How much power should I offset?
When you are purchasing a solar system, you have the option to offset part or all your power. Here in Fresno and the Central Valley, summer bills can get out of control with air conditioning use and kids being out of school so it pays to think this through before finalizing the purchase.
Many solar companies here in Fresno and the in Central Valley will usually recommend offsetting all your usage except for the "lower two tiers" of your bill. They are referring to the baseline and the next tier after the baseline, which have been locked by the California Public Utility Commission (CPUC) to low pricing to help lower income individuals from high bills.
Recently, PGE was able to coerce the CPUC into removing the pricing lock for the lower 2 tiers, meaning that PGE can raise rates even though this will affect low income individuals and raise utility bills for every one. These two tiers will run from $60 to $80 per month before moving on to higher rates, depending where you live.
Going back to how much power should you offset, when you purchase a solar system you are getting rebates and tax credits as a one time payment to help you offset the cost of solar. If you leave a part of your bill, even though they are called "cheap energy", you are still tied to the utility company paying something every month. You have made a significant investment to go solar/green and yet you still have a bill due every month, for the rest of the life of the system.
Let's think about this: the State of California the Federal Government and in some cases, your city/county is paying for such a huge part of your solar system, go ahead and offset 100% of your bill. Future rate increases, inflation on that left over bill, payments for selling overproduction to PG&E, as well as the way PGE structures their rates make offsetting all of your energy a very attractive option. Also, the larger the system you build, the better the pricing usually is.
Saturday, March 26, 2011
Sunday, March 20, 2011
Nova West Solar Offices Grand Opening
New Location
Nova West Solar is proud to announce the location of our new offices.
We are now located at 7429 N First St, Suite 104, Fresno, Ca 93720. This location is located on the North West corner of Alluvial and First Av. The complex is comprised of single story red brick buildings. What makes these buildings stand out are the "bow" glass window configuration on all of the building's corners.
With more room to accomodate accounting, marketing, sales, and business as well as construction management,we have seen our business double!
With increased sales comes even better pricing from all of our manufacturers.
At Nova West Solar we are commited to offering the best solar panels and equipment at the best prices. We routinely are the lowest bid utilizing German. We are unaware of any solar contractor that competes with the quality of our customer service and construction departments.
We would like to thank all of our customers for their patronage and look forward to being there if or when you need us.
Gary Fairhead
Robert Green
Nova West Solar is proud to announce the location of our new offices.
We are now located at 7429 N First St, Suite 104, Fresno, Ca 93720. This location is located on the North West corner of Alluvial and First Av. The complex is comprised of single story red brick buildings. What makes these buildings stand out are the "bow" glass window configuration on all of the building's corners.
With more room to accomodate accounting, marketing, sales, and business as well as construction management,we have seen our business double!
With increased sales comes even better pricing from all of our manufacturers.
At Nova West Solar we are commited to offering the best solar panels and equipment at the best prices. We routinely are the lowest bid utilizing German. We are unaware of any solar contractor that competes with the quality of our customer service and construction departments.
We would like to thank all of our customers for their patronage and look forward to being there if or when you need us.
Gary Fairhead
Robert Green
Monday, March 14, 2011
Cleaning Your Solar Panels
How and When to Clean Your Solar Panels
Cleaning solar panels should be done two to three times a year if you live in the city and three to four times a year if you live in the country.
Excessive dust and dirt build up can lower your output by anywhere from 5-15%! By generating electricity, we are in essence generating money. It only makes sense to keep your solar investment running at an optimum.
Cleaning solar panels can be accomplished in several different ways. What is important to keep in mind is not leaving hard water deposits on the glass.
Do not clean panels in the middle of the day.
The first is to make sure you have soft water and apply water after light scrubbing with a brush.
It is always best to utilize a squeegee after you rinse off the panels.
The second option is to lightly wash off 4-6 panels at a time. Utilizing a product called "Squeegee" window cleaner manufactured by Genlabs.
This product is sold by Clovis Janitorial in Clovis Ca. You simply put one capful in one gallon of warm water. Then use a sheep skin scrubber to apply cleaner & squeege. This product leaves a light sudsy film on the glass that does not evaporate for 5 minutes. Squeegee off and the glass will sparkle! And NO STREAKING!!!
This product is great for cleaning house windows. The glass on a 24 window home can be cleaned in approximately 30 minutes.
Another product "Windex Outdoor Multi-surface" spray is an easy alternative. This product is used to clean two story homes windows and comes in a spray bottle that can direct either water or windex and water as you so choose. Just spray down a few panels with straight water, then apply the Multi surface cleaner along with water. This product has a water softening agent that should not leave any streaks or water stains. After leaving the product on the determined time, just switch back to the rinse option and your done. If the panels are real dirty, you may want to scrub the panels after the Multi Surface has been applied.
As always, if a squeegie is used after the final rinse, your solar panels will sparkle and be both streak and water spot free.
The third way is to hire a cleaning service. $2-$3 per solar panel is average. Some services can go to $5 per panel or more. Be aware that a few of these services are not interested in making a $100, they want to service and maintain your system. Any service or maintenance done by an outside service will usually nullify your solar labor warranty. Always call your solar contractor if you think you have a problem. Remember, your system is warrantied for 10 years!
There are a couple of new options that are making their way onto to the solar panel cleaning scene. I will follow up in the coming months on these new cleaning methods.
Cleaning solar panels should be done two to three times a year if you live in the city and three to four times a year if you live in the country.
Excessive dust and dirt build up can lower your output by anywhere from 5-15%! By generating electricity, we are in essence generating money. It only makes sense to keep your solar investment running at an optimum.
Cleaning solar panels can be accomplished in several different ways. What is important to keep in mind is not leaving hard water deposits on the glass.
Do not clean panels in the middle of the day.
The first is to make sure you have soft water and apply water after light scrubbing with a brush.
It is always best to utilize a squeegee after you rinse off the panels.
The second option is to lightly wash off 4-6 panels at a time. Utilizing a product called "Squeegee" window cleaner manufactured by Genlabs.
This product is sold by Clovis Janitorial in Clovis Ca. You simply put one capful in one gallon of warm water. Then use a sheep skin scrubber to apply cleaner & squeege. This product leaves a light sudsy film on the glass that does not evaporate for 5 minutes. Squeegee off and the glass will sparkle! And NO STREAKING!!!
This product is great for cleaning house windows. The glass on a 24 window home can be cleaned in approximately 30 minutes.
Another product "Windex Outdoor Multi-surface" spray is an easy alternative. This product is used to clean two story homes windows and comes in a spray bottle that can direct either water or windex and water as you so choose. Just spray down a few panels with straight water, then apply the Multi surface cleaner along with water. This product has a water softening agent that should not leave any streaks or water stains. After leaving the product on the determined time, just switch back to the rinse option and your done. If the panels are real dirty, you may want to scrub the panels after the Multi Surface has been applied.
As always, if a squeegie is used after the final rinse, your solar panels will sparkle and be both streak and water spot free.
The third way is to hire a cleaning service. $2-$3 per solar panel is average. Some services can go to $5 per panel or more. Be aware that a few of these services are not interested in making a $100, they want to service and maintain your system. Any service or maintenance done by an outside service will usually nullify your solar labor warranty. Always call your solar contractor if you think you have a problem. Remember, your system is warrantied for 10 years!
There are a couple of new options that are making their way onto to the solar panel cleaning scene. I will follow up in the coming months on these new cleaning methods.
Thursday, March 10, 2011
Evaluating Solar Companies
Choosing 3 Solar Companies from Hundreds
Right now, we are seeing a flood of new solar companies joining the solar installation ranks in California. Every day, a new website goes up proclaiming years of experience and yet, there are only a couple dozen real players out there. Every year, several hundred solar companies try their hand at solar and you never hear from them again. The next year, a whole new group of 200-300 companies enter the field. The question becomes, how do you choose a solar company that knows how to properly design and install a solar system that will be safe, will function at a high level of efficiency, and will be supported over the long haul?
Solar Companies–Large or Small, Local or Global
There are a number of very large solar companies in the United States that are trying to gain market share by keeping their prices low and expanding rapidly into new markets. These companies are losing staggering amounts of money. Most of these companies are privately held and it is difficult to show just how much money they are losing. However, one good example is Akeena and here is a link to their financials. Just looking at it briefly, Akeena stock went from a high in 2008 of $15.00 to a current price just below $1.00. This company has posted huge quarterly losses as far back as I can remember. This past quarter, Akeena lost $2.4M on $6.5M in Revenue. There are a number of other large solar companies in this same boat. Losing money at this rate in the good times isn’t sustainable. So the question is, should you choose a large solar company for your solar installation because they seem on the surface to be a safe bet, or should you choose a smaller, well run local company that is financially stable? If you decide to invest in a solar home, you will have to answer this question for yourself.
Check the Solar Installation Company Contractors License
The first thing I would do before choosing a company and investing in a solar home is look their contractors license. Typically, the best type of license for solar electrical installation is the C-10 Electrical license. The State of California allows General Contractors (B), Grading Contractors (A) Electrical Contractors (C-10) and Solar Contractors (C-46) to install solar in California. We at Nova West Solar carry the C-10, C-46, B, as well as the C-39 Roofing license. You can check a solar company’s contractors license here. You can determine from this site if a Contractor has Workers Compensation, is bonded and if their license is current or expired. You can also tell how long they have had their license and/or how long the license or licensee has been affiliated with the company.
Check out Their Web Page
Photos of solar installations on a web page are very telling. If the photo of a solar installation on a home looks like it was taken in Germany, it probably was. If you live in California and are looking for a solar installation company with local experience, look at the photos on their website. There should be dozens and dozens of different installations featured and they shouldn’t look like they were photos plucked off the web or purchased from istock. Local experience with local building codes and local officials is very important. Experience with local codes makes the solar permiting and inspection process go much smoother and end up costing you much less.
Check out their BBB listing
A solar company should have a listing on the Better Business Bureau. You can check out the listings for: Fresno CaliforniaMake Sure they are Listed on the CSI databaseThe California Solar Initiative has a list of Resellers and Installers that are approved to sell and install solar in California.
Check out their references
Most Solar Companies are very proud of their reference lists. Ask for a list and call a past customer at random.
Check out their Local Installations
Most solar companies that have been around for awhile will have at least one installation in your area. Ask to be able to at least drive by one installation.
Evaluating Solar Companies
The bottom Line is a final choice can be easier that one would think. Normallly I would recommend the above listed suggestions and then temper them with who has the best producing panels at the lower/best price. (Not necessarilly the cheapest) However, with solar being a major long term investment, the warranties-production and replacement-need to be looked at very closely. Once this is done, your decision process should be complete.
Right now, we are seeing a flood of new solar companies joining the solar installation ranks in California. Every day, a new website goes up proclaiming years of experience and yet, there are only a couple dozen real players out there. Every year, several hundred solar companies try their hand at solar and you never hear from them again. The next year, a whole new group of 200-300 companies enter the field. The question becomes, how do you choose a solar company that knows how to properly design and install a solar system that will be safe, will function at a high level of efficiency, and will be supported over the long haul?
Solar Companies–Large or Small, Local or Global
There are a number of very large solar companies in the United States that are trying to gain market share by keeping their prices low and expanding rapidly into new markets. These companies are losing staggering amounts of money. Most of these companies are privately held and it is difficult to show just how much money they are losing. However, one good example is Akeena and here is a link to their financials. Just looking at it briefly, Akeena stock went from a high in 2008 of $15.00 to a current price just below $1.00. This company has posted huge quarterly losses as far back as I can remember. This past quarter, Akeena lost $2.4M on $6.5M in Revenue. There are a number of other large solar companies in this same boat. Losing money at this rate in the good times isn’t sustainable. So the question is, should you choose a large solar company for your solar installation because they seem on the surface to be a safe bet, or should you choose a smaller, well run local company that is financially stable? If you decide to invest in a solar home, you will have to answer this question for yourself.
Check the Solar Installation Company Contractors License
The first thing I would do before choosing a company and investing in a solar home is look their contractors license. Typically, the best type of license for solar electrical installation is the C-10 Electrical license. The State of California allows General Contractors (B), Grading Contractors (A) Electrical Contractors (C-10) and Solar Contractors (C-46) to install solar in California. We at Nova West Solar carry the C-10, C-46, B, as well as the C-39 Roofing license. You can check a solar company’s contractors license here. You can determine from this site if a Contractor has Workers Compensation, is bonded and if their license is current or expired. You can also tell how long they have had their license and/or how long the license or licensee has been affiliated with the company.
Check out Their Web Page
Photos of solar installations on a web page are very telling. If the photo of a solar installation on a home looks like it was taken in Germany, it probably was. If you live in California and are looking for a solar installation company with local experience, look at the photos on their website. There should be dozens and dozens of different installations featured and they shouldn’t look like they were photos plucked off the web or purchased from istock. Local experience with local building codes and local officials is very important. Experience with local codes makes the solar permiting and inspection process go much smoother and end up costing you much less.
Check out their BBB listing
A solar company should have a listing on the Better Business Bureau. You can check out the listings for: Fresno CaliforniaMake Sure they are Listed on the CSI databaseThe California Solar Initiative has a list of Resellers and Installers that are approved to sell and install solar in California.
Check out their references
Most Solar Companies are very proud of their reference lists. Ask for a list and call a past customer at random.
Check out their Local Installations
Most solar companies that have been around for awhile will have at least one installation in your area. Ask to be able to at least drive by one installation.
Evaluating Solar Companies
The bottom Line is a final choice can be easier that one would think. Normallly I would recommend the above listed suggestions and then temper them with who has the best producing panels at the lower/best price. (Not necessarilly the cheapest) However, with solar being a major long term investment, the warranties-production and replacement-need to be looked at very closely. Once this is done, your decision process should be complete.
Tuesday, March 8, 2011
Solar power Inverters
Grid Tied Inverters
Inverters work by taking the DC power from the source, such as an array of photovoltaic modules (typically 250 to 600 volts DC) or micro hydroelectric turbines, and inverting it to AC power so it can be fed into the grid. The inverter must also synchronize its frequency with that of the grid (e.g. 60 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage. Typical modern GTI’s have a fixed unity power factor, which means its output voltage and current are perfectly lined up, and its phase angle is within 1 degree of the AC power grid. The inverter has an on board computer which will sense the current AC grid waveform, and output a voltage to correspond with the grid.
Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down. This is an NEC requirement that ensures that in the event of a blackout, the grid tie inverter will shut down to prevent the energy it produces from harming any line workers who are sent to fix the power grid.
Grid-tie inverters that are available on the market today use a number of different technologies. The inverters may use the newer high-frequency transformers, conventional low-frequency transformers, or even use no transformer. Instead of converting DC current directly to 120 or 240 volts AC, high-frequency transformers employ a computerized multi-step process that involves converting the power to high-frequency AC and then back to DC and then to the final AC output voltage. Transformerless inverters, which boast lighter weight and higher efficiencies than their counterparts with transformers, are popular in Europe. However, transformerless inverters have been slow to enter the US market. Until 2005, NEC code required all solar electric systems to be negative grounded, an electrical configuration that interferes with the operation of transformerless inverters. The issue at stake currently is that there are concerns about having transformerless electrical systems feed into the public utility grid since the lack of galvanic isolation between the DC and AC circuits could allow the passage of dangerous DC faults to be transmitted to the AC side.
Most solar grid-interactive inverters on the market include a maximum power point tracker that enables the inverter to extract an optimal amount of power from the solar array by tracking the array’s maximum power point.
Micro Inverters
A solar photovoltaic micro-inverter is a device that converts direct current (DC) from a single solar module (panel) to alternating current (AC).
Unlike a central or string inverter that aggregates and converts the power generated by the entire array of solar modules, a micro-inverter converts the DC power from a single solar module to AC. The concept of panels delivering AC power has appeal for small-scale home project applications at lower voltage levels.
Disadvantages of Micro Inverters
Inverters are generally acknowledged to fail at a higher rate than other components in a photovoltaic system. The warranty of an inverter is typically 10 years, whereas the rest of the system can be warranted for up to 25 years. Thus inverters are most-often rated for shorter warranties than other components. Detractors of micro-inverter technology claim it is not advisable to distribute the least reliable component of the PV system to every module, as the failure rate of an inverter at the module level multiplies failure points. Another issue is that the Micro Inverters would be located on the roof and daily temperature cycling would be detrimental to the long term reliability of the inverter.
Inverters work by taking the DC power from the source, such as an array of photovoltaic modules (typically 250 to 600 volts DC) or micro hydroelectric turbines, and inverting it to AC power so it can be fed into the grid. The inverter must also synchronize its frequency with that of the grid (e.g. 60 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage. Typical modern GTI’s have a fixed unity power factor, which means its output voltage and current are perfectly lined up, and its phase angle is within 1 degree of the AC power grid. The inverter has an on board computer which will sense the current AC grid waveform, and output a voltage to correspond with the grid.
Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down. This is an NEC requirement that ensures that in the event of a blackout, the grid tie inverter will shut down to prevent the energy it produces from harming any line workers who are sent to fix the power grid.
Grid-tie inverters that are available on the market today use a number of different technologies. The inverters may use the newer high-frequency transformers, conventional low-frequency transformers, or even use no transformer. Instead of converting DC current directly to 120 or 240 volts AC, high-frequency transformers employ a computerized multi-step process that involves converting the power to high-frequency AC and then back to DC and then to the final AC output voltage. Transformerless inverters, which boast lighter weight and higher efficiencies than their counterparts with transformers, are popular in Europe. However, transformerless inverters have been slow to enter the US market. Until 2005, NEC code required all solar electric systems to be negative grounded, an electrical configuration that interferes with the operation of transformerless inverters. The issue at stake currently is that there are concerns about having transformerless electrical systems feed into the public utility grid since the lack of galvanic isolation between the DC and AC circuits could allow the passage of dangerous DC faults to be transmitted to the AC side.
Most solar grid-interactive inverters on the market include a maximum power point tracker that enables the inverter to extract an optimal amount of power from the solar array by tracking the array’s maximum power point.
Micro Inverters
A solar photovoltaic micro-inverter is a device that converts direct current (DC) from a single solar module (panel) to alternating current (AC).
Unlike a central or string inverter that aggregates and converts the power generated by the entire array of solar modules, a micro-inverter converts the DC power from a single solar module to AC. The concept of panels delivering AC power has appeal for small-scale home project applications at lower voltage levels.
Disadvantages of Micro Inverters
Inverters are generally acknowledged to fail at a higher rate than other components in a photovoltaic system. The warranty of an inverter is typically 10 years, whereas the rest of the system can be warranted for up to 25 years. Thus inverters are most-often rated for shorter warranties than other components. Detractors of micro-inverter technology claim it is not advisable to distribute the least reliable component of the PV system to every module, as the failure rate of an inverter at the module level multiplies failure points. Another issue is that the Micro Inverters would be located on the roof and daily temperature cycling would be detrimental to the long term reliability of the inverter.
Sunday, March 6, 2011
Power Plants and Higher Electric Rates
FUTURE UTILITY INCREASES PLANNED
The electricity that we are supplied today from PG&E and the other investor-owned-utilities is produced by a multitude of different power plants. This group of power plants is called the "portfolio." Electric power plants are characterized by their size (Megawatts) and the fuel source used to drive the generators. PG&E's electricity generation mix (fuel mix or power content) is about 50% fossil, mostly natural gas. The rest is nuclear, large hydroelectric, and about 12%-14% renewable
Current thinking on the part of the utilities is that they will increase the amount of renewables. Recently, an executive order requires them to increase renewables to 33% of total generation by 2020. New nuclear power plants are, at this point, prohibited in the State of California until there is a safe way to store the waste. No one knows when that will change. Similarly, no new large hydroelectric plants because of the ecological damage they inflict. The only remaining technology to produce low carbon electricity is Carbon Capture and Sequestration (CCS). Most or all of the existing fossil generation facilities will have to be specially fitted with systems to capture the carbon dioxide being given off and store it somewhere, either underground or under the ocean bottom, forever.
PG&E and the other utilities are telling us that reaching 33% renewables is going to be expensive. However, that cost is dwarfed by the cost of retrofitting existing fossil plants with carbon capture and sequestration. Today, it is impractical. There is no indication of what the ultimate cost of a large scale CCS retrofit would be. To hear the utilities tell it, this scenario is our only hope. The federal government so far largely agrees with them.
We should all brace for higher and higher rates due to the present exclusion of new nuclear, hydro electric, or coal plants but also the massive expense associated with replacing our infrastructure and retrofitting fossil fuel plants. This would include retrofitting and replacing major natural gas pipelines that are 50 years old as well as electrical lines, poles, trasformers, etc. PG&E is hoping to get a "flexible" increase system in place so they don't have to ask for specific increases which up to date have to be "justified".
There appears to be no winning with the utilities short of owning your own solar power plant and securing your current comfort and lifestyle for the rest of your life.
The electricity that we are supplied today from PG&E and the other investor-owned-utilities is produced by a multitude of different power plants. This group of power plants is called the "portfolio." Electric power plants are characterized by their size (Megawatts) and the fuel source used to drive the generators. PG&E's electricity generation mix (fuel mix or power content) is about 50% fossil, mostly natural gas. The rest is nuclear, large hydroelectric, and about 12%-14% renewable
Current thinking on the part of the utilities is that they will increase the amount of renewables. Recently, an executive order requires them to increase renewables to 33% of total generation by 2020. New nuclear power plants are, at this point, prohibited in the State of California until there is a safe way to store the waste. No one knows when that will change. Similarly, no new large hydroelectric plants because of the ecological damage they inflict. The only remaining technology to produce low carbon electricity is Carbon Capture and Sequestration (CCS). Most or all of the existing fossil generation facilities will have to be specially fitted with systems to capture the carbon dioxide being given off and store it somewhere, either underground or under the ocean bottom, forever.
PG&E and the other utilities are telling us that reaching 33% renewables is going to be expensive. However, that cost is dwarfed by the cost of retrofitting existing fossil plants with carbon capture and sequestration. Today, it is impractical. There is no indication of what the ultimate cost of a large scale CCS retrofit would be. To hear the utilities tell it, this scenario is our only hope. The federal government so far largely agrees with them.
We should all brace for higher and higher rates due to the present exclusion of new nuclear, hydro electric, or coal plants but also the massive expense associated with replacing our infrastructure and retrofitting fossil fuel plants. This would include retrofitting and replacing major natural gas pipelines that are 50 years old as well as electrical lines, poles, trasformers, etc. PG&E is hoping to get a "flexible" increase system in place so they don't have to ask for specific increases which up to date have to be "justified".
There appears to be no winning with the utilities short of owning your own solar power plant and securing your current comfort and lifestyle for the rest of your life.
Saturday, March 5, 2011
Why Are Solar Panels So Expensive?
How Mono Crystalline is Made
To better understand the expense of a single solar panel, it is necessary to know how the highly efficient mono crystalline cells are produced.
Silicon is a semi conductor that can either block or conduct electricity, depending on how it is treated.
It has taken decades to perfect the manufacture of mono crystalline crystals. The process starts out with heating raw poly crystalline in sealed ovens to over 2500 degrees Fahrenheit. It is then purged with argon gas to eliminate any air.
The resulting lake of molten silicon is then spun in a crucible and a silicon seed crystal, roughly the size and shape of a pencil, is then lowered into it while spinning in the opposite direction.
As the molten poly crystalline is allowed to cool, the seed crystal is slowly withdrawn at roughly 1.5 millimeters per minute. The result is a single crystalline weighing around 440 pounds and a diameter of approximately 200 millimeters. The silicon is so strong it can support its entire weight by a single thread just 3 millimeters in diameter. It is brittle but must now be cut down to size without shattering.
After testing with chemicals and x-rays to check its purity and molecular orientation, it is fed into a silicon Salomé slicer. A ten ton wire saw using a fast moving web of ultra thin wire is used to produce mono crystalline wafers. These wafers are very thin and 99.9 percent pure.
These almost pure wafers now go through a buffing and lapping process.
It is time consuming and expensive to manufacture these silicon wafers. Couple with the fact that less than half a dozen facilities even manufacture mono crystalline cells, it is easier to understand why a solar system can be so costly.
However, with paybacks on solar systems averaging between 4 and 7 years, the high cost of manufacturing silicon is less expensive than the cost of purchasing energy from our utility companies.
To better understand the expense of a single solar panel, it is necessary to know how the highly efficient mono crystalline cells are produced.
Silicon is a semi conductor that can either block or conduct electricity, depending on how it is treated.
It has taken decades to perfect the manufacture of mono crystalline crystals. The process starts out with heating raw poly crystalline in sealed ovens to over 2500 degrees Fahrenheit. It is then purged with argon gas to eliminate any air.
The resulting lake of molten silicon is then spun in a crucible and a silicon seed crystal, roughly the size and shape of a pencil, is then lowered into it while spinning in the opposite direction.
As the molten poly crystalline is allowed to cool, the seed crystal is slowly withdrawn at roughly 1.5 millimeters per minute. The result is a single crystalline weighing around 440 pounds and a diameter of approximately 200 millimeters. The silicon is so strong it can support its entire weight by a single thread just 3 millimeters in diameter. It is brittle but must now be cut down to size without shattering.
After testing with chemicals and x-rays to check its purity and molecular orientation, it is fed into a silicon Salomé slicer. A ten ton wire saw using a fast moving web of ultra thin wire is used to produce mono crystalline wafers. These wafers are very thin and 99.9 percent pure.
These almost pure wafers now go through a buffing and lapping process.
It is time consuming and expensive to manufacture these silicon wafers. Couple with the fact that less than half a dozen facilities even manufacture mono crystalline cells, it is easier to understand why a solar system can be so costly.
However, with paybacks on solar systems averaging between 4 and 7 years, the high cost of manufacturing silicon is less expensive than the cost of purchasing energy from our utility companies.
Wednesday, March 2, 2011
Solar's Glossary of Terms
Solar Terms and Definitions
Baseline Rate
This is the lowest or base rate you pay for electricity. This is shown in blue in the Tiered Rate Structure below. The entire tiered rate structure is founded on this baseline amount.
The baseline amount of electricity varies by several factors. These factors are:
Summer vs. Winter (actual electric rates can also change by Summer vs. Winter)
The region you live in (coastal, inland, mountain, or desert as defined by SDG&E SCE, or PG&E)
If you are an all electric household versus customers who use both natural gas and electricity or propane and electricity.
Some customers utilize a time of use rate (TOU) as well as subsidized rates for medically impaired customers.
There is another complexity to this: usually twice a year you get a bill that straddles between summer and winter so your baseline and tiers change in the middle of the billing cycle.
Building Integrated PhotoVoltaic Systems (BIPV)
BIPV is a term that generically refers to a PhotoVoltaic (i.e. Solar Electric) system that has been integrated as part of the building itself rather than a system that has been "bolted onto" a building. Very often the solar electric system is used as a roof or sometimes as a wall of the building.
Carbon Emissions
Carbon based pollutants released into the atmosphere that are a result of burning fossil fuels like coal and oil. One of the primary emissions is carbon dioxide that is a "greenhouse" gas that is widely accepted to be causing global warming.
Electricity (AC and DC),
Type of Solar Photovoltaic (PV) cells generate DC (direct current) electricity and the Inverter changes it to AC (alternating current) electricity that your house can use or can be exported to the utilities electric grid (Grid-Intertie).
Electricity can be thought of as flowing like water. The amount of pressure is like the "voltage" and the amount of water flowing is like the "current".
If electricity flows through the wire in only one direction it is called DC or "direct current". Batteries provide DC current to things like your cell phone and MP3 player.
AC or "Alternating Current" is when the current flows through the wire in one direction and then reverses to flow in the other direction. The electricity from the outlets in your home are a prime example of AC electricity.
Full Retail Price
The full price that you would pay the utility company for electricity used.
Grid-Intertie / Utility Grid
The utility company provides electricity to homes and businesses through its power distribution "grid". The grid is all of the interconnections that distribute power to electric utility customers. A grid-intertie is simply a connection to the utility power distribution grid.
In remote locations without power a "standalone" solar electric system would need to be installed.
Incentives / Rebates
The state of California offers rebates to offset the cost of your new Photovoltaic System. These are typically in the "thousands of dollars" range and work out to be approximately 10% of your system cost. They can be a lump sum paid when your system is first started (EPBB) or paid out over 5 years as your system produces electricity (PBI).
Additionally, there is a federal tax credit of 30% of the system cost which helps you recover much more of your initial investment, much more quickly.
Inverter
The equipment in a Solar Photovoltaic (PV) or solar electric system that converts the electricity from the DC (direct current) output from the Solar Panels to AC (Alternating Current) that can be used by home lights and appliances or exported back to the utility company.
kWh (Kilowatt Hours)
Kilowatt Hours is a measure of amount of electricity used (electrical energy). It is the basic unit the utility company uses to measure the amount of electricity you use and are billed for.
Note: Kilowatts (kW) are a unit of power. And power over time is energy. So Kilowatts (power) over a period of time can be measured in kWh (energy).
Mounting or Racking System for Solar Electric
A mounting or racking system is typically an aluminum or steel structure that solar panels are mounted on. It provides a physical connection to mount the panels on.
Net Metering
Electricity can be thought of as flowing like water. Your electric meter measures how much electricity flows through it so the utility can bill you for the amount used. Now what do you think would happen if you could "push" electricity back to the utility company. You have probably already guessed that the meter would run backwards. That's what Net Metering is and that is what a solar PV system does when you produce more electricity than you are using.
This is important because PV systems produce electricity only when the sun shines on them and they produce the most in the middle of the day. This is a time when many people are not home and are not using much electricity. So your electric meter runs backwards in this case, and allows you to "bank" electricity with your utility company for use when you are home. It's like the utility company buys electricity from you during the day and you buy it back when you need it.
In other words you pay for the "Net" amount of electricity used and so it is called "Net Metering". The utility company is effectively buying back electricity from you at Full Retail Price during the day when you are often using the least amount of electricity and generating the most.
The amount of electricity is "netted" annually starting on the first day your system is interconnected to the utility grid (Grid-Intertie). In other words, the amount of electricity generated over one year is subtracted from the amount used over one year and you pay only for the "net" or remaining amount for that year.
Pay for only for the amount of electricity that you actually use minus the amount your new photovoltaic electricity system generates.
On-Site Evaluation
An On-Site evaluation needs to be done, because every installation location is different. If you want the most out of your solar electric system a site visit is absolutely necessary. There's no way to know details about your roofline and shading without a visit. Don't believe those who say they can do a thorough job without a site visit to determine location, orientation, and sizing of your system first.
Photovoltaic Solar Cells (PV Solar Cells)
Photovoltaic (PV) solar cells are semiconductor devices that are commonly made out of very pure silicon (Si) that when exposed to the sun generate electricity. They are often called "solar cells".
Semiconductors
are materials that have unusual properties. They are not conductors like metals and are not insulators like many minerals or plastics. They have very unusual electrical properties that are not like either of these and this allows them to convert energy from the sun to electricity.
Solar Electricity Generation Systems
Systems that generate electricity directly from naturally occurring solar energy that is falling on the earth's surface every day from normal sunlight. The most common method of converting sunlight to electricity is using Solar Photovoltaic (PV) cells.
Solar Panels
Solar panels are simply groups of Solar Photovoltaic (PV) cells that have been packaged into a more useable arrangement.
The panel protects the solar PV cells from the elements, like rain. It makes them physically more durable because they are protected on the top and bottom by other materials (glass, metal, plastics) and usually on the edges by metal frames. They also provide a solid method to secure them to their mountings.
Tiered Electric Rates
Utility companies sell electricity as varying rates depending on how much electricity you use. This is known as a "Tiered Rate" because you pay a different rate in each tier as shown below. As you use more electricity you are charged more per unit of electricity used. Your Baseline rate is the lowest rate charged; then as you use more electricity the rate charged by the utility increases as shown in chart below. The basic idea is this: the more electricity you use the more you are charged per unit of electricity. The basic unit of electricity you are charged for is the Kilowatt-Hour or kWh. The utility company is trying to get you to conserve by charging a lot more if you use a lot or waste a lot of electricity. Low energy users pay less per kWh than high energy users. The idea is: if you use a lot of electricity then you pay more for your share than if you were a lower consumption user.
Here in San Diego Gas & Electric (SDG&E) territory there are 4 tiers for the rates you are charged for electricity.
Tier 1 - The first tier is called "baseline".
Tier 2 - The next tier is 100% to 130% of the baseline amount.
Tier 3 - The next tier is 130% to 200% of the baseline amount.
Tier 4 - The next tier is 200% and up of the baseline amount.
The baseline is an amount of electricity measured in kilowatt-hours (kWh) and you are charged one rate for this electricity. Then when your usage goes over this "baseline" amount and up to 130% of it (Tier 2) you are charged a slightly higher rate. Then when your usage goes over 130% of this "baseline" amount (Tier 3) you are charged a significantly higher rate. And similarly for when you go over 200% of the "baseline" amount (Tier 4).
It is very important to note that the Tier 3 & 4 rates are substantially higher than the Tier 1 and 2 rates for PG&E customers. And a solar power generating PV system will "shave off" the electric bill starting from the higher rates billed in Tier 4 and Tier 3 first. And eventually "shave off" the bill down to Tier 2 and then to Tier 1 if enough energy is produced.
This is important; because with Net Metering your total or "net" electricity used is reduced. Which means the electricity that the PV system generated is taken from the top of your usage which in effect removes the most expensive electricity used first. This is a big advantage. Your most expensive electricity is removed from your bill first.
To help understand the tiered electric rates here is an example to illustrate it. Imagine if:
the first 10 gallons of gasoline you purchase cost $3 /gallon
then the next 3 gallons cost $3.50 /gallon
then the next 7 gallons cost $8 /gallon
and anything over 7 gallons cost $9 /gallon.
Wouldn't you rather try to not use the $9 /gallon and $8 / gallon gasoline first or get it another way? That's exactly what solar electricity does with your tiered electric rates. It removes the most expensive electricity first. So if you are trying to maximize your savings then you want to size your solar system so that it gets rid of (or "shaves off") the electricity that would be charged in the Tier 3 and Tier 4 rates. This will improve your payback period and rate of return.
Baseline Rate
This is the lowest or base rate you pay for electricity. This is shown in blue in the Tiered Rate Structure below. The entire tiered rate structure is founded on this baseline amount.
The baseline amount of electricity varies by several factors. These factors are:
Summer vs. Winter (actual electric rates can also change by Summer vs. Winter)
The region you live in (coastal, inland, mountain, or desert as defined by SDG&E SCE, or PG&E)
If you are an all electric household versus customers who use both natural gas and electricity or propane and electricity.
Some customers utilize a time of use rate (TOU) as well as subsidized rates for medically impaired customers.
There is another complexity to this: usually twice a year you get a bill that straddles between summer and winter so your baseline and tiers change in the middle of the billing cycle.
Building Integrated PhotoVoltaic Systems (BIPV)
BIPV is a term that generically refers to a PhotoVoltaic (i.e. Solar Electric) system that has been integrated as part of the building itself rather than a system that has been "bolted onto" a building. Very often the solar electric system is used as a roof or sometimes as a wall of the building.
Carbon Emissions
Carbon based pollutants released into the atmosphere that are a result of burning fossil fuels like coal and oil. One of the primary emissions is carbon dioxide that is a "greenhouse" gas that is widely accepted to be causing global warming.
Electricity (AC and DC),
Type of Solar Photovoltaic (PV) cells generate DC (direct current) electricity and the Inverter changes it to AC (alternating current) electricity that your house can use or can be exported to the utilities electric grid (Grid-Intertie).
Electricity can be thought of as flowing like water. The amount of pressure is like the "voltage" and the amount of water flowing is like the "current".
If electricity flows through the wire in only one direction it is called DC or "direct current". Batteries provide DC current to things like your cell phone and MP3 player.
AC or "Alternating Current" is when the current flows through the wire in one direction and then reverses to flow in the other direction. The electricity from the outlets in your home are a prime example of AC electricity.
Full Retail Price
The full price that you would pay the utility company for electricity used.
Grid-Intertie / Utility Grid
The utility company provides electricity to homes and businesses through its power distribution "grid". The grid is all of the interconnections that distribute power to electric utility customers. A grid-intertie is simply a connection to the utility power distribution grid.
In remote locations without power a "standalone" solar electric system would need to be installed.
Incentives / Rebates
The state of California offers rebates to offset the cost of your new Photovoltaic System. These are typically in the "thousands of dollars" range and work out to be approximately 10% of your system cost. They can be a lump sum paid when your system is first started (EPBB) or paid out over 5 years as your system produces electricity (PBI).
Additionally, there is a federal tax credit of 30% of the system cost which helps you recover much more of your initial investment, much more quickly.
Inverter
The equipment in a Solar Photovoltaic (PV) or solar electric system that converts the electricity from the DC (direct current) output from the Solar Panels to AC (Alternating Current) that can be used by home lights and appliances or exported back to the utility company.
kWh (Kilowatt Hours)
Kilowatt Hours is a measure of amount of electricity used (electrical energy). It is the basic unit the utility company uses to measure the amount of electricity you use and are billed for.
Note: Kilowatts (kW) are a unit of power. And power over time is energy. So Kilowatts (power) over a period of time can be measured in kWh (energy).
Mounting or Racking System for Solar Electric
A mounting or racking system is typically an aluminum or steel structure that solar panels are mounted on. It provides a physical connection to mount the panels on.
Net Metering
Electricity can be thought of as flowing like water. Your electric meter measures how much electricity flows through it so the utility can bill you for the amount used. Now what do you think would happen if you could "push" electricity back to the utility company. You have probably already guessed that the meter would run backwards. That's what Net Metering is and that is what a solar PV system does when you produce more electricity than you are using.
This is important because PV systems produce electricity only when the sun shines on them and they produce the most in the middle of the day. This is a time when many people are not home and are not using much electricity. So your electric meter runs backwards in this case, and allows you to "bank" electricity with your utility company for use when you are home. It's like the utility company buys electricity from you during the day and you buy it back when you need it.
In other words you pay for the "Net" amount of electricity used and so it is called "Net Metering". The utility company is effectively buying back electricity from you at Full Retail Price during the day when you are often using the least amount of electricity and generating the most.
The amount of electricity is "netted" annually starting on the first day your system is interconnected to the utility grid (Grid-Intertie). In other words, the amount of electricity generated over one year is subtracted from the amount used over one year and you pay only for the "net" or remaining amount for that year.
Pay for only for the amount of electricity that you actually use minus the amount your new photovoltaic electricity system generates.
On-Site Evaluation
An On-Site evaluation needs to be done, because every installation location is different. If you want the most out of your solar electric system a site visit is absolutely necessary. There's no way to know details about your roofline and shading without a visit. Don't believe those who say they can do a thorough job without a site visit to determine location, orientation, and sizing of your system first.
Photovoltaic Solar Cells (PV Solar Cells)
Photovoltaic (PV) solar cells are semiconductor devices that are commonly made out of very pure silicon (Si) that when exposed to the sun generate electricity. They are often called "solar cells".
Semiconductors
are materials that have unusual properties. They are not conductors like metals and are not insulators like many minerals or plastics. They have very unusual electrical properties that are not like either of these and this allows them to convert energy from the sun to electricity.
Solar Electricity Generation Systems
Systems that generate electricity directly from naturally occurring solar energy that is falling on the earth's surface every day from normal sunlight. The most common method of converting sunlight to electricity is using Solar Photovoltaic (PV) cells.
Solar Panels
Solar panels are simply groups of Solar Photovoltaic (PV) cells that have been packaged into a more useable arrangement.
The panel protects the solar PV cells from the elements, like rain. It makes them physically more durable because they are protected on the top and bottom by other materials (glass, metal, plastics) and usually on the edges by metal frames. They also provide a solid method to secure them to their mountings.
Tiered Electric Rates
Utility companies sell electricity as varying rates depending on how much electricity you use. This is known as a "Tiered Rate" because you pay a different rate in each tier as shown below. As you use more electricity you are charged more per unit of electricity used. Your Baseline rate is the lowest rate charged; then as you use more electricity the rate charged by the utility increases as shown in chart below. The basic idea is this: the more electricity you use the more you are charged per unit of electricity. The basic unit of electricity you are charged for is the Kilowatt-Hour or kWh. The utility company is trying to get you to conserve by charging a lot more if you use a lot or waste a lot of electricity. Low energy users pay less per kWh than high energy users. The idea is: if you use a lot of electricity then you pay more for your share than if you were a lower consumption user.
Here in San Diego Gas & Electric (SDG&E) territory there are 4 tiers for the rates you are charged for electricity.
Tier 1 - The first tier is called "baseline".
Tier 2 - The next tier is 100% to 130% of the baseline amount.
Tier 3 - The next tier is 130% to 200% of the baseline amount.
Tier 4 - The next tier is 200% and up of the baseline amount.
The baseline is an amount of electricity measured in kilowatt-hours (kWh) and you are charged one rate for this electricity. Then when your usage goes over this "baseline" amount and up to 130% of it (Tier 2) you are charged a slightly higher rate. Then when your usage goes over 130% of this "baseline" amount (Tier 3) you are charged a significantly higher rate. And similarly for when you go over 200% of the "baseline" amount (Tier 4).
It is very important to note that the Tier 3 & 4 rates are substantially higher than the Tier 1 and 2 rates for PG&E customers. And a solar power generating PV system will "shave off" the electric bill starting from the higher rates billed in Tier 4 and Tier 3 first. And eventually "shave off" the bill down to Tier 2 and then to Tier 1 if enough energy is produced.
This is important; because with Net Metering your total or "net" electricity used is reduced. Which means the electricity that the PV system generated is taken from the top of your usage which in effect removes the most expensive electricity used first. This is a big advantage. Your most expensive electricity is removed from your bill first.
To help understand the tiered electric rates here is an example to illustrate it. Imagine if:
the first 10 gallons of gasoline you purchase cost $3 /gallon
then the next 3 gallons cost $3.50 /gallon
then the next 7 gallons cost $8 /gallon
and anything over 7 gallons cost $9 /gallon.
Wouldn't you rather try to not use the $9 /gallon and $8 / gallon gasoline first or get it another way? That's exactly what solar electricity does with your tiered electric rates. It removes the most expensive electricity first. So if you are trying to maximize your savings then you want to size your solar system so that it gets rid of (or "shaves off") the electricity that would be charged in the Tier 3 and Tier 4 rates. This will improve your payback period and rate of return.
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