MQ
Even though, this system is still never going to provide more energy out than in (losses always occur).. Hydrogen (and petroleum) are just energy carriers, not an original source of energy, that would be the sun (in combination with the earth's gravitational energy providing the processing reactor for oil etc) .
It is the Cost per gallon equivalent which matters (price point).
Remember, we never have to manufacture Rock Oil, petroleum suffers from massive inefficiencies in its creation / manufacture, fortunately for us it was laid down in the strata a long time ago. (Sure we do make some synthetic fuels, as in synthetic diesel, and methanol, but that is still using a resource we didn't have to create (methane) ).
If this can produce more fuel than the equivalent acreage with agriculture, it may be a goer, as long as the backers are willing to invest.
Noting also, that places which are most suitable for solar thermal energy, may not be so good for intensive agriculture.
Just sayin.
Craig Jennings
"With the aid of a solar thermal plant, the team believes that they can generate 100,000 kg (222,460 lb) of hydrogen per day" Sigh... we gizmag readers do love projected yields with no area/cost information. Since we are gizmag readers, I suppose we could extrapolate how much land area that would take v time to make that much based on amplifying sunlight 2000 : 1. Any takers? I already have a headache.
Nairda
I see a lot of negative vibes floating around. 100,000kg or 10,000kg is irrelevant. The point is it can continue the process as long as there is light. Hydrogen is expensive. A plant like this would pay for itself within a year.
In simple principles, a solar furnace with stainless steel mirrors is only going to have a carbon footprint for smelting the steel and fabricating the various metal parts. From a monetary point, it can also be fabricated very inexpensively.
Beyond that, the run ongoing requirement will just be the water for the turbine and washing the mirrors.
In the case for the water splitting, concept, its just bumping up the temperature. All it will cost environmentally is the water required to make the product. Initial fabrication will be about the same.
Ongoing maintenance is chicken feed, and fabrication of hydrogen is also going to be as expensive as the water required to make it.
As far as discussions around land area required for the task, it really depends how well the lenses focus. Nothing stops the designer from incorporating a second set of lenses at the focal point for a refined focus.
Robt
@Nairda How do you know that it would pay for itself within a year? Do you have documenetd sources of build cost and ongoing costs versus output?
waleed Al Gharabally
One does not need all that acreage if you use 10 meter diameter water filled lenses and redirect all the focal points to one location.
Fretting Freddy the Ferret pressing the Fret
I'm curious where the water is drawn from. The sea? Aquifers? What water purification systems are needed before it goes into the system?
Considering the volume of hydrogen produced and the relatively inexpensive materials (although I'm curious what those metal oxides are) involved, I can see this project paying for itself in a few years.
This is the next step in concentrated solar power plants. Previously, pilot plants focused light to heat a medium (water, molten salts, oils). This goes through a heat exchanger to produce steam for the turbine and then produces electricity.
The capital investment for those CSP are large, because of heat exchangers, large medium storage tank, auxiliary heating systems, turbines. Not to mention corrosion problems with molten salts.
All in all, this is a positive step going from a CSP system that utilizes specific heat, to one utilizing chemical energy (skipping over a step that uses latent heat). It delivers an energy carrier which is energy dense per kg.
Dekarate
let's see - New York City has 5,602 buses and a land area of 195,000 acres. So if we replace all the buildings in the city with mirrors, we will be able to generate about enough fuel to run the buses for the people who are no longer there. Economics of scale - even with desert land prices are not favorable towards a cost effective solution
Ashtom1
Has hydrogen storage and haulage been worked out? Last I knew it was really hard and expensive to store hydrogen being the smallest element with ability to leak out. How does hydrogen storage and haulage factor into the cost?
yinfu99
I wonder if its any cheaper for the same amount of energy gain to instead of using mirrors to focus sunlight on a single tower, to rather use fresnel lens to focus light on a spot (not a tower), similar to what a magnifiying glass. Since the lense takes sunlight and focuses it to a smaller point, where as the mirrors take light and reflect it, which one is more energy efficient. I would think the fresnel len system would take less space and generate similar power levels. Perhaps someone could add more to this speculation.
WhoIsBramStoker
Something does not add up here. 120,000 acres is 188 sq miles!
Divide it all out and you get about 1000 ft squared ( 1 million sq ft) per bus.
Rocket bus?