Solar Energy and Hydrogen

There is often the question why not build solar powerplants out in the
desert ? Well, solar panels require surface area and they require
sunlight with both things being available in the desert. I suppose the
answer is that while alternating-current can be transmitted long
distances, the distances are probably held to about 200 miles.
But Los Angeles and surrounding metros are near to the desert and sure
enough there is a 354 MW solar powerplant in the Mojave Desert. Now
these large solar powerplants don't use solar panels to produce
electricity but use solar mirrors to heat water, make steam, turn
turbines, and then produce electricity.
But here's an idea or question:
Why not use solar mirror powerplants in the desert to make hydrogen
from pumped water and then send the hydrogen further distances in
pipelines than electricity could be transmitted on power lines ?
Well, I'll answer my own question and say that likely there is more
power to be had from the steam than from the hydrogen production.
But don't forget, there are solar powerplants in the desert.
Reply to
PolicySpy
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And solar panels in the desert would not require any water while solar mirrors making steam would require water. It's a strange combination of fundamentals but there are solar mirror powerplants in the desert.
Reply to
PolicySpy
200 miles is nothing for a large transmission line with very littel in losses, especially DC lines (Tesla had limited foresite)
We prefer to get over 40% of our generatef energy to be **NOT*** lost. Hydrogen ranges about 3% delivery rate, according to experts. It's a waste.
And solar panels in the desert would not require any water while solar mirrors making steam would require water. It's a strange combination of fundamentals but there are solar mirror powerplants in the desert.
Reply to
Josepi
Dear PolicySpy:
We'd sure love the jobs...
No issues with that. Any well-defined problem has a solution. Microwave beams, superconductive buried power lines.
Yes. Solar cell panels (so far) barely make up the energy cost to form them, in their service life. Additionally, they are toxic, so potentially difficult to dispose of at the end of that life. Lawyers like deserts too.
Or better still, just pump water. Fluid power systems can be very energy efficient.
It is beast we know and can deal with. Loss of hydrogen, embrittlement problems and such, are major issues.
No. First of all, most powerplants end up using steam, and the steam can be operated in a closed loop, requiring no makeup. Second of all, some solar power plants use other fluids for carrying solar energy from place to place, like molten sodium...
I repeat myself, when under stress. I repeat myself, when under stress. I repeat myself, when under stress.
David A. Smith
Reply to
dlzc
What about the waste heat rejected to condense the steam at the outlet of the last turbine?
If you're near a river or ocean then you have a convenient large heat sink, if you don't have a large body of water then evaporative cooling towers are the next choice. I haven't run any numbers, but I would argue it's a substantial use of water.
Lance *****
Reply to
Lance
That might explain why they're made in China.
Reply to
The PHANTOM
The loss of investment income, or the cost of loan interest, on the solar PV installation usually exceeds the payback rate of income from solar PV installations, on home systems.
The manufacturers aren't usually losing money of the ones that haven't gone bankrupt or live on Gov. grants trying to produce a product.
dlzc wrote: I keep seeing this claim,but have a question. How can it be that solar cells "barely make up the energy cost to form them"? If this is true, wouldn't the manufacturers be losing money selling them? They have to pay for every unit of energy they use to make them. And energy can't be the only cost to manufacture them
.
Reply to
Josepi
You're not up to date on solar cells:
from Wikipedia:
"...Energy payback time and energy returned on energy invested
The energy payback time is the time required to produce an amount of energy as great as what was consumed during production. The energy payback time is determined from a life cycle analysis of energy. The energy needed to produce solar panels is paid back in the first few years of use.[76]
Another key indicator of environmental performance, tightly related to the energy payback time, is the ratio of electricity generated divided by the energy required to build and maintain the equipment. This ratio is called the energy returned on energy invested (EROEI). This should not be confused with the economic return on investment, which varies according to local energy prices, subsidies available and metering techniques.
Life-cycle analyses show that the energy intensity of typical solar photovoltaic technologies is rapidly evolving. In 2000 the energy payback time was estimated as 8 to 11 years[77], but more recent studies suggest that technological progress has reduced this to 1.5 to 3.5 years for crystalline silicon PV systems[71].
Thin film technologies now have energy pay-back times in the range of 1-1.5 years (S.Europe).[71] With lifetimes of such systems of at least 30 years[citation needed], the EROEI is in the range of 10 to 30. They thus generate enough energy over their lifetimes to reproduce themselves many times (6-31 reproductions, the EROEI is a bit lower) depending on what type of material, balance of system (or BOS), and the geographic location of the system.[78]..."
Reply to
Sid9
Dear Lance:
Here in Arridzona, we use grey water, which everyone is afraid to drink.
David A. Smith
Reply to
dlzc
Your first paragraph indicates the rest is all a big exageration also. Your wikipedia article is incorrect.
You're not up to date on solar cells:
from Wikipedia:
"...Energy payback time and energy returned on energy invested
The energy payback time is the time required to produce an amount of energy as great as what was consumed during production. The energy payback time is determined from a life cycle analysis of energy. The energy needed to produce solar panels is paid back in the first few years of use.[76]
Another key indicator of environmental performance, tightly related to the energy payback time, is the ratio of electricity generated divided by the energy required to build and maintain the equipment. This ratio is called the energy returned on energy invested (EROEI). This should not be confused with the economic return on investment, which varies according to local energy prices, subsidies available and metering techniques.
Life-cycle analyses show that the energy intensity of typical solar photovoltaic technologies is rapidly evolving. In 2000 the energy payback time was estimated as 8 to 11 years[77], but more recent studies suggest that technological progress has reduced this to 1.5 to 3.5 years for crystalline silicon PV systems[71].
Thin film technologies now have energy pay-back times in the range of 1-1.5 years (S.Europe).[71] With lifetimes of such systems of at least 30 years[citation needed], the EROEI is in the range of 10 to 30. They thus generate enough energy over their lifetimes to reproduce themselves many times (6-31 reproductions, the EROEI is a bit lower) depending on what type of material, balance of system (or BOS), and the geographic location of the system.[78]..."
Reply to
Josepi
Try backing up you unsupported statement.
Reply to
Sid9
Simple math if you can multiple more than two figures together.
Try backing up you unsupported statement.
Reply to
Josepi
I don't really believe that hydrogen produced from water is commerically viable...but wanted to think about hydrogen production.
But think about North Africa near the Mediterranean Sea. A solar powerplant could make electricity but where would the demand for the electricity be ? So the solar powerplant could take the electricity, make hydrogen, and pump the hydrogen to the nearest port. At the port hydrogen could be liquefied and loaded onto tankers for export.
Now a solar powerplant that uses mirrors to heat water for steam must have a source of water. Well, the Mojave Desert has the Mojave River. It's just a situation of a desert next to mountains and the river flows out of the mountains. Obviously, the desert is only irrigated at the river. Now I don't know if the solar powerplants in the Mojave Desert get their water from the Mojave River or elsewhere but wanted to explain water in the desert.
Reply to
PolicySpy
Well, I can take a quick look at web sources on hydrogen-from-water.
The energy efficiency of producing hydrogen from water with electricity could be 50% to 80%. But that doesn't include the energy lost in making the electricity. However, there is a High Temperature Electrolysis that uses both steam and electricity and that would seem to fit well with a solar mirror powerplant.
I suppose it would be a rare situation of some location that could build a solar powerplant but not need the electricity.
Reply to
PolicySpy
I forgot to mention another point:
Hydrogen for fuel cells should come from electrolysis so as to have the required purity.
Reply to
PolicySpy
Dear PolicySpy:
Your choices are to have a thermal neutron source and wait for them to decay into hydrogen, or chemically strip the hydrogen from some other molecule. Currently, hydrogen is removed form fossil fuels.
Could just pressurize water, and use the pressurized fluid stream to act as the "energy carrier".
Snicker...
Elsewhere.
Wells.
David A. Smith
Reply to
dlzc
It appears that hydrogen for fuel cells must be made by electrolysis for purity.
The idea is to export hydrogen from locations where solar mirror powerplants are effective.
Hydrogen can be pumped to ports, liquefied, and loaded onto tankers.
Finally, there is a high-temperature electrolysis that seems to be a good fit with solar mirror powerplants.
I suppose the bottom line is how long it takes to pay for the plant.
Reply to
PolicySpy
Okay, let's build the complete system:
By international agreement, governments around the world contract to buy designated amounts of high-purity hydrogen produced by solar mirror powerplants.
The solar mirror powerplants for the production of high-purity hydrogen are built around the world in locations where solar mirror powerplants are effective and where port export is possible.
Fuel-cell fueling locations are put in place by governments near ports and along populated coastlines. Hydrogen delivery is from the port and by truck.
The car manufacturers seeing fuel-cell fueling locations in populated areas, begin making fuel-cell vehicles.
As lines back-up at the hydrogen fueling locations then private industry begins adding hydrogen fueling locations and pipelines.
But what is the advantage of fuel-cell vehicles over electric vehicles ?
Well, fuel-cell vehicles have quicker fueling, less weight, and a lower cost of battery replacement.
Reply to
PolicySpy
Well, Honda has a fuel-cell car for the U.S. market and MB will have a fuel-cell car in the U.S. market in a few months.
I'm saying that the government could establish a market for Hydrogen produced from water and produced by solar mirror powerplants. If the governments will establish the market then the solar mirror powerplants will be built around the world and in the locations where they are most effective. Then the hydrogen can come into ports and fueling stations can be established within trucking distance of the ports.
The advantage of a fuel-cell vehicle over a plug-in electric vehicle is that the fuel-cell vehicle has quicker fueling, less vehicle weight, and a lower cost of battery replacement.
Reply to
PolicySpy
Let me add a calculation...
Lets say you wanted to deliver a terawatt, and lets say you pumped the pressure on the water to in excess of 60,000 psi (so that biogrowth was not possible)
60,000 psi =3D 4,137 bar
formatting link
kW * 600 / 4,137 =3D 145,000 liters/min This is a large force main (55 mgd), and some big thick-walled pipe to go 250 miles, and you'd want probably at least three pipes, and some sequencing of which was under max pressure (to keep all pipes sterilized in turn).
But energy delivery could be on the order of 90-95%, rather than 20-30% by making hydrogen first.
David A. Smith
Reply to
dlzc

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