Some people have what is called "dual fuel" for heat -- both a combustion fuel and a heat pump.  Note that while technically the "backup" strips are a "dual" fuel they're really not since both are electricity -- and resistance heating is the worst choice.

The question thus arises "at what temperature outside should I set the unit to change over?"

This is a math problem; the general formula is found on this page.

You need to know (1) your kilowatt-hour charge for electricity, (2) the cost for therms if you have natural gas (or the cost-per gallon for propane; each gallon is 0.916 therm), (3) the efficiency of your gas furnace (0.80 is typical for old-style non-condensing, 0.90 to 0.95 for the newer condensing furnaces) and you need to find the chart in your heat pump's installation manual (if you don't have it, get the model number and look online) that gives you the COP, which is Coefficient of Performance curve for various outdoor temperatures, indoor coil input temperatures and airflow.

With the indoor coil you have you can determine the airflow setting in use, or if you don't know use the middle one -- it'll be pretty close.

So here's an example:

Electricity costs 0.15/kWh
Natural Gas costs $1.35/therm
Your furnace is new (95% efficient)

Therefore the COP changeover point is: (0.15 * 0.95 * 29.3) / 1.35 = 3.09

Now look on your chart or table for your heat pump and find where the COP for your typical conditions indoors (usually 70F at the coil) and airflow (if you know, or use the middle if you have to guess) crosses 3.09 for outdoor temperature.

Above that outdoor temperature the heat pump is cheaper to run, below it the fuel is cheaper.

That is where you set the changeover.

Note that as the power or fuel cost changes so does the proper change point and most of the time that's reasonably stable during a winter season but changes from year to year, possibly by quite a bit, especially for either gas or propane.  Also note that with propane being wildly more expensive than natural gas most of the time the difference between those two alternative fuels is huge if the power cost is identical.

This is all a numbers question and if you can use either at your discretion why would you spend more money than you need to keeping your house warm in the winter?

Calculate the correct place each fall, set that, and whenever the power or fuel cost change get out the calculator and see if you need to move it.

You might think that dual fuel makes no sense up north but you'd be wrong; it in fact makes more sense up north than it does anywhere else because up north there are very significant parts of the year where a heat pump wins big on operating cost but at the same time it gets cold enough that it can be a huge lose, especially if you size it sufficiently to be able to keep the house warm at all in cold temperatures.  Most modern systems will produce quite a bit of usable heat even at zero Fahrenheit outdoors but they usually lose massively to natural gas at that temperature as their COP is down to 1.5 or so.  At 40F, however, modern units can produce a COP of 3.0 which can be a huge win, especially against propane.  In fact if your secondary fuel is propane the heat pump is often cheaper to run, depending on electrical cost, even down into the single digits outdoors!

This is a math problem so run it for your unit and see where the correct place to set it is.  If you're looking to replace an HVAC and have a secondary fuel available run some typical scenarios -- you might be surprised at how fast the dual-fuel setup pays for its additional up-front expense and the further north you are and thus the larger your "shoulder" season the more-likely that is to be true.

If you have read Leverage one of the key points made fairly early on, and one I've made repeatedly in this column, is this:

Behind every unit of GDP there is a unit of energy.

It has always been thus and always will be thus.  It is akin to the laws of thermodynamics, which you cannot do anything about and it does not matter if you like them or not.  Attempting to go "beyond them" will not only always fail it will hurt in some regard since it will at best be a less-than-optimal experience and at worst will be a death-causing one.

Fracking was considered a "miracle."  It was no such thing.  I noted many years ago during its "heyday" that it was nothing more than a parlor trick: Yes, you get hydrocarbons out of the ground in places where they were formerly uneconomic to attack, but the problem with doing so is that you haven't changed the amount in the ground -- only the speed of extraction.  Therefore if you double the speed of extraction you also double the rate of depletion!

One of the common chestnuts is that we're "running out of oil."  We are not.  There is a crap-ton of oil.  The problem is the cost of extracting it.  We've run out of cheap to get to oil.

Indeed, we have more than 500 years of reasonably-recoverable and consumable fuel that can be used as liquid hydrocarbons and, if you do not care about cost, we actually have an infinite amount!

What, you say?  That's impossible!

My riposte is that you failed high school chemistry class.

Hydrocarbons are simply chains of hydrogen and carbon, when you get down to it.  Natural gas is a simple one; CH4, or one carbon and four hydrogen atoms.  It has much more energy than coal (which is basically just Carbon) because hydrogen has much more electronegative potential, and thus when burned you get much more energy released for each unit of fuel you use.  This has been the primary reason the United States has in fact dropped its per-BTU CO2 emissions dramatically over the last 30 or so years; natural gas has been cheaper than coal.

We don't use hydrocarbons for energy because we're pigs that hate the Earth, in short.  We do so because they are the only reasonable means to get the energy required for modern life in a package form that works.  All the screaming about EVs and similar is nothing more than a bunch of ignorant jackasses who think they can violate the laws of thermodynamics..

You can't.

The person who figures out how to do it, if it can be done, creates a world that is wildly beyond the dreams of Lucas and Roddenberry.  Even in the Star Wars and Star Trek fictional universes they follow the laws of thermodynamics -- in Star Trek they use dilithium as an energy medium, and in Star Wars it is Kyber crystals -- both of which have to be mined, in other words, both of which were created as a result of the formation of planets and stars and both of which are finite resources.

Let's take a simple example: An electric car.  It's "more efficient" than burning gasoline, right?

Uh, nope.

A modern gasoline engine is about 35% efficient in terms of taking the BTUs in the gasoline and turning it into movement.  That's horrible, you'd think -- electric motors can reach 90% efficiency with modern controls (and the motors in electric cars typically are near that range.)

Electric wins, right?

WRONG.

Every transfer or transformation of energy involves loss.

The best combined-cycle natural gas generating plant has roughly 60% energy efficiency.  These are the most-modern; everything else is worse.  Nuclear is a lot worse, typically, about half that (that is, for every watt that comes out of a nuclear plant as electricity about two more wind up dumped, typically into a body of water.)  So we'll use the best.

The natural gas plant is 60% efficient making the electricity.

The transmission of the power from the generating plant to your house is 95% efficient (5% is lost, roughly.)

The charging of the EV battery is about 75% efficient during normal (slow) charging but this drops wildly when "superchargers" or similar are used.  Such charging is unlikely to exceed 50% efficient due to the requirement to keep the batteries cool.  In short charging at more than "1C" for a lithium cell results in much lower charge efficiency because you are attempting to "overdrive" the chemical process that charges the cell, and doing so radically increases loss.  We'll use 75%.

Assuming you do not let the EV sit (all batteries self-discharge over time) and drive it the next day the loss from self-discharge is very small.  We'll ignore it, and give you the entire 90% "best of breed" efficiency between the battery and the wheels (the withdrawal of said energy, control electronics and motor turning the stored battery power into movement.)

So where are we thus far?

0.6 * 0.95 * 0.75 * 0.9 = 38.5% efficient for the EV assuming the best case, which of course is bullshit, but even if you assume such it is still nearly identical to that of the gas-powered car that cost far less money to buy!  Never mind that there is no economically-viable means to recycle a lithium battery pack in an EV; it is toxic waste when it wears out and inevitably, as with all such things, it does.  Nearly every part of a traditional car is recyclable; the metal the vehicle, including its engine and transmission all is, much of the plastic is, and the starting battery is almost 100% recyclable into a new starting battery.

But while you can't violate the laws of thermodynamics you can deliberately cripple yourself.  We can, for example, make all the liquid hydrocarbon we want out of atmospheric (or sea-sequestered carbonate) sources of carbon.  Indeed the CO2 bottle that is refilled at your local brewery or fast-food store that dispenses fountain drinks was almost-certainly condensed out of the air; that is the most-common means by which industrial CO2 is produced.  The reason we don't do this to make fuel is that you must put the energy back in you wish to liberate, plus something for the inevitable losses which you cannot eliminate.  In short what we're doing is using that which the sun put in via energy rather than doing it ourselves and the reason we do it is that it is cheaper.  That's all.

It does not matter if you like these facts or not; they are nonetheless facts.  No amount of braying at the moon nor complaining by the "green wokesters" will change it.  What you can do, however, is foolishly jack up the price to the point that nobody can afford it, at which point modern society as we know it ceases to exist.

Consider that while you may think it would be great to not have all those vehicles running around spewing CO2 into the air where the CO2 goes into the air doesn't change that it does so, and the "more refined" form energy takes the more loss and less efficient it is.  Electricity is a very highly-refined form of energy particularly when compared to, for example, a gallon of diesel fuel.

The premise that we can shift all our energy needs to "renewables" is pure folly.  We cannot at a price that can be paid by the common person, and whether we like it or not renewables are largely unreliable as well so you must add massive storage costs which makes them even more uneconomic.  While the ultra-rich do not care if their power bill at their mansion goes from $2,000 a month to $5,000, since they make north of a million a month anyway, the common person cannot pay a $500 electric bill that used to be $200.  That's roughly $3,500 a year of additional expense they do not have.  To cut that $500 bill back to something they can afford they cannot have either heat or air conditioning, and might not be able to have hot water!

Years ago I penned a column that was an expansion of part of what I wrote about on energy in Leverage called "Let's Talk About An ACTUAL Energy Policy" that, unlike the woke dreams and fairy tales does not violate the Laws of Thermodynamics nor does it require that we conquer something (e.g. fusion) we do not know how to do.  It does require engineering progress, but engineering is something that humans have always been good at, given the will.  Our landing on the moon is but one example; there were no actual breakthroughs required in terms of what we knew how to do, but engineering, the application and refinement of what we know, was required.  The same holds true here.

It is indeed easier to scream at people about them being pigs than to put your nose down and solve engineering problems, especially if you lack the intellectual firepower required to do the latter.  Those who fly all over the world yet scream about fossil fuel use are in that group -- to an individual.  So are those who live in mansions rather than 1,000 sq/ft hyper-insulated homes, have swimming pools and other personal accoutrements.  Fenestration (windows) are energy pigs; the person who claims to be a "green woke individual", if they're not lying, has no business living in a structure with floor-to-ceiling "natural light" that both gains energy in the summer and loses it in the winter, both of which must be reversed by artificial (and earth-damning, by their claims) means.

Perhaps as the self-imposed stupidity begins to bite we will force some of these people to live by their own standards.

I might also grow six heads, but somehow I suspect both are equally likely, and given the public's unwillingness to take the time to understand even the most-basic principles of both chemistry and physics I hold out little hope on a forward basis.

Meh.....

More than 50 U.S. companies are developing advanced reactor designs that will bring enhanced safety, efficiency and economics to the nuclear energy industry.

X-energy, located just outside the nation’s capital in Greenbelt, Maryland, is working on a pebble bed, high-temperature gas-cooled reactor that the company says can’t meltdown.

X-energy is developing its Xe-100 reactor and specialized uranium-based pebble fuel that could be available in the market as early as the late 2020s.

Who gives a shit?

Seriously, I mean it.

This design does have advantages -- don't get me wrong.  It's also not new.  The premise is that you construct fuel "pebbles" (about the size of a cueball, so more like "fuel rocks" rather than pebbles) that contain the fuel inside an allegedly "impervious" sphere.  The pebbles, being spherical, allow gas (Helium in this case) to pass between them, which takes the reaction heat away, and you use that to produce electricity through a traditional heat exchanger mechanism.  The moderator is graphite and in the reactor vessel; the fuel is cycled through from top to bottom, which means it is continually refueled in operation, with each fuel unit running for about three years.

Traditional water-cooled reactors use zirconium for the fuel rods.  Zirconium is "transparent" to neutrons; that is, it neither interrupts their passage nor does it get "activated" (absorbing them and becoming a radioactive isotope.)  This is good; you want what looks like a window to the sun for neutrons, because they have to get into the fuel in order to cause fission.

But zirconium has some problems.  Chief among them is thermal tolerance.  This is not a problem provided the reactor remains flooded with water, since water has a critical point of ~3200psi and ~705F.  Therefore you must keep the pressure below that and the temperature below it too, since water is also the moderator.  Above 705F it's steam no matter the pressure.  For this reason water-cooled reactors tend to run around ~1,000psi in normal operation for a BWR and ~2,200psi for a PWR.  BWRs are simpler in that as water boils it loses its moderation; this is a negative feedback on the power level and makes designing control systems, and their inherent safety, easier.

However in the event of loss of circulation (the ability to dump heat) or coolant (e.g. pipe break, etc) you have a severe problem because zirconium melts at ~3,300 F -- and once it does, you're screwed.  Silicon carbide, which is what the pellets in a pebble-bed reactor have their outer shell made of, doesn't melt until nearly 5,000F.  That's a huge safety factor.

But, there's a rub.  The "safety analysis" has run tests that postulate that in an accident the temperatures should not exceed 1,800C.  I note that this is below the melting point of zirconium, yet as we know in Fukushima and elsewhere, that temperature is indeed exceeded in bad situations.

There are also general issues with graphite moderators; they're manageable however, albeit at some cost.

So how safe is this thing?  Well, good question.  But in the end, it doesn't matter.

No fission design is safe end to end, which is all that matters, until and unless you have a closed fuel cycle.  The problem is that the burn-up in a TRISO fuel reactor -- that is, a pebble bed, while much better than a BWR or PWR (20% .vs. ~10%, roughly) still sucks in that 80% of what you put in there comes out and has to be reprocessed somewhere or discarded as high-level waste.

There is no reprocessing in the United States today, and hasn't been since Jimmy Carter shut it down.  Therefore any plant design that does not inherently separate and reprocess its own fuel as an inherent part of its operation is manifestly unsafe and unsuitable for deployment until and unless there is a viable reprocessing cycle available in the United States.

There is only one way to safely deal with most transuranics, which remain dangerous for tens or even hundreds of thousands of years.  You have to put them back into a reactor and burn them up.

Short-lived isotopes that reach a stable, non-radioactive element with half-lives in the range of single-digit years or less we can deal with.  After 10 half-lives basic mathematical theory tells us that the substance is no longer dangerous no matter how high-level of radiation it emitted originally.  But that's not something you can fudge; anything with half-lives in the tens, hundreds or thousands of years has to be returned to a reactor and reduced in this fashion until it reaches either a stable isotope or one with a half-life of less than 10 years.

Period.

Now there will always be a small amount of waste that isn't amenable to this, but if it's small enough in volume it never has to leave the plant until the plant is decommissioned.  What we cannot accept is a no-reprocessing paradigm, which is what we have now, where fuel comes out of these units full of hundred or thousand-year or more half-life highly-radioactive elements for which we have no rational disposal mechanism.  Without reprocessing we cannot put those elements back into a reactor and burn them up and we have nowhere we can safety put them either.

Nuclear power safety is not solely about meltdown safety, although pebble bed designs look promising in that regard.  In addition these designs have other challenges, one of them being that they use Helium as a coolant -- and Helium is a non-renewable gas that is in short supply and in addition it's a very small molecule so it leaks like crazy.  Helium, incidentally, is used as a coolant in these units for a number of reasons -- among them is that it is not easily activated (that is, it doesn't capture more neutrons easily) and when it does it decays extraordinarily quickly, so it doesn't form dangerous reaction products.  This means that if it's released (e.g. due to a pipe break) it won't hurt anyone as any activated isotopes will decay before it can get out of the building.  It also has a pretty good specific heat ratio; that is, it carries heat well as gases go (much better than air, for example), so it's a good choice for that reason as well.  Being inert it has no reactive issues with the various materials inside the reactor either, which is a big bonus.  And it has a very low neutron cross-section, so it doesn't interfere with the fission reaction itself.

Finally, due to the use of gas as a coolant and the much higher temperature tolerance of the fuel these units run at materially higher temperatures than a common PWR or BWR, which means they're materially more thermally-efficient.  It also means they can, at least theoretically, be run in places where large-volume water cooling is not available (e.g. inland, and not near oceans, fault lines or huge lakes) with reasonable overall efficiency.  That's a plus.

But on the downside our supply of Helium is basically all from natural gas wells, where it's a trace component of what comes out of the hole.  It's completely non-renewable and non-capturable, in that it is so light it effectively disappears into the upper atmosphere when released.  For this reason consumption of it is a serious long-term problem since our ability to get more of it is inherently tied to natural gas production.

Nonetheless the big problem with all of these types of reactor designs remain -- there is no sane means of dealing with the waste products out of these units.  Of the fission designs currently known and on the board there is only one that is amenable to continual, on-site reprocessing that burns up basically all of the high-level reaction products as part of its normal operation.

That's the LFTR, which uses Thorium as its fuel, is started on Uranium (since Thorium is fertile and not directly fissile) and since the fuel is dissolved in the working fluid it can be reprocessed chemically online in the plant itself, thereby allowing on-site burn-up of most of the high-level reaction products.

Oh, and it is also passively safe since are no fuel pellets or rods that can overheat, crack and release the material inside, and we know that passive safety system works because it was run for several years at Oak Ridge in the 1960s and when the scientists went home for the night they literally just turned the power off to the systems and walked away.

I wrote an article on a viable hydrocarbon replacement strategy here, and also covered it extensively in my book Leverage in Chapter 10.  It's as valid today as it was then; go read it.

The LFTR was abandoned, incidentally, because being Thorium fuel-cycle based it is almost entirely unsuitable for the production of nuclear bombs -- and we wanted dual-use nuclear technology.

Go figure.

We are so fooked here in this country by our willful blindness....

Last year, Kirk Dorius and I travelled to London to participate in the kickoff of the Weinberg Foundation, an advocacy group for thorium energy.  I am pleased to announce with them the formation of an “All-Party Parliamentary Group” or APPG that contains members of both the House of Commons and House of Lords, to consider the potential of thorium as an energy source. 

In a word, "Duh."

Here's the thing folks, when you boil it all down -- thorium is a no-brainer when it comes to a nuclear fuel and fuel cycle, assuming you want power and not bombs.  It also is the enabling pathway to petroleum independence without changing the consuming end of the pipeline.

Many "green" evangelists are all ga-ga over electric cars.  But they forget that while chargers are quite efficient (~80-85%) and electric motors are too (~85% for the best of what we can offer today) the fact remains that batteries have a crap energy density (meaning the amount of energy the contain per unit of both mass and volume is poor), they have a poor energy acceptance rate (how quickly you can charge said battery, requiring hours .vs. minutes to fill a fuel tank) and in addition they simply shift where the energy production takes place (to the coal plant behind the undesirable neighbor's house.)  In other words they simply move the exhaust pipe instead of getting rid of it.

Indeed when you stack the inefficiencies electric cars don't look so good.  A typical gasoline or diesel car is somewhere around 30% efficient end-to-end (that is, the number of BTUs of energy that go into the fuel tank .vs. the amount of energy that actually moves the car.)  The rest is lost as heat in some form or fashion, whether out the tailpipe, rejected by the radiator or as friction somewhere in the middle.

But neither do electric cars.  When we stack efficiencies we see the problem quite quickly:

30% (conventional nuclear or coal) to 50% (combined-cycle such as natural gas) at origin.
90% efficiency in transmission (transformers, loss on the electrical line, etc)
85% efficient (battery charger)
80% efficient (battery itself, assuming 50% charge state -- much less at 85%+ of full charge, perhaps as little as 50%)
85% motor, controller and gearing (in the car)
=====
15.6 - 26% end-to-end

Oops; that's no better and if you start with 30% gross at the generating end it's actually worse!

So the argument for "energy efficiency" doesn't work in favor of electric.

Why does this mean we should use thorium?

Simple -- thorium reactors can be run not on pellets of fuel as conventional reactors using water as both a moderator and coolant, but rather with the fuel dispersed in a molten salt used as the working fluid and a fixed moderator in the reactor chamber.

This is a huge win for a number of reasons:

• The reactor runs at much higher temperatures. Typical operating temperatures are in the 550-650 Celsius range as opposed to water-cooled reactors which are limited by the critical point (374 Celsius); beyond that temperature irrespective of pressure water does not remain liquid.  This means that the heat of vaporization is zero, which in turn limits the useful working temperature of the coolant.  The other problem with water is that to approach the critical temperature requires containment at extraordinary pressures; 217 atmospheres to be exact (over 3,100 psi!)
  
  
• LFTR reactors run at normal atmospheric pressure.  A big part of the danger with conventional reactors comes from the properties of water at high temperature.  In order to keep it liquid you must hold it under extraordinary pressure.  Everything is much more difficult from an engineering perspective and any failure of that pressurized state is catastrophic as the water instantly flash-boils to all steam, resulting in the reactor having no coolant!  This is also why a conventional reactor requires uninterrupted power all the time; you cannot allow the coolant temperature to go over the critical point and since the fuel produces decay heat after shutdown you therefore must provide continual coolant flow until that heat is extracted.  The failure of that continual flow is what led to the Fukushima disaster.  LFTRs do not suffer from this problem as they do not operate under high pressure.  If all power is lost at a LFTR plant the coolant containing the fuel can be allowed to drain by gravity into tanks where, with no moderator present, the reaction stops and it simply cools over time on its own.  This passive safety was tested and proved effective in the United States in the test plant operated at Oak Ridge some 40+ years ago!
  
  
• You can use the higher process heat level, up to 650C, to directly convert any carbon source to liquid hydrocarbons.  Coal happens to be a convenient source of both thorium and carbon, but in point of fact carbon can come from any source -- including atmospheric CO2. The Germans figured out how to turn coal into liquid synfuel during WWII and we have refined that process since then.
  
  
• Reprocessing is continuous and online in form; the reaction products are thus nearly all consumed over time, producing a waste footprint that is a tiny fraction of conventional nuclear plants.  Conventional uranium-fuel-cycle reactors only have ~5% of the fuel material in the reactor that is actually fissile; the rest is bombarded over time.  Some turns into plutonium that can then be reprocessed and burned up, but a large amount of the remainder winds up as highly-radioactive byproducts that are dangerous for enormous lengths of time.  A commercial LFTR would be built with "online" reprocessing to separate out the neutron poisons (specifically Xenon) and introduce more thorium as the fuel is consumed.  The result is that most of the reaction byproducts remain in the reactor until they are reduced to less hazardous (or non-hazardous) elements and compounds; the decay heat released in this process also is harvested to produce useful energy instead of being dispersed in big cooling pools.

This is not necessarily a "cheap" oil replacement, but "cheap" is relative.  Can we produce $20/bbl equivalent oil products with this technology?  No.  Can we match $100/bbl oil?  Probably, and that's the point -- we can both produce electricity and 100% independent liquid hydrocarbons to fuel our buses, trucks and cars.

In addition we would be using a far safer technology than we use today for nuclear power.

I highlighted this alternative in Leverage for a specific reason -- behind every unit of GDP is a unit of energy.  If we are to ever rationalize our federal government spending on all things, including most-particularly our military, we must become energy independent.

We proved that these reactors can work in the 1950s and 60s at Oak Ridge.  This is not "pie in the sky" technology or the subject of science fiction.  It is a matter of science fact that we can, if we're willing, exploit to resolve our domestic energy requirements.

It appears that Britain is going to join China and India in heading down this road, leaving America behind.

We cannot afford to be left behind.

Sigh.......

Batteries are now "part of the clean-tech boom, with all the dewy and righteous credibility of thin-film solar and offshore windmills," Seth Fletcher asserts in "Bottled Lightning." Righteous? Surely. Credible? Maybe.

Uh, credible, no.

Some commentators worry that we're going to replace our dependence on foreign oil with a dependence on foreign batteriesand foreign lithium. "Bottled Lightning" alleviates at least one worry: By taking us to the salt flats of the "Lithium Triangle" in Chile, Bolivia and Argentina, Mr. Fletcher shows us the abundance of the metal and puts to rest any fears of "peak lithium."

Mr. Fletcher is in love with the Volt. After a test drive, he gushes: "The car, in short, is fantastic." And it is technically sweet. But at $41,000 per copy, will it interest American drivers?

Hypesterism is not scientific evidence or supportable.

Look, I'd love to find a solution that works in the "battery" realm.  But Seth (and everyone else!) has two problems he has to deal with (and hasn't):

• Charge acceptance.  That is, how fast can you stuff energy into the battery.  This is largely a function of the battery's effective series resistance while being charged; the more of it the more energy gets dissipated as heat in the battery rather than being stored chemically.  Lithium batteries can be charged at higher rates than other chemistries, but the practical maximum is "2C", or double the amp-hour rating.  Going beyond that tends to do a lot of damage to the cell in a big hurry, reducing capacity dramatically, and this assumes you can dissipate the heat (if you can't you get a fire, which of course is very bad!)  As a practical matter this means that while a 30 minute charge is possible assuming you can find a plug that can deliver the amps necessary to do so, the expected "5 minute fillup" is NOT.  Note that the Chevy Volt has a 16 kWh battery pack in it but can only realistically draw down the pack to 30% before protective actions limit further discharge (cell damage occurs below this level.)  That is, we have about 11kWh usable in the pack, so to recharge it in 30 minutes (assuming "2C" can be done) we'd have to source 22 kW before losses.  That's about 100 amps @ 240V.  That's bad news but it in fact gets significantly worse because as batteries go over about 80% charge their acceptance goes down materially, and as a consequence trying to get the last 20% into them on a "rapid charge" is going to both decrease efficiency significantly and increase the heat dissipation problem.  As a result with losses we probably need around 125 amps @ 240V and we can only realistically charge for 25 minutes, leaving us 15-20% short of "full."
  
  Note that if you have a larger battery, allowing a longer range, in order to be able to charge it in 25 minutes or so your power requirement is going to go up a lot.  Let's assume that we want not 40 miles of range but two hundred miles, and we will accept a 30 minute charge after that (that is, we'll travel for three hours @ 70mph and will accept a 30 minute layover after those three hours.)  Note that this is quite conservative - the average modern car can travel about 400 miles before refueling, so a 200 mile range is actually quite a decrease.  But now we need five times the electrical delivery rate, or over six hundred amps of 240V power.  That's three times the total electrical capacity of a modern home's power feed - per vehicle that is charging at one time.  Exactly how many cars did you say that "filling station" was going to be able to support?
  
  
• Energy density.  Batteries are chemical devices; they perform a chemical reaction called a "redox" reaction, or reduction + oxidation.  But unlike combustion (e.g. a gasoline engine) a battery has to carry its oxygen inside the case where a hydrocarbon fueled engine gets the oxygen from the air.  In the case of burning natural gas, for example, you have CH4 + 2O2 -> CO2 + 2H2O.   The total mass of the reactants for this chemical reaction is 12 + 4 + 64 or 80 amu of which 64, or 80% of them, come from the atmosphere rather than being carried in the vehicle. 
  
  In the case of the battery all of the reactants are in the case and the cell has to contain the products and have the other half-reaction (reduction) present so the discharge of the battery can be reversed.  This produces a huge disadvantage for the battery in terms of the amount of energy per unit of mass (and usually volume) for the battery that cannot be reasonably overcome.

These are the realities of chemical reactions folks.  I know there are a lot of people who would love to find a way to "replace" liquid hydrocarbons, but the fact remains that we don't use them due to some conspiracy.  We use them because they pack a lot of energy into a small space and the majority of their reactant mass comes from the atmosphere.

There's no getting around these facts.  Better technology will, over time, improve charge acceptance, but it is going to be hard-pressed to do much for density problem which comes about from carrying the necessary reactants in the battery's case.

Hype must give way to physical and chemical reality.