Jobs said.... "There is not a straight piece of glass in this building. It's all curved. We've used our experience making retail buildings all over the world now, and we know how to make the biggest pieces of glass in the world for architectural use. And, we want to make the glass specifically for this building here. We can make it curve all the way around the building...It's pretty cool."
A conventional Todos-Santos style glass brick would cost half the price or less of the current design, be easier to heat and cool, use less ground footprint and it would be more convenient to get around in with elevators, walkways etc. even with the same floor space per drone.
It's amazing what you can do with other people's money though, isn't it?
I think the ticket price for the building is about $5 billion, it may rise as the project goes ahead -- there's lots of custom curved glass panels and such involved. With 14,000 workers expected to use the building that works out at about 350,000 dollars each. Office space in Cupertino leases at about $35/sq. ft./year so for the proposed upfront cost they could lease 500 square feet for each employee for twenty years and not have to pay for the structural maintenance, landscaping etc.
Reprocessing and MOX manufacture is expensive, a lot pricier than using cheap freshly-mined uranium ore in a once-through operation. The big win with reprocessing is that it vastly reduces the mass and volume of dangerous waste needing dealt with, even after vitrification and encapsulation. That makes final disposal a lot cheaper and simpler as well as reducing proliferation worries since none of the resulting waste is at all suitable for nuclear weapons development.
No-one takes in another country's nuclear waste, at least not spent fuel or reprocessed waste. Britain and France used to reprocess spent fuel from Japan but the recovered uranium and plutonium was reformatted into fresh fuel elements and they along with the waste from the reprocessing operation has been returned to Japan.
Reagan reversed the ban Carter imposed on commercial reprocessing of spent fuel in the US in the early 80s. Nobody has funded a reprocessing operation (other than the lines used to produce weapons-grade materials from military breeder reactors) in the US for various reasons; raw uranium is cheap, nobody wants to use MOX fuel for cost and operating licence reasons and the US government is in charge of making spent fuel go away for which the generating companies pay a levy, currently over $30 billion dollars over the past few decades (it's what paid for Yucca Mountain).
The Rokkasho reprocessing plant started test operation about a year ago, based on a prototype reprocessing operation at Tokai. When it's up to speed Rokkasho will reprocess about 800 tonnes of spent fuel a year. Simply speaking you're totally wrong.
Japan has been importing LNG for decades now and has the specialised ports to handle large quantities of it; the Chiba oil and gas terminal near Tokyo is one of them. It suffered major damage and fires during the earthquake but was speedily brought back into service.
Coal is about half the energy of LNG tonne for tonne. TEPCO generates about 40% of Japanese electricity and they are importing about 5 million tonnes of coal a year and about 24 million tonnes of LNG to burn in their fossil-fuel power stations. There's a small amount of fuel oil and crude used as well (maybe a million tonnes in total) but the overwhelming majority of their generating capacity is LNG-fired.
Fukushima Daiichi took a magnitude 7+ Richter hit from the Great Tohoku earthquake, it was magnitude 9 at the epicentre out at sea. The plant's buildings got through that shock pretty well though (there may have been some damage to some internal equipment in the reactor buildings, it's too difficult to inspect them properly at the moment). The reactors at Onagawa further up the coast and closer to the epicentre rode out the earthquake and tsunami safely with no problems.
The tsunami killed about 20,000 people, not 30,000. Nearly all of them died because the towns and cities along the Tohoku coast weren't as well protected from the tsunami as the Fukushima Daiichi plant and other nuclear plants like Onagawa were.
Japan is currently burning mostly natural gas for its electricity generating needs. It has to import all of its fossil fuels and NG is as easy to transport and handle as coal and burns a lot cleaner. It's still releasing a lot of CO2 and causing an increase in smog and air pollution. Efforts are being made to bring about a dozen reactors back online this winter, whether that happens or not is in the lap of the gods.
Aluminium smelters need predictable cheap electricity. They don't do well with variable renewable sources like solar and wind since when the power drops the bauxite melt in the electrolytic cell solidifies and stops being a conductor and the crud needs to be jackhammered out before the cell can be re-used.
Hydro is the best source of electricity for this purpose; Norway is another country exporting their cheap hydroelectricity in the form of refined aluminium billets.
Folks have mostly stopped exploring for large uranium ore bodies in part because current reserves are being exploited so efficiently the actual value of uranium is very low -- the current price for yellowcake (refined U3O8) is $35 per pound at the minehead. There are big known reserves (probably counted in the overall availability estimates) in placves like northern Canada which can't be exploited commercially as yet since the geographical limitations would put the price up above the market rates.
If the price of yellowcake doubled, by the way, it would add less than a cent US to the cost of a kWh of nuclear power. This is not true for gas, coal and other fossil fuel generators.
Yep, fascism was a big thing with the Founding Fathers -- "We must all hang together, or assuredly we shall all hang separately" was (reputedly) said by Benjamin Franklin, for example. The preamble to the Constitution talks of "a More Perfect Union", more "strength through unity" ideology.
Educated folks of the mid-18th century were fascinated with the history of the Romans from the Republic through to the Empire and of course this is where the fasces concept came from. Not surprising the nascent rebels thought it was a good idea, along with slaveholding, expansion and conquest and ruthless suppression of internal dissent and rebellion.
Fascists have mottos like "E Pluribus Unum" -- "One out of Many". If you want to see what a real fasces looks like take a close look at the Lincoln Memorial sometime and notice what the Republican President depicted there is resting his hands on.
No the coal stations don't power down significantly overnight. The CCGT systems do wind up and down significantly over a daily cycle, not so much with coal. A quick check shows that over the last 24 hours in the UK coal has delivered between 14GW and 16GW, nuclear has been steady at just over 7GW, CCGT has swung between 3GW and 20GW and wind between 2GW and 4GW.
There are Europe-wide carbon-emission restrictions on generation from some older coal plants meaning they can only operate for a limited number of hours each year; these stations are being cycled up and down as necessary to reduce their total burn time but the newer stations outside that restriction run balls-to-the-wall to provide baseload absent outages for refurbishment.
To absorb the RF energy -- b/g/n Wifi is very close to the frequency used in microwave ovens and so it's optimised to heat up meaty tissue (and vegetables too; this is Georgia Tech we're talking about, isn't it?)
In the UK where I live coal generation output doesn't fluctuate much, just when plants are taken offline for scheduled downtime so it's fair to call it baseload, same as the nuclear plants since they're so cheap to run in terms of fuel cost per kWh generated.
Wind generating capacity goes up and down with the weather -- a few weeks ago the national grid was getting 50MW from grid-connected wind during a quiet period, a few days ago in the aftermath of a storm is was producing 5GW or a hundred times as much. CCGT is used for peaking to fill in the gaps plus a couple of interconnectors bringing in power from France (80% nuclear low-cost electricity) and the Netherlands (cheap gas generating capacity) pretty much steady-state. Solar doesn't account for much as you might expect this far north.
Electricity demand at night in the summer in the UK is about 25-30GW; a lot of industry uses electricity overnight and its value is not zero. Nuclear plants run 24/7 unlike variable renewable generators so they don't need to have storage costs factored in. Of course the renewable generators don't pay for storage anyway, relying on baseload nuclear, coal and CCGT to fill in the times when the wind doesn't blow and the sun doesn't shine.
As for cheap renewable power, the most expensive electricity for consumers in Europe in Germany which has the greatest penetration of renewable energy in its generating mix -- Germans pay about twice as much per kWh as British consumers or even the 80% nuclear French which is kind of strange given that Germany still generates about 50% of its electricity using cheap lignite and brown coal with a good helping of Russian gas to fill in the gaps.
Exactly when renewable energy will become cheap I don't know, it's getting to the point where the first generation of wind turbines built in the 1990s are being decommissioned and will need replacing, adding more capital costs to the generating budgets. I don't know who's going to fund the removal of obsolete wind turbines and remediation of the sites -- several wind farm operators have gone conveniently bust before those costs hit the balance sheet.
The strike price for the proposed 3.2GW Hinckley EFR project is about £95 per MWh i.e. the grid operators will pay that price for the electricity generated. The current strike price for offshore wind which the grid operators are required to buy due to Renewables Obligation Certificates (ROCs) is about £140 per GWh, about 50% higher. At the moment British consumers are paying about 15 pence per kWh which works out at £150 per MWh or nearly the base cost of offshore wind with no allowance for the cost of transmisison, grid support etc.
Coal generates the largest share of electricity in the UK with gas filling in the gaps. Our nuclear fleet runs flat-out (apart from scheduled maintenance downtimes) producing about 7GW and we buy in about a GW of nuclear power from France pretty much continuously. The rest is a small amount of hydro (less than a GW total) and a very variable amount of grid-connected wind -- right now it's producing about 2.3GW but a couple of weeks ago it was less than 50MW. Grid solar is not even noticeable on that scale.
The EPRs and other GenIIa and GenIII nuclear plants being built around the world are expected to operate for at least 60 years; this is a difficult proposition to finance in today's world of millisecond financial trading and live-or-die quarterly accountancy. They are national infrastructure rather than commercial operations and should realistically be looked upon as similar to, say, major highways and railroads, bridges, water supply systems etc.
Windows 8 Pro on the Surface Pro can run up to 4 VMs so anyone who wanted to experiment with, say FreeBSD on this hardware could do so without having to install an alternative OS. I don't know if the touch screen and digitiser is supported by other OSes though.
What are the few people in the village able to read books in this magical library going to build the magical water condensers out of? The nearest Home Depot is five thousand miles away and they don't take IOUs. New farming techniques are a faster way to die of starvation in most situations as it takes a few years of experimental crop failures to develop something new and better than the locals hadn't discovered over the past few hundred years of famines.
Is Dell enough of a major manufacturer for you? I just got a replacement 27" Dell 2560x1440 monitor delivered today after a big electricity spike blew out my previous Dell 27" monitor a few days ago.
Sure it costs more than piddly little HD-resolution monitors but I'm looking at nearly twice the number of pixels as HD, it's an IPS panel, high-gamut and with a lot of useful extra functionality (a USB 3.0 hub, for example). Well worth the £550 I dropped on it.
If you are willing to compromise and really want a 24" 1920x1200 monitor Dell make them too. The 2412M is affordable, the U2413 has a higher gamut at a higher price. Your choice.
Oddly enough, uranium mining produces noticeably radioactive waste. The ores are radioactive mostly because of decay products from the uranium built up over hundreds of millions of years. After the ore is processed and the long half-life uranium is extracted those decay products are more concentrated in the spoil. It's not much of an increase but it is noticeable. There's also a noticeable release of radon gas into the atmosphere during the mining process.
The good news is that there isn't a lot of waste since a uranium mine only processes a comparatively small amount of ore. The proposed mine in Greenland would produce about 220,000 tonnes of uranium; at about 2-3% metal in the ore (at a guess) that means roughly 6 million tonnes of ore would be dug up during its lifetime. The world digs up about 7 billion tonnes of coal each year, most of which is burned to produce electricity. In comparison about 70,000 tonnes of uranium metal is used to provide power annually around the world, the result of mining about 20 million tonnes of ore. With more recycling and reuse of spent fuel that figure would be much less.
The problem with the contaminants I mentioned is they are created on the fuel cell's catalytic surface which is usually at a thousand deg C or hotter. A simple hydrogen-oxygen fuel cell produces only water, adding nitrogen and carbon molecules to the feedstocks generates assorted pollutants, some of which are not good for you if released in quantity -- dioxins, nitric acid, smog-NOx compounds etc. They also corrode and will eventually destroy the catalyst itself.
The assorted wonder-fuels that can be created using electricity and atmospheric CO2 (dimethyl ether has a big following among some folks) can be burned in gas turbines or piston engines to power aircraft, cars, trucks, trains etc. or even be used to regenerate electricity on demand. Fuel cells are, in this case, a solution looking for a problem.
As much as I regard Elon as a self-aggrandising pillock, I have to agree with him here.
The perfect fuel cell as used on spacecraft and the like burns hydrogen and oxygen to produce electricity, heat and water. Fuel cells intended for use on Earth use air rather than pure oxygen for logistical reasons, air is all around us after all, and the resulting exhaust contains nitrous compounds as well as water. Sometimes the NOx, nitric acid etc. corrodes the red-hot fuel cell catalysts which can be an expensive bummer.
Fuels used in fuel cells can range from hydrogen up through assorted hydrocarbon fuels like butane, ammonia, oddballs like dimethyl ether and the like. Adding carbon gets more energy per kilo of fuel but adds CO2 to the exhaust and possibly traces of other interesting chemicals like CO, cyanogens, dioxins etc. and may cause more damage to the catalysts in conjunction with the NOx compounds.
Hydrogen is a piss-poor fuel for vehicles. It's low-density per joule stored, damages ordinary steels through hydrogen embrittlement and in gas form leaks very easily through joints, gaskets and even through the metal walls of containers given a chance as hydrogen is the smallest molecule known, the escape artist of the periodic table. Liquefying it is energy-intensive, it has to be kept very cold and LH2 is also very low density, the least dense liquid known in fact.
Slashdot Mirror
Jobs said.... "There is not a straight piece of glass in this building. It's all curved. We've used our experience making retail buildings all over the world now, and we know how to make the biggest pieces of glass in the world for architectural use. And, we want to make the glass specifically for this building here. We can make it curve all the way around the building ...It's pretty cool."
Excerpted from an International Business Times report on the new building. Ka-ching!
A conventional Todos-Santos style glass brick would cost half the price or less of the current design, be easier to heat and cool, use less ground footprint and it would be more convenient to get around in with elevators, walkways etc. even with the same floor space per drone.
It's amazing what you can do with other people's money though, isn't it?
I think the ticket price for the building is about $5 billion, it may rise as the project goes ahead -- there's lots of custom curved glass panels and such involved. With 14,000 workers expected to use the building that works out at about 350,000 dollars each. Office space in Cupertino leases at about $35/sq. ft./year so for the proposed upfront cost they could lease 500 square feet for each employee for twenty years and not have to pay for the structural maintenance, landscaping etc.
It's a pretty way to use up money, I suppose.
Reprocessing and MOX manufacture is expensive, a lot pricier than using cheap freshly-mined uranium ore in a once-through operation. The big win with reprocessing is that it vastly reduces the mass and volume of dangerous waste needing dealt with, even after vitrification and encapsulation. That makes final disposal a lot cheaper and simpler as well as reducing proliferation worries since none of the resulting waste is at all suitable for nuclear weapons development.
No-one takes in another country's nuclear waste, at least not spent fuel or reprocessed waste. Britain and France used to reprocess spent fuel from Japan but the recovered uranium and plutonium was reformatted into fresh fuel elements and they along with the waste from the reprocessing operation has been returned to Japan.
Reagan reversed the ban Carter imposed on commercial reprocessing of spent fuel in the US in the early 80s. Nobody has funded a reprocessing operation (other than the lines used to produce weapons-grade materials from military breeder reactors) in the US for various reasons; raw uranium is cheap, nobody wants to use MOX fuel for cost and operating licence reasons and the US government is in charge of making spent fuel go away for which the generating companies pay a levy, currently over $30 billion dollars over the past few decades (it's what paid for Yucca Mountain).
The Rokkasho reprocessing plant started test operation about a year ago, based on a prototype reprocessing operation at Tokai. When it's up to speed Rokkasho will reprocess about 800 tonnes of spent fuel a year. Simply speaking you're totally wrong.
Japan has been importing LNG for decades now and has the specialised ports to handle large quantities of it; the Chiba oil and gas terminal near Tokyo is one of them. It suffered major damage and fires during the earthquake but was speedily brought back into service.
Coal is about half the energy of LNG tonne for tonne. TEPCO generates about 40% of Japanese electricity and they are importing about 5 million tonnes of coal a year and about 24 million tonnes of LNG to burn in their fossil-fuel power stations. There's a small amount of fuel oil and crude used as well (maybe a million tonnes in total) but the overwhelming majority of their generating capacity is LNG-fired.
A few corrections:
Fukushima Daiichi took a magnitude 7+ Richter hit from the Great Tohoku earthquake, it was magnitude 9 at the epicentre out at sea. The plant's buildings got through that shock pretty well though (there may have been some damage to some internal equipment in the reactor buildings, it's too difficult to inspect them properly at the moment). The reactors at Onagawa further up the coast and closer to the epicentre rode out the earthquake and tsunami safely with no problems.
The tsunami killed about 20,000 people, not 30,000. Nearly all of them died because the towns and cities along the Tohoku coast weren't as well protected from the tsunami as the Fukushima Daiichi plant and other nuclear plants like Onagawa were.
Japan is currently burning mostly natural gas for its electricity generating needs. It has to import all of its fossil fuels and NG is as easy to transport and handle as coal and burns a lot cleaner. It's still releasing a lot of CO2 and causing an increase in smog and air pollution. Efforts are being made to bring about a dozen reactors back online this winter, whether that happens or not is in the lap of the gods.
Aluminium smelters need predictable cheap electricity. They don't do well with variable renewable sources like solar and wind since when the power drops the bauxite melt in the electrolytic cell solidifies and stops being a conductor and the crud needs to be jackhammered out before the cell can be re-used.
Hydro is the best source of electricity for this purpose; Norway is another country exporting their cheap hydroelectricity in the form of refined aluminium billets.
Folks have mostly stopped exploring for large uranium ore bodies in part because current reserves are being exploited so efficiently the actual value of uranium is very low -- the current price for yellowcake (refined U3O8) is $35 per pound at the minehead. There are big known reserves (probably counted in the overall availability estimates) in placves like northern Canada which can't be exploited commercially as yet since the geographical limitations would put the price up above the market rates.
If the price of yellowcake doubled, by the way, it would add less than a cent US to the cost of a kWh of nuclear power. This is not true for gas, coal and other fossil fuel generators.
Yep, fascism was a big thing with the Founding Fathers -- "We must all hang together, or assuredly we shall all hang separately" was (reputedly) said by Benjamin Franklin, for example. The preamble to the Constitution talks of "a More Perfect Union", more "strength through unity" ideology.
Educated folks of the mid-18th century were fascinated with the history of the Romans from the Republic through to the Empire and of course this is where the fasces concept came from. Not surprising the nascent rebels thought it was a good idea, along with slaveholding, expansion and conquest and ruthless suppression of internal dissent and rebellion.
Fascists have mottos like "E Pluribus Unum" -- "One out of Many". If you want to see what a real fasces looks like take a close look at the Lincoln Memorial sometime and notice what the Republican President depicted there is resting his hands on.
No the coal stations don't power down significantly overnight. The CCGT systems do wind up and down significantly over a daily cycle, not so much with coal. A quick check shows that over the last 24 hours in the UK coal has delivered between 14GW and 16GW, nuclear has been steady at just over 7GW, CCGT has swung between 3GW and 20GW and wind between 2GW and 4GW.
There are Europe-wide carbon-emission restrictions on generation from some older coal plants meaning they can only operate for a limited number of hours each year; these stations are being cycled up and down as necessary to reduce their total burn time but the newer stations outside that restriction run balls-to-the-wall to provide baseload absent outages for refurbishment.
To absorb the RF energy -- b/g/n Wifi is very close to the frequency used in microwave ovens and so it's optimised to heat up meaty tissue (and vegetables too; this is Georgia Tech we're talking about, isn't it?)
In the UK where I live coal generation output doesn't fluctuate much, just when plants are taken offline for scheduled downtime so it's fair to call it baseload, same as the nuclear plants since they're so cheap to run in terms of fuel cost per kWh generated.
Wind generating capacity goes up and down with the weather -- a few weeks ago the national grid was getting 50MW from grid-connected wind during a quiet period, a few days ago in the aftermath of a storm is was producing 5GW or a hundred times as much. CCGT is used for peaking to fill in the gaps plus a couple of interconnectors bringing in power from France (80% nuclear low-cost electricity) and the Netherlands (cheap gas generating capacity) pretty much steady-state. Solar doesn't account for much as you might expect this far north.
Electricity demand at night in the summer in the UK is about 25-30GW; a lot of industry uses electricity overnight and its value is not zero. Nuclear plants run 24/7 unlike variable renewable generators so they don't need to have storage costs factored in. Of course the renewable generators don't pay for storage anyway, relying on baseload nuclear, coal and CCGT to fill in the times when the wind doesn't blow and the sun doesn't shine.
As for cheap renewable power, the most expensive electricity for consumers in Europe in Germany which has the greatest penetration of renewable energy in its generating mix -- Germans pay about twice as much per kWh as British consumers or even the 80% nuclear French which is kind of strange given that Germany still generates about 50% of its electricity using cheap lignite and brown coal with a good helping of Russian gas to fill in the gaps.
Exactly when renewable energy will become cheap I don't know, it's getting to the point where the first generation of wind turbines built in the 1990s are being decommissioned and will need replacing, adding more capital costs to the generating budgets. I don't know who's going to fund the removal of obsolete wind turbines and remediation of the sites -- several wind farm operators have gone conveniently bust before those costs hit the balance sheet.
The strike price for the proposed 3.2GW Hinckley EFR project is about £95 per MWh i.e. the grid operators will pay that price for the electricity generated. The current strike price for offshore wind which the grid operators are required to buy due to Renewables Obligation Certificates (ROCs) is about £140 per GWh, about 50% higher. At the moment British consumers are paying about 15 pence per kWh which works out at £150 per MWh or nearly the base cost of offshore wind with no allowance for the cost of transmisison, grid support etc.
Coal generates the largest share of electricity in the UK with gas filling in the gaps. Our nuclear fleet runs flat-out (apart from scheduled maintenance downtimes) producing about 7GW and we buy in about a GW of nuclear power from France pretty much continuously. The rest is a small amount of hydro (less than a GW total) and a very variable amount of grid-connected wind -- right now it's producing about 2.3GW but a couple of weeks ago it was less than 50MW. Grid solar is not even noticeable on that scale.
The EPRs and other GenIIa and GenIII nuclear plants being built around the world are expected to operate for at least 60 years; this is a difficult proposition to finance in today's world of millisecond financial trading and live-or-die quarterly accountancy. They are national infrastructure rather than commercial operations and should realistically be looked upon as similar to, say, major highways and railroads, bridges, water supply systems etc.
Windows 8 Pro on the Surface Pro can run up to 4 VMs so anyone who wanted to experiment with, say FreeBSD on this hardware could do so without having to install an alternative OS. I don't know if the touch screen and digitiser is supported by other OSes though.
What are the few people in the village able to read books in this magical library going to build the magical water condensers out of? The nearest Home Depot is five thousand miles away and they don't take IOUs. New farming techniques are a faster way to die of starvation in most situations as it takes a few years of experimental crop failures to develop something new and better than the locals hadn't discovered over the past few hundred years of famines.
Is Dell enough of a major manufacturer for you? I just got a replacement 27" Dell 2560x1440 monitor delivered today after a big electricity spike blew out my previous Dell 27" monitor a few days ago.
Sure it costs more than piddly little HD-resolution monitors but I'm looking at nearly twice the number of pixels as HD, it's an IPS panel, high-gamut and with a lot of useful extra functionality (a USB 3.0 hub, for example). Well worth the £550 I dropped on it.
If you are willing to compromise and really want a 24" 1920x1200 monitor Dell make them too. The 2412M is affordable, the U2413 has a higher gamut at a higher price. Your choice.
Oddly enough, uranium mining produces noticeably radioactive waste. The ores are radioactive mostly because of decay products from the uranium built up over hundreds of millions of years. After the ore is processed and the long half-life uranium is extracted those decay products are more concentrated in the spoil. It's not much of an increase but it is noticeable. There's also a noticeable release of radon gas into the atmosphere during the mining process.
The good news is that there isn't a lot of waste since a uranium mine only processes a comparatively small amount of ore. The proposed mine in Greenland would produce about 220,000 tonnes of uranium; at about 2-3% metal in the ore (at a guess) that means roughly 6 million tonnes of ore would be dug up during its lifetime. The world digs up about 7 billion tonnes of coal each year, most of which is burned to produce electricity. In comparison about 70,000 tonnes of uranium metal is used to provide power annually around the world, the result of mining about 20 million tonnes of ore. With more recycling and reuse of spent fuel that figure would be much less.
The problem with the contaminants I mentioned is they are created on the fuel cell's catalytic surface which is usually at a thousand deg C or hotter. A simple hydrogen-oxygen fuel cell produces only water, adding nitrogen and carbon molecules to the feedstocks generates assorted pollutants, some of which are not good for you if released in quantity -- dioxins, nitric acid, smog-NOx compounds etc. They also corrode and will eventually destroy the catalyst itself.
The assorted wonder-fuels that can be created using electricity and atmospheric CO2 (dimethyl ether has a big following among some folks) can be burned in gas turbines or piston engines to power aircraft, cars, trucks, trains etc. or even be used to regenerate electricity on demand. Fuel cells are, in this case, a solution looking for a problem.
So RP-1 isn't gasoline, correct.
Do YOU know what the "snark" tag is in HTML5? I've not been able to find it on the W3C pages.
As much as I regard Elon as a self-aggrandising pillock, I have to agree with him here.
The perfect fuel cell as used on spacecraft and the like burns hydrogen and oxygen to produce electricity, heat and water. Fuel cells intended for use on Earth use air rather than pure oxygen for logistical reasons, air is all around us after all, and the resulting exhaust contains nitrous compounds as well as water. Sometimes the NOx, nitric acid etc. corrodes the red-hot fuel cell catalysts which can be an expensive bummer.
Fuels used in fuel cells can range from hydrogen up through assorted hydrocarbon fuels like butane, ammonia, oddballs like dimethyl ether and the like. Adding carbon gets more energy per kilo of fuel but adds CO2 to the exhaust and possibly traces of other interesting chemicals like CO, cyanogens, dioxins etc. and may cause more damage to the catalysts in conjunction with the NOx compounds.
Hydrogen is a piss-poor fuel for vehicles. It's low-density per joule stored, damages ordinary steels through hydrogen embrittlement and in gas form leaks very easily through joints, gaskets and even through the metal walls of containers given a chance as hydrogen is the smallest molecule known, the escape artist of the periodic table. Liquefying it is energy-intensive, it has to be kept very cold and LH2 is also very low density, the least dense liquid known in fact.