good article with good informaiton Solar power technology can run a small air-conditioner for boat.

I am confused. If you say the meter is moving backwards, then the solar is doing two things. One- providing electricity for your CURRENT HOUSE LOAD as well as, TWO- Providing EXTRA POWER during the day, to make up for power used at night. Therefore, the payback also has to include what your normal PG&E bill would have been PLUS the extra you are putting back into the system. Should be a sooner payoff. Also, the 2683 WATTS of power indicated... is that the total going back onto the grid or does that include what your house is using during the day?

I am trying to size up what I would need in solar panels to cover my DAY usage, plus more to turn the meter backwards for my usage during the night.

i don't really get it why must everything have a tax break for you to want to do it .effectively meaning you need to be paid to be enticed .even a small system i am happily living off and adapting and enlarging and improving ,everyone can start small and just use led lighting .4 leds in a enclosed shell uses 1/2 a watt and is perfect for lighting to see what your doing so 3 or 4 can light up a very large room.30 leds in an arrangment like downlighting uses 3 watts and replaces a 50 watt halogen because of the heat differance lasting approx 8/10 years of service .and of course the electricity grid isn't going to pay you and slap you on the back for using them the way you choose too they want you locked into there service and charges as a lifetime customer .don't you think it would send the wrong signal to pay you well and have word of mouth fuel a new business of selling your unwanted energy recouping your startup costs and paying for more and more cells on top of your roof .it needs to be something you want to do ,i have looked at solar for 30 years and your right it's still too expensive but if you never start or try you'll never know what it feels like to be free of the bills syndrome and have some autonomy ,i think it is also a bit inflated telling you of a higher cost to keep most people uninterested in a change because in reality $5000 can buy you a good sized system if some of your most expensive items are secondhand instead of all new ,and being able to build your own apart from accomplishment also means a large saving on shop bought products and shop design and instalation fees .i like probably most always thought it was a dream to maybe have a solar system after being told i needed $20 000+ to run a small house but that is if you run all your high power devices and make no changes .the lights are just one change there are many if you invest more time and effort the $ factor will drop a lot ,start small and expand and it's available to all who wish it .

From a science-experiment angle, this is a cool idea. But let's consider if this would be practical if everybody did it. First, you can't get any tax breaks or subsidies. That just means your neighbors are paying for part of your system. But if your neighbor is buying a system too, then you would have to pay for part of his. Second, the power company can't buy your power at retail rates. It's a business, and it has overhead that must be paid from profits. These tricks are only tolerated now because solar power is a trivial industry, and the dollars are still in the nuisance range. Eventually, it must be cost-effective all by itself, or it will never become widespread. -Carl Spearow

I love the article, the concept, and the discussion. The discussions have covered the consumer, the power companies, and local politics. However, lets expand it a little more to political and economic issues. First, moving away from oil moves wealth from outside the US to hopefully back into the US if manufacturing stays on shore. Why give money to people who hate us and don't have to work because we subsidize them through oil purchases. Yes, a good portion of our electricity is generated by coal, but that is an on shore supply and will continue as we can replace oil. Second, all of this pay back is dependent upon energy pricing remaining the same, if it goes up the payback time goes down. The efficiency is the key factor, not only the efficiency of the cells but the efficiency of the applicances. Low voltage DC power can be used for most applicances today, with the exception of refrigerators (air conditioners), washers, and hot water heaters. A whole business economy could be set up around developing products in this low voltage DC world bypassing even the inverter efficiency loss. For instance solid state lighting, plasma or LCD TVs, computers, fans, and other small appliances can be optimized for straight DC rather than having an AC to DC converter. The exceptions mentioned either have large motors or high current requirements, that is where solar heat comes in for the hot water heater. Even some of these exception areas are not immune to DC technology. Vacuum refrigerators originally for space savings due to the superior thermal insulation of the vacuum could make TEC refrigeration competitive with standard refrigerators (true a compressor on a vacuum refrigerator would be better). What remains to be seen is if someone has the vision to bring these products to market and if they do will that company be in the US or overseas. Other countries are far more progressive than the US in this respect and it is probably due to inertia and the oil lobby. One should remember the US is one of the main consumers of oil but one of the lowest spending countries in the world in supporting alternative energy technology. For instance Spain and Brazil have larger solar energy budgets than the US (at least they did several years ago), not only that but part of the US budget goes to those countries. Looking at the big picture shows that alternative energy can create a much stronger US economy by creating new industrial opportunities while at the same time being environmentally sound, fiscally secure (potentially no transfer of wealth outside the US), and politically correct. Where else can you get a win/win/win/win scenario?

hi it's sad to see the economists are always about they will waste $100 000 plus on the latest audi as a pose factor,but severly balk at the prospect of trying to be self sufficient and helping the enviroment at the same time,if goverments and other individuals got behind alternative technology it wouldn't be alternative and would costed lower .here in australia we have the beginning of sliver cell technology which chemically slices silicone to make a metre coverage out of a few square centremetres of silicone effectively dropping the price of solar panels when it goes in mass production around the world next year.the use of wind ,solar and hydro if available compliment each other to make a much bigger power system available to all ,if we start to use or brains and can see that enviromental change is happening and in a few years you'll have bigger worries than if your airconditioning is on the fritz ,here we already have that problem and others from all the people wanting to be in there own artificialy cooled or heated enviroment consuming a huge ammount of power in peak times that a system has to be many times bigger to cope and then a large waste when most are asleep ,if you noticed even the saving of turning of all your standby devices for a week when not in use it might make you notice a little more,but believe it or not there is always a cost and at present it's our enviroment over a few cents differance to the electricity company ,also if you live near a nuclear plant how many millions of years do you think it's going to take to work that one out and step on that glow in the dark landscape when those barrels rust or are damaged they have to go somewhere right in the sea under the ground maybe ,out of sight out of mind ground water is almost everywhere and sooner or later they will leach,a little forsight is such a good thing ,too bad most goverments want to make people happy immediately to stay in office instead of fostering and fixing large problems .i myself live on 12v power and it quite expensive for me to buy panels setup solar movers for the panels and low wind speed turbine genertors which perfectly compliment each other as i get power at night when the solar panels are down and hydro power day and night,but if you consider using say gas for heating which is much lower co2 and more faster and economical here than electricity ,and your own battery power or grid fed system with low power consuming devices you'll be surprised how far you can go and the feeling of self reliance to makes up for anything else and if something goes down i fix it myself so there's no tradesman callouts .when enviromental factors eventually are brought into the equation which sooner or later power companies will be forced to do i wonder which way you will turn then not everything in life is about money

I like solar energy, but I think there are some screwed up bits along the way.

1. I first saw solar conversions hawked at trade fairs in the '70s. I clearly remember a selling point being that they pay for themselves in about 15 years. Here we are 30 years later, and everything has improved but the relative cost of the system. 15 years of power bills in this day would have to equal the cost of power bills for generations of owners.

2. Here in California, if you get your power from PGE, the "meter can run backward", and PGE has to buy back excess energy from you, but only up to the amount it has sold you, and no excess. That is, even if you have a 10kw solar system and put excess power on the grid every day, PGE doesn't have to pay you for it. Hardly fair.

3. Has anyone looked at the process of putting a solar inverter on the market here in CA? It's really not that complicated of a piece of equipment. They should really be available as an OTS appliance at the local "Megga Electronics Store" for a few hundred dollars. Instead, the government has a system of design and vendor approval. It's very expensive, and very exlusive. Once you're approved, then you get to be on an exclusive list of products approved for use in solar systems in CA. If you make it to this list, you've essentially bought your way to sell in a protected market, so what you should sell for $300-$500, you can now sell for $2000-$3000. Now you can see the multi-thousand dollar tax credit a home owner gets for installing a solar system in a whole new light. Your hard earned cash along with your neighbors', paid in taxes, is being used to subsidize a rather exclusive market. Let the solar panels be the expensive comodity that's the financial hitch of a solar project, that's OK. However I see no reason for a government program that endorses the elevation of solar inverters to the same level.

Is there a switch to remove yourself from the grid in case of a down line wire so the line worker doesn't get shocked? Is there signal conditioning requirements that must be met? I want to avoid start up costs by building a power generation system myself but these are questions I need answered first.

Keep talking!! Solar gives you 1KW/M2 if 100% eff. These things last a long time and there are no moving parts. But they are not efficient and won't run a 200HP car. But they will run a house or a 2 HP car with hard wheels at a good clip. Thermal processes are more efficient, maybe a MHD generator or just a reverse 1 or 2 cycle engine. A.B.Meinel had a gadget for trapping heat using a thermos bottle like pipe. Gold film was used to reflect downconverted heat back onto the pipe capturing > 90% of the energy!! 800 degrees F!!

Very interesting article and reader's comments. I was seriously considering solar shingles for my 2nd story addition roof this summer. However, as others have stated, the cost/payback numbers are not great. Still I was almost willing to make the investment when I found there was a 6 month lead time to get a shipment. I guess there are many others using the solar shingles these days, at least more than are being produced.

I'm hoping some of us engineers and scientists will make some solar conversion breakthroughs in the next 5-10 years. For example, if we could efficiently and economically convert solar heated water (directly) to electricity.

It's fine for our meter to run backwards. The meter's initial setting was 50,000 KWH to allow for this. 5 days later the readings are 49978 for regular and 49972 for Time of Use. We'll see how this looks in January. If we are still generating a surplus in the winter we will start to heat individual rooms with electric space heaters in order to reduce the gas bill.

Another financial consideration was investment diversification. What were alternatives in investing this money which I had inherited? Real estate seems to be peaking. I have a 401k with mutual funds already. This seemed to me to be an investment that would increase in relative value if energy costs continue to increase which seems very likely.

I would like to install an on demand water heater in the kitchen. The water heater is on the other end of the house and we waste a lot of water just waiting for the hot water. Maybe when we get the rebate.

The legalilty of running the meter backwards depend on the state you live in. In Minnesota utilities are required to purchase back excess power from small producers at the retail rate. Regulated electric utiltiies are also required to produce or purchase a certain percentage of the power they sell from renewable sources. If your state doesn't do that then get on your legislators to change the laws.

It's illegal to run the meter backwards. Buy-back rates are much lower than the rate you pay when you use. I agree with the others that said the money could have been better spent on other solar items.

Good to see some still willing to jump in. One writer did mention that the power companies costs may be going up dramatically in the next 20 years. By going solar now you are reducing the risk of having to chose between eating and running the refregerator in your retirement years.

Being out in a almost rural part of Colorado, we power our entire ranch with solar power, with battery storage and a generator for large loads (Power tools in the workshop that need big power - I geek out building furniture on the side).

While it's true that cost wise it may not make sense to some folks, that's making the assumption that costs remain stable, or at a core rate of inflation lower than the cost of money (to Dave S' point). If you look @ energy costs as a whole they are growing faster than core inflation. Second, being that my alternative is all coal fired, and that I literally live next to the largest coal railway in the US, I'm reminded every day why I chose this path. An energy efficient frige and freezer, a DC water pump, compact florescent bulbs, and LCD screens cut things to a really reasonable level you know.

3rd, It's great fun to watch neighbors figure out how to get water from 400 feet in the ground up to their horses when the grid goes down AGAIN! We have offered to sell them some, so far no takers :-)

As for air conditioning, well you all can keep dreaming of cool nights, but if you don't kill the feedback loop now, it's only going to get hotter, and then the loop goes faster. A well insulated house and a HUGE attic fan will work for now because it's cooler @ night. When nights are @ 85 degrees some day, not so much.

The article was good and did a fine job of explaining the experience. Thanks to the author. However, the feedback and comments are GREAT and really offer the most insights, experience, perspectives and overall view (with some technical info) of solar power today.

Cool Story.! Before doing a solar conversion it may be useful to look into where you could conserve power. My electric bill was running $ 85.00 – $100.00 a month. I replaced a large and really old freezer. When my electric hot water tank broke I replaced it with an instant hot water tank and saw a huge savings. Lastly I finally got rid of the waterbed. I miss that waterbed! Now the electric bill runs $ 48.00-62.00. I wonder how much more I could save if I replaced that 47 year old frig? Hmmmmm.

P.S. Of course by these small amounts ya jus know it isn’t for a family of 4.

Regarding the lifetime of solar panels. In 1981 I assembled from surplus solar cells two arrays to power my cottage. I cemented the cells to cheap mirrors and coated the front surface with clear epoxy resin. When I replaced the deteroating array with new ones in 2001, the homemade array was still putting out about 75% of its original power in spite of some of the surface contacts being erroded away by the weather. My new panels are rated to put out 90% of their rated power for 25 years. By this comparison I expect my grandchildren to be using this system when they retire!

You can better spend your money on other things. For example, $10k for a geothermal heat pump system and the remaining $7,5k for a thermal solar collector. You can try to put them togheter for free.

A Solar Story. Just think how fast that meter would run backwards if some of that roop area were dedicated to "Solar Thermal". ST is six to seven times more efficient than SE. When you are planning solar always consider a water heater before electric PV. They are cheaper and will return a lot more energy for the same space. Dan Fieldman Ivan Labs, Inc. Mfg. of El-SID static (DC)impeller drivers for hot water circulation. ivandelsol@bellsouth.net

The family who is charging their cars with with their PV solar cells must either have a lot bigger solar array or some mighty cozy cars. (Or perhaps they just don't USE the cars). Let's see... 3KW (let's be generous) for six hours a day, that's about the same as 4hp (at 100% effecient conversion). So over an entire day, they could soak up 24 HP-hours worth of energy (now THERE's a units conversion problem for the freshmen)... Divide this into 3 cars and we have 8 HP hours of power for each car. I seriously doubt that would take a car very far, perhaps a golf cart could run down to the corner store a time or two on that much power...

Living solar is more of a lifestyle choice. I'm sure that there are ways we can live with a smaller energy footprint, and I'm sure that as this industry develops further, prices will come down and effeciencies will go up... BUT, I have been waiting 25 years so far and progress has been slow at best.

It seems to me that one would need at least 5KW worth of power output (for the 30% of the day when it's producing) for the system to be powerful enough to "cut the cord", at least in the hot-muggy midwest where I live. Air Conditioning is a necessity, not a luxury in our climate.

Let's not even start down the silly conspiracy theory road... I don't think that the price of PV technology has anything at all to do with Exxon's balance sheet.

Keep it real.

Great artical

Solar power technology is a moving target, new advances are taking place on an almost daily basis. For example,PV roof shingles are now available. Being much lighter and designed to be an integral part of the roof, installation costs are substantially lower. Also, appropriate use of the power being generated must be considered. Why waste the engergy on powering a water heater when a solar water heater would make much more sense? Conservation practices must be an integral part of process as well. One family installed panels on their home located somewhere in the Palo Alto area. They have 3 electric cars which are charged from the PV array. In three years they have yet to pay a dime for gas. There will always be a bleeding edge where the intial costs are high but drop rather dramatically with increased production and efficiency. Another part of the problem is the petoleum economy. With about 200 trillion in assets, they are not going to let go very easily.

Congratulations, good article! I had a similar installation put in Jan 2006. In Austin, TX the Utility is promoting and subsidizing these systems. Mine cost just under $20K, the utility paid $14.5K, so my cost was $5.5K. Next January I will get a Fed tax credit of almost $2K, coupled with my belief that the system will add value to the house when I sell it and our Electricity rates continue to go higher. I am seeing a estimated savings of at least $60 per month.

As an engineer who built solar cell testers, I just want to make you aware of one thing. Cell performance DOES degrade over time and their main enemy is HEAT, not the heat from the sun but the heat generated internally, in so called "black spots". Let me explain. Solar panels are made of solar cells wired both in series and parallel. When the voltage produced by a cell is less than of its neighbor, the cell will consume some of the power generated by the higher voltage cell. This will produce an avalanche effect. The cell will heat up, voltage will decrease even more which will produce even more heat, and so on. To avoid this effect, manufacturers group cells with similar characteristics (open voltage and short-circuit current, etc), when building a panel and use some diodes to prevent currents from flowing in the wrong directions. Nevertheless, black spots will occur and are mainly caused by the DIRTY CELLS and SHADOWS and these situations have to be avoided.

Most panels are warranted for 20 - 25 years to produce at least 80% of their "new" output. While they may not be strictly economically feasible now; over the ~ 20 year lifespan of such a system, what will electric rates be then? And consider that if done with battery back-up; how one will fare in the inevitable grid-down days . . . lost food . . . no heat . . etc. I've got a similar system . . provides about 85% of my power on an annual basis. Living efficiently but not in a dark cold cave makes it possible . . .

Glad to see others are doing this as well . . my payoff from the system is more than just economics . .

Not to throw a wet blanket on, but doesn't the perfomance of PV panels degrade over time? This would push your payback date out progressively farther and if they degrade badly, they may never pay for themselves. :(

Who is the manufacturer of the Solar panels ? Is there any do it yourself kit available ? What is the efficiency of solar panels ? I think it is only about 20% efficient. Is there any system available to capture remaining 80% for heating the water.

14 year payback doesn't sound practical. What's the life of the panel's? Any warranty? Not sure what Tim means by down time? The plus may be if the price of Elec. goes up payback should increase but I think 24,000 $$ in a CD would save you more money. Keep thinking "green"

Very good article with some good informaiton but, the payoff will be longer than 14 years. You need to include interest on the $17600. I calaulate with interest rate of 6% the payoff will be just shy of 30 years.

So for $18K you get a system that can produce 50% of the power a typical electric water heater requires (while the sun is at it's peak).

I suppose if nobody is home or if you are just running the lights the meter would run backwards but it seems to me that 2 or 3 KW generated during the hot of the day would not even run a small central air-conditioner.

I have long advocated Solar Energy. I even engineered, built and lived in a pioneering (and very effective) passive solar home in the early 1980's. But it sounds to me like even 20 years later PV solar power is still a very dicey proposition. Long on feel good, and short on realistic performance...

Still, kudo's to you for being a pioneer!

Jay

Yea to solar panels. Boo to dependence on foreign oil.

I would expect for safety reasons that the power to the main house needs to be cut off one or more times. What was your total down-time? And do people have to worry about their fridge defrosting? Or worse yet, loosing their internet connection! ;-)

An interesting article for roof top solar power.I wonder how much maintenance is needed for this system.

Good information. It would be worthwhile to see what the progress has been after a year or so. It would be also neat to have some links regarding solar panel efficiency calculators.