You may not have noticed... but the United States Navy doesn't have access to billions of tonnes of limestone while its in the middle of the Pacific Ocean steaming at 30 knots.
You might have noticed that I'm open to other possibilities, and even named one. However, mining and calcining a few billion tons of limestone per year is going to have some negatives.
Apart from having a series of giant holes in the ground where the limestone used to be, I can't really think of that many.
The arguments against mining of limestone often revolve around things like the dust from thousands of mining lorries and the like.
Since the calcining plant can be constructed on the site and supplied by the supergrid at ultra high voltage the only thing going out will be trainloads of cement to the coast or to construction sites.
One train a day extra on the railway line (plus another of empties) is not going to cause many of the ecological nightmares associated with massive scale quarrying.
No. I propose to re-purpose the existing natural gas distribution network from the provision of space heat and DHW to motor fuel. One of the benefits is better year-round averaging of usage. Eaton is/was designing a home-scale CNG compressor in the $500 price range. Gas can also be used as a backup for electricity if the grid fails or is overloaded.
It's only worthwhile as long as you have competitively-priced natural gas to use in it. I don't see gas remaining cheap for very long.
Problem with that is the existing domestic natural gas grid that is what currently goes near most fuel stations, certainly in the UK, is the low pressure "last mile" system.
Trying to load huge demand spikes on the system (such as when lots of vehicles want fueling in rapid succesion - such as in rush hour) would lead to nasty pressure drops and all sorts of problems.
Really you would either need a huge LNG staging tank where the existing petroleum tanks are, but that is likely to have planning and permitting problems since such a tank is likely far more unstable than a petrol tank in a case of a fire or whatnot or you would need to directly connect the fuel station to the high pressure grid which could require a few miles of extra pipework for each station.
It's strange that you should say this, because a network of LNG fueling stations started being built out at the nation's truck stops some time ago and is well on its way to completion. The net cost of LNG is a fraction of the price of ULSD. Entire fleets of CNG buses are being purchased in California. Cummins Westport has a line of natural-gas engines for heavy vehicles. If the stuff makes such bad motor fuel, why are they bothering? Hint: your premise is wrong.
And yet, despite the enormous subsidies thrown at compressed natural gas vehicles in the United States, and elsewhere, its use in long distance vehicles appears to remain a rounding error. (And note that the busses in California will tend to make runs that only ever take them a few miles from their home depot, making range concerns moot).
Why is this? It is simply a political statement designed to claim that they are doing something to reduce oil dependency while not actually spending any money.
LNG is apparently "taking off" as well, but trying to run a cryo plant in every single filling station is going to be far more troublesome than a simple compressor.
That is definitely going to require some new infrastructure, or simply resort to LNG deliveries by truck/lorry.... but that is going to require an enormous fleet of cryogenic-rated trailers.
Because it's the only way oil companies can make money on it. Unfortunately for them, if they build plants based on today's feedstock price of $3/mmBTU they'll get burned badly when the shale-gas bubble collapses and prices head towards $10 or even higher.
You mean like it is in Europe right now?
The import price for natural gas into the UK
today is $11.87/mmBTU.
The only place with such insanely depressed natural gas prices is the US, while most synthetic fuel production capacity is focussed on places like Qatar, where they are building synthetic fuel plants because they calculate it is better value to build those and make value added goods than it is to export liquid natural gas with all the infrastructure that has to bebuilt for that.
The amount of energy in one US of natural gas in the UK is about 88MJ, compared to about 48MJ for one dollar of diesel or petrol. (These are the wholesale prices).
Unfortunately distribution of natural gas is rather more expensive, especially when you have to deliver a compressed/liquefied product at the end.
It tends to erode natural gas' price advantage.
You might end up marginally cheaper but is hardly a game changer that is going to make everyone jump for it. (In europe almost all lorries are diesel which means they are not convertible).
If you view CNG as the gas-fuel answer to the PHEV, you'll see that there's no such expense. If we take Eaton's $500 compressor as a given, and 3500 PSI 80 ft³ SCUBA tanks for under $200 retail also, you can use natural gas the way a PHEV uses electricity: as the energy supply of first choice until the tank is empty. Since the average daily commute is 22 miles, it doesn't take very much capacity to replace a large fraction of liquid motor fuel use. A $1000 system can pay for itself in about a year.
If people just wanted to use cars for the average commute, they would already be using electrics since they could charge up at the destination and make the return journey with even something like a Leaf.
People like the freedom a car gives them in that they can drive 30 miles to go for a day out or shopping and then drive back without worrying about locating a charging point or similar once they arrive.
And it might pay for itself compared to a PHEV, but PHEVs are a looong way from being viable at the present time.
A 3500psi Scuba tank... is about 240bar, which makes the density of the natural gas..... 0.160kg/L.
This translates to an energy value of 7MJ/L compared to ~40MJ/L for petrol or diesel.
You are looking at
six times the fuel volume for CNG compared to diesel or petrol.
And then since Natural Gas requires the use of a spark ignition type engine this means you are hamstrung by the Otto cycles inferior efficiency. Leaving you ~20% down compared to the diesel cycle. (this also erodes your fuel cost advantage compared to diesel)
(As an example, a fifty cubic feet tank ends up having an energy capacity equivalent to roughly one litre of liquid fuel).
Even LNG ends up with an energy density half that of diesel.
What you need is something to perform the job that natural gas would have done at home. Heating water and air is easily done with electricity, and nukes are carbon-free.
Indeed it is, air source heat pumps can do space heating more efficiently than anything I know of. (with air to air pumps we are looking at COPs of ~5). Although if you do use an air to air system this means that the cheapest solution for hot water is to use a simple immersion heater on "Economy 7" electricity, atleast in the UK, since the capital cost of air-to-water heat pumps is absolutely enormous (compared to £30 for the heater) and the COP isn't brilliant anyway.
Depends on the chemistry; there are Li-ion electrodes with very long cycle lives coming down the pike. Several claim very low degradation despite 100% DoD per cycle.
I've seen those, some of them appear to be yet more benefits from the discovery of things like Graphene (its more bragging rights for me snice that nobel prize went to people from my department
).
Unfortunately many of them seem to be quite a long way away and I worry that they won't arrive in time.
It is physically identical to SMR hydrogen. Its real biggest problem is cost.
Hydrogen generally has some enormous problem as a motor fuel, its even more problematic than natural gas. (80kg/m
3 for a cryogenic fuel, even one with such a high heating value, is insane).
33 miles a day, 300 days a year. At 250 Wh/mi at the terminals, 8.25 kWh out of the battery. A 12 kWh battery is sufficient for this, less than 90 kg at 140 Wh/kg. Braking performance: 6 C is 72 kW, which is a lot of braking power. The Fusion Hybrid Energi claims 70 kW power in EV mode. Charging a 12 kWh battery at C/10 can be done twice a day with an extension cord.
Those estimates of 250Wh/mi tend to assume rather tepid driving at low speeds with none of the auxiliaries turned on, a more accurate figure as far asi can tell is ~500Wh/mi. (once engine efficiency is accounted for that gives you similar energy consumption to a mid sized conventional vehicle).
And another thing I didn't note earlier, you still hae to account for the absurd purchase price of most electric vehicles.
You will end up with a Nissan Leaf in price terms once you add in a safety margin at the higher and more reasonable energy consumption.
They would have a better time dealing with both their fuel price problems and air-pollution problems if they just distributed syngas as town gas for heating and also compressed as motor fuel. It eliminates all the downstream chemical processing, its costs and its losses. The flame speed of CO mixtures improves with increasing H2 content.
Unfortunately the density of syngas in energy terms ends up even more dire than natural gas due to the oxygen atom that is hauled along with the carbon monoxide and the low molecular mass of the average mixture (which leads to low densities, even when compressed at very high pressures).
Because diesel and petrol are far more expensive than CNG and LNG, and do not burn nearly as cleanly.
They aren't really
that much more expensive once you use European natural gas values which are likely to be the average once the shale gas shock works its way through the system in the US.
The particulate and nitrogen oxide emissions from diesel engines have been improved to a very large degree by a combination of gas bag filters and selective catalytic reduction using products like "AdBlue".
And before you ask how much extra AdBlue costs... almost nothing. If you buy in bulk it is ~45cents/L, and is used up at ~4% of diesel consumption which means it adds effectively 1.8 cents to the price of a L of diesel, which is rather small.
Let me remind you here that the only way to improve the environment and standard of living is to substitute cleaner energy for dirtier, and cheaper energy for costlier. Uranium is extremely cheap and clean, NG is intermediate in cleanliness, oil is costliest and a distant third to NG for pollution, and coal an even more distant fourth in cleanliness (though next-cheapest to uranium).
Coal elimination is the most important thing by miles in my opinion.
I calculated that without synthetic fuel production ro anything like that nuclear could cut carbon dioxide emissions in the UK by ~65%.
But you need something like synthetic fuel to do anything about the last 35% since it is basically motor fuels.
That is changing very rapidly; many truck stops along major routes already have LNG dispensers. I'd hyperlink the announcements but that seems to guarantee that the comment disappears forever.
According to the DoE's
Alternative Fuel Data Centre , there are a total of
28 LNG capable fueling filling stations in the entire continental United States.
What I have on electrification of railways is, IIRC, around $1 million a mile.
Wow, I haven't seen costs like that proposed for projects beyond the end of the 90s, and that was cut price ~25kV Mark 3D overhead wiring for British Rail. If only it was still that cheap today.
A more reasonable estimate for overhead wiring these days is about ~$2-2.5m per
track mile using Network Rail 'Series 2' equipment that been optimised for minimum life cycle cost.
You then have to account for the fact that truck overhead wiring by definition has twice as much suspended conductor and must then substitute far stronger cantilevers with far longer reach and taller supports (because lorries have a far larger "loading gauge" than British railways do).
Even electrifying only one lane in each direction you will strugle to get short of $5m/
route mile considering that you must use rather lower voltages than on railways for safety reasons, and must thus provide a lot more substations. (eHighway appears to use a ~3kV potential between the two conductors, which implies 1500V between each conductor and the ground).
There's only about 35,000 miles of Interstates in the USA, and $35 billion in capital cost would likely be repaid in fuel savings in the first year.
You are more likely to have to spend $175bn and there are significant maintenance costs to consider. And then there is the greater capital cost of the vehicles which means that many hauliers will be slower to transfer across, especially those that don't spend a huge proportion of there time on interstates.
Heavy trucks should probably be diverted from pavement anyway; dual-mode schemes like Bladerunner would put them on cheaper, more durable rails which can be maintained with hand tools.
Bladerunner-esque roadrailers failed because of the increased capital cost of the equipment and its maintenance compared to things like swap bodies.
I unfortunately get the feeling that this latest "Bladerunner" concept has been produced by people who have absolutely no idea how a railway functions and how it gains its energy use advantage.
It also claims that there would be little wear on the road, which unfortunately has been proven to be rather incorrect due to experience with Bombardier's GLT, since while this system will only put weight on the road wheels when accelerating, braking or climbing steep gradients, this will happen with the road wheels in
exactly the same place.
On steep climbs you will get horrifically concentrated road wear which is very expensive to repair, just as GLT has lead to all sorts of problems.
You need to review your EM field theory. You aren't going to get significant amounts of power except with a very tightly-coupled plate; anything on the roadside would be lucky to collect milliwatts.
I had to re-read your earlier statement.... attempting capacitive coupling to the
tyre reinforcing is insane. I found a paper on it that suggests only 70% efficiency.
That is rather lower than overhead wiring, and also reduces the effectiveness of regenerative braking since you would have to return the power to the road through that efficiency loss.
Also you could still steal power by running a single cable along the sides of a dual carriage such that they are on the edge of the coupled roadway, that would likely be inconspicious at the high speeds prevalent on major arterial roads, although that is a rather minor concern.
Road haulage can switch to overhead wires in principle but I think motorail has a better chance of cutting fuel consumption overall than capacitative coupling, all the extra substations neccesary to support that equipment could probably buy you enormous operating subsidies for such services.
How to pay for it: road tolls.
That is a political impossibility unfortunately, it is th world we live in.
That wouldn't separate the transuranics and fission products from the graphite. The CaCO3 scheme is just to sequester C-14.
There are no measurable transuranics or fission products in the graphite, how could there be?
They would have to escape a metallic uranium rod, penetrate the magnesium alloy fuel cladding and then penetrate the magnesium alloy channel cladding.
Across a gap filled with high pressure carbon dioxide coolant.
The artists' concepts are very pretty, I admit. I'll wait for them to prove that the Skylon engine isn't another SSME before betting on it.
The hardest bit of the SABRE/Scimitar engine technological has now been demonstrated, they tested a mock up pre-cooler assembly this summer and apparently it works as designed.
The rest is fairly simple, and the Scimitar proposed for use in the A2 doesn't have any of the extra rocket type stuff that makes the SABRE complicated.
I think they can do it if someone gives them the money.