Is it practical to generate all US power by solar PV?

[OmCheeto]

Jim Hardy is tagged as the OP author. Am I now confused or are you?
...

Maybe Greg is allowing, um, what did they call sock puppets in the olden days?
(googles mind)
Nom de pleurs?
(googles internet)
Yes!

 

[anorlunda]

I'm afraid that Jim and I didn't make it clear at the start. 100% solar was not meant to be a serious proposal, merely as a thought experiment to carry it to the extreme to see where it leads.

It is part of being open minded to give some laymen ideas fair consideration rather than dismissing them our of hand.

I worked hard to make the financial estimates. Of course there are many considerations other than money, but a forum post can't be a 50 page study report.

 

[rbelli1]

There is a difference between possible, do-able and logical to do. Jim is asking whether it would be something we could accomplish and would be workable if we wanted to. Not necessarily if it is the best thing to do.

BoB

 

[mheslep]

... I merely say that it can be done, it's technically possible.

Cost aside, no proposals for the storage required have been made in this thread that conform to the existing supply of raw materials.

 

[jim hardy]

Title asks

...is it practical ..' and that was my original question
and nikkom deserves credit for planting the thought in Nuclear thread,

honestly i have been surprised by some of the numbers .
I have more respect now for rooftop solar

old jim

 

[Baluncore]

I have more respect now for rooftop solar

This post was powered by rooftop solar. It is 1PM here and overcast, but I am still running the property and pushing a spare 1200 watt onto the grid.

[Edit]: Unsubsidised installed cost of panels here is now about AU$1000 per kW, even if that was to produce only 4 kwh per day, they will keep doing that for 20 years. That is 29200 units @ $0.22 = $6425 worth of power per kW installed at an original cost of only $1000. For me that is economic.
At the moment I sell my excess power to the grid during the day. I get power back at night for the same price I sold it. The unused excess pays the network maintenance component of my connection.
When the network buy price drops to 33% next year, I can justify a storage battery and disconnection so as to save network maintenance fees. They will have priced themselves out of the market.[end edit]

There is dignity in being a good worker bee. Ever read "Trustee from the Toolroom" ?

Yes.
Lieutenant “Neville Shute” Norway was an engineer who designed airships, (R100), and aircraft, (Airspeed Ltd), then worked for the Department of Miscellaneous Weapons Development during WW2, while he became an author. I think his best book is “Round the Bend”, which introduced a new interpretation to the discipline of quality control, well ahead of it's time. "Slide Rule" is well worth a read for Engineers.
https://en.wikipedia.org/wiki/Round_the_Bend_(novel)

 

[Dr. Courtney]

Nice discussion. Thanks to all the contributors.

Just like all resources, there are production challenges, storage challenges, and distribution challenges.

I think the free market would sort out most of the issues, if government would get out of the way.

 

[Salvador]

Yes Nikkkom and started arguing about other alternative energy producing ways instead of nuclear in my at first scientific and then rather philosophical thread in the nuclear engineering section so he might as well consider himself the OP along Jim.And frankly that doesn't change anything but just to let you know in case someone is wondering about it. If someone is interested in RBMK design points , nuclear reactor scare and and the end a glimpse of world history and politics in my opinion then he or she can check out that thread.

As for free market I don't praise it as much as others.It's not the free market that will save us from energy problems.It's the scientific and technological breakthrough and also some common sense and much needed higher living morale and adapting to times that can only save us from were we are heading.
Our energy storage technology is the way it is for example not because the government is standing in the way or else , but because physics is the way it is and we don't know any better as of yet.the free market can help to spread the technology once it's there.And also once it's affordable.Solar is affordable already it's rather that it's not usable everywhere.
But as technology progresses we may have solar panels incorporated into our backyard grass , our building facades , our roofs and some of that is done already.
Also I have read about the idea of extraction of Earth's heat even though I am not fully sure about the feasibility of such adventure.

In any way we should atleast aim to have as much from renewables, that in case we have problems of getting the new major large scale energy production ways into operation before the current ones run out, that we atleast have a backup for some of the most important of our needs.

 

[mheslep]

Nice discussion. Thanks to all the contributors.

Just like all resources, there are production challenges, storage challenges, and distribution challenges.

I think the free market would sort out most of the issues, if government would get out of the way.

Government, IMO, is most in the way of nuclear power in the US, if the 3x or 4x price difference between China and the US is any indication.

 

[mheslep]

This post was powered by rooftop solar. It is 1PM here and overcast, but I am still running the property and pushing a spare 1200 watt onto the grid.

[Edit]: Unsubsidised installed cost of panels here is now about AU$1000 per kW, even if that was to produce only 4 kwh per day, they will keep doing that for 20 years. That is 29200 units @ $0.22 = $6425 worth of power per kW installed at an original cost of only $1000. For me that is economic.

Net present value and discount rate?

At the moment I sell my excess power to the grid during the day. I get power back at night for the same price I sold ...

Which is a rather large subsidy paid by the non-solar neighbors. The fuel portion of the typical electric bill is only a couple cents per kwh. The balance of the bill goes to all that grid infrastructure, running or not.

A few batteries can't cover a full disconnect from that grid for the average residence.

 

[jim hardy]

[Edit]: Unsubsidised installed cost of panels here is now about AU$1000 per kW,

That sure beats the current estimates of $3 to $6 / watt in US.
http://www.pv-magazine.com/news/details/beitrag/us-installed-solar-pv-costs-continue-to-fall_100016490/
http://www.pv-magazine.com/fileadmin/lbnl_us_installed_costs_by_year.jpg

Hmmm stumbled across a nifty NREL site that figures numbers for your address if it's in the US
http://pvwatts.nrel.gov/pvwatts.php
here's what it says for a hypothetical 4kw system for my houseit's a cool site !

If i converted clothes dryer and water heater to propane i might break even in non airconditioning months. My winter heat is a wood burning fireplace plus a small propane gas heater .

Even at $2.50 a watt it'd be a $10,000 investment
to unplug from grid i'd have to add BIG batteries , and maintain them
and give up airconditioning or use the little diesel generator i keep for emergency backup (and wear it out...)

Myself i think i'd rather collect solar to heat water directly , eliminating that 3.5kw load
and have a couple hundred watt panel & battery for 12V DC lights and a TV when power is off
use the diesel generator's starting battery...that way it'll stay charged...

Rooftop solar looks to me affordable for DIY'ers. As OM points out , the parts are getting cheaper. (Google returns panels for $1 a watt.)
But it doesn't replace the grid or central station generators. Yet.

Electric company still enjoys economy of scale and delivers energy dirt cheap.
I cut firewood mostly to retain some semblance of physical strength . You swing an 8 lb splitting maul for an hour and you too will appreciate that steam turbine somewhere out there, sending you hot water by wire.

old jim

 

[jim hardy]

Also I have read about the idea of extraction of Earth's heat even though I am not fully sure about the feasibility of such adventure.

I stumbled across this talk by a geophysics fellow working on that idea
i think you might enjoy it

in some places it works well

 

[anorlunda]

As for free market I don't praise it as much as others.It's not the free market that will save us from energy problems.It's the scientific and technological breakthrough and also some common sense and much needed higher living morale and adapting to times that can only save us from were we are heading.

Sorry, but I disagree. Electric power infrastucture is capital intensive. It requires huge capital investments from people who are free to invest instead in Apple, or Google, or entertainment, or gold, or anything or nothing.. It is the investors who must be convinced, not technologists, not government, not the public. Government can create obstacles and incentives (which IMO mostly backfire), but in the end it is private investors who determine the direction of our energy future.

Many people believe that public utilities use only public money. In most cases, that's not true. They too must raise massive capital injections from the private market to finance their bonds

If the public wants a more direct say in our energy future, they must instruct their pension managers to redirect their funds into the energy industry. The public can also stop consuming so much energy via substantial (even drastic) changes in life styles.
.

 

[jim mcnamara]

@anorlunda -

US electric utilities fall into these groups:
IOU - investor owned
Municipal - owned by a local government
Cooperative - "owned" by the consumers funded with Federal money as very low-rate loans.
All of risk of ownership is, IMO, relegated to the insuror of the loan - the NRECA,
not the consumers.
Transmission cooperatives like TriState provide transmission services for places with huge territories
and few customers.

This page has all of the detailed data. Knock yourself out, there's stuff there I never even knew existed.
http://www.eia.gov/electricity/annual/
Specifically note that IOU's which tend to be urban, have the most electric services by a long shot.

Most of the IOU and municpals have a relatively large meter/mile of distribution line. Ex: 40 electric
meters per mile of distribution.

Cooperatives are kind of a loss leader in terms of profitability. They have
often got horrible values, from the efficient use of resources point of view.
Rio Grande Cooperative in the Big Bend area of TX had less than 1 meter per
mile. (an aside): They also had the distinction of the worst transmission line
- Old Leaky was the eponym. It had terrible line loss statistics. Needless to
say, Rio Grande Cooperative is the poster child of why rural electrification
only happened because of government intervention.

Based on the above post I do not buy everything anorlunda said about growth in the industry. For 90% of it, sure.
As a set of fully applicable statements. No way.

 

[OmCheeto]

...

Hmmm stumbled across a nifty NREL site that figures numbers for your address if it's in the US
http://pvwatts.nrel.gov/pvwatts.php
here's what it says for a hypothetical 4kw system for my house

it's a cool site !

I am seriously envious of your Nov-Feb stats:

Solar Rads ( kWh / m2 / day )

Mo___Ol Jim___Ol Om
Nov___3.65____ 1.69
Dec___3.04 ____1.38
Jan____3.46____1.79
Feb___4.18_____2.83​

My sister talked me into finally building a solar thermal collector last summer, which had been on my mind for, gulp, 7 years.

Total cost: $100
Theoretical output: 1500 watts

I'm glad it started raining when it did, as looking at it now, I can double the output for only $10.

But getting back to your 4k system, that would totally supply my summer needs

_______Om's________4k
_______Summer___system
Mo____kwh/mo___output
May___620________497
Jun____412________552
Jul_____420________597
Aug____415________574
Sep____520________507
Oct____356________298​

The winter months though, is why I really appreciated your link.

...
old jim

I would expand on the rest of your comments, but the whores of summer are knocking on my door.
(We get about 3 to 4 months worth up here...)

 

[Salvador]

The public can also stop consuming so much energy via substantial (even drastic) changes in life styles.

Exactly , as many are too keen on all kinds of " living for the moment" and when the majority starts to live like this not only our energy future and spending goes "bananas" but also the whole society demoralizes and economics go down.As for the investment in energy sure it needs a lot of investment.Here's the big difference and also some of the big advances and drawbacks in capitalism.You always need an investor to do something.Somehow when the US government understood that the nazis are up to getting the A bomb they didn't ask for investment nor waited for one but put in all the money and effort to just make what is needed.
I have nothing against private companies nor investors as long as they play by the rules , the rules themselves have common sense.But sometimes big projects that are not appealing in the short run but will maybe even save our civilization in the long run have to simply be paid by either government or someone with authority and knowledge.
maybe I'm biased because I come from a place were all the basic infrastructure when it first arrived as technology in the first half of the 20th century was entirely built by special state run agencies.Everything from the biggest nuke plants to hydro to the last pole with three phases running into your house was entirely state controlled as it was seen as something strategically important and so not to be given to any private companies (well there were no private companies :d)

Anyway look at projects like ITER for example , maybe even CERN although CERN is probably an overkill example for this discussion yet these big but important things are funded by states because private investors I think are too greedy and want the money to get to them in their lifetimes I doubt they care much about what's going to happen after them.P.S. @OmCheeto

I would expand on the rest of your comments, but the whores of summer are knocking on my door.

Maybe I'm not that fluent in English and I must say I have a feeling what it might mean but the way I understand it now is rather funny and seems you are living up to the expectations of Robert De Niro's latest role in the film " Dirty Grandpa" :D:D

 

[OmCheeto]

...

P.S. @OmCheeto

Maybe I'm not that fluent in English and I must say I have a feeling what it might mean but the way I understand it now is rather funny and seems you are living up to the expectations of Robert De Niro's latest role in the film " Dirty Grandpa" :D:D

Never saw the movie.
But 10 seconds after I pushed the "POST REPLY" button, someone called.
I told her that I'd referred to her as "a whore of summer".
Then we chatted for a bit, and concluded that I was also a "Whore".

ps. I'm supposed to take a bath, before arriving at her house, within the hour. If I should not respond, for the rest of eternity, let it be known, that I died, happy.

 

[Salvador]

"The whores of summer" might be a perfectly good album title for a wide range of modern pop artists starting from Justin Bieber to a guy who refers to himself as having two chains.According to him and others in the pop industry like Drake he doesn't take them off while being asleep at night.
i think there is a possible suicide by misadventure situation right there.

 

[nikkkom]

I have nothing against private companies nor investors as long as they play by the rules , the rules themselves have common sense.But sometimes big projects that are not appealing in the short run but will maybe even save our civilization in the long run have to simply be paid by either government or someone with authority and knowledge.
maybe I'm biased because I come from a place were all the basic infrastructure when it first arrived as technology in the first half of the 20th century was entirely built by special state run agencies.Everything from the biggest nuke plants to hydro to the last pole with three phases running into your house was entirely state controlled as it was seen as something strategically important and so not to be given to any private companies (well there were no private companies :d)

What makes you think it's a good idea? Did you not notice that that economic system *failed miserably*?

Anyway look at projects like ITER for example , maybe even CERN although CERN is probably an overkill example for this discussion yet these big but important things are funded by states because private investors I think are too greedy and want the money to get to them in their lifetimes I doubt they care much about what's going to happen after them.

Does ITER and generally tokamak-based fusion reactors make economic sense as power plants?

 

[Salvador]

the system failed because the very aim and goal was unrealistic from the very beginning and also the illusion that the selfish and sometimes self destructive nature of mankind can be changed by external means and force.It can't and history just has another big and thick page to prove that and it's named communism. Also remember that this whole thing incorporated in itself so many countries and nationalities that something like that is hard to keep contained even in modern Europe we see this.(although it showed that strong and one of a kind control if implemented with harsh force and authority can keep large masses contained for rather long periods of time to follow an ideology which half of them disagree with , I think we could use some of this to make up a new green and futuristic ideology to change ourselves and make this Earth better for us and the ones after us)
the only systems able to work are the ones that somehow embrace and manage to use the naturally selfish human to also bring some common good along his own selfish desires.Capitalism is a prime example of this.And even capitalism is under such a pressure to collapse and has been for so many parts of it's existence and it's all thanks to the desires and unstoppable appetite of mankind and especially those who have the money.
The world we live in now is not the one we could live in nor the best we can achieve, it's simply the best we can squeeze out of a civilization driven by selfish desire and consumerism which is balanced out with some little common sense and the instinct to survive.

No need to blindly reject and put down every single thing socialism had as some of them were advantages to both the system and mankind especially when it came to large science projects and other large scale yet very expensive projects.
many things were needed to be changed as they didn't work good enough yes surely.

That being said I don't think we should start the same political thing we enjoyed in my other thread ,I myself can write hours of world history and the way I see all of this but let's respect Jim and others who came here to talk solar panels and alternative energy.As for ITER , I think you should ask that question to the multiple scientists and people with engineering degrees that have proved themselves to the worlds largest nations to give them billions of dollars for this project.
I have an opinion myself based on both what i have read and understood but I don;'t want to get into that here as it would be sort of offtopic and rather long.
All in all it's an old soviet design picked up and refined by western scientists so both sides of the world agree it's worth to try it out on large scale. from the chorus of Eurythmics song Sweet dreams " Who am I to disagree"

 

[mheslep]

That sure beats the current estimates of $3 to $6 / watt in US.
http://www.pv-magazine.com/news/details/beitrag/us-installed-solar-pv-costs-continue-to-fall_100016490/
http://www.pv-magazine.com/fileadmin/lbnl_us_installed_costs_by_year.jpg

Hmmm stumbled across a nifty NREL site that figures numbers for your address if it's in the US
http://pvwatts.nrel.gov/pvwatts.php
here's what it says for a hypothetical 4kw system for my houseit's a cool site !

View attachment 100117View attachment 100120View attachment 100109If i converted clothes dryer and water heater to propane i might break even in non airconditioning months. My winter heat is a wood burning fireplace plus a small propane gas heater .

Even at $2.50 a watt it'd be a $10,000 investment
to unplug from grid i'd have to add BIG batteries , and maintain them
and give up airconditioning or use the little diesel generator i keep for emergency backup (and wear it out...)

Myself i think i'd rather collect solar to heat water directly , eliminating that 3.5kw load
and have a couple hundred watt panel & battery for 12V DC lights and a TV when power is off
use the diesel generator's starting battery...that way it'll stay charged...

Rooftop solar looks to me affordable for DIY'ers. As OM points out , the parts are getting cheaper. (Google returns panels for $1 a watt.)
But it doesn't replace the grid or central station generators. Yet.

Electric company still enjoys economy of scale and delivers energy dirt cheap.
I cut firewood mostly to retain some semblance of physical strength . You swing an 8 lb splitting maul for an hour and you too will appreciate that steam turbine somewhere out there, sending you hot water by wire.

old jim

Jim, your reference price includes installation, inverters, the works. I don't think $1 per W includes installation.

 

[nikkkom]

the system failed because the very aim and goal was unrealistic from the very beginning

The goal was unrealistic. You know, that's typical. The whole problem of politics is to determine which goal to set; how to detect early that a bad goal was chosen, and change course. The Soviet system was unable to do so. Free market in economics and freedom in politics are much better in this regard.

(although it showed that strong and one of a kind control if implemented with harsh force and authority can keep large masses contained for rather long periods of time to follow an ideology which half of them disagree with , I think we could use this to make up a new green and futuristic ideology to change ourselves and make this Earth better for us and the ones after us)

You come up with one excellent idea after another. Environazism is the ticket. Yes. [Sarcasm].

And even capitalism is under such a pressure to collapse

Capitalism is alive and well, while examples of socialism fail left and right (Venezuela, North Korea, Syria, Cuba).

 

[Salvador]

It seems to me that you understand the basic concepts but refuse to see deeper behind them which results in stereotypical and almost generic like answers , i am not accusing you just saying.
The idea about environmentalism isn't meant to be an ideology in itself like socialism or it's hardcore brother communism.Its just a logical way of life given that we are 7+ billion people living on a rather small planet and must somehow make it last.Much like food stamps were a logical way of life in the postwar Europe because in a total devastation you only have as much as you have and you have to somehow share that in order for everyone to get along.

You can refute some socialistic idea all you want but the modern world is such that we just have to embrace some things we dislike otherwise we will get into problems.Our abilities and resources are limited but our desire is not so something must give.

North Korea and such is not an example of socialism , you should know that , it's an example oh total idiocy by the ruling class , just because someone hides behind a label doesn't mean it has to do with the ideals and policies of that label.
Cuba was merely a satellite state the Soviets used for spying and control , so it's also a bad example, Wy don't you look at countries like Sweden for a change.

Check your PM Nikkkom as I already invited you to a private chat before.

 

[mheslep]

...You always need an investor to do something.Somehow when the US government understood that the nazis are up to getting the A bomb they didn't ask for investment nor waited for one but put in all the money and effort to just make what is needed.

The US appealed non stop for investors during the war, nearly running out of money.

...I come from a place were all the basic infrastructure when it first arrived as technology in the first half of the 20th century was entirely built by special state run agencies...

By Marxist slaves to the state. No thanks.

 

[Salvador]

calling those people slaves just because they worked in a company owned by the state is not the way it was but rather the way you were taught.
They were no more slaves than the workers that today can't make enough money to feed their family and pay the bills.
Also I know my family and trust me no one was a slave here but I totally understand your hate and I admit that the evil and imperialistic policies that have come from the Kremlin have painted both Russians and other European and Asian countries in a bad light and since I'm from Europe I also happen to be unfairly judged , but I also suspect that people reading a forum about physics should know better about history and world affairs.

I didn't know the government used private investment to fund war but I should have known better since the late Iraq and other wars have been done much the same.Although I assume they didn't exactly put up an investment offer for the " worlds first A bomb".

Just a personal sidenote , if prisoners for example are used in the construction of infrastructure like railroads etc I don't see anything bad in atleast they can give some benefit to a society they have otherwise hated and done evil against.

Ok i will have to keep out of politics in this thread otherwise I'm starting to feel guilty and bad for messing it up.
Looks like I have to open a thread in general discussion titled "misunderstandings and stereotypes of world history"

 

[nikkkom]

The idea about environmentalism isn't meant to be an ideology in itself like socialism or it's hardcore brother communism.Its just a logical way of life given that we are 7+ billion people living on a rather small planet and must somehow make it last.

If some ideas are such that you agree with them, does not mean they are not "ideology". Every set of logically consistent ideas of how to organize society is an ideology.

An ideology always looks "correct" to some people. But it may look good on paper but fail miserably when implemented in practice. Imagine that: even your, or my, ideas can be wrong.

You propose to use "strong and one of a kind control if implemented with harsh force and authority can keep large masses contained for rather long periods of time to follow an ideology which half of them disagree with , I think we could use this to make up a new green and futuristic ideology".

Why do you need "strong control"? "Harsh force and authority"? "keep large masses contained for rather long periods of time"?? "to follow an ideology which half of them disagree with"? Listen to what you are saying! That's dictatorship!

North Korea and such is not an example of socialism , you should know that

Socialism is defined as an economic doctrine where most, or even all, economic activity is performed by state-owned and controlled entities. That's EXACTLY what is happening in NK.

 

[Salvador]

I said we shouldn't have harsh control and force to push an agenda or ideology like environmentalism.Please read my posts carefully.
And also please let's talk this in private or at a different thread , thanks.

 

[nikkkom]

calling those people slaves just because they worked in a company owned by the state is not the way it was but rather the way you were taught.

In this case, the salient point is that if only state-controlled companies exist, you can't find a different employer. Because there is only one employer. Sakharov, when he become a dissident and voiced his disagreement with Soviet doctrine, found himself unable to find ANY job.

This is not exactly a slavery - the government does not own you as a thing - but quite close.

They were no more slaves than the workers that today can't make enough money to feed their family and pay the bills.

In "evil capitalist" society, you can find a different job. Or you can start your own business.

 

[nikkkom]

Cuba was merely a satellite state the Soviets used for spying and control , so it's also a bad example, Wy don't you look at countries like Sweden for a change.

I don't discuss Sweden as an example of socialism because Sweden has a capitalist economy, not socialist.

 

[nikkkom]

I said we shouldn't have harsh control and force to push an agenda or ideology like environmentalism.Please read my posts carefully.

This post?

"""(although it showed that strong and one of a kind control if implemented with harsh force and authority can keep large masses contained for rather long periods of time to follow an ideology which half of them disagree with , I think we could use this to make up a new green and futuristic ideology to change ourselves and make this Earth better for us and the ones after us)"""

 

[Salvador]

Then go and tell every American for example who is now without a job for a good reason (no drugs ,stealing etc) to simply start a business or find another job in today's complicated labor situation and see what he has to say to you for an answer.One of the reasons why Donald Trump is so popular is the very unemployment problem.Nikkkom I think we should stop this political debate here , I won't answer any more political stuff in this thread.

 

[jim hardy]

The winter months though, is why I really appreciated your link.

I think the calculator let's you adjust tilt of the panels. it set mine at 20 degrees,
I don't know whether that's off vertical or off horizontal...
and whether it's a simple default or some function of the local 35° latitude it used for local irradiance.
Might you try tilting for perpendicular to sun around winter solstice and see if winter output gets any better ?
Optimize for winter , accept a little less in summer when you don't need it ?

I'll probably experiment with tilts too, after some more cement work in the yard...

U of Florida did research on thermal collectors forty-five years ago
and concluded a DIY'ers can't beat flat plate collector with intimate contact between plate and tubes.
They used copper sheet with copper pipes soldered to it on 12" centers
because the average home handyman can solder copper but he can't weld aluminum.
4 X 12 feet makes plenty of hot water for a family of four in Florida.
Does it ever freeze where you live? If not , consider replacing your water heater with a flat plate collector & elevated tank for thermosiphon .

Zero moving parts, zero maintenance.
Doesn't make kilowatts but displaces them with zero complexity. No electronics.
At a conservative 100kwh/month for two people(most water heater estimates are twice that see https://www.keysenergy.com/appliances.php )
and 15cents/kwh = $15/month
a thousand dollar homebuilt would pay back in 5.5 years vs ten for PV

this is not a hijack - a kwh saved is 3412 BTU's earned.
Save that beautiful electrical energy for more noble things than heating water - like posting on PF.

old jim

 

[Salvador]

what do you think Jim , is a solar collector more efficient than a heat pump/exchainger, I'm not sure how to call them , you know the ones that work after the same system a fridge uses , were one part of the piping is set underground outside. ?
I think it counts partly as a renewable since the heat underground comes from Earth and sun combined and we invest only in the electricity running the pump which then pumps the working fluid.

maybe we should make solar panels that have both the cells that generate electricity and some water piping beneath them , and so for a larger array one would get out direct electricity + heated water which could then be used to either heat homes for those who live in colder climate or other needs.Although I'm not sure about the efficiency of such a proposal , I assume that infra red is harder to convert to electricity than the other wavelenght's in the sunlight.
I read that newer panels promise to convert much more of the spectrum that has some significant power in it also including infra red.

 

[jim hardy]

what do you think Jim , is a solar collector more efficient than a heat pump/exchainger, I'm not sure how to call them , you know the ones that work after the same system a fridge uses , were one part of the piping is set underground outside. ?
I think it counts partly as a renewable since the heat underground comes from Earth and sun combined and we invest only in the electricity running the pump which then pumps the working fluid.

If you take the physicist's meaning of efficient, useful output / input,
then a heat pump has to count the energy extracted from the ground as part of the input. The electricity to run it is the rest.
That's because any heat engine has to be less than 100% efficient (unless it can reject heat to absolute zero) .

But if as a layman i just want to get the most heat for my money
My heat pump delivers X BTU's to my hot water tank for Y kwh of electricity, and my layman's efficiency is X/Y .
(when corrected to get same units in numerator & denominator)
But a solar panel with thermosiphon runs with zero electric input so my layman's denominator is zero giving it layman's efficiency of ∝.

In a strict scientific sense that's lying with statistics. But it's what matters where the rubber meets the road., my checkbook .

Common sense says if i don't have to run electricity to it or fix leaky pumps or microcontrollers that succumbed to lightning strikes
now THAT's life cycle efficiency

https://en.wikipedia.org/wiki/Solar_water_heating

A laundromat in California with panels on the roof providing hot washing water.

sixty percent-ish ? As a physicist you get 0.6 BTU's for every one that fell on your collector as sunshine.

Now to that heat pump
An EER of 20 for a really good unit would be in terms of my "layman's efficiency" , heat delivered / work bought from electric company
EER is BTU's (per hour) delivered per watt of electricity, Layman's efficiency if you will ..
20 BTU's per watt hour = 20,000 BTU's per kwh
Now a KWH is 3412 BTU's...
meaning you get from that EER 20 heat pump 20,000/3412 = 5.86 times more energy than you paid the electric company for. 4.86 of them came out of the ground... but does my checkbook care ?
Beats plain old water heater, eh ? It gives you 1::1 heat delivered/heat bought.

It appears to beat the solar panel, too. 5.86 heat units per unit bought vs 0.6 heat units per unit of sunshine
but remember you put zero kwh of electricity into the solar panel...

It helps to get an intuitive feel for heat.
A BTU/sec is within ~5% a kilowatt, (1BTU/sec = 3600BTU hr / 3412 BTU/kwh = 1.05kw)
That's about the output of one stove burner on high setting.
And it's also roughly the sunlight falling on a square meter of earth.
(http://education.gsfc.nasa.gov/experimental/July61999siteupdate/inv99Project.Site/Pages/science-briefs/ed-stickler/ed-irradiance.html )

Stick to your basics... complex things are just an assemblage of simple ones.

old jim

 

[anorlunda]

@jim mcnamara

I don't understand the foundation of your disagreement in #119, unless you confuse what I said about investors with the phrase "investor owned utilities" IOU. They are very different things.

Municipals and coops have private investors who purchase their bonds. Municipals bonds alone in 2011 were $3.7 trillion. I was not able to to find the number for coops. Having private companies insure privately owned bonds does not shift the public/private mix of finance.

In post #118, I was talking about public versus private investment sources (i.e. taxes versus all other sources of money). That has nothing to do with IOU/municipal/cooperative kinds of utilities. The reason I mentioned it was to counter the widespread public belief that they can dictate the energy future at the ballot box. That IMO is incorrect.