[KaiserJeep]

I would say, Republicans and Democrats. I hate partisanship, it has broken our government.

[Keith_McClary]

Tom Murphy
http://physics.ucsd.edu/do-the-math/201 ... lar-power/
figures that the higher cost of space+ground installations would far outweigh the advantages of ground based solar.

[Tanada]

KaiserJeep, thought you would get a kick out of this thread. Enjoy.

[KaiserJeep]

$this->bbcode_second_pass_quote('Tanada', 'K')aiserJeep, thought you would get a kick out of this thread. Enjoy.

[John_A]

$this->bbcode_second_pass_quote('KaiserJeep', '
')===> If you think AGW is bad, try comparing that to widespread species extinctions in an Ice Age.

[Keith_McClary]

$this->bbcode_second_pass_quote('KaiserJeep', 'N')ow as an exercise for the student, what would happen to the Earth if major expansions were made to the total amount of Solar Photo-voltaic panels in use?
...
Unfortunately, when one removes solar energy as electricity, there is a net cooling effect in the immediate area of the PV panels. (My own solar PV roof has reduced my Air Conditioning usage from 15-20 days/year to less than 5 days/year.)

Answer: Big time global cooling, perhaps enough to tip the planet into a real Ice Age.

[John_A]

$this->bbcode_second_pass_quote('clv101', 'T')he space industry is one of the most energy intensive, energy expensive things we do. It's not something to promote when facing a lower energy future.

[KaiserJeep]

Keith, I'm not joking, and I have first-hand experience that says that having a Solar PV roof has eliminated 3/4 ths of my energy expenses for A/C. Most of this of course is from the shade they create on my mineral-coated steel shingles, solar heat gain that is avoided. But as an exercise, you could measure the temperature of a PV panel with an open circuit to one that has a complete circuit and is producing power, and the functioning panel is much cooler, because of the energy removed as electricity versus heat. (The mono-crystalline silicon cells are a very deep blue, almost black.)

Your point that most such electricity ends up as heat in other locations is well taken and compliant with Thermodynamics. The exception being that electricity which is used to a phase change in matter. The simplest example of this would be a "swamp cooler" - which extracts heat from air by turning water into water vapor. I do that too, to cool the central atrium in my home, using mister nozzles. It is quite refreshing on a hot day, and the tropical plants out there love the extra moisture.

Then of course, the water ends up as extra cloud cover, water vapor being the primary GHG, not carbon dioxide. These if present in the upper atmosphere do reduce the solar gain of the planet by reflecting more heat into space. Which cooling reduces the cloud cover, of course....

[Keith_McClary]

$this->bbcode_second_pass_quote('KaiserJeep', 'Y')our point that most such electricity ends up as heat in other locations is well taken and compliant with Thermodynamics. The exception being that electricity which is used to a phase change in matter. The simplest example of this would be a "swamp cooler" - which extracts heat from air by turning water into water vapor. I do that too, to cool the central atrium in my home, using mister nozzles. It is quite refreshing on a hot day, and the tropical plants out there love the extra moisture.

Then of course, the water ends up as extra cloud cover, water vapor being the primary GHG, not carbon dioxide. These if present in the upper atmosphere do reduce the solar gain of the planet by reflecting more heat into space. Which cooling reduces the cloud cover, of course....

[KaiserJeep]

CO2 is not cumulative either. Extra CO2 stimulates plant growth and phytoplankton growth which in turn removes more atmospheric CO2.

[Keith_McClary]

$this->bbcode_second_pass_quote('KaiserJeep', 'C')O2 is not cumulative either. Extra CO2 stimulates plant growth and phytoplankton growth which in turn removes more atmospheric CO2.

[KaiserJeep]

Ah, the Mauna Loa data.

The only place on Earth where rising CO2 levels are measured - on top of an active volcano which is becoming more active over time. It's useless, a single point measurement.

Then there is the Antarctic ice core data, which inconveniently shows that carbon dioxide and temperatures have had extremes beyond present levels in the past, and totally unrelated to the burning of fossil fuels:



....and worst of all: atmospheric carbon dioxide content lags temperature data by 70-140 years, it does not drive temperatures.

[Keith_McClary]

$this->bbcode_second_pass_quote('KaiserJeep', 'A')h, the Mauna Loa data.

The only place on Earth where rising CO2 levels are measured - on top of an active volcano which is becoming more active over time. It's useless, a single point measurement.

[dorlomin]

$this->bbcode_second_pass_quote('KaiserJeep', '
')The only place on Earth where rising CO2 levels are measured - on top of an active volcano

[ralfy]

$this->bbcode_second_pass_quote('KaiserJeep', 'A')h, the Mauna Loa data.

The only place on Earth where rising CO2 levels are measured - on top of an active volcano which is becoming more active over time. It's useless, a single point measurement.

Then there is the Antarctic ice core data, which inconveniently shows that carbon dioxide and temperatures have had extremes beyond present levels in the past, and totally unrelated to the burning of fossil fuels:



....and worst of all: atmospheric carbon dioxide content lags temperature data by 70-140 years, it does not drive temperatures.

[Keith_McClary]

$this->bbcode_second_pass_quote('Keith_McClary', 'T')om Murphy
http://physics.ucsd.edu/do-the-math/201 ... lar-power/
figures that the higher cost of space+ground installations would far outweigh the advantages of ground based solar.

[JV153]

$this->bbcode_second_pass_quote('KaiserJeep', '')$this->bbcode_second_pass_quote('Tanada', 'K')aiserJeep, thought you would get a kick out of this thread. Enjoy.

[JV153]

$this->bbcode_second_pass_quote('Keith_McClary', '')$this->bbcode_second_pass_quote('KaiserJeep', 'A')h, the Mauna Loa data.

The only place on Earth where rising CO2 levels are measured - on top of an active volcano which is becoming more active over time. It's useless, a single point measurement.

[KaiserJeep]

This month's IEEE Spectrum has an article on orbital solar plants with microwave beam delivery to Earth:

http://spectrum.ieee.org/green-tech/solar/how-japan-plans-to-build-an-orbital-solar-farm



Although I continue to have doubts about how "green" such a power source is, the tech is impressive and the message is that there are plans going in place to implement this idea.

[Graeme]

Could a space-based solar farm become a reality by 2040?

$this->bbcode_second_pass_quote('', 'S')pace-based solar power seems like an idea from a Star Trek script, but given the uncertain future of its power generation industry, Japan stands to gain as much as anyone by exploring this potential source of renewable energy. The disaster at Fukushima, limited access to fossil fuels and advances in technology has, at least in the eyes of the Japan Aerospace Exploration Agency (JAXA), added further weight to the notion of a space-based solar power system. The agency is developing a complex roadmap involving a 1 GW extraterrestrial solar farm, a microwave beam and a man-made island in the Tokyo harbor which could be used collect solar energy in space and supply power to Earth by 2040.


JAXA is working on two concepts. The simpler one involves a huge square panel that measures 2 km (1.24 mi) per side. The top surface would be covered with photovoltaic elements, with transmission antennas on the bottom side. A small bus housing controls and communication systems would be tethered to the panel via 10 km (6.2 mi) long wires. A limitation with this design is that the orientation of the panel is fixed, meaning that as the Earth and the satellite spin, the amount of sunlight the panel receives will vary, impacting its ability to generate power.

The more complex solution seeks to address this problem by positioning two huge mirrors alongside two photovoltaic panels. These mirrors would reflect sunlight onto the panels 24 hours a day and would be free-flying, meaning that they are not tied to the panel nor the transmission unit. While the technology that enables formation flying in space continues to develop, Sasaki says considerable advances would need to be made to coordinate formation flying with kilometer-long structures. Other challenges in building this type of SPS include developing light materials for the mirror and high-voltage power cables to transmit the power from the two solar panels to the unit, technologies that Sasaki says are still years away.


JAXA is planning to conduct tests by the end of this year demonstrating its retrodirective beam control system. In 2018 it hopes to perform the first microwave power transmission in space, channeling several kilowatts from low Earth orbit to the ground while ensuring that the microwave beam doesn't interfere with existing communications infrastructure.