Saving the Environment One Step at a Time

[Borek]

According to this study (couldn't find out if it is peer reviewed or not but it looked serious), there is a slight advantage to PV, but the energy payback time is still several years.

I believe more important is comparison of total (lifetime) payback, and it looks much better then what I read before. The better for PV

 

[Chi Meson]

http://www.energybulletin.net/17219.html

According to this study (couldn't find out if it is peer reviewed or not but it looked serious), there is a slight advantage to PV, but the energy payback time is still several years.

According to http://www.solarwrights.com/" guys, and as of last year, the energy payback for the standard silicon wafer PVs is down to two and a half years, and falling. When thin-film PVs reach mass-production stage, that time should be down to months.

Just a short while ago, in the past year, thin-film PVs got a bump in efficiency due to the application of silver nano globules to the surface. This boosted the efficiency (incident light vs electric power output) from 15% to 19%. I think that was in Physics Today, last February? I can't find it right now.

 

[TheStatutoryApe]

It's amazing to find that many people think this is what my panels are doing. Most people can't distinguish between "Solar heating Panels" and "photovoltaic panels." I point out that most of my hot water is from my panels, and they ask "does the electric company pay you money if you make extra?"

I'm going to make a million bucks selling my idea for a "solar reading light." Place it in direct sunlight and it will produce enough luminescence to read any book or magazine.

My grandfather used to have these, or something like them. They're essentially large flat water tanks on the roof with solar heat collectors to heat the water inside yes?

 

[Borek]

My grandfather used to have these, or something like them. They're essentially large flat water tanks on the roof with solar heat collectors to heat the water inside yes?

Not exactly, at least the type I see from here on the roof of my neighbor doesn't contain water, but some other liquid, with much higher biling point and much lower freezing point. Something like brake fluid. Then there is a pump, a heat exchanger and a water tank.

 

[vanesch]

According to http://www.solarwrights.com/" guys, and as of last year, the energy payback for the standard silicon wafer PVs is down to two and a half years, and falling. When thin-film PVs reach mass-production stage, that time should be down to months.

I'm a bit reluctant to take the numbers from a manufacturer at face value, but even 2 or 3 years of payback time is ok with me.

 

[rewebster]

According to http://www.solarwrights.com/" guys, and as of last year, the energy payback for the standard silicon wafer PVs is down to two and a half years, and falling. When thin-film PVs reach mass-production stage, that time should be down to months.

Just a short while ago, in the past year, thin-film PVs got a bump in efficiency due to the application of silver nano globules to the surface. This boosted the efficiency (incident light vs electric power output) from 15% to 19%. I think that was in Physics Today, last February? I can't find it right now.

I remember seeing something about the 'silicon' part being silkscreened on and baked--I think it was on the TV show called 'Wired Science'.

--and there was some other report 'someplace' about the cost of the war in Iraq and some huge number for how many solar panels that could have been installed for the same cost--and for the 'energy' equivalent that could have been generated.

 

[Chi Meson]

Not exactly, at least the type I see from here on the roof of my neighbor doesn't contain water, but some other liquid, with much higher biling point and much lower freezing point. Something like brake fluid. Then there is a pump, a heat exchanger and a water tank.

Not brake fluid, it's antifreeze. Specifically, I have a 30% solution of Dowfrost "food grade" glycol-blah-blah-blah. THe more anti-freeze, the less heat capacity of the fluid, so you don't want the solution to be any more than necessary to prevent burst pipes. Otherwise, your description is correct.

If you live in an area without any chance of freezing, then you can go with the much simpler method of having the sun heat your water directly. That's not an option for 2/3 of us in the US.

 

[Chi Meson]

I'm a bit reluctant to take the numbers from a manufacturer at face value, but even 2 or 3 years of payback time is ok with me.

These guys are the salesmen, so you can trust what they say!

 

[mgb_phys]

So being green is just the same as being cheap!

If a 'green' product really costs more to produce (and isn't just profiteering) then it must be using more energy either because the raw materials need more processing or need more handling and transport to collect. If it is using more energy then it is hardly green.
Of course green stuff that is purely profiteering ends up going to buy BMWs for the stores owners so is equally non-green.

I turn off lights, combine shopping/recycling site trips, cycle and use the bus to save money - I figure if it is saving money it is saving energy and so is green.

 

[Borek]

Not brake fluid, it's antifreeze. Specifically, I have a 30% solution of Dowfrost "food grade" glycol-blah-blah-blah. THe more anti-freeze, the less heat capacity of the fluid, so you don't want the solution to be any more than necessary to prevent burst pipes. Otherwise, your description is correct.

I wrote "like brake fluid" - it must have low freezing point like anti-freeze, but at the same time it must have high boling point, as it can be easily heated to over 100 deg C. Brake fluid is low freezing, high boiling (so far what we need) and has low compressibility - this part we can safely ignore

 

[rewebster]

I wrote "like brake fluid" - it must have low freezing point like anti-freeze, but at the same time it must have high boling point, as it can be easily heated to over 100 deg C. Brake fluid is low freezing, high boiling (so far what we need) and has low compressibility - this part we can safely ignore

brake fluid doesn't taste good though


(if there's a leak in the heat exchanger/hot water pre-heater tank)

 

[Moonbear]

So being green is just the same as being cheap!

Pretty much. Us old cheapskates are now the cool "green" people.

 

[Chi Meson]

If a 'green' product really costs more to produce (and isn't just profiteering) then it must be using more energy either because the raw materials need more processing or need more handling and transport to collect.

Not necessarily true. Some things cost more because they are not mass produced in China. But you are correct that some businessmen see the green in green, and market goods toward customers who might choose to pay a little bit extra to buy a "green" product to make themselves feel better.

But as I stated on the first page of this thread, I'm choosing to do what I'm doing to save money. If I can't see the difference it makes to my own pocket, what possible difference could it make to the planet?

 

[rewebster]

here it comes---"Buy all your PV panels --Direct---from...China!"

 

[Chi Meson]

here it comes---"Buy all your PV panels --Direct---from...China!"

You KNOW it's true!

It's where all the CFs are made.

 

[binzing]

Anybody watch "Invention Nation"? There's a lot of cool, cheap, even scavenged, green ideas that people have.

 

[rewebster]

You KNOW it's true!

It's where all the CFs are made.

yep, yep, yep-----and as soon as the 'USA' (or someone else) perfects PV panels--they will be

but they'll include lead in them somehow anyway

------------

I'd like to know how China can produce anvils and have them shipped here cheaper than what we in the USA can make them

 

[vanesch]

If a 'green' product really costs more to produce (and isn't just profiteering) then it must be using more energy either because the raw materials need more processing or need more handling and transport to collect. If it is using more energy then it is hardly green.

That's the flawed logic that is also used by some anti-nuclear guys (Storm van Leeuwen and Smith) to "show" that nuclear (because it is capital-intensive) is necessarily an energy-hog: they take expenses in several sectors, look at the average ratio of "cost versus energy use" in the sector, and estimate from there the "energy use" of, say, the construction of a nuclear power plant. But that's heavily flawed as a technique from the moment that the added value is large (in fact from the moment that the added value is larger than the average in the sector).

For instance, I'm not sure it takes that much more energy to *produce* a Ferrari than a Skoda (I'm not talking about *driving* it). If you use the above logic, nevertheless, a Ferrari (the making of a Ferrari) should be an energy hog compared to the Skoda. Another example is medically certified instruments. Exactly the same instrument can cost tens of times more if it is to be certified for medical use than if it is "grand public". It is the same material object, with the same manufacturing. But certification makes the difference in cost. Nuclear is the same.

 

[mgb_phys]

It's always difficult to calculate end-end energy and environmental costs. Yes, nuclear reactors are capital expensive to build which is why the 'dash for gas' - but for an oil fired one do you take into account the cost of the army to invade the country the oil comes from?

I think the idea has some validity for the manufacturing process.
Compare a cheap car that is stamped out in a factory with the minimum number of parts and the fewest workers compared to a luxuy car that takes longer to build by a large number of workers who all drive to work in their own large cars. You then have to factor in how long a Skoda lasts vs a ferrari. Actually given that they are now basically VWs and presumably last as long I think a small skoda could well come out as the most environmental car!

 

[vanesch]

I think the idea has some validity for the manufacturing process.
Compare a cheap car that is stamped out in a factory with the minimum number of parts and the fewest workers compared to a luxuy car that takes longer to build by a large number of workers who all drive to work in their own large cars. You then have to factor in how long a Skoda lasts vs a ferrari. Actually given that they are now basically VWs and presumably last as long I think a small skoda could well come out as the most environmental car!

I was only talking about the price of the thing versus the energy cost in *production* (not in use, and not over a lifetime). If one basically says that the price of the thing is a measure for the energy cost during the production, then *the production of a Ferrari* should be tens of times more energy consuming than a Skoda, which I'm sure is not the case. There's probably even less metal in the Ferrrari than in the Skoda.
Now, as you point out, environmental impact is always fuzzy, because you have to place a boundary somewhere. After all, it took a whole solar system, and several supernovas and 4 billion years of existence to make a Ferrari, AND a Skoda.

 

[Ivan Seeking]

I was only talking about the price of the thing versus the energy cost in *production* (not in use, and not over a lifetime). If one basically says that the price of the thing is a measure for the energy cost during the production, then *the production of a Ferrari* should be tens of times more energy consuming than a Skoda, which I'm sure is not the case. There's probably even less metal in the Ferrrari than in the Skoda.

How many days of production were required? What is the energy cost per day to run the factory? What percent of the factory was dedictated to the production of the car? How many people drove to work how many times to produce the car? What sort of exotic or energy intensive materials were used? These still seem to be valid questions.

Just a high priced paint job can tie up space in a paint shop for weeks and even months.

 

[Greg Bernhardt]

did anyone catch last months special issue of National Geographic? It was all about going green, great read!

 

[binzing]

Even though I have a lifetime subscription to Nat Geo, I'm starting to dislike them. Particularly how many ads they have, both the 3X5 card types and the ones that are full pages (or even multiple pages) and these "Special Issues" are annoying. Like the one on China, it was all about the poverty, human rights abuses, and pollution, LOVELY!

(And no, I haven't caught that issue yet, is it the July issue?)