Orbiting Lasers for Hydrogen Power

DerekLyons writes: "Yahoo is carrying a story about a Japanese scientist who plans to use giant orbiting lasers to extract H2 from seawater. The interesting part of the scheme is that design uses solar pumped lasers, which avoid the loss of efficiency (and increased launch weight) from powering the laser with electricity from solar cells. Is the way to finally break the main dilemma of the hydrogen economy? (That it takes more energy to make the hydrogen than you gain in using it.)"

Comments

Solar Lasers suck

[Anonymous Coward]

All known solid state laser gain substances have fairly narrowband excitation spectrums. This presents a two fold problem: 1) fairly little power is available in that window (the sun is a blackbody raditator) 2) Energy outside of that window tends to just heat the medium and either cause breakdown or unacceptable thermal lensing.

I've built a solar pumped nd:yvo4 laser, but it was a waste: because of those factors I could have extracted more power and probably energy from a solar electric system.

Without some serious new developments in laser substances with ultra broadband pump inputs, this won't work too well.

Re:There is always a catch...

[s20451]

Unlike in the States, big compaines in Japan have a little bit of everything. Mitsubishi makes cars, trains, ships, aircraft, televisions, stereos, agricultural chemicals, food additives, synthetic rubber, molasses, canned foods, textiles, semiconductors ... the list goes on. Any large project in Japan couldn't avoid being associated with a company that also makes cars.

Risks

[Antity]

A giant orbital laser that fires to the ground into a giant salt water swimmingpool.

• What is the impact of fried birds dropping onto this pool?

• What can this concentrated energy do to some of the earths outer layers that are important for climate? Atmosphere, stratosphere, and so on.

• Impact on the ozone layer, which is already (by definition, not by human interaction) quite thin and easy to disturb?

• What are they going to do with all the Oxygenium? Since the air we breathe consists to more than 70 percent of Nitrogen, not Oxygene, simply freeing large volumes could be problematic. (And can be quite a risk for the installation itself. Think of "no smoking".)

• What if a mislead plane happens to fly into the beam? A weather balloon?

• Impact on clouds? Hitting them (and the H2O within them) will also split the H2O, and then Ozone will react from the Oxygenium radicals. And: Ozone is only good in exactly the right height over ground. Every Ozone lower than that is poisonous and, in the volumes we're talking about, could lead to quite interesting weather effects within these clouds.

• Don't talk about what happens if this cloud of ozone happens to drift over some city. In cities, we usually call this "smog" and try to avoid it.

• Sulfur dioxide, raising up in clouds from big cities or other things that burn fuel (oil plants?) is known to react to Sulfur Acid in the athmospere, with the help of the power of sunlight. A while after, we call this "sour rain" or "acid rain". What amount of acid could react if a cloud like this is hit by this _very_ strong artificial sun?

Nice idea, but done by company scientists for company scientists. IMHO, this could cause far too many things to be implemented.

And, remember: "They" are not fiddling with a x square miles big sector of air above their installation. They're fiddling with the atmosphere that is shared by some billion of people. There is hardly a thing like local effects with wind, clouds, and weather. Ask your European friend if he sometimes finds a thin layer of very fine sand outside his house or on his windows. This comes straight from the Sahara desert in Africa. (No, I'm not kidding.)

When the reactor in Tchernobyl went "blob", the radioactive dirt was distributed over half of Europe, 1000s of kilometres, which still ended up with enough dirt to have them throw away every vegetable in their gardens.

And: Science doesn't have any data about what happens to the very highest layers above us when hit by a concentrated stream of energy on a single point that is several times stronger than the strong rays of the real sun around it. It might well cause something or, doing this several months in a row, burn a hole into a layer of gases that we not even know about yet. We Just Don't Know.

Fiddling with this is just stupid.

Thermodynamics

[nanojath]

Precisely. Why is this so hard to understand? Every form of fuel or energy storage requires more power to create than it can produce. Otherwise you could simply hook the power production process up to the power storage/fuel creation process and - Viola! - perpetual motion, all our energy problems are solved.

The main problem of all renewable energy schemes is that fossil fuels are formed by millions of years of solar energy accumulated by the biosphere and millions of years of geological pressure. It isn't that these fuels are more fundamentally efficient - in fact, they are relatively innefficient from many perspectives. It is that nature has done all the work for us - leaving us to liberate the value at our leisure. Convenient, and in the extremely narrow and short-sighted view we've taken of energy, cheap.

The problems, of course, are that we are stuck with relatively dirty fuels like coal and oil, and that these fuels are not renewable in the short term. Hence, any renewable fuel will face us with a cost-benefits problem: it will cost more to produce than an equivalent unit of coal or oil. Until we start measuring the environmental, political and future stability/planning impacts as part of the cost of burning fossil fuels, it will always seem economically preferable to stick with our old standbys.

The real issue of hydrogen or any alternative fuels (biomass derived, ethanol, etc.) is to find the most efficient way to use a renewable or sustainable energy source. Hydrogen has the convenience and benefit of being a fuel: useful from points of view of storage and self-containment.