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how eco is solar?  RSS feed

 
paul wheaton
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Writing in another thread reminded me of something else that I'm a little skeptical about: Rampant consumerism for solar stuff. 

It seems that they start off with a power wasting household and then spend 20 grand on going off the grid, while at the same time cutting their power consumption by a factor of ten, and then they have no more power bill - but they do have to keep buying more solar stuff over the years.  Not to mention that they need to become pretty damn savvy in how all of that works.  Maybe the real solution is to cut your energy use and be less of a consumer.

I have to qualify all of this by saying I have not done the research in years.  But I would really like to see stuff that is more of a level playing field:  how about comparing the off grid power usage level to the on grid power usage level. 

If your on-grid electric bill is $20 per month, that's $240 per year.  Or $2400 for ten years.  Kinda hard to justify $20,000 to go off grid.  And in the $20 per month, you might run the electric stove once in a while.  Or the electric clothes drier.  Or do a bit of arc welding.  But I think the $20,000 solar off grid system doesn't allow for that.

So .... this skepticism of mine could be errant.  I would like to learn more.  How many KWH does a $20,000 off grid solar system provide in a year?  What would that same KWH cost on grid? 

 
Jami McBride
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I agree with you Paul....

The idea of solar is wonderful, but the equipment, politics and price are all suspect.

It's such a shame, those in power fight to retain that power.  So we are left with the things we can do for ourselves, passive solar and other simple solutions.
 
                    
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Oh how simple life must have been before electricity and gasoline.....
 
Brenda Groth
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i tend to agree that solar is a bit OUT THERE price wise..esp for us Michigan people who seldom ever even see the sun.

while i was looking for propane geneartors (which i just ordered one)..i did find a few wind generators online that are more reasonable than any i have seen in the past..they don't produce a LOT of electricity..but  i bet they would charge some batteries and run some stuff..they were around $1,000 for the smallest and $3,000 for a larger one..better than the $10,000 and up prices we've been seeing..

i think wind would be a better way for us to be going here..we almost always have some wind going..

these were a lot smaller than the ones that i've seen elsewhere..but it did get me thinking..

I would like to try a few solar things like maybe trickle chargers for batteries and water..but am fairly sure they would only work in the summer here
 
Joel Hollingsworth
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One of the major benefits of distributed solar production is its benefit to the functioning of the grid.

Amorphous and polycrystalline solar cells on the roofs of commercial and industrial buildings in sunny locales are a good ecological choice in almost any circumstances where they make financial sense.

This is partly because they will, on average, cause less energy to be wasted in transmission lines, and because fewer cascading network failures will mean hospitals etc. will fire up their diesel generators less often.

Solar-powered absorption-type A/C and refrigeration is also a tremendously good idea, especially for businesses like movie theaters whose energy consumption is so closely correlated to sunshine. Grocery stores (especially WalMart) would also benefit, but a backup system that co-generates refrigeration and room heat would probably be necessary.

Paul's point about home systems is one I absolutely agree with: improve efficiency first! And giving up access to the grid, just because your home might operate without it, makes no sense to me. A negative monthly power bill is better than a zero bill, and it might be nice to do some arc welding from time to time...and if the grid fails temporarily or permanently, you're still prepared. It's nice that good, cheap inverters are on the market now: they make some of the old advice on home systems completely obsolete.

Brenda's point about wind is a good one, too: where space allows, wind generation is a good idea. The homebrew options are also a lot more appealing than for solar.
 
Brenda Groth
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knowing so little about invertors..where would one find the good lower cost ones on the market..

we are looking for emergency power right now (that is why we just ordered the propane generator)...but would be interested in turning over some of our home to inverted power..possibly wind to power the led lights in the house at first..or whatever.

in the 1930's my mom's entire electric came from wind power..but in the 1930's they didn't require much elec either
 
Mark Reaves
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Solar panel prices are insane. As for wind turbines I did see a 400 watt one once for around $500. Can't remember what it included.

When I get my land in NC and get my home build, I plan on a small solar panel setup with a backup wind turbine. I still require a computer and internet (most likely will have to be dialup or sat net). Other than that, simple lighting will be all I'll be using electricity for.
 
Joel Hollingsworth
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Professionals will know much more about this than I do.

For a really small-scale, off-grid system, the invertors they sell for auto or truck use might be appropriate. These are definitely not meant to allow a DC system to interface with the grid, but they would allow you to keep your old appliances in a new renewable-energy home.

I'm not an electrical engineer, but I think it's fairly straightforward to synchronize the alternator on a wind turbine with the grid. It seems silly to rectify the AC that a wind turbine produces into DC, only to put it through an inverter to get AC again. Even if an active circuit is necessary, it can be something more efficient than in inverter.

If you're building a wind power system, I understand that alternators pulled from large Diesel vehicles are good for small wind turbines: they're built tough, and because they're designed for 24V, they have twice as many windings as inverters for passenger cars. A good electronics hobbyist can make a control circuit that drives the field coil (aka the "exciter" wire) in a way that regulates the turbine's speed.
 
Mark Reaves
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BTW found the site again.. 600 watt wind turbine for about $500. No clue how reputable they are or how good their turbines are.

http://www.survivalunlimited.com/hornetwindturbine.htm
 
Irene Kightley
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That turbine has good reviews but it's a machine which needs a very windy site to work well. If you're thinking about installing a wind turbine you must choose one that suits your site.

We've been off grid for about 18 years and do fine on very little electricity. The grid is often down where we live and it's very expensive to get connected initially. Our system has paid for itself over and over and (fingers crossed) should keep working for some time to come.

We started off with 300 watts of solar and 75 watts of wind for lighting, shearing and internet then added another 300 watts a few years ago for more lighting recharging power tools and television and last week we added another 450 watts.

We don't generally use an inverter except for equipment which is AC only and then I only switch the inverter on while it's needed. Most of our electrical goods are perfectly happy running off direct current.

You don't have to be an electrical engineer to install a solar or wind system, I designed and connected our system and it works just fine.





 
Jocelyn Campbell
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Inverters: for more info see Jeff Gee's presentation that he gave at the WA Permaculture Convergence and very kindly posted online. He's with the Twin Harbors Coalition, a transition town and permaculture group on the coast of Washington.

If I recall correctly, there are two types of inverters. The cheaper, off-grid ones, and the more expensive ones that automatically shut down the link to the grid when the power company has an outage, so that your home electric production doesn't electrocute repair workers.

Skip over Gee's data on Washington State alternative energy rebates, and it just might be a decent primer on this stuff. (She says, knowing she's not very educated on this topic...)
 
ronie dee
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Brenda Groth wrote:
knowing so little about invertors..where would one find the good lower cost ones on the market..

we are looking for emergency power right now (that is why we just ordered the propane generator)...but would be interested in turning over some of our home to inverted power..possibly wind to power the led lights in the house at first..or whatever.

in the 1930's my mom's entire electric came from wind power..but in the 1930's they didn't require much elec either


Major Truck Stops have inverters....ten times cheaper than 10 years ago.
 
Irene Kightley
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Brenda,

For just lighting you'd be better staying with DC so you don't need an inverter.

Most LED lamps are DC anyway. So you need a panel, a controller, some batteries, fuses, wire - the thickness depends on the distances and the power carried.

Here's a rough guide for the cables:

http://www.energymatters.com.au/climate-data/cable-sizing-calculator.php

Also, some light connections and some LED bulbs.

With that, you'll have lights every day - not just for emergencies ! The sun's power is free and it's a shame not to use it.
 
Irene Kightley
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...but first position your panels where you can scrape the snow off them easily !!! 



It's very, very cold here at the moment.

 
Neal McSpadden
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Amorphous Si panels are starting to come down in price.  There's a Chinese panel on the market now (can't remember the name) that's running at $1 / watt.  I did the math a little while ago, and for an averagely sunny spot in the US, it works out to about $0.08/kw-hr over a 15 year lifespan.  Space-wise it has low efficiency, so you need more surface area, but the $ costs are starting to get where they are competitive.

So don't write them off just yet
 
Jim Argeropoulos
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According to the graph for that 600W turbine, you need 30mph wind to go with it. At 10mph you'll get 50w.
I guess I'd say you get what you pay for.
 
                          
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If I recall correctly, there are two types of inverters. The cheaper, off-grid ones, and the more expensive ones that automatically shut down the link to the grid when the power company has an outage, so that your home electric production doesn't electrocute repair workers.


Actually, the difference in inverter types you're speaking of are inverters that can 'force' a surplus of solar / wind generated power backwards into the utility line ( so called 'synchronous' inverters ) versus inverters that are only designed to provide inverted power to a load.  The whole 'syncronous' inverter issue is a hot topic in my home state of NY, where utilities have been forced to 'buy' surplus solar / wind generated power from homeowners at full retail prices.  There are also heavy state funded rebates for the purchase of 'syncronous' inverters / solar cells / wind generators.

But in the 'real world', and in the absence of heavy state funded rebates, a 'synchronous' inverter costs significantly more than a standard one-directional inverter.  Also, 'synchronous' inverters are more or less useless if you will never have a 'surplus' of solar / wind generated energy versus your actual consumption.  And you can achieve essentially the same end result by using a 12-24vdc battery bank which can be charged by either the utility line or solar cells or a wind generator as the 'indirect' power source for a standard inverter.

Thus in the 'real world' the 'synchronous' inverter installations only make sense if tax money is available to help defray a large chunk of the initial costs.

and then they have no more power bill - but they do have to keep buying more solar stuff over the years


Yup that's the 'overlooked' factor where alternative electricity is concerned.  Solar cells lose efficiency over time.  Wind generators experience bearing and winding failures.  Batteries lose storage capacity or fail outright.  All of these require the owner to invest yet more money in future years.

In a nutshell, alternative electricity will ALWAYS be more expensive than utility electricity unless your tax-paying neighbors are actually footing a large chunk of your alternative electricity costs.
 
Henry Bjorklid
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What I am concerned about when I buy different kind of equipment: How much energy has been spent on producing this?

The product should always:
- save energy
- save my money
- not use too much energy when it is produced

This is the reason why I am so interested in DIY-stuff. I just do not know how to produce solar panels, but I know how to produce wind-mills.
I try to find a thread about wind-mills and go there with these thoughts. 


Henry
 
                          
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How much energy has been spent on producing this?


Well, where eco in general is concerned, the question actually goes beyond energy requirements for original manufacture.  In general, the manufacture of batteries involves some fairly toxic processes.  In particular, the mining and manufacture of rare earth magnet material needed for high efficiency electric motors and generators involves very nasty processes.  This is the reason that essentially all such mining and manufacturing has been offshored to asia / China.

 
Henry Bjorklid
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Melonie wrote:
Well, where eco in general is concerned, the question actually goes beyond energy requirements for original manufacture.  In general, the manufacture of batteries involves some fairly toxic processes.  In particular, the mining and manufacture of rare earth magnet material needed for high efficiency electric motors and generators involves very nasty processes.  This is the reason that essentially all such mining and manufacturing has been offshored to asia / China.




Hmmm... I think that the mining elsewhere is shut down because China can sell so cheap, because they use these environmentally nasty processes.

On the other hand, we should buy only products that are "ethically clean". And that can be done (in EU anyhow).
Anyhow, I prefer wind-power, where it can be done.

Henry
 
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