I said in #22:
> Currently PV module costs go down 75% per decade (exponential decay of the costs).
CORRECTION: The first part is true, the part in parentheses is false due to a mistake I made. In a log-log plot power functions like f(x) = C*x^(-k) where k is some positive real number appear as straight lines (with a negative slope). So it's not exponential decay of costs, it's power law decay of costs:
x being the cumulative installed PV capacity given in watts (W), C being a constant of proportionality given in the strange unit of
$ per W^(1-k)
and k being a dimensionless exponent (just a number). f(x) is of course given in $ per W.
In the case of Swanson's law the power function comes out as roughly:
f(x) = 27777.8*x^(-0.407283)
Again, f(x) is measured in units of dollars per watt. And the constant of proportionality is C = 27777.8 $/(W^0.592717)
Here's how it looks like:
www.wolframalpha.com/input?i=log-log+plot+of+27777.8*x%5E%28-0.407283%29+from+10%5E5.9+to+10%5E12.1
I got confused because Moore's law is usually shown in a semi-log plot, not a log-log plot. And in a semi-log plot straight lines correspond to exponential functions like g(t) = C*b^(r*t). The number of transistors on a microchip actually doubles every two or so years, so it grows exponentially in time. In that context (semi-log plots) straight lines with negative slope correspond to exponential decay. Hope I'm not leaving anyone with a false impression:
PV prices per unit of electric power do not decay exponentially, they roughly decay according to the above (mathematical) power law f(x).
I also said in #22:
> The total installed solar power is also growing exponentially (tenfold increase in installed power per decade)
This is mostly true, but I messed up a litte reading off the graph. It's more of a tenfold increase in installed power every 8 years (actually faster than I first claimed).
> Currently PV module costs go down 75% per decade (exponential decay of the costs).
CORRECTION: The first part is true, the part in parentheses is false due to a mistake I made. In a log-log plot power functions like f(x) = C*x^(-k) where k is some positive real number appear as straight lines (with a negative slope). So it's not exponential decay of costs, it's power law decay of costs:
x being the cumulative installed PV capacity given in watts (W), C being a constant of proportionality given in the strange unit of
$ per W^(1-k)
and k being a dimensionless exponent (just a number). f(x) is of course given in $ per W.
In the case of Swanson's law the power function comes out as roughly:
f(x) = 27777.8*x^(-0.407283)
Again, f(x) is measured in units of dollars per watt. And the constant of proportionality is C = 27777.8 $/(W^0.592717)
Here's how it looks like:
www.wolframalpha.com/input?i=log-log+plot+of+27777.8*x%5E%28-0.407283%29+from+10%5E5.9+to+10%5E12.1
I got confused because Moore's law is usually shown in a semi-log plot, not a log-log plot. And in a semi-log plot straight lines correspond to exponential functions like g(t) = C*b^(r*t). The number of transistors on a microchip actually doubles every two or so years, so it grows exponentially in time. In that context (semi-log plots) straight lines with negative slope correspond to exponential decay. Hope I'm not leaving anyone with a false impression:
PV prices per unit of electric power do not decay exponentially, they roughly decay according to the above (mathematical) power law f(x).
I also said in #22:
> The total installed solar power is also growing exponentially (tenfold increase in installed power per decade)
This is mostly true, but I messed up a litte reading off the graph. It's more of a tenfold increase in installed power every 8 years (actually faster than I first claimed).
@Rainbow_Pink_Lover said in #31:
> pls explain in short!
Short bullet points (even shorter version below):
- solar power today is not as bad as it was in the 1980s.
- solar cells can convert an increasing share of the energy of the sunlight that hits them (they become more efficient).
- the price per unit of electric power gets lower and lower over time (learning curve). So it becomes cheaper and cheaper.
- this is partly because solar cells are made of the same materials as the computing chips in your phone (semiconductors) and benefit from development in this industry (computer hardware)
- coal power plants have largely reached their technological limits (will not become significantly better or cheaper in future)
- coal power plants are already much more expensive than solar power (price per unit of electric power)
- coal power plants emit lots of harmful pollutants (bad for human health, particulate matter harms the lungs and kills many thousands of people every year) including CO2 (heating the atmosphere, contributing massively to human-caused climate change)
- lignite (brown coal) is a fuel used in (most) coal power plants. Extracting it requires surface mining/open-pit mining, carving huge holes into the landscape with massive environmental impacts (water pollution, problems with the groundwater, etc.)
Even SHORTER: coal (especially lignite) shouldn't be used for power generation in future, solar power should be used where it can be (it depends on geography and other factors).
This video shows quite well why continuing to use coal for power generation is not a good idea:
www.youtube.com/watch?v=SD9yVca6hHI
weplaychess90 said in #29:
> Thanks!
> Do you think Graphene could be used in batteries of Solar Energy?
I'm not an expert on battery technology or material science, so I really don't know. A quick look with a search engine seems to confirm that graphene based approaches to battery tech seem to be taken. But it appears to still be in the R&D phase, not ready for commercial application yet.
> pls explain in short!
Short bullet points (even shorter version below):
- solar power today is not as bad as it was in the 1980s.
- solar cells can convert an increasing share of the energy of the sunlight that hits them (they become more efficient).
- the price per unit of electric power gets lower and lower over time (learning curve). So it becomes cheaper and cheaper.
- this is partly because solar cells are made of the same materials as the computing chips in your phone (semiconductors) and benefit from development in this industry (computer hardware)
- coal power plants have largely reached their technological limits (will not become significantly better or cheaper in future)
- coal power plants are already much more expensive than solar power (price per unit of electric power)
- coal power plants emit lots of harmful pollutants (bad for human health, particulate matter harms the lungs and kills many thousands of people every year) including CO2 (heating the atmosphere, contributing massively to human-caused climate change)
- lignite (brown coal) is a fuel used in (most) coal power plants. Extracting it requires surface mining/open-pit mining, carving huge holes into the landscape with massive environmental impacts (water pollution, problems with the groundwater, etc.)
Even SHORTER: coal (especially lignite) shouldn't be used for power generation in future, solar power should be used where it can be (it depends on geography and other factors).
This video shows quite well why continuing to use coal for power generation is not a good idea:
www.youtube.com/watch?v=SD9yVca6hHI
weplaychess90 said in #29:
> Thanks!
> Do you think Graphene could be used in batteries of Solar Energy?
I'm not an expert on battery technology or material science, so I really don't know. A quick look with a search engine seems to confirm that graphene based approaches to battery tech seem to be taken. But it appears to still be in the R&D phase, not ready for commercial application yet.
@Thalassokrator I think it is good that you try to share wisdom with other people
i think it's interesting (not like that irrelevant troll's spam around)
@Thalassokrator
What is your opinion regarding the thorium reactor? As I understand thorium is more plentiful that uranium,does not produce weaponizable byproducts and those it does produce are safe in 600-700 years.
I'm not suggesting this as an alternative to solar power which I agree is probably our best bet. I just wondered what you thought of it as an interim solution.
I have read of the work to develop a paint on solar panel essentially turning any roof into a source of electricity though I haven't heard anything recently.
What is your opinion regarding the thorium reactor? As I understand thorium is more plentiful that uranium,does not produce weaponizable byproducts and those it does produce are safe in 600-700 years.
I'm not suggesting this as an alternative to solar power which I agree is probably our best bet. I just wondered what you thought of it as an interim solution.
I have read of the work to develop a paint on solar panel essentially turning any roof into a source of electricity though I haven't heard anything recently.