Best Source of Energy

Off-topic talk on music, art, literature, games and forum games.

What energy source(s) should humanity invest in?

Coal
2
4%
Oil
1
2%
Natural Gas
3
7%
Biofuel
4
9%
Solar
7
16%
Wind
5
11%
Hydro
9
20%
Nuclear
12
27%
Other
2
4%
 
Total votes: 45

User avatar
miniboes
Master of the Forum
Posts: 1575
Joined: Mon Sep 15, 2014 1:52 pm
Religion: None (Atheist)
Diet: Vegan
Location: Netherlands

Re: Best Source of Energy

Post by miniboes » Sat Jul 16, 2016 11:12 am

I have now started reading "Energy for future presidents", which is once again a fascinating book. The author (Richard A. Muller, physics professor) is in favor of the use of natural gas (which he says emits 50% less Co2 than coal) along with nuclear energy in the developing world as cheap alternatives to coal. He argues that these steps are far more important than any domestic energy policy since the developing world will soon account for the vast majority of emissions if they keep on using coal. He thinks we should export our knowledge on extracting natural gas and generating nuclear energy, and perhaps even subsidize the transitional efforts of countries like China. What do you think of this position? Would it be more effective to advocate for natural gas and nuclear in the developing world rather than just nuclear (and perhaps solar in deserts)? How about encouraging the use of carbon capture and storage in coal power plants?

(the next part is not so much a question, but more so me being frustrated with my meager knowledge of physics)

I finished SEWTHA, and it basically came to the conclusion that the world cannot be sustained by renewable energy. I stopped reading before the technical chapters, which require more extensive knowledge of physics. I'll probably return to those later, since their conclusions serve as important premises for the other chapters. For instance, in his calculations for how much wind energy can be generated in a country he uses a power per unit land area of 3W/m² for offshore wind. The chapter in which he gets to that number is not understandable to me yet.
(this chapter can be found here http://www.withouthotair.com/cB/page_263.shtml)

I tried doing some calculations with the vision report of Dutch climate activism group Urgenda. Using 3W/m² I calculated that they would need 5,600 km² of sea area for their goal of producing 16,800 MW with offshore wind turbines. Urgenda states, using 3MW wind turbines with 1km distance in between them, we need only 2,800 km². That's half of what I got. This is exactly the reason I want to get into physics, because if I'm serious about getting involved in energy policy and arguing against renewable plans I have to be able to be certain about my calculations.
"I advocate infinite effort on behalf of very finite goals, for example correcting this guy's grammar."
- David Frum

User avatar
brimstoneSalad
neither stone nor salad
Posts: 9499
Joined: Wed May 28, 2014 9:20 am
Religion: None (Atheist)
Diet: Vegan

Post by brimstoneSalad » Sat Jul 16, 2016 8:34 pm

miniboes wrote:The author (Richard A. Muller, physics professor) is in favor of the use of natural gas (which he says emits 50% less Co2 than coal) along with nuclear energy in the developing world as cheap alternatives to coal.
If it's a lesser evil, that's great. Natural gas can be useful for cooking and heating the home by piping the gas straight to a house. The problem is that natural gas requires substantial infrastructure to pipe it around if the source isn't nearby, and then quite a bit of doing in a city too.
For countries in Africa, Solar is probably a better option because it produces energy on the spot; but for heating and cooking, it has some problems that need to be solved.

The trouble of how to get energy from here to there is a serious one in undeveloped countries.

Although, I'd rather pipe gas around than electricity. You can pipe gas around in cheap plastic tubes, electricity requires copper, which will be dismantled and stolen. Another advantage of gas is you can fill canisters with it and move it by hand (as is already done).
miniboes wrote:He argues that these steps are far more important than any domestic energy policy since the developing world will soon account for the vast majority of emissions if they keep on using coal.
Maybe, but the trouble is then you look like a hypocrite (as the U.S. does) by advocating developing countries reduce their energy consumption and use clean energy while developed countries are currently using much more, and aren't relying on clean sources.
Failure to change or adopt new practices could be a matter of pride.
miniboes wrote:He thinks we should export our knowledge on extracting natural gas and generating nuclear energy, and perhaps even subsidize the transitional efforts of countries like China. What do you think of this position?
If we want them to do it, we had better put up. Telling them to do something we won't, and then not helping isn't going to fly.
I don't think much of subsidies, though, they tend not to work well particularly in the corrupt countries they're most needed in.
Better we start using renewables like nuclear and solar wide scale in the west, and develop better technologies, and then invest in their energy sectors by letting our companies go over there.
miniboes wrote:Would it be more effective to advocate for natural gas and nuclear in the developing world rather than just nuclear (and perhaps solar in deserts)? How about encouraging the use of carbon capture and storage in coal power plants?
I don't think so, due to infrastructure issues. Where infrastructure for electric distribution is already in place, nuclear is the best IF you trust them with the technology.
If natural gas is available on site or nearby, then that probably becomes a little easier, and you don't need to trust them with anything.
miniboes wrote: I tried doing some calculations with the vision report of Dutch climate activism group Urgenda. Using 3W/m² I calculated that they would need 5,600 km² of sea area for their goal of producing 16,800 MW with offshore wind turbines. Urgenda states, using 3MW wind turbines with 1km distance in between them, we need only 2,800 km². That's half of what I got.
(((16,800 MW) / (3 W)) * (1 (m^2))) / (1 (km^2)) = 5600

But that's giving 3W/m^2 as ground area.

Wind power is usually given by blade area.

Blade area = pi r^2
Distance between turbines laterally should be 5 blade diameters = 10 r
Distance between them in the windward direction should be 10 = 20 r

Footprint = 200 r^2
Area generating power = pi r^2

% of area generating power: pi/200 = 0.01570796326 = 1.570796326% , or about 1.6%

Then you have to know the kinetic energy of the wind based on wind speed, which varies considerably:
http://www.wwindea.org/technology/ch02/ ... _img11.jpg

Looks like 800 W/m^2 there at 50m, which is pretty good.

Then take into account the efficiency of the windmill. Probably around 45%

1.6% * 800 * 45% = 5.76 W/m^2

So, it should be about half of the area you calculated, since the wind energy there is a very good case. Most places it isn't.
miniboes wrote:Urgenda states, using 3MW wind turbines with 1km distance in between them, we need only 2,800 km². That's half of what I got.
That doesn't compute. They probably mean 1km downwind distance. Wind turbines are spaced closer together perpendicular to the wind direction. 5 blade diameters instead of 10. 10 diameters only in the wind direction.

Note pictures of wind farms for reference on spacing:
http://www.power-technology.com/project ... amalia.jpg

Based on that maximum spacing of 1 km, I assume they have 100 meter diameters (which is common, and then we assume a 50 meter height for the center; the same as the last calculation).
(pi * (50m)^2) * ((800 W)/m^2) * 45% = about 2.8 MW. So, about right based on their claims.
miniboes wrote:This is exactly the reason I want to get into physics, because if I'm serious about getting involved in energy policy and arguing against renewable plans I have to be able to be certain about my calculations.
It's probably their fault for not explaining their spacing properly. Anyway, now you know.

User avatar
miniboes
Master of the Forum
Posts: 1575
Joined: Mon Sep 15, 2014 1:52 pm
Religion: None (Atheist)
Diet: Vegan
Location: Netherlands

Post by miniboes » Mon Jul 18, 2016 5:22 am

brimstoneSalad wrote:Maybe, but the trouble is then you look like a hypocrite (as the U.S. does) by advocating developing countries reduce their energy consumption and use clean energy while developed countries are currently using much more, and aren't relying on clean sources.
Failure to change or adopt new practices could be a matter of pride.
Yeah, that was my concern as well.
brimstoneSalad wrote:Better we start using renewables like nuclear and solar wide scale in the west, and develop better technologies, and then invest in their energy sectors by letting our companies go over there.
That seems like a better approach indeed. I think we should certainly invest more into R&D of sustainable energy and energy conservation.
BrimstoneSalad wrote:[...]So, it should be about half of the area you calculated, since the wind energy there is a very good case. Most places it isn't.
Thanks for the explanation, that helps. Do you think offshore wind might actually be useful for north-western Europe then, supplementing nuclear? I still oppose it; the cost of building and maintaining them is still very large, then there's unreliability concern, not to mention the great resistance of the Dutch population against wind turbines on the horizon.
"I advocate infinite effort on behalf of very finite goals, for example correcting this guy's grammar."
- David Frum

User avatar
brimstoneSalad
neither stone nor salad
Posts: 9499
Joined: Wed May 28, 2014 9:20 am
Religion: None (Atheist)
Diet: Vegan

Post by brimstoneSalad » Mon Jul 18, 2016 9:37 pm

miniboes wrote:Do you think offshore wind might actually be useful for north-western Europe then, supplementing nuclear?
No, I think that would be extremely stupid. Nuclear can provide for all of the world's energy needs, cheaper, and more reliably. And it won't cause mass extinction of migratory seabird species.

miniboes wrote:I still oppose it; the cost of building and maintaining them is still very large, then there's unreliability concern, not to mention the great resistance of the Dutch population against wind turbines on the horizon.
All sensible. However, wind turbines can be placed far enough away to be invisible from the coast (this increases costs).

User avatar
miniboes
Master of the Forum
Posts: 1575
Joined: Mon Sep 15, 2014 1:52 pm
Religion: None (Atheist)
Diet: Vegan
Location: Netherlands

Post by miniboes » Wed Jul 20, 2016 2:35 pm

I've finished reading "Energy for future presidents" now. Once again I feel like my understanding of all these energy issues is much better. Most of the book seems to agree with the positions you and I already hold. Except for his position on electric vehicles, which he summarizes as following:

"Hybrid autos have a great future, but plug-in hybrids and all-electric automobiles do not; they cost much more to operate than do gasoline cars once you include battery replacement cost. There is an exception: autos that run on lead-acid batteries, with very short ranges (on the order of 40-60 miles), could achieve widespread use in China, India, and the rest of the developing world."

He says that there are three fundamental problems that need to be solves for all-electric cars to become popular in the US:

- Density: the useful energy density (300% efficiency advantage included) for batteries is about 4% that of gasoline.
- Cost: if you include battery replacement cost, he calculates for the Tesla Roadster, Nissan Leaf and Chevy Volt that they are 4-7 times as expensive per mile as internal combustion engines with average efficiency.
- Recharge time: Tesla boasts charging rates of about an hour, compared to up to 5 minutes for filling a gasoline car. If batteries were switched at the station rather than charged, this would be solved, but you'd have to pay the depreciation for the battery. That would, according to the author's calculation, amount to 44-75c per driven mile.

He goes on to calculate how efficient electric cars are if the electricity is produced with fossil fuels. This is 45% (fuel burned) * 93% (transmission line) * 80% (batteries charge and discharge) * 80% (electric motors) = 27%. Internal combustion engines are 20% efficient. If the electricity was generated by coal, which emits twice as much CO² as oil, the CO² emissions of the electric car would be higher.

The only way I see him being wrong is if battery lifetimes/prices have or will drop significantly.

It seems like the prices of Tesla batteries have already dropped to around $20,000 (although I've had trouble finding a price from a reliable and recent source), where Richard Muller assumed $44,000 in his book. Tesla has an 8 year warranty with unlimited miles. With an average annual miles of 13,476 for Americans, assuming you'd have to replace it after 8 years, the cost would only be $20,000/(13,476*8)=$0.186 replacement cost per mile. That's already much better than the $0.4-0.7 the author calculated. The 8 years is probably on the short side, because Tesla would presumably put the warranty duration well below the average lifetime.

Assuming my calculations are correct, the author was wrong in his belief that lithium-ion batteries would not drop in price significantly. If the problem of battery replacement cost is solved, the problem of charge time can easily be solved through replacing batteries instead of charging them. The idle batteries could be used as a back-up energy storage to compensate for irregular solar or wind energy.

Am I making sense? Do you think battery replacement costs will drop much lower?
"I advocate infinite effort on behalf of very finite goals, for example correcting this guy's grammar."
- David Frum

Minos
Junior Member
Posts: 55
Joined: Sat Feb 20, 2016 8:49 am
Religion: None (Atheist)
Diet: Reducetarian
Location: Czech republic

Post by Minos » Fri Jul 22, 2016 6:07 am

EquALLity wrote: The first 'negative' aspect was the thermal pollution, so I mentioned the cooling towers. According to her, they cool up some of the water, but not all of it, so it's still a problem? :?
Found a good page about it (http://www.world-nuclear.org/informatio ... lants.aspx). Heat is transferred to air in cooling towers, where steam condense to water. Water itself goes then to reservoir or is dispensed back to river / sea few degrees warmer than is natural temperature of water body.

In my opinion problem isn't big though. Big dams have same effect, and it even occur naturally due to geothermal activity.

User avatar
brimstoneSalad
neither stone nor salad
Posts: 9499
Joined: Wed May 28, 2014 9:20 am
Religion: None (Atheist)
Diet: Vegan

Post by brimstoneSalad » Fri Jul 22, 2016 5:47 pm

miniboes wrote: - Density: the useful energy density (300% efficiency advantage included) for batteries is about 4% that of gasoline.
Which is ultimately the source of range anxiety.

Electric isn't ideal for long-distance commute yet, but good for daily work commute. Individuals and families need to stop buying cars based on the most distant possible commute, and start thinking about the more common commute: you can always rent a vehicle for a road trip (one which is both larger, and a hybrid so you won't have the range limitations).
Use a small vehicle with a short range for daily use.

This isn't an issue most of the time, consumers have to change the way they think about their cars. Since many families also have two cars, in the very least being smart about purchases could replace almost half of cars with electric.
miniboes wrote: - Cost: if you include battery replacement cost, he calculates for the Tesla Roadster, Nissan Leaf and Chevy Volt that they are 4-7 times as expensive per mile as internal combustion engines with average efficiency.
I don't think he had any basis to make that claim. When do you replace the battery? At some arbitrary point? You have to look at the actual numbers for capacity loss until the point that it's no longer useable.

What you're dealing with is range loss: http://www.greencarreports.com/news/1096801_tesla-model-s-battery-life-how-much-range-loss-for-electric-car-over-time

The battery doesn't simply stop working after eight years. Like all of us know who have owned a mobile phone or laptop, it just gives you less and less use time over many charges. Eight years is an arbitrary deadline for defects in the Tesla battery that make it stop working, not even a range guarantee.

I'll quote from that article a bit:
In the wake of more-rapid-than-expected battery capacity losses in Leafs in hot weather, Nissan now guarantees that the Leaf battery will retain at least 70 percent capacity after five years and/or 60,000 miles.
And that's pessimistic:
When Tesla first introduced the Roadster in 2008, it predicted that the battery pack would retain at least 70 percent of its capacity after five years and 50,000 miles of driving.
[...]
Using data from 126 Roadsters driven a total 3.2 million miles, the study concluded that the typical Roadster would still have 80-85 percent battery capacity after 100,000 miles.
The recent Model S numbers from The Netherlands are even more encouraging.
Based on 84 data points from the 85-kWh version of the Model S and six from 60-kWh cars, the study concludes that the Model S will retain about 94 percent of its capacity after 50,000 miles, with losses thereafter shrinking to about 1 percent per 30,000 miles.
Lead acid batteries are cheaper, sure: and I agree that it's possible they could make more sense in some cases. But for the vast majority of uses where a car can be plugged in overnight and even at work or while grocery shopping, the user is only going to need about a 25 mile range (assuming no charging anywhere else),
That's a very old battery, given that it was originally over ten times that range.

https://www.fhwa.dot.gov/policy/2010cpr/execsum.cfm
The average automobile commuter spends 22.8 minutes commuting a one-way distance of 12.6 miles; bus commuters travel a shorter average distance of 9.4 miles, but have a higher average commuting time of 48.9 minutes.
You have already correctly identified that battery replacement costs have dropped:
miniboes wrote: It seems like the prices of Tesla batteries have already dropped to around $20,000 (although I've had trouble finding a price from a reliable and recent source), where Richard Muller assumed $44,000 in his book.
You may have forgotten (as Muller seems to have too) to take into account the trade-in value. Lithium ion batteries contain a lot of very expensive recyclable materials: they take the old battery apart, and through a recycling process, make new batteries from it; or even just resell the batteries for less demanding use with different electronics (like home solar systems). They could even have several homes before ultimately being recycled for materials.

https://forums.tesla.com/forum/forums/tesla-model-s-85kw-battery-replacement-cost

Tesla apparently quotes 12k for replacement after eight or so years with the trade-in value (that was with their prepay program, though, I assume based on their estimates for the price with their new battery plant). Nisan is even less, as quoted in the article I linked to earlier:
By contrast, a Nissan Leaf replacement battery costs $5,500, after the trade-in allowance.
http://www.greencarreports.com/news/109 ... -over-time
That's a lower kWh battery, though perfectly suitable for commuting use.

Without the trade-in value, it's kind of like quoting the cost of a whole new refrigerator instead of a freon refill.
Tesla has an 8 year warranty with unlimited miles.
As mentioned, it should still be perfectly fine to drive with after eight years.

You need to use the range degradation numbers. While it's fine for most people to drive until it gets down to 25 miles, let's say 60 miles to be really safe.

Based on a 10% DoD, this site would suggest the battery would last well over ten years:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Discharging batteries to a great depth is a good way to ruin them, basically. It shouldn't be necessary for cars used to commute.

(From that greencarreports article I linked earlier again) Starting range:
My 2013 Tesla Model S, when new, had an EPA range of 265 miles. But six or eight years down the road, with 100,000-plus miles on the odometer, there’s no way to know what my range will be.
We need to lose 205 miles for it to really need to be replaced. That's a 77% reduction.
Based on 84 data points from the 85-kWh version of the Model S and six from 60-kWh cars, the study concludes that the Model S will retain about 94 percent of its capacity after 50,000 miles, with losses thereafter shrinking to about 1 percent per 30,000 miles.
50k miles = 6%
+ 1% for each 30k miles.

Total = 50k + (30k * 71) = 2180k miles.
The it will cost you 12k to replace it.

That's about $0.005 per mile for replacement cost. Not substantial by any means. That's the best case, if your battery never outright breaks. And that's assuming there aren't any weird effects from low voltage as it loses capacity.

Some people try to avoid discharging it entirely (which is a good idea), although I assume that mile range has a buffer on it. You could look at what it would be avoiding lower than a 30% charge.
So, if we use a 47% reduction (to keep things above 30% charge):

Total = 50k + (30k * 41) = 1280k miles
At 12k, that's about 1 cent.
If we assume 20k, it's a little over two cents.

Still a much longer life than the eight years.
miniboes wrote: The 8 years is probably on the short side, because Tesla would presumably put the warranty duration well below the average lifetime.
Yes, well, the 8 years has nothing to do with range. Computers last far beyond their typical one year warranties, for example. That's just an arbitrary line to inspire consumer confidence. It's possible your battery could break after that and your car just wouldn't start, in which case the number is closer to your calculation if you got unlucky.

Somehow it seems unlikely that the battery would last 80 years, though, based on low useage driving. Storage time, and temperature, can affect the battery too, it's just not very clear how much. Lithium ion batteries seem to survive very well with a decade of storage, at least... but they've only been around for about 25 years, and only the oldest models can have been properly tested.

So, we really don't know how long these batteries will last.

miniboes wrote:If the problem of battery replacement cost is solved, the problem of charge time can easily be solved through replacing batteries instead of charging them. The idle batteries could be used as a back-up energy storage to compensate for irregular solar or wind energy.
This is very true. Solar and wind are much more suitable for powering cars than houses and industry, because the battery cost is already there, and if it's done in situ, at the storage facility it could be pretty efficient. Second hand batteries from cars also apparently increase availability of affordable batteries for in-home solar battery banks.

The whole energy source thing gets to his other point:
miniboes wrote:He goes on to calculate how efficient electric cars are if the electricity is produced with fossil fuels. This is 45% (fuel burned) * 93% (transmission line) * 80% (batteries charge and discharge) * 80% (electric motors) = 27%. Internal combustion engines are 20% efficient. If the electricity was generated by coal, which emits twice as much CO² as oil, the CO² emissions of the electric car would be higher.
Electric cars give us the ability to get off gas, and onto something clean like nuclear to power our vehicles. It's still an important job to resist fossil fuel burning plants. The two have to go hand in hand to solve the problem of transportation emissions. Without electric cars, though, we don't have that option.

As you mentioned above, battery swapping could even make solar and wind more viable options.

In his calculations, he probably also failed to consider methane leak emissions from drilling oil, which are substantial.

miniboes wrote:Am I making sense? Do you think battery replacement costs will drop much lower?
I think they will. But even as expensive as they are now, I think it's viable.

miniboes wrote: - Recharge time: Tesla boasts charging rates of about an hour, compared to up to 5 minutes for filling a gasoline car.
It's kind of irrelevant, though, because you can charge your car up in your garage at home -- you can't fill up your gas there. These things are different; gas isn't superior.

As mentioned before, there are also more charging stations spreading across the country (and quickly, because they're relatively cheap and easy to install compared to a gas pump). I've seen them at grocery stores, and a growing number of employers are offering them.
http://www.greencarreports.com/news/1076629_need-electric-car-charging-at-work-heres-how-to-get-it

Apparently, a company can even get a third party managed station for free (like a vending machine).

User avatar
miniboes
Master of the Forum
Posts: 1575
Joined: Mon Sep 15, 2014 1:52 pm
Religion: None (Atheist)
Diet: Vegan
Location: Netherlands

Post by miniboes » Sat Jul 23, 2016 10:03 am

brimstoneSalad wrote:
miniboes wrote: - Density: the useful energy density (300% efficiency advantage included) for batteries is about 4% that of gasoline.
Which is ultimately the source of range anxiety.

Electric isn't ideal for long-distance commute yet, but good for daily work commute. Individuals and families need to stop buying cars based on the most distant possible commute, and start thinking about the more common commute: you can always rent a vehicle for a road trip (one which is both larger, and a hybrid so you won't have the range limitations).
Use a small vehicle with a short range for daily use.

This isn't an issue most of the time, consumers have to change the way they think about their cars. Since many families also have two cars, in the very least being smart about purchases could replace almost half of cars with electric.
That's a good point. Muller does recognize this, and thinks electric cars with lead-acid batteries will be very popular in the developing world, where most people are not used to long distance commute. Perhaps he thinks trying to change people's lifestyle/mindset is too hard and we should just try to meet current standards as much as we can. Or he just doesn't feel qualified to make such recommendations because he's not an economist/social scientist/policy advisor. I imagine there are some very cheap and effective policies you can come up with to incentivize using a small car for daily commute and hiring a larger one for travel.
I don't think he had any basis to make that claim. When do you replace the battery? At some arbitrary point? You have to look at the actual numbers for capacity loss until the point that it's no longer useable.
You're right, it was not argued well.
Richard Muller wrote:The batteries of these cars are lithium-ion, which range widely in price - from #30 to $150 per pound. The replacement battery for my laptop is $120 per pound. Generally speaking, the cheap batteries are not a bargain, because of their typically shorter lifetime. I no longer buy them for my digital camera because I've learned the number of recharges they deliver is often less than 100. The good batteries (such as the one for my laptop) are guaranteed to last 400 recharges. Some battery manufacturers claim that their batteries can recharge 1000 times or more, but be wary. For my calculations, I'll assume that the batteries bought in bulk cost $40 per pound and can be recharged 500 times.
You may have forgotten (as Muller seems to have too) to take into account the trade-in value. Lithium ion batteries contain a lot of very expensive recyclable materials: they take the old battery apart, and through a recycling process, make new batteries from it; or even just resell the batteries for less demanding use with different electronics (like home solar systems). They could even have several homes before ultimately being recycled for materials.
I did indeed forget that. Lithium is very valuable, and I can imagine there's much more valuable stuff in there. Good point.
Yes, well, the 8 years has nothing to do with range. Computers last far beyond their typical one year warranties, for example. That's just an arbitrary line to inspire consumer confidence. It's possible your battery could break after that and your car just wouldn't start, in which case the number is closer to your calculation if you got unlucky.

Somehow it seems unlikely that the battery would last 80 years, though, based on low useage driving. Storage time, and temperature, can affect the battery too, it's just not very clear how much. Lithium ion batteries seem to survive very well with a decade of storage, at least... but they've only been around for about 25 years, and only the oldest models can have been properly tested.

So, we really don't know how long these batteries will last.
It would be very interesting to see a large scale study on this, perhaps in Norway where the Tesla Model S is the #1 selling car.
Electric cars give us the ability to get off gas, and onto something clean like nuclear to power our vehicles. It's still an important job to resist fossil fuel burning plants. The two have to go hand in hand to solve the problem of transportation emissions. Without electric cars, though, we don't have that option.
That's right, I don't think he would deny that. He probably just wanted to point out that as long as we use fossil fuels for our electricity, electric cars are not much more clean.
In his calculations, he probably also failed to consider methane leak emissions from drilling oil, which are substantial.
That's correct, I haven't seen that come up. He does mention the leak emissions somewhere but not in these calculations.
It's kind of irrelevant, though, because you can charge your car up in your garage at home -- you can't fill up your gas there. These things are different; gas isn't superior.
It's another change of behaviour. It should be pretty easy to get used to, though. Replacing batteries seems like a great solution for long-distance travel.

Thanks for your reply. I had the sense he was missing something, but aside from the fact that battery costs are clearly dropping I wasn't sure what.

I think I've got a pretty good understanding of what our best sustainable energy supply options are now. Nuclear is great, and solar energy in deserts may have a future too, especially if we use idle car batteries as back-up. Tesla certainly seems to think their cars should run on solar energy, I'm curious if this is what they have in mind.
"I advocate infinite effort on behalf of very finite goals, for example correcting this guy's grammar."
- David Frum

User avatar
EquALLity
I am God
Posts: 3005
Joined: Thu Jul 10, 2014 11:31 am
Religion: None (Atheist)
Diet: Vegan
Location: United States of Canada

Post by EquALLity » Sat Jul 23, 2016 1:44 pm

Minos wrote:
EquALLity wrote: The first 'negative' aspect was the thermal pollution, so I mentioned the cooling towers. According to her, they cool up some of the water, but not all of it, so it's still a problem? :?
Found a good page about it (http://www.world-nuclear.org/informatio ... s.aspx).[b] Heat is transferred to air in cooling towers, where steam condense to water. Water itself goes then to reservoir or is dispensed back to river / sea few degrees warmer than is natural temperature of water body.[/b]

In my opinion problem isn't big though. Big dams have same effect, and it even occur naturally due to geothermal activity.
Wait, so the cooling towers don't prevent the rise in temperature levels? :?
"I am not a Marxist." -Karl Marx

User avatar
brimstoneSalad
neither stone nor salad
Posts: 9499
Joined: Wed May 28, 2014 9:20 am
Religion: None (Atheist)
Diet: Vegan

Post by brimstoneSalad » Sat Jul 23, 2016 3:18 pm

EquALLity wrote:
Minos wrote:
EquALLity wrote: The first 'negative' aspect was the thermal pollution, so I mentioned the cooling towers. According to her, they cool up some of the water, but not all of it, so it's still a problem? :?
Found a good page about it (http://www.world-nuclear.org/informatio ... s.aspx).[b] Heat is transferred to air in cooling towers, where steam condense to water. Water itself goes then to reservoir or is dispensed back to river / sea few degrees warmer than is natural temperature of water body.[/b]

In my opinion problem isn't big though. Big dams have same effect, and it even occur naturally due to geothermal activity.
Wait, so the cooling towers don't prevent the rise in temperature levels? :?
They do. Minos misunderstood the source cited and seems to have confused once through with recirculating evaporative cooling (using cooling towers). It discusses three methods of cooling.
This cooling function to condense the steam may be done in one of three ways:
  • Direct or "once-through" cooling. If the power plant is next to the sea, a big river, or large inland water body it may be done simply by running a large amount of water through the condensers in a single pass and discharging it back into the sea, lake or river a few degrees warmer and without much loss from the amount withdrawn[5]. That is the simplest method. The water may be salt or fresh. Some small amount of evaporation will occur off site due to the water being a few degrees warmer.
  • Recirculating or indirect cooling. If the power plant does not have access to abundant water, cooling may be done by passing the steam through the condenser and then using a cooling tower, where an updraught of air through water droplets cools the water. Sometimes an on-site pond or canal may be sufficient for cooling the water. Normally the cooling is chiefly through evaporation, with simple heat transfer to the air being of less significance. The cooling tower evaporates up to 5% of the flow and the cooled water is then returned to the power plant's condenser. The 3 to 5% or so is effectively consumed, and must be continually replaced. This is the main type of recirculating or indirect cooling.
  • Dry cooling. A few power plants are cooled simply by air, without relying on the physics of evaporation. This may involve cooling towers with a closed circuit, or high forced draft air flow through a finned assembly like a car radiator.
http://www.world-nuclear.org/information-library/current-and-future-generation/cooling-power-plants.aspx

Cooling towers only discharge smaller amounts of probably quite cool salt water (into on site ponds or into the ground, I think) to keep the system from becoming too salty, not hot water in large volumes as once through systems do.

Environmental regulations limit the temperature at which water can be returned, so even that isn't a big issue. It does require them to reduce the power output of the plants in the summer, though, which is a problem.

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests