A fair comparison is that the same factory that Tesla is using now used to produce 428,000 internal combustion cars in one year, back when it was owned by GM and Toyota.
Rooftop residential fell to $2.98/Wdc in the 3rd quarter of 2016, while utility tracking came in at $1.21. Tracking systems tilt the panels to follow the Sun, and therefore produce more power than fixed ones on rooftops. So overall, the utility systems are about three times cheaper. Why are they so much less? It is much more efficient for a work crew on level ground than on a sloped roof, and they don't have to pack up their gear and drive to a new location every two dozen panels. You only need one big connection to the utility grid for a solar farm, rather than one for every house, so less wiring/transformers/etc.
At $1.21/W, and assuming the solar farm returns 8% annually and produces for 2000 hours/year, the net cost is $0.0484/kWh, which is competitive with wind and natural gas.
> Take for example asteroid mining, how long have we heard about that?
It's been a feature of science fiction since the early days. But making a serious effort at it depends on several things that are more recent:
* The discovery of 15,000 Near Earth asteroids, 90% of which have been found in the last 15 years : http://neo.jpl.nasa.gov/stats/ The Near Earth group are much easier to reach than the Main Belt asteroids. The more of them you find, the better the chance of some of them being the right composition and right orbit to mine.
* The development of higher power electric propulsion (ion and plasma) and high efficiency solar arrays, in order to power space tugs to bring back asteroid rock to a high Earth orbit. This has also happened over the last 15 years.
* Improvements in space robotics and high-bandwidth communications, which would allow real-time control of a processing plant in high orbit from the ground. This reduces the need for astronauts on site and lowers the cost.
* Growth of a market for the products of asteroid mining. There are now about 1400 active satellites in space : http://www.sia.org/wp-content/... (see page 8) and the number is growing. Without a way to refuel or repair them, they have to be replaced at great cost. Asteroid mining can supply fuel, both for the satellite itself, and to bring them to a repair station. That market is worth billions a year, but again, 15 years ago it was much smaller.
Not surprisingly, now that the pre-conditions exist, people are making serious efforts to develop asteroid mining.
but instead of focusing the light on a tube to boil water, they focus it on narrow windows in the greenhouse. Since Mars has a similar day length and axial tilt to Earth, the main thing is to increase the amount of light getting into the greenhouse. So the reflectors need to be about 2.5 times the area of the greenhouse floor. I assume most of the greenhouse will be buried under a layer of dirt, because the nights on Mars are *cold* and you want to maintain the greenhouse temperature. A slot at the top of the dirt layer leading to windows would allow the light in, and you can cover the windows at night if needed to retain heat.
The reflectors can be pretty lightweight, because of the low gravity, and relatively low wind loads.
My guess is it's a precessing pulsar with an offset magnetic field. Pulsars are well known to produce repeating pulses as their magnetic poles rotate in and out of view. To see the pulses requires they cross our field of view, meaning a specific alignment of the rotation axis vs location of the magnetic pole (which don't have to be the same). If there is a second body near the pulsar, with an orbit offset from the equator, it would cause the rotation axis to precess, just like the Earth's does due to the Moon and Sun. Therefore the alignment of the magnetic pole would move in and out of view, and we only see pulses on the rare occasions they line up just right.
This guess would be defeated if the pulses look nothing like normal ones from pulsars, and confirmed if enough data is collected to detect the orbital motion of a second body.
> is there such a thing as a possible saturation of the PV market?
Yes, in the near term when it supplies all the daytime electricity a grid can handle without becoming unstable. It's not always sunny, so the grid needs enough other power sources to compensate for bad weather. Estimates when this point would be reached with the current grid range around 20-30%. US electric production is between 1 and 2% solar at the moment. I say daytime because power demand is lower at night, and the sun doesn't shine then.
In the long term, with better transmission infrastructure (to overcome local weather), and storage solutions (solar thermal, or batteries), total solar could go higher
> could there be a day in near future (10 years) that there are PV on all the roofs that can handle it?
Only a minority of solar installations are on home rooftops. In the US, the majority are "utility" systems, with many thousands of panels installed at ground level. Most of these today are "tracking systems", that tilt rows of panels to follow the sun, and get more output. Because it's installed at ground level by specialized work crews, and needs fewer support systems per panel, it is 60% cheaper than residential. There is no shortage of open land. Commercial rooftops fall in between residential and utility. For example, WalMart and Target have each installed 300 MW of solar panels on their store roofs. It offsets some of the power used by the stores.
> mostly due to Political ideology against Climate Change Science
No, it's because we have a lot of trees in the south, which causes friction and lowers wind speeds. It's no coincidence that most wind farms are in the midwest/Texas areas where it's flat open prairie and crop land. Wind speeds are actually just as high at higher altitudes in the South. The same weather systems blowing through other states eventually come here. But it's not economic to build wind turbines that tall yet. The same logic is why offshore wind is much stronger than inland - no obstructions.
> I'm not comfortable with amending the Constitution for something as specific as this,
Southern states commonly put a lot of stuff in their state constitution, and require it be passed in a general election. The theory is it restricts the legislature from doing stuff the people explicitly have said they want or don't want.
> And nobody is installing tracking PV, for the cost is too high and it requires too much maintenance,
As of 2014, 61% of new utility-scale solar plants were tracking systems (https://emp.lbl.gov/sites/all/files/lbnl-1006037_slides.pdf) (see page 23). The 10% higher cost for the tracking hardware is more than offset by the extra output you get from always facing the Sun.
Don't forget the orbiting colonies, where the sun shines 100% of the time, and it's 36% brighter than on Earth (no atmosphere to block any of it).
The amount of solar energy that crosses closer than the Moon is equal to the whole world's fossil fuel reserves *every minute*. It's a mind-bogglingly large resource. We just have to tap it economically.
Residential averages $3/W, while Utility tracking is down to $1.21/W. Tracking systems tilt the panels to follow the Sun, thus get more watts for more hours than fixed-tilt panels. The extra 10% it costs for tracking hardware is more than made up by the extra output, so they are now the best option in terms of cost per kWh produced.
The reality is the solar industry employs twice as many people as the coal industry (200,000 vs 100,000), and they are cleaner jobs too. But many of those jobs are in Democratic-leaning California, which isn't where Trump's base is.
Nope. Drawings for the Apollo program are on file at the Data Repository at the Marshall Space Flight Center, in Huntsville, AL, all two million of them. I've seen them myself. They are on IBM aperture cards, which are punch cards with a square of microfilm inserted into them. More compact and lasts longer than the original blueprints. At the time I was working for Boeing on the Space Station program, and we were using an MSFC building just down the road.
There are lots of things the government isn't very good at, but storing records forever is one they are. Von Braun had the foresight in the early days of NASA to instill a strong recordkeeping ethic for engineering. On the Space Station we had a whole frikken basement in one of our buildings for document storage. It used to be a running joke in aerospace that when the documentation exceeds the mass of the vehicle, it's ready to fly. On Space Station it was literally true.
You can find about half a million NASA technical documents online: https://ntrs.nasa.gov/search.j... That doesn't include all the Apollo documents, but it does have a fair number of them.
> Have you any idea how unutterably mindbogglingly insane the inside of the jet engine that takes you on holiday is?
Hell, I used to do blacksmithing as a hobby. You can easily reach temperatures that will melt steel with nothing more than charcoal and a hair dryer, though I used coal and a larger centrifugal blower.
> How much energy can we take out of the air with windmills before we start seeing an effect on the weather?
As much as three trillion trees do. Trees are pretty effective at slowing wind, which is why areas like the Southeast aren't so good for wind power. We have lots of trees, the midwest not so much. It's also why offshore wind is generally better than land, in terms of available power - no trees.
Because on human time scales, the resource renews itself. Suck heat out the ground with a geothermal plant, and the ground will heat up again from deeper sources. Collect solar and wind energy, and there will be more tomorrow. This is unlike coal or oil, where the resource does not renew itself on human time scales.
Strictly speaking, all energy sources are finite. The Sun's fuel will eventually run out, and the Earth's interior heat will run out. But that will take billions of years, and energy projects are measured in decades to centuries.
> You also have yet to prove why 2C (current prediction) of potential warming does anything except bring unprecedented prosperity to humanity.
The 6 meters of sea-level rise that will eventually happen as a consequence of 2C in temperature increase will put major parts of coastal areas underwater.
In New York City, where an awful lot of rich people live, normal travel is to call downstairs to the doorman, and tell them to hail a taxi. By the time you ride the elevator to the lobby, the taxi is waiting. Uber just has better than average quality vehicles. Limos take longer to get hold of, because there aren't 30,000 of them driving around Manhattan like taxis. They often lounge around nice hotels and restaurants, but not every building, because there just aren't that many of them. So they take longer to arrange.
The choice will depend on things like "are you running to a business meeting or trying to impress a date?" - speed vs quality.
> negative inflation (deflation) is really really bad, because in that situation, the economy grinds to a halt because nobody wants to spend money (because it'll be worth more tomorrow),
This is a fallacy, because most people need to spend most of their income on immediate needs (food, mortgage/rent, utilities, car payments, gasoline, etc.). Therefore the economy will still function. For the people who have surplus income to invest, they already calculate a "real rate of return" by subtracting inflation from the nominal rate of return (i.e. measured in inflating currency). Thus if your stocks went up 2%, but inflation was also 2%, your real return is zero, because you can only buy the same amount of goods and services as the original investment could. If inflation was -2% (deflation) instead of +2%, it doesn't affect the method to calculate of real return, only the value you subtract. The market values of various investments would adjust to yield the same real return they do now. This is no different than what happened in past times when the inflation rate changed from one value to another.
This discussion applies to *mild* deflation, on the order of a few percent per year. Rapid deflation and rapid inflation are both bad. We have an example of the first in India, where they are trying to suddenly withdraw large bills from circulation, disrupting the normal flow of funds. We have an example of the second in Venezuela, which is now probably classed as hyperinflation (>100%/year)
Slashdot Mirror
A fair comparison is that the same factory that Tesla is using now used to produce 428,000 internal combustion cars in one year, back when it was owned by GM and Toyota.
The batteries can be recycled, and the batter factory will be solar powered. How is that not green?
> I don't believe the claim that "solar photo-voltaic electricity is now less expensive than grid electricity" as bare fact.
That only applies to utility-scale tracking arrays, not to residential: http://www.seia.org/research-r...
Rooftop residential fell to $2.98/Wdc in the 3rd quarter of 2016, while utility tracking came in at $1.21. Tracking systems tilt the panels to follow the Sun, and therefore produce more power than fixed ones on rooftops. So overall, the utility systems are about three times cheaper. Why are they so much less? It is much more efficient for a work crew on level ground than on a sloped roof, and they don't have to pack up their gear and drive to a new location every two dozen panels. You only need one big connection to the utility grid for a solar farm, rather than one for every house, so less wiring/transformers/etc.
At $1.21/W, and assuming the solar farm returns 8% annually and produces for 2000 hours/year, the net cost is $0.0484/kWh, which is competitive with wind and natural gas.
> Take for example asteroid mining, how long have we heard about that?
It's been a feature of science fiction since the early days. But making a serious effort at it depends on several things that are more recent:
* The discovery of 15,000 Near Earth asteroids, 90% of which have been found in the last 15 years : http://neo.jpl.nasa.gov/stats/ The Near Earth group are much easier to reach than the Main Belt asteroids. The more of them you find, the better the chance of some of them being the right composition and right orbit to mine.
* The development of higher power electric propulsion (ion and plasma) and high efficiency solar arrays, in order to power space tugs to bring back asteroid rock to a high Earth orbit. This has also happened over the last 15 years.
* Improvements in space robotics and high-bandwidth communications, which would allow real-time control of a processing plant in high orbit from the ground. This reduces the need for astronauts on site and lowers the cost.
* Growth of a market for the products of asteroid mining. There are now about 1400 active satellites in space : http://www.sia.org/wp-content/... (see page 8) and the number is growing. Without a way to refuel or repair them, they have to be replaced at great cost. Asteroid mining can supply fuel, both for the satellite itself, and to bring them to a repair station. That market is worth billions a year, but again, 15 years ago it was much smaller.
Not surprisingly, now that the pre-conditions exist, people are making serious efforts to develop asteroid mining.
The solution to this is reflectors that send additional light into the greenhouses. I'm thinking of something like these linear concentrators:
http://www.redrok.com/images/h...
but instead of focusing the light on a tube to boil water, they focus it on narrow windows in the greenhouse. Since Mars has a similar day length and axial tilt to Earth, the main thing is to increase the amount of light getting into the greenhouse. So the reflectors need to be about 2.5 times the area of the greenhouse floor. I assume most of the greenhouse will be buried under a layer of dirt, because the nights on Mars are *cold* and you want to maintain the greenhouse temperature. A slot at the top of the dirt layer leading to windows would allow the light in, and you can cover the windows at night if needed to retain heat.
The reflectors can be pretty lightweight, because of the low gravity, and relatively low wind loads.
My guess is it's a precessing pulsar with an offset magnetic field. Pulsars are well known to produce repeating pulses as their magnetic poles rotate in and out of view. To see the pulses requires they cross our field of view, meaning a specific alignment of the rotation axis vs location of the magnetic pole (which don't have to be the same). If there is a second body near the pulsar, with an orbit offset from the equator, it would cause the rotation axis to precess, just like the Earth's does due to the Moon and Sun. Therefore the alignment of the magnetic pole would move in and out of view, and we only see pulses on the rare occasions they line up just right.
This guess would be defeated if the pulses look nothing like normal ones from pulsars, and confirmed if enough data is collected to detect the orbital motion of a second body.
> is there such a thing as a possible saturation of the PV market?
Yes, in the near term when it supplies all the daytime electricity a grid can handle without becoming unstable. It's not always sunny, so the grid needs enough other power sources to compensate for bad weather. Estimates when this point would be reached with the current grid range around 20-30%. US electric production is between 1 and 2% solar at the moment. I say daytime because power demand is lower at night, and the sun doesn't shine then.
In the long term, with better transmission infrastructure (to overcome local weather), and storage solutions (solar thermal, or batteries), total solar could go higher
> could there be a day in near future (10 years) that there are PV on all the roofs that can handle it?
Only a minority of solar installations are on home rooftops. In the US, the majority are "utility" systems, with many thousands of panels installed at ground level. Most of these today are "tracking systems", that tilt rows of panels to follow the sun, and get more output. Because it's installed at ground level by specialized work crews, and needs fewer support systems per panel, it is 60% cheaper than residential. There is no shortage of open land. Commercial rooftops fall in between residential and utility. For example, WalMart and Target have each installed 300 MW of solar panels on their store roofs. It offsets some of the power used by the stores.
> mostly due to Political ideology against Climate Change Science
No, it's because we have a lot of trees in the south, which causes friction and lowers wind speeds. It's no coincidence that most wind farms are in the midwest/Texas areas where it's flat open prairie and crop land. Wind speeds are actually just as high at higher altitudes in the South. The same weather systems blowing through other states eventually come here. But it's not economic to build wind turbines that tall yet. The same logic is why offshore wind is much stronger than inland - no obstructions.
> I'm not comfortable with amending the Constitution for something as specific as this,
Southern states commonly put a lot of stuff in their state constitution, and require it be passed in a general election. The theory is it restricts the legislature from doing stuff the people explicitly have said they want or don't want.
> And nobody is installing tracking PV, for the cost is too high and it requires too much maintenance,
As of 2014, 61% of new utility-scale solar plants were tracking systems (https://emp.lbl.gov/sites/all/files/lbnl-1006037_slides.pdf) (see page 23). The 10% higher cost for the tracking hardware is more than offset by the extra output you get from always facing the Sun.
Don't forget the orbiting colonies, where the sun shines 100% of the time, and it's 36% brighter than on Earth (no atmosphere to block any of it).
The amount of solar energy that crosses closer than the Moon is equal to the whole world's fossil fuel reserves *every minute*. It's a mind-bogglingly large resource. We just have to tap it economically.
> IIRC installed pricing is now arround $2.50 a watt,
Depends where it is installed: http://www.seia.org/sites/defa...
Residential averages $3/W, while Utility tracking is down to $1.21/W. Tracking systems tilt the panels to follow the Sun, thus get more watts for more hours than fixed-tilt panels. The extra 10% it costs for tracking hardware is more than made up by the extra output, so they are now the best option in terms of cost per kWh produced.
> So in 2017 solar might hit 1% and probably max out.
Given the 75 GW utility solar pipeline (built, contracted, and announced), that's not likely:
http://www.seia.org/research-r...
Assuming a 20% capacity factor (average vs rated capacity), the 15 GW of average output is more than 3% of total US electric use.
The reality is the solar industry employs twice as many people as the coal industry (200,000 vs 100,000), and they are cleaner jobs too. But many of those jobs are in Democratic-leaning California, which isn't where Trump's base is.
Nope. Drawings for the Apollo program are on file at the Data Repository at the Marshall Space Flight Center, in Huntsville, AL, all two million of them. I've seen them myself. They are on IBM aperture cards, which are punch cards with a square of microfilm inserted into them. More compact and lasts longer than the original blueprints. At the time I was working for Boeing on the Space Station program, and we were using an MSFC building just down the road.
There are lots of things the government isn't very good at, but storing records forever is one they are. Von Braun had the foresight in the early days of NASA to instill a strong recordkeeping ethic for engineering. On the Space Station we had a whole frikken basement in one of our buildings for document storage. It used to be a running joke in aerospace that when the documentation exceeds the mass of the vehicle, it's ready to fly. On Space Station it was literally true.
You can find about half a million NASA technical documents online: https://ntrs.nasa.gov/search.j... That doesn't include all the Apollo documents, but it does have a fair number of them.
Seems to work fine for me:
https://torrentz2.eu/search?f=...
> Have you any idea how unutterably mindbogglingly insane the inside of the jet engine that takes you on holiday is?
Hell, I used to do blacksmithing as a hobby. You can easily reach temperatures that will melt steel with nothing more than charcoal and a hair dryer, though I used coal and a larger centrifugal blower.
> How much energy can we take out of the air with windmills before we start seeing an effect on the weather?
As much as three trillion trees do. Trees are pretty effective at slowing wind, which is why areas like the Southeast aren't so good for wind power. We have lots of trees, the midwest not so much. It's also why offshore wind is generally better than land, in terms of available power - no trees.
Because on human time scales, the resource renews itself. Suck heat out the ground with a geothermal plant, and the ground will heat up again from deeper sources. Collect solar and wind energy, and there will be more tomorrow. This is unlike coal or oil, where the resource does not renew itself on human time scales.
Strictly speaking, all energy sources are finite. The Sun's fuel will eventually run out, and the Earth's interior heat will run out. But that will take billions of years, and energy projects are measured in decades to centuries.
> Think of a King, his courtiers and the court.
So who's going to play the part of Jamie Lannister?
You left out the billion dollars in property tax breaks he's gotten, putting the tax burden on everyone else (mostly in New York City).
> You also have yet to prove why 2C (current prediction) of potential warming does anything except bring unprecedented prosperity to humanity.
The 6 meters of sea-level rise that will eventually happen as a consequence of 2C in temperature increase will put major parts of coastal areas underwater.
In New York City, where an awful lot of rich people live, normal travel is to call downstairs to the doorman, and tell them to hail a taxi. By the time you ride the elevator to the lobby, the taxi is waiting. Uber just has better than average quality vehicles. Limos take longer to get hold of, because there aren't 30,000 of them driving around Manhattan like taxis. They often lounge around nice hotels and restaurants, but not every building, because there just aren't that many of them. So they take longer to arrange.
The choice will depend on things like "are you running to a business meeting or trying to impress a date?" - speed vs quality.
> negative inflation (deflation) is really really bad, because in that situation, the economy grinds to a halt because nobody wants to spend money (because it'll be worth more tomorrow),
This is a fallacy, because most people need to spend most of their income on immediate needs (food, mortgage/rent, utilities, car payments, gasoline, etc.). Therefore the economy will still function. For the people who have surplus income to invest, they already calculate a "real rate of return" by subtracting inflation from the nominal rate of return (i.e. measured in inflating currency). Thus if your stocks went up 2%, but inflation was also 2%, your real return is zero, because you can only buy the same amount of goods and services as the original investment could. If inflation was -2% (deflation) instead of +2%, it doesn't affect the method to calculate of real return, only the value you subtract. The market values of various investments would adjust to yield the same real return they do now. This is no different than what happened in past times when the inflation rate changed from one value to another.
This discussion applies to *mild* deflation, on the order of a few percent per year. Rapid deflation and rapid inflation are both bad. We have an example of the first in India, where they are trying to suddenly withdraw large bills from circulation, disrupting the normal flow of funds. We have an example of the second in Venezuela, which is now probably classed as hyperinflation (>100%/year)
> Agreed. I am surprised that they don't go after any exchange that transacts more than 6 figures.
Coinbase, in fact, does run a bitcoin exchange, which traded $96.6 million USD worth in the last 30 days:
https://bitcoincharts.com/mark...