Re: The Climate, Environment and Energy Thread
Reply #541 –
If you electrolyse seawater to produce hydrogen, as a by-product you get pretty much every critical element needed for advanced economies in some trace level. Luckily by volume, the sea has more than enough to pretty much last the human race long after it's made a home in space.
Batteries and SolarPV consume trace elements before they create any energy, so they need a long payback period.
As a energy storage medium, the energy density is the energy in watts per kilogram of weight. By that factor hydrogen has an energy density of 35,000 watts per kilogram, while lithium-ion batteries have an density of just over 200 watts per kilogram. That is why Cannon-Brookes and Twiggy Forest want to store energy as hydrogen, to be converted back to power via fuel cells, it's a no brainer. As a clean energy option it's so far ahead there isn't even a competition, and there wouldn't be a competition without the barrage of publicly subsidised marketing by Battery and SolarPV, industries using your tax dollars to sell you the EV / Battery con!
I've even read cons where they try to paint the generation and transportation of hydrogen as a negative compared to batteries getting efficient power from power plants delivered by cable. But of course they ignore that your EV carries around a tonne of battery whether it's fully charged or nearly discharge, while a hydrogen tank gets lighter as the fuel level gets lower. Actually, when compared on all terms even given the lower efficiency of a fuel cells versus a battery, they break about even on efficiency. However in a static application, after the initial recovering of all the overheads, hydrogen for something like bulk storage of excess grid energy is miles ahead!
Then there is the bogus claim green hydrogen will use all the water. Hydrogen is produced from water at a ratio of about 9:1, even though hydrogen has almost 200x the energy density of a LIoN battery we still need 2 to 3 GT(Gigatonnes ) of hydrogen every year. So naysayers quote that figure and claim the worlds water will be used up, except that 2 -3GT / per year equates 20 - 30 GT of water, which is less than 2ppm of the atmospheres available water, actually closer to 1.5ppm. Assuming no further technological advancement, it'll take humans at least 250k years to use 1/2 the planets freely accessible water, of course we can't expect people to accept that in 250k years time, vandals that we are! And we won't learn jack-shizen in the intervening period given we are naturally luddites, and we will of course be grounded by space debris, which is a bust because just one of those big frozen asteroids which float freely around the solar system can apparently power us at our current level of demand for hundreds of years. btw.
By freely accessible water I'm not talking about water, oceans, crust et., all, that total amount of water would be 1,388,464,566,929 GT!
Even if our estimates are out by a factor of 100 or even 1000, supply and demand is irrelevant!
But we will dry out the air, except Greenland is currently losing 280 GT of ice annually, Antarctica lost 120 GT of ice just last year, roughly 4x what we would need to hydrogen fuel the planet!
I can imagine the protests now, "Save the asteroids!"