.
After all, who wants to ship fuel miles out into the desert and then burn it in an enclosed underground space when you can use solar panels and electric motors?
If you're extra clever, you can actually generate electricity as you bring the heavy ore down to sea level.
> What magical property of fossil fuels is needed to mine?
Energy density. You need large amounts of energy throughout the mining and refining process. Digging, grinding, washing, refining, transporting - all done with petrol and gas. The energy density of solar & wind is just not there.
> Large mining corporations seem to be on the leading edge of decarbonisation.
Source?
> After all, who wants to ship fuel miles out into the desert and then burn it in an enclosed underground space when you can use solar panels and electric motors?
1. Most mining operations today are open mines. 2. Petrol is burned in ICE digging and grinding machines. 3. If you want to mine in the desert you also need large amounts of water in order to wash the ores. Just look at what's happening in Chile [1].
Taken to the limit with infinite energy there's zero reason to cause any pollution at all. You can incinerate into pure molecular material anything and then convert it back into any product you want. Consumption does not mean pollution.
An electric conversion for the BN-2 Islander was being developed for exactly this purpose; island-hopping around Scotland. It looks like they've switched to hydrogen fuel cells now though - https://en.wikipedia.org/wiki/Project_Fresson
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