Science and Helping the World

[brimstoneSalad]

I guess the radiation levels everywhere are so low that it is insignificant and studies don't show a correlation because of the very low numbers?

Right. Smoking, diet, and genetics play such a strong role that there's so much noise you can't control for in population studies; the actual effect of that low level radiation gets hidden by the noise.

If only one extra person in a million might die, you'd have to study millions of people to show the effect, and control for every single one, in terms of smoking, diet, genetics, and other factors which are stronger and would hide the results. Just not practical.

The average American produces about twice the amount of CO2 than Germany does, however, and America is much more reliant on nuclear energy than Germany is (which the documentary should mention). So nuclear isn't necessarily the only solution here (going back to this later).

This is due to different lifestyles.

Interestingly, the average citizen in China produces less CO2 than the average person in France per year.
That's pretty amazing given how much coal China is using in relation to the rest of the world.

No heating, no air conditioning, generally no refrigeration (they just leave food sitting out all day), one shower a week (usually in cold water), no car (they ride bikes or take a bus), most of their calories are from rice and vegetable oil.

Even though I don't have a problem with nuclear energy, and I think it's definitely important in combating climate change (it's really amazing that a pound of uranium [which is apparently the size of a fingertip o_O] can produce as much energy as about 5,000 barrels of oil), I think that solar energy and wind energy (and possibly other forms of renewable energy also, but those two seem to be the most advanced and helpful ones at the moment) can also be a part of the solution.

Used together with nuclear which can kick on when the sun goes down or the wind stops blowing, and in certain situations, solar and wind can be useful. On their own, they're too unreliable.

Like the documentary mentioned, intermittency is an issue, but there are potential solutions. One example is energy storage.

How do you store the energy?

That's like saying: "Distance is an issue for visiting other galaxies, but there are potential solutions, like making the space ships faster."

"Our analysis shows that today's wind industry, even with a large amount of grid-scale storage, is energetically sustainable,"

Yes, it's theoretically possible. That says nothing about the cost. In order to be actually possible it has to be financially viable.

It's also theoretically possible to pipe electricity across the planet at residential voltages using liquid nitrogen cooled superconducting power lines so there's always solar energy available everywhere with virtually no transformer or transmission losses beyond cooling, and with enough insulation using advanced technologies like aerogels, argon, etc., the energy costs for cooling too could be reduced to result in energy efficient enough transmission to power the world on solar if we cover all surfaces in solar panels.

http://www.extremetech.com/extreme/182278-the-worlds-first-superconducting-power-line-paves-the-way-for-billions-of-dollars-in-savings

This is currently not a realistic prospect.

One interesting thing that solar energy could do to combat intermittency is to have solar panels in outer space.

Of course, that'd be really expensive.

It's fine for satellites. You produce the power where the power is used. But it's not just expensive as a power solution for the ground, it's impossible. You can't run a cable up there. A space elevator isn't even possible currently, but even if it were, that's a geosynchronous orbit. When it's night on the ground, it's night in the Earth's shadow in orbit too.

Even so, nuclear energy is so controversial that developing other technologies that generate energy from solar rays and wind seems like a good idea in addition to building more power plants (especially wind energy, because that is the energy source that causes the least deaths per year).

It's controversial because of the fear mongering and human stupidity. Another approach is to tackle that head-on and destroy it with science education.

Is it easier to develop revolutionary new technology, and then try to get people to accept it (whatever fear mongering that stirs up), or to just try to get people to accept existing solutions? Attempting to develop new technology may fail entirely, and then you wasted precious decades. The time to act is now.

Only five new nuclear reactors are currently under construction, and some of the existing reactors are in danger of shutting down.

We need to build more, and keep the old ones online, fighting for them with everything we have.

Until we have all the nuclear power plants built that could sustain the world, we should build more wind turbines and solar panels.

Why? We should build more nuclear plants. Building solar panels and wind power is a distraction and waste of resources.

And at that point, nuclear energy will be able to supplement solar and wind instead of natural gas, so they'll be perfectly environmentally friendly resources.

They're only environmentally sustainable AFTER we have the nuclear plants built. We can also use nuclear power to manufacture the solar and wind plants. Right now it's fossil fuel. These things are energy intensive to build.

[EquALLity]

This is due to different lifestyles.

Perhaps, but then it's also unfair to contribute France's success to nuclear energy when there could be multiple factors.

No heating, no air conditioning, generally no refrigeration (they just leave food sitting out all day), one shower a week (usually in cold water), no car (they ride bikes or take a bus), most of their calories are from rice and vegetable oil.

Ah.

Used together with nuclear which can kick on when the sun goes down or the wind stops blowing, and in certain situations, solar and wind can be useful. On their own, they're too unreliable.

So you agree that we should try to develop solar and wind energy in addition to nuclear?

Yes, it's theoretically possible. That says nothing about the cost. In order to be actually possible it has to be financially viable.

It's also theoretically possible to pipe electricity across the planet at residential voltages using liquid nitrogen cooled superconducting power lines so there's always solar energy available everywhere with virtually no transformer or transmission losses beyond cooling, and with enough insulation using advanced technologies like aerogels, argon, etc., the energy costs for cooling too could be reduced to result in energy efficient enough transmission to power the world on solar if we cover all surfaces in solar panels.

http://www.extremetech.com/extreme/1822 ... in-savings

This is currently not a realistic prospect.

Estimates that nuclear energy is going to last a very long time are also based on theoretical future technology and findings.

I'm not sure about finances, but like the link says, it would be energetically viable.

The picture quickly gets more complicated when you add the fact that wind and solar power alone can't provide consistent, uninterrupted power output. One option to smooth that intermittency is grid-scale storage, but all storage systems -- be they pumped hydro, chemical batteries or compressed air -- come with their own energy costs.
The Stanford report focuses on this combination of renewable energy and storage infrastructure. Even with the addition of grid-scale storage, they found, there is enough surplus wind power in the United States today to support 72 hours of energy storage.
Solar energy, which enjoys a slimmer margin of surplus, could sustain about 24 hours of backup energy storage, they found.
"Our analysis shows that today's wind industry, even with a large amount of grid-scale storage, is energetically sustainable," said Michael Dale, a research associate at Stanford and lead author of the report, in the release. "We found that the solar industry can also achieve sustainable storage capacity by reducing the amount of energy that goes into making solar photovoltaics."
The energy needed to expand the existing renewable fleet depends on the speed of the expansion, of course. The more new wind turbines, solar panels and batteries enter the grid, the more their energy costs.
Existing onshore wind power could sustain global wind capacity's current growth rate, at 100 percent, and still maintain an energy surplus, the authors found.
How much excess energy would be available to the public after providing for the costs of expanded renewables and accompanying storage depends on many factors, Barnhart said. Further declines in the energy costs of manufacturing renewables and greater energy efficiency would grow the net energy surplus.
Better batteries would likewise increase the surplus, particularly over longer time scales, he said. "The amount of surplus available to society is widely different depending on the technology you use. Not all storage technology is created equal. We're finding that in some cases the cheapest batteries also have the lowest energy costs, but we've also seen that in many other cases, they're not."
Low-cost, long-lived technologies, like pumped hydro, often yield a greater surplus over time than cheap lead acid batteries, which must be replaced after only a short life span, he said.

Things that would make nuclear energy last a long time, like extracting uranium from oceans, would also probably cost a lot of money.

? What? It's a potential solution. Yes, it seems like a science fiction, but it's possible. It probably won't happen in the near future, but you can't just write it off.

It's fine for satellites. You produce the power where the power is used. But it's not just expensive as a power solution for the ground, it's impossible. You can't run a cable up there. A space elevator isn't even possible currently, but even if it were, that's a geosynchronous orbit. When it's night on the ground, it's night in the Earth's shadow in orbit too.

You don't need a cable or a space elevator.

Self-assembling satellites are launched into space, along with reflectors and a microwave or laser power transmitter. Reflectors or inflatable mirrors spread over a vast swath of space, directing solar radiation onto solar panels. These panels convert solar power into either a microwave or a laser, and beam uninterrupted power down to Earth. On Earth, power-receiving stations collect the beam and add it to the electric grid.

The two most commonly discussed designs for SBSP are a large, deeper space microwave transmitting satellite and a smaller, nearer laser transmitting satellite.

http://energy.gov/articles/space-based-solar-power

As for the shadow stuff, that's not true-

In space the sun is always shining, the tilt of the Earth doesn't prevent the collection of power and there’s no atmosphere to reduce the intensity of the sun’s rays.

It's controversial because of the fear mongering and human stupidity. Another approach is to tackle that head-on and destroy it with science education.

Is it easier to develop revolutionary new technology, and then try to get people to accept it (whatever fear mongering that stirs up), or to just try to get people to accept existing solutions? Attempting to develop new technology may fail entirely, and then you wasted precious decades. The time to act is now.

Most people already support prioritizing solar and wind- even most republicans (albeit it's 51% with the republicans). http://www.gallup.com/poll/190268/prior ... l-gas.aspx
Solar and wind also aren't met with extreme opposition. There are no street protests about the dangers of renewable energy (minus nuclear).

Nuclear energy is apparently supported by most people, but over a third of Americans believe it is unsafe.

We need to build more, and keep the old ones online, fighting for them with everything we have.

I agree, but I think we should also work to develop other forms of renewable technology.

Why? We should build more nuclear plants. Building solar panels and wind power is a distraction and waste of resources.

Because they're also useful to combating climate change, and they have more support than nuclear energy.

They're only environmentally sustainable AFTER we have the nuclear plants built. We can also use nuclear power to manufacture the solar and wind plants. Right now it's fossil fuel. These things are energy intensive to build.

Like that link from before says-

To be cost-effective, any source of power has to produce more energy than it consumes. Oil companies would hardly turn a profit, for example, if extracting a barrel of oil required the energy output of a second barrel of oil.
The same holds true of renewable energy sources like wind and solar. Though renewable projects pay the lion's share of both their energetic and financial costs up front, they still have to recover those costs over a lifetime of service and continue to produce value if they are to yield a net-energy surplus.
Thanks to dramatic improvements in the manufacture of both wind and solar technologies, that appears to be more than possible. A new study published in the journal Energy & Environmental Science finds that wind and solar not only produce enough power to be energetically sustainable but could support grid-scale energy storage as well.
"What we're saying is that theoretically, it is now theoretically possible to have this perfect world that's just based on wind and solar," said Charles Barnhart, a postdoctoral scholar with the Global Climate and Energy Project at Stanford University and a co-author of the study. Rather than using existing "stock" fuels like fossil fuels, he said, renewables put out enough excess energy to fuel their own expansion.
While the majority of deployed renewables yield surplus benefits, those benefits aren't necessarily equal, said Sally Benson, a professor of energy resources engineering at Stanford University and co-author of the study, in a release from the institution.
"Within a few months, a wind turbine generates enough electricity to pay back all of the energy it took to build it," she said. "But some photovoltaics have an energy payback time of almost two years."

Once they're built, they don't require any additional fossil fuel energy to be supported, and soon outweigh the fossil fuels used to produce them. It's a worthy investment.

Don't nuclear plants require fossil fuels to be built as well?

IMO the problem isn't fossil fuels being used to produce solar and wind technology; it's that intermittency is supplemented with fossil fuels (primarily natural gas, apparently).

[brimstoneSalad]

Perhaps, but then it's also unfair to contribute France's success to nuclear energy when there could be multiple factors.

France's success IS nuclear energy; it's about the percentage of energy they use coming from non-emitting sources.
The success has to be looked at in terms of the public policy and education that made nuclear successful.

Yes, we should also reduce usage, but it's not going to be able to drop much without affecting quality of life. We need to get on better energy sources.

Used together with nuclear which can kick on when the sun goes down or the wind stops blowing, and in certain situations, solar and wind can be useful. On their own, they're too unreliable.

So you agree that we should try to develop solar and wind energy in addition to nuclear?

I've never disagreed, but they have very limited applications. I don't agree with considering them a potential solution to the current problem; that's a red herring.

Solar is useful for non-grid energy. Like street lights that don't all have to be connected by miles and miles of copper wire. Or trash cans which alert the base when they're full and have to be collected, or even compact the trash in them to limit the number of trips needed.

When you think solar or wind, think non-intensive distributed operations. Stuff that only needs a tiny bit of power, and is all spread out so it'd be a waste to run power lines to all of them. Low wattage activities which can be supplied by an on-site solar panel which eliminates the need for power transmission.

It makes sense to run your home computer and led house lighting off solar and a small (cheap) battery. These are low wattage behaviors, AND they require DC power (make sure to know the difference between AC and DC).

It doesn't make sense to expect to run your heating, air conditioning, your refrigerator, your washing machine, etc. off these power sources. These are power hogs, and they draw too many watts to be reliably supplied by a small solar and battery system (one that could be easily and cheaply installed in most houses).

Estimates that nuclear energy is going to last a very long time are also based on theoretical future technology and findings.

You're misunderstanding,

The fissile material is there. Current supplies (at the current price) will last X years. Once that's used up, the price will rise a bit, and more supply (at the new price) will open up; like reprocessing fuel, and deeper mines and more anemic ores. At the new price, there will be supply to last for Y years. Then the price will go up a little more, and there will be new sources at that new price (like sea water extraction), and that supply will last for Z years.

Nuclear is currently economically viable. Solar is not.
Nuclear only requires a gradual development of technology to stay viable. Solar requires an instantaneous leap in technological development to become viable.

It's the difference between the prospect of leaping directly to the top of a hundred story building (Solar), and being expected to climb the stairs to the top over the next few hundred years (Nuclear).

We have time to bring the price of technologies like fuel reprocessing and seawater extraction down. We have huge amounts of time to do this. And nuclear is already a viable source for the world's power today based on current supplies that will give us that time.

The same is not true of solar.
IF we had an immediate supply of elementally pure silicon, and it's doping elements, to produce solar panels cheaply and with virtually no energy input (a supply that will gradually run out), then the situation would be a little more similar.

Self-assembling satellites are launched into space, along with reflectors and a microwave or laser power transmitter. Reflectors or inflatable mirrors spread over a vast swath of space, directing solar radiation onto solar panels. These panels convert solar power into either a microwave or a laser, and beam uninterrupted power down to Earth. On Earth, power-receiving stations collect the beam and add it to the electric grid.

The two most commonly discussed designs for SBSP are a large, deeper space microwave transmitting satellite and a smaller, nearer laser transmitting satellite.

http://energy.gov/articles/space-based-solar-power

I'm familiar with the science fiction. I don't know who wrote that, but I guess I'll have to tear it to pieces.

Like solar power, lasers also don't work on a cloudy day, but it's much, MUCH more expensive.
Did you look at the pie in the sky price estimates? 1 to 10 MW for 500 million to a billion dollars? (these seem to be ridiculous low-ball estimates, by the way)

Residential systems today are around $5 per watt. So such a system is ten times more expensive (at the best case, if it delivers 10 MW for 500 million dollars) than just putting solar panels on rooftops. There's no reason or advantage to putting these things in space. I would say this was yellow journalism to sell copy, but this is a government web page... I think it's just an example of government waste coming from enthusiasm generated around a cool sounding idea with no practical viability. Or maybe NASA clamoring for funding and trying to stay relevant. This could very well be fueled by bias.

Remember Solar Freaking Roadways?
https://www.youtube.com/watch?v=H901KdXgHs4

Government bought into that nonsense too.

Microwave based systems are even more risky, and more expensive.
While they don't suffer as much from atmosphere, do you think the oil industry isn't going to launch the same fear mongering campaign against this that they did against nuclear?
Literal beams of radiation from space!

We have perfectly viable options for power here on Earth that are well within the scope of current technology and affordable today.
This is intriguing for science fiction, but appears to be far outside the scope of current technology, and may never be financially viable.

There's also an important con the author left out of the graphic: thermodynamic efficiency of lasers is not very high, as is the thermodynamic efficiency of solar panels even lower, we also have to consider the thermodynamic efficiency of conversion on the ground.
THREE times you have to change the form of power.

Sun -> electricty: 25% efficiency (which is a margin above the current record holder, and may never be passed for all we know)
Electricity -> laser (let's say an infrared diode): 70% (again, above anything I've found by a large margin).
Laser -> Electricity: 50% (best case for a solar cell, which are more efficient for lasers)

That's 8.75% efficient for a laser.
For microwave it's slightly better, at 13.5% total.

What does inefficiency mean?

If you want to get 10,000 MW of electricity on the ground, that means you have 18,571 MW of waste heat in your laser in space.
That's 18,571,000,000 joules of heat building up every second.

If I calculated this correctly, that's the equivalent of four tons of TNT exploding every second.

Something kind of like this:
https://www.youtube.com/watch?v=FAYVMXYYAp4

Every second.
Where does that heat go? Remember that space is a vacuum; it's a perfect insulator (like a vacuum thermos). Things can only cool by radiative cooling, which is extremely slow and inefficient.

You could certainly build such a satellite, but trying to run it and generate a laser would melt it. Such a device would require an incredible cooling system, and I don't think these people have accounted for the difficulty of such an endeavor. Or they've ignored it or waved it off for political reasons because they don't want to argue themselves out of funding for superfluous technology.

To put this into perspective, check out the ISS:
https://en.wikipedia.org/wiki/Electrical_system_of_the_International_Space_Station

It maxes out at about 120 kW. A pretty trivial amount of power. And even that amount was a monumental challenge for cooling.
This is 154,758 times larger.
Let that sink in a little bit.

And that's not the half of it (literally). I didn't even get into the inefficiency of the solar panels themselves. That multiplies the amount of heat that needs to be dissipated by over four times (25% efficient), because they're talking about using mirrors to concentrate power on the solar cells (which means, unlike the ISS, the solar cells themselves aren't able to act as radiators of at least some of the excess heat).

You could operate at a higher temperature, but then you get into a negative feedback loop, because the higher temperature you operate at, the lower your efficiency, so the more heat you're producing for the same power output.

When you reach sizes like these, you start running into serious limitations of radiators and require larger and larger installations and active cooling systems. We'd probably be looking at something like a death-star. All for the sake of a measly 10,000 MW of power. You will need to build a small moon.

Bear in mind that these are just back of the envelope calculations, but I'm just trying to give you an understanding that unless you get into the physics of something and show where all of the energy is going, the efficiency of each step, AND where the waste heat is going, you can't really say something is "possible".

As for the shadow stuff, that's not true-

In space the sun is always shining, the tilt of the Earth doesn't prevent the collection of power and there’s no atmosphere to reduce the intensity of the sun’s rays.

This is also incorrect. The sun is not shining in the shadow of the Earth, which can be seen as far as the moon quite clearly. This is most relevant for a space elevator style solar collector.
The satellite has to be positioned to beam energy to the ground, night and day. This may not be trivial to avoid Earth's very large shadow.

Nuclear energy is apparently supported by most people, but over a third of Americans believe it is unsafe.

It's something we have to tackle. We have a similar problem with adoption of veganism. We have to use evidence against the myths and ignorance.
Our job is education foremost.

I agree, but I think we should also work to develop other forms of renewable technology.

Why?

I'm OK with continual research into fusion as an academic project, but that may never yield positive energy output, and may never be financially viable.
When we put money into these things it's a gamble, and nuclear is not. It's already a viable solution.

Because they're also useful to combating climate change, and they have more support than nuclear energy.

Eating Organic meat has more support than veganism, but it's not useful, and even counterproductive.

Talking about solar for grid power is a distraction. The technology we already have for solar (like rooftop solar, and solar water heaters) is great. You can buy and install these systems today, and they aren't going to improve much. We just need to adopt the currently available technology where we can, develop viable innovations with low power consumption (like solar trash cans and lighting that makes sense) and focus on nuclear for grid power.

Once they're built, they don't require any additional fossil fuel energy to be supported, and soon outweigh the fossil fuels used to produce them. It's a worthy investment.

Don't nuclear plants require fossil fuels to be built as well?

It's an issue of Energy Returned On Energy Invested.

IMO the problem isn't fossil fuels being used to produce solar and wind technology; it's that intermittency is supplemented with fossil fuels (primarily natural gas, apparently).

And the cost. And the environmental and health impacts.