Donate Bitcoin

Donate Paypal


PeakOil is You

PeakOil is You

Wind & Solar Are Wrong Path Pt. 2

Discussions of conventional and alternative energy production technologies.

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby vtsnowedin » Fri 13 Nov 2020, 17:12:21

Newfie wrote:Mustang,

Living in temperate climates, at our population levels, is a modern luxury, that is not sustainable.

I have to doubt that. Most of or population today is urban or suburban spending most of our time indoors or in a transport vehicle. The energy to provide that controlled climate inside that living space can be had both by fossil fuels but also by renewable sources. As long as the farmland and oceans can be kept productive I see no reason why the mid latitudes would not be viable. It is the arid desert countries without sufficient water to supply the population that will be the first to become nonviable.
User avatar
vtsnowedin
Fission
Fission
 
Posts: 11933
Joined: Fri 11 Jul 2008, 03:00:00

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby Newfie » Fri 13 Nov 2020, 21:03:15

Not arguing which becomes non-viable first, you may well be right regarding desert countries and water.

My comment was about heat in temperate climates. It takes a LOT of energy to heat NY City or Chicago or Toronto.

Ine can learn to conserve on many things; drive less, use LED lights, turn light off at night. But heat has limitations, you can only let it get so cold. And cold happens in winter without a lot of sun.

Sure ultra high efficiency houses can be built. We are not going to build new ultra high efficiency houses for 200 million, just in the USA.

The goal is, supposedly, to get to zero emissions. NO fossil fuels. Thats gonna be tough in those 3 cities and elsewhere. Maybe with nuclear.
User avatar
Newfie
Forum Moderator
Forum Moderator
 
Posts: 15754
Joined: Thu 15 Nov 2007, 04:00:00
Location: Between Canada and Carribean

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby vtsnowedin » Fri 13 Nov 2020, 21:32:08

Heat in Toronto, AC in Atlanta, two ends of the spectrum. Both can be provided off the electric grid with whatever energy source you choose. I would think that urban High rise buildings would tend to be efficient just from the ratio of floor space to walls and roof heat losers compared to single family suburban houses.
I'm already seeing very energy efficient houses being constructed with walls ten to twelve inches thick and heat exchangers recapturing heat from vented stale air.
My ancestors survived here in Vermont with fireplaces fed with hand chopped wood. Of course they wore wool inside in the winter.
Other then places like Hawaii with uniform year round temperatures I think the mid latitudes are the most livable with at least six months of comfortable temperatures followed by a few months of discomfort that is easily adapted to. Of course if you can summer in Vermont and winter in Atlanta you can have your cake and eat it to. I need to talk to the Atlanta daughter about getting a house with a mother-in law apartment for us to migrate to in the winter. :)
User avatar
vtsnowedin
Fission
Fission
 
Posts: 11933
Joined: Fri 11 Jul 2008, 03:00:00

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby REAL Green » Sat 14 Nov 2020, 06:52:11

vtsnowedin wrote:Heat in Toronto, AC in Atlanta, two ends of the spectrum. Both can be provided off the electric grid with whatever energy source you choose. I would think that urban High rise buildings would tend to be efficient just from the ratio of floor space to walls and roof heat losers compared to single family suburban houses. I'm already seeing very energy efficient houses being constructed with walls ten to twelve inches thick and heat exchangers recapturing heat from vented stale air.
My ancestors survived here in Vermont with fireplaces fed with hand chopped wood. Of course they wore wool inside in the winter.


You forget overshoot, delocalization, and diminishing returns to tech. You are also pointing to a period long ago when people were mentally acclimated to harsh conditions and manual labor. They were not delocalized in overshoot either. You are fantasizing, mixing the old with the new but missing the key mitigating factor of a decline process. While I preach a hybridization of old and new with green prepping I do not agree this will be a painless process of optimism. In fact this is why there is the prepping component to the green in my REAL Green. The green is not your standard green liberalism either which is a fake green techno optimism. This is the harsh green of lower scale of affluence and mobility. The lower mobility is more than physical it is also less techno reach.
realgreenadaptation.blog
User avatar
REAL Green
Heavy Crude
Heavy Crude
 
Posts: 1090
Joined: Thu 09 Apr 2020, 05:29:28
Location: MO Ozarks

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby mustang19 » Tue 24 Nov 2020, 00:25:25

Vestas is sued for blade failures

https://www.windpowermonthly.com/articl ... -ohio-site

Manufacturers lied, everything about lifespan and eroi of blades is fake.

There is no way wind energy can work becuase it is 40% efficient. 60% of energy goes into deforming the blade. It can never hope to eroi for basic physical reasons.

Only flexible materials can be used, rigid turbines are an impossible task.
mustang19
Tar Sands
Tar Sands
 
Posts: 585
Joined: Fri 06 Nov 2020, 20:43:52

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby kublikhan » Tue 24 Nov 2020, 08:49:54

mustang19 wrote:Vestas is sued for blade failures

https://www.windpowermonthly.com/articl ... -ohio-site

Manufacturers lied, everything about lifespan and eroi of blades is fake.

There is no way wind energy can work becuase it is 40% efficient. 60% of energy goes into deforming the blade. It can never hope to eroi for basic physical reasons.

Only flexible materials can be used, rigid turbines are an impossible task.
Read the article. No mention of a lawsuit. No mention of lying manufactures. No mention of fake EROEI. And the blade failed because it was struck by lightning. Is everything you write BS?
The oil barrel is half-full.
User avatar
kublikhan
Master Prognosticator
Master Prognosticator
 
Posts: 4661
Joined: Tue 06 Nov 2007, 04:00:00
Location: Illinois

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby REAL Green » Tue 24 Nov 2020, 11:39:11

This is a great look at EROI of various sources with an excellent explanation of EROI. I got this off the news section. I highly recommend reading the PDF with its well rounded analysis of a deeper EROI viewpoint.

"A summary of Weisbach’s EROI study, which is generally considered to be the most reliable."
https://festkoerper-kernphysik.de/Weiss ... eprint.pdf

"EROI of onshore wind power in northern Germany is ~16. It is worth noting that EROI will be different depending upon turbine design, where it is situated (I.e. wind speed) and its effective lifetime. An EROI of 16 implies an ECoE of 6.25% – which is marginal but still workable. The ability of wind power to support industrial civilisation depends largely on our ability to harness it without wasting exergy. That means minimising energy transitions, energy lost in storage and transmission, etc. That implies in my mind that we should avoid wasteful solutions like the hydrogen economy or battery electric cars and concentrate instead on direct use of the electrical and mechanical energy as it is produced. That means grid connected electric transport like trains and trams and industrial manufacturing powered by grid electric wind power. We need to adapt to intermittent energy, by having some functions that are capable of responding to supply. For example, heating and cooling can be switched off when electricity supply is low, if thermal inertia is built into the system. Transport can run more slowly if energy levels are lower. Manufacturing can postpone some functions when energy levels are low. This is how it will need to work. Labour productivity will be lower. EROI of light water nuclear reactors is estimated to be 75. This is superior to any fossil fuel power generation, with the possible exception of natural gas. But there is institutional inertia to the use of nuclear energy that may prove difficult to overcome. In China, where fewer such limitations exist, nuclear power is expanding rapidly."
realgreenadaptation.blog
User avatar
REAL Green
Heavy Crude
Heavy Crude
 
Posts: 1090
Joined: Thu 09 Apr 2020, 05:29:28
Location: MO Ozarks

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby mustang19 » Tue 24 Nov 2020, 14:48:47

kublikhan wrote:
mustang19 wrote:Vestas is sued for blade failures

https://www.windpowermonthly.com/articl ... -ohio-site

Manufacturers lied, everything about lifespan and eroi of blades is fake.

There is no way wind energy can work becuase it is 40% efficient. 60% of energy goes into deforming the blade. It can never hope to eroi for basic physical reasons.

Only flexible materials can be used, rigid turbines are an impossible task.
Read the article. No mention of a lawsuit. No mention of lying manufactures. No mention of fake EROEI. And the blade failed because it was struck by lightning. Is everything you write BS?


They are in losses becuase of repair costs
mustang19
Tar Sands
Tar Sands
 
Posts: 585
Joined: Fri 06 Nov 2020, 20:43:52

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby Peak_Yeast » Tue 24 Nov 2020, 16:06:27

Re: Inverters are complicated.

Yes - some are complicated - others not so much.

FPGAs are not needed - I am sure someone is stupid enough to over engineer the inverter, but it is total overkill. The very simplest of grade of microprocessors (<2$ cost) is plentiful of power to control the power electronics - which again is not very complicated.

Some also has graphics displays - not needed. All you need is a 2$ wifi module or a 2$ USB interface. The ESP-32 for example would be plenty of cpu power and include communications.

There need to be no significant losses (in materials) in solar power over any amount of time when and if the products are matured.
It could easily be done if we gave it the effort. But yes it requires an effort that is not necessarily good in a market economy. Companies dont earn money on selling something that never break or is easily and cheaply repaired/renewed.
"If democracy is the least bad form of government - then why dont we try it for real?"
User avatar
Peak_Yeast
Lignite
Lignite
 
Posts: 293
Joined: Tue 30 Apr 2013, 17:54:38
Location: Denmark

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby kublikhan » Tue 24 Nov 2020, 19:09:27

REAL Green wrote:This is a great look at EROI of various sources with an excellent explanation of EROI. I got this off the news section. I highly recommend reading the PDF with its well rounded analysis of a deeper EROI viewpoint.

"A summary of Weisbach’s EROI study, which is generally considered to be the most reliable."
https://festkoerper-kernphysik.de/Weiss ... eprint.pdf

"EROI of onshore wind power in northern Germany is ~16. It is worth noting that EROI will be different depending upon turbine design, where it is situated (I.e. wind speed) and its effective lifetime. An EROI of 16 implies an ECoE of 6.25% – which is marginal but still workable. The ability of wind power to support industrial civilisation depends largely on our ability to harness it without wasting exergy. That means minimising energy transitions, energy lost in storage and transmission, etc. That implies in my mind that we should avoid wasteful solutions like the hydrogen economy or battery electric cars and concentrate instead on direct use of the electrical and mechanical energy as it is produced. That means grid connected electric transport like trains and trams and industrial manufacturing powered by grid electric wind power. We need to adapt to intermittent energy, by having some functions that are capable of responding to supply. For example, heating and cooling can be switched off when electricity supply is low, if thermal inertia is built into the system. Transport can run more slowly if energy levels are lower. Manufacturing can postpone some functions when energy levels are low. This is how it will need to work. Labour productivity will be lower. EROI of light water nuclear reactors is estimated to be 75. This is superior to any fossil fuel power generation, with the possible exception of natural gas. But there is institutional inertia to the use of nuclear energy that may prove difficult to overcome. In China, where fewer such limitations exist, nuclear power is expanding rapidly."
Actually that paper is written by nuclear engineers who tweaked every value they could to make renewables look bad and nuclear look good. It is not a very good source for EROI values. Other studies put the EROI of nuclear around 14 or 15, not 75.

Energy Returned on Energy Invested (EROI or EROEI) is an expression of energy payback – how much energy we get out of the energy we put into a system. Now, a new scientific paper by nuclear researchers in Germany is making the rounds. In general, the authors seem keen on tweaking the calculation in order to make nuclear look better – and renewables worse.
Renewables K.O.-ed by EROI?

Meta-analysis of EROI values for nuclear energy suggests a mean EROI of about 14:1 (n of 33 from 15 publications)
Image
EROI of different fuels and the implications for society
The oil barrel is half-full.
User avatar
kublikhan
Master Prognosticator
Master Prognosticator
 
Posts: 4661
Joined: Tue 06 Nov 2007, 04:00:00
Location: Illinois

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby Outcast_Searcher » Sat 05 Dec 2020, 13:27:24

kublikhan wrote:
mustang19 wrote:Vestas is sued for blade failures

https://www.windpowermonthly.com/articl ... -ohio-site

Manufacturers lied, everything about lifespan and eroi of blades is fake.

There is no way wind energy can work becuase it is 40% efficient. 60% of energy goes into deforming the blade. It can never hope to eroi for basic physical reasons.

Only flexible materials can be used, rigid turbines are an impossible task.
Read the article. No mention of a lawsuit. No mention of lying manufactures. No mention of fake EROEI. And the blade failed because it was struck by lightning. Is everything you write BS?

For this one, like many fast crash doomers, you have to view everything they write with suspicion as thy are OFTEN distorting things to try to claim short term doom.

This one is particulary blatant about it in this example, but the BS quotient is very high overall, IMO. :roll:

The reality is wind and solar aren't magical and are far from free, and it certainly takes energy and materials to build and install them, BUT where the climate and conditions are decent for the technology, they do VERY WELL INDEED. And they don't spew GHG's and pollution or burn hydrocarbons thoughout their typical lifespans, which can often be in the range of 2 to 4 decades or so, despite random skewed claims by various deniers. 8O

And in the modern world with computers, science, and math, we can even statistically evaluate whether they make sense to deploy. Despite the false claims of those of a certain ilk. 8)

It's too bad the internet can't screen for a certain level of idiocy. :idea:
Given the track record of the perma-doomer blogs, I wouldn't bet a fast crash doomer's money on their predictions.
User avatar
Outcast_Searcher
COB
COB
 
Posts: 9200
Joined: Sat 27 Jun 2009, 21:26:42

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby TomWayburn » Mon 07 Dec 2020, 03:05:34

Assuming purveyors of wind and solar do accurate eMergy accounting in their respective sectors, I would like to compare these eMergy balances with the petroleum balance for the State of California. Perhaps renewable energy is subsidized by fossil fuels as I suspect ERoEI-star (ERoEI*) accounting might reveal. However, someday we shall have true renewable energy. That day has not yet come, I believe.
User avatar
TomWayburn
Wood
Wood
 
Posts: 14
Joined: Thu 13 Aug 2020, 08:14:12

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby vtsnowedin » Mon 07 Dec 2020, 07:45:26

TomWayburn wrote:Assuming purveyors of wind and solar do accurate eMergy accounting in their respective sectors, I would like to compare these eMergy balances with the petroleum balance for the State of California. Perhaps renewable energy is subsidized by fossil fuels as I suspect ERoEI-star (ERoEI*) accounting might reveal. However, someday we shall have true renewable energy. That day has not yet come, I believe.

While wind and solar installations today are built with fossil fuels they don't have to be but in today's market they will continue to be built using fossil fuels.
For example one of the largest energy inputs for a large wind turbine is the concrete in the foundation and the kilns used to make the portland cement that binds the aggregates together. Those kilns are often fired by coal or shredded old tires and are a major pollution source. You could use hydroelectricity to get away from the fossil fuel and pollution but at present there is not enough available (except in Quebec possibly) and would require new plants to replace those designed to burn coal etc.
When we get enough capacity in a renewable based electric grid we could make that switch but that is a decade or two away. In the meantime we should not fret about where the energy comes from to build our renewables and just enjoy the fact that once built they work for years without any daily fossil fuel consumption.
User avatar
vtsnowedin
Fission
Fission
 
Posts: 11933
Joined: Fri 11 Jul 2008, 03:00:00

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby REAL Green » Mon 07 Dec 2020, 08:19:15

vtsnowedin wrote: While wind and solar installations today are built with fossil fuels they don't have to be but in today's market they will continue to be built using fossil fuels...When we get enough capacity in a renewable based electric grid we could make that switch but that is a decade or two away. In the meantime we should not fret about where the energy comes from to build our renewables and just enjoy the fact that once built they work for years without any daily fossil fuel consumption.


Wind and solar at the scale techno greens are calling for has to be built with fossil fuels and maintained with fossil fuels as a significant component. Honest science and common sense point to this. I agree a scientific research effort could be attempted to create a small scale world of 100% renewables that replicate themselves but this would not scale up to the world we live in. It would probably not even work but I am assuming a test could be made to at least point to it working in a perfect world. The decade or two away argument for the switch is just more hopium. It does not add up. Yes, we should heavily invest in renewables where they make the most sense and triage out the absurdity that most of the fake green techno green world is engaged in. Get real about renewables and get with green prepping for the decline and fall of modern civilization.
realgreenadaptation.blog
User avatar
REAL Green
Heavy Crude
Heavy Crude
 
Posts: 1090
Joined: Thu 09 Apr 2020, 05:29:28
Location: MO Ozarks

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby Outcast_Searcher » Mon 07 Dec 2020, 18:44:12

REAL Green wrote:
vtsnowedin wrote: While wind and solar installations today are built with fossil fuels they don't have to be but in today's market they will continue to be built using fossil fuels...When we get enough capacity in a renewable based electric grid we could make that switch but that is a decade or two away. In the meantime we should not fret about where the energy comes from to build our renewables and just enjoy the fact that once built they work for years without any daily fossil fuel consumption.


Wind and solar at the scale techno greens are calling for has to be built with fossil fuels and maintained with fossil fuels as a significant component. Honest science and common sense point to this. I agree a scientific research effort could be attempted to create a small scale world of 100% renewables that replicate themselves but this would not scale up to the world we live in. It would probably not even work but I am assuming a test could be made to at least point to it working in a perfect world. The decade or two away argument for the switch is just more hopium. It does not add up. Yes, we should heavily invest in renewables where they make the most sense and triage out the absurdity that most of the fake green techno green world is engaged in. Get real about renewables and get with green prepping for the decline and fall of modern civilization.

As if fossil fuels, are going away soon. Especially coal and natural gas.

As if using green energy instead of just BURNING fossil fuels isn't a vast improvement.

As if maintaining windmills or solar panels for 4 decades or so doesn't take a HELL of a lot less fossil fuels than burning it it in light vehicles, week after week for decades.

Your histrionics aren't at all credible. Try using your brain, or at least BACKING your claims with credible data sources. (I have science and math on my side. What do you have besides decades of insta-doom FAIL?)
Given the track record of the perma-doomer blogs, I wouldn't bet a fast crash doomer's money on their predictions.
User avatar
Outcast_Searcher
COB
COB
 
Posts: 9200
Joined: Sat 27 Jun 2009, 21:26:42

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby REAL Green » Mon 07 Dec 2020, 19:03:08

Outcast_Searcher wrote:As if fossil fuels, are going away soon. Especially coal and natural gas.


As if where did I say that?


Outcast_Searcher wrote: As if using green energy instead of just BURNING fossil fuels isn't a vast improvement.


Duh, that took a lot of brain cells


Outcast_Searcher wrote:As if maintaining windmills or solar panels for 4 decades or so doesn't take a HELL of a lot less fossil fuels than burning it it in light vehicles, week after week for decades.


Another Duh

Outcast_Searcher wrote:Your histrionics aren't at all credible.


What histronics? Maybe you don't know what you are talking about. Maybe using the word "histornics" is a fancy way of you saying "I sound smart" but the reality is you are not very smart. You are just a cocky guy who thinks he is smart. You are just grasping at a way to deflect the obvious that I am right about renewables and you wrong. BTW, I have some. I don't believe you do. You are just an Fake Green EV guy.

Outcast_Searcher wrote: Try using your brain, or at least BACKING your claims with credible data sources. (I have science and math on my side.


Obviously you don't have much of a brain. All you did was have a circular conversation with yourself. BTW do you have credible sources? Where is the science and math? They are on your side?? Says who. LOL

Outcast_Searcher wrote:What do you have besides decades of insta-doom FAIL?)


More of your worn out anti-Doom stupidity. It seems like every comment you make you insert that phase. Maybe it is cognitive dissonance.
realgreenadaptation.blog
User avatar
REAL Green
Heavy Crude
Heavy Crude
 
Posts: 1090
Joined: Thu 09 Apr 2020, 05:29:28
Location: MO Ozarks

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby Newfie » Tue 08 Dec 2020, 21:53:11

Thought some of you might find this article of interest.

Jimmy Cornell is a world renowned sailor and author.
Outreamer makes very fast and high quality catamarans.
This was an attempt to prove electric regeneration works.

Here is Jimmies explanation of the situation.

http://nauticmag.com/2020/12/07/electri ... _y38DiZbiM
User avatar
Newfie
Forum Moderator
Forum Moderator
 
Posts: 15754
Joined: Thu 15 Nov 2007, 04:00:00
Location: Between Canada and Carribean

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby jawagord » Mon 15 Feb 2021, 18:27:53

Texas wind turbines freezing up.

https://poweroutage.us/area/state/texas

ERCOT calls for rotating outages as extreme winter weather forces generating units offline

Almost 10,000 MW of generation lost due to sub-freezing conditions

AUSTIN, TX, Feb. 15, 2021 – The Electric Reliability Council of Texas (ERCOT) entered emergency conditions and initiated rotating outages at 1:25 a.m. today.

About 10,500 MW of customer load was shed at the highest point. This is enough power to serve approximately two million homes.

Extreme weather conditions caused many generating units – across fuel types – to trip offline and become unavailable.

There is now over 30,000 MW of generation forced off the system.

"Every grid operator and every electric company is fighting to restore power right now," said ERCOT President and CEO Bill Magness.

Rotating outages will likely last throughout the morning and could be initiated until this weather emergency ends.
Don't deny the peak!
jawagord
Lignite
Lignite
 
Posts: 271
Joined: Mon 29 May 2017, 10:49:17

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby kublikhan » Mon 15 Feb 2021, 19:09:31

jawagord wrote:Texas wind turbines freezing up.

https://poweroutage.us/area/state/texas

ERCOT calls for rotating outages as extreme winter weather forces generating units offline

Almost 10,000 MW of generation lost due to sub-freezing conditions

AUSTIN, TX, Feb. 15, 2021 – The Electric Reliability Council of Texas (ERCOT) entered emergency conditions and initiated rotating outages at 1:25 a.m. today.

About 10,500 MW of customer load was shed at the highest point. This is enough power to serve approximately two million homes.

Extreme weather conditions caused many generating units – across fuel types – to trip offline and become unavailable.

There is now over 30,000 MW of generation forced off the system.

"Every grid operator and every electric company is fighting to restore power right now," said ERCOT President and CEO Bill Magness.

Rotating outages will likely last throughout the morning and could be initiated until this weather emergency ends.
All fuel types are experiencing outages in Texas, not just wind. The majority of the outage is from thermal generators like fossil fuels and nuclear going offline.

Historically frigid temperatures across Texas forced 34 GW of generation—across all fuel types—off the Electric Reliability Council of Texas (ERCOT) system. ERCOT President and CEO Bill Magness in a statement on Sunday morning noted the region was already grappling with higher-than-normal generation outages due to “frozen wind turbines and limited natural gas supplies available to generating units.” But after the Feb. 14, 7 p.m. peak, beginning around 11 p.m., “multiple generating units began tripping offline in somewhat rapid progression due to the severe cold weather.”

Woodfin did not precisely break out the generation capacity that ERCOT lost leading up to its 1:25 a.m. decision to shed load, but he noted: “Most of those generators that went offline during the night, last night, were either—there a few additional wind generators that went offline during the night—but the majority of them were thermal generators, like generation fueled by gas, coal, or nuclear, And so most of the plants that went offline during the evening and morning today were fueled by one of those sources.”

ERCOT Sheds Load as Extreme Cold Forces Generators Offline
The oil barrel is half-full.
User avatar
kublikhan
Master Prognosticator
Master Prognosticator
 
Posts: 4661
Joined: Tue 06 Nov 2007, 04:00:00
Location: Illinois

Re: Wind & Solar Are Wrong Path Pt. 2

Unread postby OutcastPhilosopher » Mon 15 Feb 2021, 19:12:57

This just goes to show the futility of it all.

Wind/Solar will never be a replacement for Fossil Fuels.
The hand that gives is above the hand that takes
OutcastPhilosopher
Peat
Peat
 
Posts: 148
Joined: Fri 06 Nov 2020, 17:39:05

PreviousNext

Return to Energy Technology

Who is online

Users browsing this forum: No registered users and 21 guests