Cheap PV Panels

Harborfreight tools @ about $1 a watt

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Good steer

based on $.15/kW-hr escalating at 20% per year for 20 years to $3.8/kW-hr in 2028, you would be better off putting your money in the bank earning 5% interest.

There will not be a continous 20% price increase in electricty.

OH No! Not that old chestnut. The crazy assumption that money has inherent value. If electricity ever reached $3.80 Kw Hr equivalent then society would rapidly collapse. Of course in reality the dollar would devalue to such an extent that you hoarded monet wouldn't be worth much anyway. Bob Heinlein was right!!

"If electricity ever reached $3.80 Kw Hr equivalent then society would rapidly collapse."

I also was told by someone back in 2004 that if oil ever got to $40/barrel, our economy would collapse. I guess it seemed plausable then, but my-oh-my how time does change our thinking.

"I also was told by someone back in 2004 that if oil ever got to $40/barrel, our economy would collapse."

Look around, the economy isn't doing so hot.

Agreed, it isn't as good as it has been! But far from collapsed.

No It isn't! But the point was that money will just devalue to suit the situation. That's what I meant about the mythical "real" value of money.

I have solar lighting in my place here in NZ with 150 watts of solar panels feeding a 400 watt inverter and batteries. With modern "non Edison" bulbs I can light the house fine for about 89% of the time. But it is debateable if it is economic really, I reckon its payback time would be a decade or 2 as of now. However solar water heating is very good value. I have a 4 sq Metre collector on the roof with a 400 litre insulated tank.

It has paid for all its installation costs over those of a conventional electric mains pressure system in the first 3 years. With that, passive solar heating and a 5Kw heat pump everything runs fine and our power bills are very low. Remember it is mid winter here also and my batteries were fully charged today while the solar tank is at about 40 deg C before boosting.
If electricity was at $4 a KwH then how much would a dollar actually buy?

The power companies are planning continued raises in the rate they charge us. While they have programs that incentize PV use, they will continue to raise rates - because they can. 4.5 to 7.5% is expected each year.

There is no such thing as cheap PV panels. There are rejects, they sell cosmetic defected panels. You can get power from potatoes if you took freshman science in high school, but cheap PV is not reality for the next 10 years. It is coming though. WIth all the research in PV, expect "relatively" cheap power within 10 years - it will never be free. Relative to $10 per gallon of gasoline that is.

GlenRad

That is the basis for my question. Is it economical to invest in PV or is it a pipe dream? Will I ever recoup the expense? I live in central Ohio; I'm looking at cost of units even if I do the install. Tax credits if any. Normal sun lit days. What can I expect as a turn around? 10 or 20 years? I'm thinking a water-jacket furnace would cut my heating bills. I am now paying about $400.00 monthly during the winter and 100.00 during the summer months for my all electric home. That will turn around in less than 4 years with free scrap wood 24 / 7 / 365. I want to do my part to SAVE the world, but I'm no Al Gore. If I can save my wallet wile trying to save the world that would be great. What about Teselas (Spelling ?) energy machine.

GreenPanSteve, Tesla's energy machine (if it is the one I'm thinking of) was a transmitter that anyone could build a receiver for. Free energy for the receiver not the sender.

The same big money that black listed Tesla will fight tooth and nail to not let the cat out of the bag that cheap.

Back in the early 90's my wife worked for TI making computer chips, and they had an internal news paper with all kinds of neat stuff published in it. One article was on how these engineers had figured out how to make dirt cheap solar cells that rolled out onto the roof or building side. The process used dirty silicon on aluminum foil. The cost was suppose to retail for something like a dollar a watt or ten watts. A hundred square feet was claimed to produce 1kw. It was claimed to be a revolution in power. Never heard about it again. My wife inquired about it and was politely told not to bring it up again.

As for the indiscretion in tact above sugar gets more flies than vinegar.

Brad

for all electrict, you need a geothermal heat pump system.

Refer to post #25 follow link and discern

Hi,

There was a recent edition of Discovery Channel's 'Planet Greet', in which was a piece about a company who has a 'breakthrough' in photovoltaics. Allegedly, they will be able to market their product for about 10-cents per watt. It's a thin, printed film, and is flexible. It opens up a lot of interesting applications if actually viable. I haven't done much research yet.

I don't know is if their product is yet available.

Check it out ...

http://dsc.discovery.com/news/2007/04/13/solarcells_tec.html

Planet GREEN

... damn new keyboard

Yep, all of their production is already spoken for the next several years (to the private sector), oh, and their plant isn't even online yet.

If your main household costs are for hot water and central heating then solar water heating is a much better bet.

http://en.wikipedia.org/wiki/Solar_hot_water

http://www.bigginhill.co.uk/solar.htm

http://cr4.globalspec.com/blogentry/4969

If you don't mind doing some research you can hunt around for the companies that replace the PV's on road signs. Both the mobile and stationary. They only run these for about 5 years or until a car trashes the trailer they are setting on. Then they replace them. Call the state you are in and the company that makes the signs.It will at least be a start. It works off the "good ole' boy" system. You have to know somebody that knows somebody.But if you get in good with the repair guys, they may be more likely to put the old panels in you truck than the trash. I have gotten a couple this way but it also is "the right place at the right time".

At current prices, PV will not pay back the ROI for a minimum of 15 years, more likely closer to 20. You need to define for yourself the reasons why you want to do this. if this is intended as standby power, then you would be better off with a NG powered generator. If the point is to save money, there are much better places where you can invest your money to reduce your energy costs (double insulated windows, low e glass, attic insulation, attic ridge and soffit vents, tankless NG fired water heaters, more efficient HVAC systems, OLED lighting where color correction is not important, etc.) and get a much quicker and better ROI.

Solar power is one of those things that sounds neat and cool until you start looking at the economics of it, that is when you start to realize that it still is not ready for prime time.

One other point I will make about PV Solar. The biggest issue you will run into is the cost and inefficiency of the inverters required to change the low voltage DC panel output to 120VAC that all of your appliances will generally use. Inverters are generally only about 60-70% efficient. So you will need a minimum of 140% excess capacity in the panels just to overcome the losses in the inverter, add in the fact that you will need overcapacity to compensate for a lack of full sun at all times too, especially for fixed panels that don't track the sun (and which burn power to do so lowering thier efficiency as well.).

The cost of the inverter will usually run about 150% of the cost of the panels themselves.

At this point the only real good use for PV Solar is for charging/maintaining batteries for standby power for things like skid mounted engines and such.

In addition to that, if not mentioned yet, is the cost of good quality deep discharge cycle batteries with sufficient ampere-hour capacity. Very expensive - maybe in excess of $5000.

HUH!!!

Sorry mate but your figures are off with the fairies!

Sure PV panels are not cheap, mine cost about $1,000 US for 150 watts of monocrystal silicon. But where on Earth do you get your figures on inverters?

I am looking at my little solid state inverter as I type this. It cost $89 NZ (about $60 US) and it has a MEASURED efficiency of 92%. I tested it myself as I have a well equipped electronic and mechanical workshop. Even fancy high powered full sine wave inverter of about 2Kw would be only around $600/$800.

<>Your figures are about right for the old rotary converters <>but they haven't been used for 20 years or more. It was their cost, noise, unreliabilty and inefficiency that put them out of use.

<>I've used a lot of FET power switching circuits as I have experimented with small electric vehicles since I retired.
When you can control a 36 volt DC motor drawing 30 amps with a postage stamp sized FET without it even getting warm then you know that the efficency is VERY high.

<>

<>

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About 5 or 6 years ago, I was involved with a fuel cell research project in connection with Centerpoint Energy and Jacobs Engineering that took natural gas, steam reformed it into hydrogen rich syngas, and fed it to a PEM type fuel cell stack. The output was fed to a large FET type switchmode power inverter. We were generating 4 kw fairly routinely and 8kw in a pinch, and the true sine wave inverter we were using which was the most efficient we could find on the market had a measured efficiency of 72%. we were losing a total of 1/4 of our output to inverter loses. What's worse, the reformer took 21 kw to operate, so we were burning more power than we were generating. The switchmode topology of these inverters uses low voltage high current FET's or IGBT's to feed step up transformers. the loses are almost totally transfomer hysteresis losses. DC to DC switchmode regulators, depending on the topology can run efficiencies between 60% and 93%, but that is entirely dependant on the circuit topology. AC inverters on the other hand, must in the end supply 60 AC. since they must operate at such low frequencies, far to much energy is lost to transfomer heating losses. DC to DC switchmode power supplies can operate at much higher frequencies and can use much more efficient inductors.

I think I DO know what I am talking about.

excuse me, that should read "must in the end supply 60Hz AC"....

I'll have to confirm most of this. I did research on how to impliment Siemans new consumer ready fuel cell in 1996. We were going to use H2 from world class reformers or build our own in large cities using natural gas. The best effiecency we could hope for was 55%, but 50% was realistic, for the conversion of CH4 to H2. The fuel cell was 80% eficient and siemans was to have a high efficency inverter at 90%, so >5 * .8 *.9 = 36%. 36% of 21 kw = 7.56.

There was also the issue of the dangers of hydrogen leaks and H2S generation resulting from the mercaptan going through the reformer. H2S even in small amounts can ruin your entire day. The reformer therefore had to be all electric because they did not want ANY open flames. I think some efficiency could have been gained by the use of catalytic burners burning NG to generate the steam, but our part of the project was the PEM stacks, not the reformer. Our PEM stack crew consistently met or exceeded our developmental milestones throughout the project, the other partners... eh, not so much. The reformer was three times larger than the rest of the system combined and would have barely fit in a 8' x 8' x 20' seagoing container. That crew was not interested in hearing any suggestions from us. It is possible that there have been advances in inverter technology since we played with it, but 72% was the state of the art at the time and I am unaware of any major revolutions in inverter technology since then.

About that time, Centerpoint/Reliant energy/Reliant resources were undergoing an internal meltdown/reorganization as a side effect of the Enron mess and our project was shut down as a cost saving measure. Our project I don't think was ever really thought to be a real one, I think our existance was a bone thrown to the environmentalists to show that Reliant/Centerpoint really did care about the environment. That and the fact that since it was distributed generation, the power didn't have to go through the power distribution system which has really amazingly high losses in of itself plus the fact that here in Texas, the distribution system is still regulated and therefore profit limited.

Ah! I thought it might be something like that.

However a 50 or 60 Hz transformer would typically have losses of 2 to 5 % if properly designed. The low frequency output sinewave is actually synthesised from higher freqency square waves and thus the switching is not done at supply frequency. My inverter runs at about 20KHz as a basic switching frequency.

<>I have just looked up an Australian catalogue of pure sine 2 Kw 50Hz inverters and they claim an efficiency of over 90%. Since they are made by the same manufacturer as my inverter (which is modified square
wave) and claim the same efficiency I have no reason to doubt their claims. Defintely also, even my inverter will run the majority of AC powered devices OK. Only a few devices find a pure sine wave critical and with changes in technology these are becoming fewer every year, (Motors using solid state switching etc).

Your inverter seems to be extremely inefficient even for some years ago, indeed it is comparable with rotary converter and the old car radio vibrator systems as far as that went.

Perhaps however there was some requirement for an extremely pure 60Hz sinewave output and admittedly that would be a potentially difficult problem, as there is always some switching "hash" with fast switching FET switches. However given the garbage on a lot of mains supplies these days it would indeed have to be critical.
Also transformer core materials have improved markedly in recent years.

GA

Perhaps however there was some requirement for an extremely pure 60Hz sinewave output and admittedly that would be a potentially difficult problem, as there is always some switching "hash" with fast switching FET switches. However given the garbage on a lot of mains supplies these days it would indeed have to be critical.
Also transformer core materials have improved markedly in recent years.

May a Sola hevy-duty transformer w/rectifier bridge help in such a case?

Yes, since we were feeding excess power back to the lines, the power had to be extremely clean and the power factor had to be unity and the phase lock had to be dead on to the line freq., much more stringent than you would really expect you'd need. That could have been part of the issue. It could also have been a size/scaling issue too. As you are probably aware, very high current FET's and IGBT's have relatively large parasitic gate capacitances which make it hard to switch them quickly as well as relatively large Rds's as well. You can parallel multiple low current FET's (and they share loads rather well in that mode) which would also lower the effective on resistance, but the gate capacitances would be in parallel and therefore additive, the resulting capacitance is usually higher than if you used one or two very high power FET's even if the Rds is quite high. You also must beware of specmanship too, companies lie like dogs on spec sheets usually. But since we were not tasked with the inverter selection either, it is entirely possible that that crew was blowing smoke up our arse as well and were simply using the company/brand that gave them the best gimme caps or who's saleswoman looked the hottest.

If you don't mind sharing, what is the name of the manufacturer you are using? Where I work we still have to contend with offline standby systems (that don't have to interface with the power lines) for skid mounted oilfield equipment and we use inverters fairly often. Do they make a 60Hz UL/NEMA version?

BTW, after our discussions, I did a bit of google research and found this article that may be of interest to you. It would appear that there have been some significant improvements in grid interactive inverters since I played in that sandbox.

http://www.apec-conf.org/2006/APEC_2006_SP4_1.pdf

I think I see what you are getting at, but the thing is, that this predated a lot of DSP type applications so the unit was analog, not digitally controlled. Digitally controlling the unit could probably increase the efficiency a good bit.

The discussions have been good. Not only you should look for cheap solar panels , but have to be cheaper overall.

1. Cheaper inverter in terms of cost and efficiency

2. Cheaper battery or stotrage device

3. harnessing maxumum available sunlight by loaction

The Solar panel costs will come down substantially in future . With Nano Technology , we will get wafer thin soalr panels and may be we can stitch them as our clthing. Roof contours can be fitted with easily.

One think one should know that any roof in any dirtection is not OK. Depending on your location the panels must face maxiumum Sunlight intensity over the year. If it is not then you loose a lot and it wont be cheap overall , even if the panel is cheap.

Now lastly what is cheap solar panel > Cheap ness in buying per peak watt regardless of efficiency ? Cheaper panels may be of very low efficiency say 8% or so !

what should be target price of Panels per peak watt 3 years from now ? If it is more than bank interest , then buy now . Can any expert on solar panel making give an indication?

That is very true re the solar panel orientation. As well as being a retired electronics engineer I am also an Amateur astronomer so it was easy for me to calculate the optimun angle for the collectors. In my case at latitude 36 South it works out about correct if the cells are mounted at a 20 degree angle on a roof facing due north with a 20 degree pitch.

Thus they are at 40 degrees. This gives optimum results around the equinoxes (2 per year) while being Ok during the hot summer months, November to Feb, and passable during winter. Even now in June I can get up to 12 amps of charge into my 12 volt battery on a sunny day and today, which was overcast, I was still getting 3 or 4 amps.

However PV generation is still rather too expensive unless as you say the cells drop in price by an order of magnitude and also the price and reliabilty of batteries must also improve. It is however a great comfort when we have a power failure!

I have been wondering about the efforts to generate Hydrogen from natural gas for fuel cells?

Is this really worth it at all? My own idea was to use existing gas lines to carry methane synthesised from electrolytical Hydrogen and burn this for transport fuel.

Then with an energy input from any source one has a closed cycle renewable fuel source. It doesn't even have to be a continuous source so solar, nuclear, wind, wave or tidal power would all be useful.
N.B Methane is of course to prevent the excessive leakage of Hydrogen from existing pipelines, if these were improved, which would be very expensive, then Hydrogen could be used directly.

The system were were looking at used high temp steam to crack natural gas into CO, CO2, and H2. One of the problems was the odorant injected into natural gas called mercaptan. A few PPM of mercaptan is all that is in there, but after the cracking process, it comes out as H2S which is poison at very low concentrations, and it also can cause cracking and corrosion failure in many alloys, especially any steel harder than 22HrC. That necessitates treating the gas with an amine sweetening process. That also absorbs the CO and CO2 from the stream, but now you've got to deal with the H2S laden amine waste which can be recycled by boiling off the H2S and flareing it. but again, no open flames are allowed because now everything is pressurized with relatively pure H2S which as you note can leak through dang near anything including solid steel. CO also has a tendency of poisoning the PEM catalyst so removing CO is advantageous.

H2S can be removed with rust. It combines to FeS, which is what we call fools gold. Iron sponge and its derivatives like sulfaTreat are cheap and environmentally saver methods. The CO and CO2 are not removed.

There is also a competeing process of CO2 + H2O + H2S <=> COS + 2H2O COS is corrosive.

Why not switch to un ordorized natural gas. You can buy it as LNG or set up shop near a pipeline that is not odorized.

Better yet, just rent the cracking system from Honda, they are leasing methane crackers to make H2 to feed their new fuel cell car.

Because the NG was to be delivered via the normal home piping from the conventional distribution network and there are severe safety issues with non-odorized methane. Besides, as i stated, the CO and CO2 removal is actually advantageous because they eventually poison the PEM stack. I find it hard to believe you can legally buy non-odorized methane, it is simply too dangerous.

Thanks for pointing out a problem I hadn't taken into consideration with synthesised methane. However a small dose of one of those highly "Stinky" additives should cure that OK. Methyly captinate? or something like that?

The inverters I was looking at were in the Jaycar catalogue, an Australian company. The 2Kw model is by Powertech and is model MT-5169. It has a 2Kw continuous rating and a 5Kw surge rating with a nominal 24 volts DC input. Its output regulation is +- 3%.
While I was typing I just noticed that the same company now produce a "mains connect" inverter of 1.5Kw. This is designed to work with high voltage battery supply, but claims the following figures current distortion <3%, power factor >0.99 and a maximum conversion efficiency of >95%. This is model MI-5190. Australia now has a rebate of $8 per watt of solar generation connected to the grid up to 1000 watts. Thats what I call forward thinking. I only wish that New Zealand was as sensible!

As you say however using many inverters to drive "difficult" loads like refrigerators of the older type is bad news. But for example my heat pump, is an "inverter" type which has in effect a "soft start". This should be Ok but an old "brute force" compressor could really cause problems.
Its the same problem we had when electricity was first used, we have to match the devices we connect, to the supply.

However when feeding power back into the lines the regulation of voltage and frequency must be pretty perfect. I wonder if there is a case to be made to reform our power grid design and use a somewhat higher frequency, in theory it would have several advantages and many modern devices are NOT sensitive to the type of supply.
After all 60 Hz comes from Tesla's theory about Earth reasonances (which was wrong) and the European/Australasian 50 Hz seems to date back to the Seimens brothers for no special reason that I could ever uncover.

There are 8 trucks per day of unodorized gas that go by my area, taking -250 F 98% pure methane to the west cost to use in busses. It's un ordorized. Pipelines can be operated. Heres the law on the subject fro 49 CFR 192.

§ 192.625 Odorization of gas.

(a) A combustible gas in a distribution line must contain a natural odorant or be odorized so that at a concentration in air of one-fifth of the lower explosive limit, the gas is readily detectable by a person with a normal sense of smell.

(b) After December 31, 1976, a combustible gas in a transmission line in a Class 3 or Class 4 location must comply with the requirements of paragraph (a) of this section unless:

(1) At least 50 percent of the length of the line downstream from that location is in a Class 1 or Class 2 location;

(2) The line transports gas to any of the following facilities which received gas without an odorant from that line before May 5, 1975;

(i) An underground storage field;

(ii) A gas processing plant;

(iii) A gas dehydration plant; or

(iv) An industrial plant using gas in a process where the presence of an odorant:

(A) Makes the end product unfit for the purpose for which it is intended;

(B) Reduces the activity of a catalyst; or

(C) Reduces the percentage completion of a chemical reaction;

(3) In the case of a lateral line which transports gas to a distribution center, at least 50 percent of the length of that line is in a Class 1 or Class 2 location; or

(4) The combustible gas is hydrogen intended for use as a feedstock in a manufacturing process.

(c) In the concentrations in which it is used, the odorant in combustible gases must comply with the following:

(1) The odorant may not be deleterious to persons, materials, or pipe.

(2) The products of combustion from the odorant may not be toxic when breathed nor may they be corrosive or harmful to those materials to which the products of combustion will be exposed.

(d) The odorant may not be soluble in water to an extent greater than 2.5 parts to 100 parts by weight.

(e) Equipment for odorization must introduce the odorant without wide variations in the level of odorant.

(f) To assure the proper concentration of odorant in accordance with this section, each operator must conduct periodic sampling of combustible gases using an instrument capable of determining the percentage of gas in air at which the odor becomes readily detectable. Operators of master meter systems may comply with this requirement by—

(1) Receiving written verification from their gas source that the gas has the proper concentration of odorant; and

(2) Conducting periodic "sniff" tests at the extremities of the system to confirm that the gas contains odorant.

You have just proved, not disproved, my point with your post. The gas was to be delivered via the normal distribution network which is legally required to be odorized. And since all of this is happening after May 1975, many of those legal exceptions are unavailable even if we were to lay a separate distribution network which we had no intention of doing.

Any advantages to parabolic solar dishes?

Thanks

As a telescope maker I can safely say "not many".

Firstly they have to track the sun which takes energy or connection to a VERY large sunflower!!!

Secondly even an approximately parabolic reflector is not that easy to mount or support against the weather, or even its own weight.

My Voltaics cover about 1 sq metre for 150 watts and my solar water heater has an area of 4 sq metres. That would represent quite a lot of wind resistance and weight if it tracked the sun even without a parabolic reflector.

However I intend to follow up shortly some ideas I have seen re fitting fixed reflectors to increase the output of the voltaic panels, as long as their temperature rating isn't exceeded. This is helped by using Aluminium reflectors which have low Infra Red reflectivity. It should be possible to boost the output of my panels to at least 250 watts. Since I have temperature sensors on them it will be an interesting project when we get towards Spring in the Southern hemisphere.

oops, I meant "pressurized with relatively pure H2" not H2S, mea culpa.

What means, Cheap?