Photovoltaic modules or PV is composed of solar cells converting sun energy to electricity. There are abundance of different manufacturers to choose from, which can be a challenge in deciding the best PV module for you. There are 3 major factors in identifying what specifications are essential.
1. Efficiency
Ideally the sun produces 1 kWh per square meter at noon on a clear day at sea level. This is defined as the "full sun." Unfortunately, current technology is not very efficient. Most PV modules can only harvest 12-18% of the sun's energy. SunPower and Sanyo's HIT are the leaders of the industry on efficiency but that comes with a price. The benefit in getting higher efficient PV modules is if you are constrained with space. You can maximize the limited area you have with the most power you can get from the sun. This basically means the PV modules would be a little smaller with almost the same power you would get with the standard less costly modules. Sanyo and SunPower are about $200-300 more expensive (about $3.70/kWh).
2. Power Rating
Power is the product of voltage (V) and current (A). This probably is the first thing that is essential in looking for a PV module. PV modules are connected in series and/or parallel to attain the total required power. They range from 40 kWh to 230 kWh. Commonly 165-190 kWh modules are used due to cost. But due to loss from the heat of the sun and electrical connection of the solar cells, power ratings are categorized in 3 different standards. STC or Standard Test Conditions are based on laboratory test conditions. This is unrealistic but is a basis on maximum performance of a given module. This is also known as "template rating." PTC or Practical Test Conditions (usually 6-12% less than its STC rating) considers loss and more realistic environment conditions yet still not real world conditions.
3. Temperature Coefficient
This is the power that you would loose as temperature goes beyond the PV modules operating temperature. This is rated by percentage loss per degree centigrade (%/C). Again, Sanyo and SunPower market their products to perform better than others in higher temperature. SunPower claims -0.38% / C while Sanyo HITs at -0.34% / C. Less expensive PV modules like Evergreen is at -0.44% / C
Another specifications that is not commonly advertised is the PV module's performance degradation in time. Technically a brand new module should perform at 100% out from its packaging. Although modules last for a very long time (25+ years), its actual performance drops per year of use. Some manufacturers might have this in there spec sheet but if not expect from 0.25% to 0.50% degradation per year.
My 2 cents
I have done my own research on different manufacturers on their pricing, efficiency, and compared specifications side by side. First I was focusing on both leaders in the industry, Sanyo and SunPower but the cost difference is just not worth it. You would be better off getting 2-3 extra panels, if you have the space, and still save a huge chunk of cash since 60% of the cost for a solar power system would be on your PV modules. I would recommend going with Evergreen. They have been tested to perform well on the field and has the shortest payback time for return of your investment.
Thursday, July 23, 2009
Solar Power: DIY or Hire Pro
If you are now really decided to to go solar there are many compelling reasons to do it now. Costs have come down, incentives have gone up, and electric rates only promise to go up more.
There's more than one way to go about installing your new solar power system. There are many articles out there telling how you can save money by doing it yourself. You would probably save $5-10K but there is more to it than what most people think. While this is a good solution for some, many would be better served if you hired a qualified professional. Why is that a good choice?
Construction and Electrical Knowledge
Do you have experience with construction or electrical wiring? This job involves installing photovoltaic panels, usually on a roof. In addition to securing the panels to the roof, you need to be able to wire the system to the home electrical system. If you are handy around the house and have done many projects like this, DIY may be the way to go. But for those who lack this type of knowledge, hiring a professional will probably save you a lot of headaches.
Permits
Do you know what permits are required by your city and/or county? Do you know the process for applying, and what the inspectors will be looking for? Solar energy, being relatively new for residences, is new to some of the building inspectors too. A professional will be able to get through the permit process smoothly.
Thinking of going without permits? The worst case scenario is that the city might make you take it down or that the system is improperly installed and causes damage. Even if everything goes well, appraisers usually can't take non-permitted additions into consideration for your home's value. This might mean that you won't be able to get the full value of the system when you sell your house.
Guarantees
One requirement to get your rebate and tax incentive is to have a 25 year warranty for the system. If your PV panels or inverter goes bad, you need to ship it back to the manufacturer yourself. PV weights about 35lbs and the inverter is about 100lbs. Is the savings worth the maintenance and servicing you might need in the future? Probably not unless you hav a lot of free time and willing to troubleshoot and service your own solar system.
While doing it yourself may be the answer for some, I think that hiring a qualified contractor is the wisest decision for most.Although Im an electronics engineer and pretty confident I can install the whole system, there is just more to it than just installation and its operation. Be sure to get two or three bids, look for a licensed contractor, and check references from other clients.
Now if you still feel that you are up to the challenge, heres a reference video from Roderick Young who did a DIY of his own solar home. In addition to his video, he provides references, advises, and downloadable documents which I find very valueable for DIY.
There's more than one way to go about installing your new solar power system. There are many articles out there telling how you can save money by doing it yourself. You would probably save $5-10K but there is more to it than what most people think. While this is a good solution for some, many would be better served if you hired a qualified professional. Why is that a good choice?
Construction and Electrical Knowledge
Do you have experience with construction or electrical wiring? This job involves installing photovoltaic panels, usually on a roof. In addition to securing the panels to the roof, you need to be able to wire the system to the home electrical system. If you are handy around the house and have done many projects like this, DIY may be the way to go. But for those who lack this type of knowledge, hiring a professional will probably save you a lot of headaches.
Permits
Do you know what permits are required by your city and/or county? Do you know the process for applying, and what the inspectors will be looking for? Solar energy, being relatively new for residences, is new to some of the building inspectors too. A professional will be able to get through the permit process smoothly.
Thinking of going without permits? The worst case scenario is that the city might make you take it down or that the system is improperly installed and causes damage. Even if everything goes well, appraisers usually can't take non-permitted additions into consideration for your home's value. This might mean that you won't be able to get the full value of the system when you sell your house.
Guarantees
One requirement to get your rebate and tax incentive is to have a 25 year warranty for the system. If your PV panels or inverter goes bad, you need to ship it back to the manufacturer yourself. PV weights about 35lbs and the inverter is about 100lbs. Is the savings worth the maintenance and servicing you might need in the future? Probably not unless you hav a lot of free time and willing to troubleshoot and service your own solar system.
While doing it yourself may be the answer for some, I think that hiring a qualified contractor is the wisest decision for most.Although Im an electronics engineer and pretty confident I can install the whole system, there is just more to it than just installation and its operation. Be sure to get two or three bids, look for a licensed contractor, and check references from other clients.
Now if you still feel that you are up to the challenge, heres a reference video from Roderick Young who did a DIY of his own solar home. In addition to his video, he provides references, advises, and downloadable documents which I find very valueable for DIY.
Wednesday, July 22, 2009
Is Solar Power for you?
The benefits did not justified its cost when I first started researching about solar power for my home 5 years ago. I was optimistic at first when new incentives has been drastically revamped by the current administration to make solar power more affordable. The the PV (Photovoltaic) modules has dropped from $10/kWh to like $3/kWh. The government incentives has offered better rebates and tax credit. Early this year the $2K tax credit cap limit has been removed.
Basically, you end up paying only 1/3 the cost of the whole system. 1/3 is the rebate check that you get within 6 months from the time your system is operational. Another 1/3 is the tax credit that the IRS basically owes you. You can either use this one time or within 5 years. The credit will be a little less if you decide to split your credit within 5 years of course. With this you can get back whatever income tax you have paid the IRS by the end of the year.
First question you would hear from a PV system installer/contractor is how much you actually consume a year. Most US homes consumes about 600 kWh/month on a average. This will require you to have a 5kWh solar power system if you decide to cover 100% of your monthly electric bill. Another common standard they use is $/kWh. This is how much you will pay per kilo watt hour. There will be $/kWh rating on each component you need like the PV module, grid-tied inverters, etc...
Now how much does it really cost? The same rating unit is used on a completed or installed solar power system. I have taken 7 different bids and they range from $6.50/kWh to $8.50/kWh. You need to make an informed decision on which contractor to go with depending on there experience, company profile, components they use, guarantee, and even talk to their customers within your area to see the qulaity of there work and satisfaction level of there customers. I have determined that the $7/kWh was the better choice among all the bids, which for a 5kWh system would cost $35K !
Now the bottom line. Even with all the rebates and credit you would still either need to raise that $35k or get a loan. You will be hyped and deceived by all these contractors that all this would cost you is $11k. Well yes and now. Unless you have enough savings you would have to factor in to your decision the monthly payments on the loan. In most cases, the loan will pretty much be the same amount you have been paying monthly for your electric bills.
There are 2 ways of looking at this. You can either see this as an investment for your home to increase it's property value or instead of forever paying the electric bill, the same money you spend on your electric bill will be relocated the monthly cost of your loan.
What does this mean? In 10 years or so, the money you have paid for your loan has pretty much paid for the $11K you have spent for your system. Provided that you paid your loan with the rebate check and tax credit you got back from the IRS.
Things you should ask yourself:
1. Are you going to be in your home 10 years from now?
2. Are you going to pay for your loan when you get that $11,000 rebate check?
3. Are you going to send that tax credit you get at the end of the year to pay the loan?
4, Lastly, with the current banking situation and economy, how confident are you to get a loan?
Personally, I doubt if I'll still be in the same house after 10 years. I can barely pay for the mortgage for my house that is worth so much less now. I really dont trust myself if I can actually control myself with the rebate check and tax credit. I'll probably end up paying off my bills, car, and maybe spoil myslef a bit ...lol . If your fortunate enough to have home equity with your property you'll probably get a 30 yr loan for about $100 a month at 7% interest. Im not so lucky.
If your purpose is to save money now, solar power is not for you because it is still very expensive in spite of all the rebate and tax credit. If you plan to sell your home within 10 years, it adds about 10% to the value of your property which is probably is a good idea to go solar. Now if you want to take advantage of renewable energy and want to go green then go for it!
Basically, you end up paying only 1/3 the cost of the whole system. 1/3 is the rebate check that you get within 6 months from the time your system is operational. Another 1/3 is the tax credit that the IRS basically owes you. You can either use this one time or within 5 years. The credit will be a little less if you decide to split your credit within 5 years of course. With this you can get back whatever income tax you have paid the IRS by the end of the year.
First question you would hear from a PV system installer/contractor is how much you actually consume a year. Most US homes consumes about 600 kWh/month on a average. This will require you to have a 5kWh solar power system if you decide to cover 100% of your monthly electric bill. Another common standard they use is $/kWh. This is how much you will pay per kilo watt hour. There will be $/kWh rating on each component you need like the PV module, grid-tied inverters, etc...
Now how much does it really cost? The same rating unit is used on a completed or installed solar power system. I have taken 7 different bids and they range from $6.50/kWh to $8.50/kWh. You need to make an informed decision on which contractor to go with depending on there experience, company profile, components they use, guarantee, and even talk to their customers within your area to see the qulaity of there work and satisfaction level of there customers. I have determined that the $7/kWh was the better choice among all the bids, which for a 5kWh system would cost $35K !
Now the bottom line. Even with all the rebates and credit you would still either need to raise that $35k or get a loan. You will be hyped and deceived by all these contractors that all this would cost you is $11k. Well yes and now. Unless you have enough savings you would have to factor in to your decision the monthly payments on the loan. In most cases, the loan will pretty much be the same amount you have been paying monthly for your electric bills.
There are 2 ways of looking at this. You can either see this as an investment for your home to increase it's property value or instead of forever paying the electric bill, the same money you spend on your electric bill will be relocated the monthly cost of your loan.
What does this mean? In 10 years or so, the money you have paid for your loan has pretty much paid for the $11K you have spent for your system. Provided that you paid your loan with the rebate check and tax credit you got back from the IRS.
Things you should ask yourself:
1. Are you going to be in your home 10 years from now?
2. Are you going to pay for your loan when you get that $11,000 rebate check?
3. Are you going to send that tax credit you get at the end of the year to pay the loan?
4, Lastly, with the current banking situation and economy, how confident are you to get a loan?
Personally, I doubt if I'll still be in the same house after 10 years. I can barely pay for the mortgage for my house that is worth so much less now. I really dont trust myself if I can actually control myself with the rebate check and tax credit. I'll probably end up paying off my bills, car, and maybe spoil myslef a bit ...lol . If your fortunate enough to have home equity with your property you'll probably get a 30 yr loan for about $100 a month at 7% interest. Im not so lucky.
If your purpose is to save money now, solar power is not for you because it is still very expensive in spite of all the rebate and tax credit. If you plan to sell your home within 10 years, it adds about 10% to the value of your property which is probably is a good idea to go solar. Now if you want to take advantage of renewable energy and want to go green then go for it!
Subscribe to:
Posts (Atom)
