timing the purchase of a solar system for your home

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Permalink Reply by Martin Herzfeld on August 13, 2009 at 12:05pm

The time to invest and use in solar energy was yesterday. Solar technology is proven and reliable.

".... be a difficult question" ... financing is complex, but solar is simple. - " ... maximize modules, minimize panels"

For discussion only:

Briefly, the size of the array would typically remain consistent, the cost of the array would remain approximately the same - historically, but the power of the array typically increases. The increase in approximately 5 years has been approximately 20% increase in power. In two years, expect a power increase of the module STC, for instance, if ~ 200 watts, then ~ 210 watts in approximately two years. For 8 modules would be 80 watts for an array which is now at 1,600 watts STC. In the future, same size at approximately 1680 watts STC with would result in approximately 120 kWh of energy per year, depending on location, or 10 kWh per month or 3 dollar per month or ~ 36 dollars per year with the cost of energy at ~ 30 cents per kWh. Therefore, for 24 modules would be approximately $108 per year if all the energy is valued at approximately ~ 30 cents per kWh. If 5 years would be approximately $540. But, the future value, would be different than the present value. In addition, the value of equipment require to be substantially discounted, which is now at ~30% in incentives ... with also the option of a lower STC watt modules at a lower cost

Depending on the marginal cost of capital today, the value of energy is likely to increase. As a result, if the value of energy increase with a solar electric system installed, specifically if the value of energy is based on time, then there would be a benefit without increasing the size of the array and the internal rate of return (IRR) increases. However, the value of energy increases without an solar electric system installed, creates a greater justification in the future with an increased IRR. However, the module sizes have remained consistent and increased power or the the area requirements increases, with consistent power and a decrease in cost - thin film. Although the cost of the structure is likely to remain consist or reduce, the cost would increase, if incentives or discounts decrease over time. However, likely in ~5 years the value of energy would have increased.

ftp://ftp.cpuc.ca.gov/puc/energy/electric/rates+and+tariffs/cpuc01_...

"California has among the highest rates of electricity in the country, with electricity rates reaching as high as $0.50 per kWh, for some customers, and steadily increasing. Over the last 30 years, rates for residential customers in California have increased at an average of 6% per year."

http://www.eia.doe.gov/

If you are looking for solar energy systems the factor may not be how much the value of energy increases, but how the value of equipment decreases.

But here's the situation ... the value of energy is based on time and usage. Therefore, on the time of use rates would be larger during specific times and for those customers which which increase energy on usage. In other words, the rates increase the more is used and the rate structures change.

Power of the array likely to increase in the future - there are currently % limits for the proven reliable specifically for Crystalline and Multicrystalline Silicon Modules - as proven and reliable.

Resource:

The REAL Story on Moore's Law for Solar

http://tonto.eia.doe.gov/cfapps/STEO_Query/steotables.cfm?tableNumb...

What do you think?

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Permalink Reply by Anja Atkinson on August 13, 2009 at 2:02pm

@Thomas Luehrsen

Hi Thomas. I liked your question and thought it poses some very important considerations. The primary goal of Research and Development of Photovoltaic applications for both residential and commercial use is given a lot of attention globally. However a technology tends to evolve most rapidly under market demand as it becomes more lucrative to become involved and invest in the Industry, as happened with computer hardware like you said. Transitioning to a healthier environmental model of sustainable living will be ongoing for decades to come that is certain.

Silicon PV panels are still the most efficient products home owners have available. Improvements are being researched and bound to become available, but when who can say. Improving a home solar system with good home energy efficiency, like sound insulation goes a long way to making the most of your Solar PV array at home, which lowers your costs ongoing.

From a global point of view on the importance of sustainable development, I believe we will continue to see the efficiency of PV technology improve because environmental citizenship and market factors are demanding that this occur. PV Industry players are jockeying for position which brings about healthy competition that stands to improve things from here on in with PV efficiency. The primary factors considered are cost production and energy efficiency, silicon PV being the standard so far as being most efficient. IRENA or the International Renewable Energy Agency was established in January of this year to address our global need to transition rapidly to renewable energy technologies, including PV, so the issue is on the burner, so to speak. Government policy is needed to direct the development of PV. As it is rightly deemed an essential pursuit by the global community, we will see improvements over time.

Policy seems like a dry subject but countries like Germany, Israel, Japan and Denmark are examples of what effective government policy can accomplish in the interest on national energy security and the support for Research and Development both privately and government funded. These countries provide the rest of us with some "learn from example" models.

Not sure that that answers your question, but it gives you some input on the broadness of the PV question worldwide and the factors to look for when watching the development of products in your own country.

There are also some newer technologies that I personally believe will revolutionize things in the years ahead and that's CSP technology. That's my personal view. If you're interested you can check out Zenith Solar online to read about some development of this cool technology that concentrates the sun's light to produce electricity.

Anja

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Permalink Reply by Martin Herzfeld on August 13, 2009 at 9:40pm

Concur with you, sunlight as the substantial solution from worldwide perspective, would be CSPV, CPV, CSP, and USSPV, ...

"... in the years ahead and that's CSP technology." consider "micro-CSP™", Power 250 (kW) to 5 (MW) ?

http://www.sopogy.com/pdf/contentmgmt/App_Sheet_Power_Print.pdf

@Anja What is your thinking on m-CSP?

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Permalink Reply by Martin Herzfeld on August 14, 2009 at 8:28am

http://www.csptoday.com/

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Permalink Reply by Tom S on September 23, 2009 at 5:11pm

be nice to have one these bad boys in the backyard. I can light up the whole neighborhood

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Permalink Reply by John Denman on January 6, 2010 at 6:42pm

After rebates, local and federal incentives I spent about $5500 to install a 4KW solar panel system in my home last June. July - December the system produced about $800 worth of electricity. My ROI is going to be under 4 years. The added value to my home is over $10,000.

How could anyone go wrong with that?

Also I followed the instructions at to reduce my power consumption except for the appliances; as a result my power bill for the last 6 months was lower then my May 2009 bill alone.

The time is NOW to have a system installed. At that very least try the conservations stuff at that website.

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