PV arrays can be used to generate electric power for just about anything. The power systems can be either connected to the electric utility grid “grid tie”, or be "off-grid". The economics of the PV system are determined by both the capital and operating costs and long term benefits. The analysis varies according to the type of PV power system; off-grid, grid connected (non-interactive), and grid connected (interactive).
Off Grid PV
PV systems in California are currently cost competitive with electric utilities for many areas of applications such as: Situations requiring utility line extension at high cost (generally for extensions of over 0.5 miles, charged to the customer), remote cabins or homes that do not have access to conventional power suppliers or applications. Another common use is for small power use equipment such as roadside call boxes, irrigation control equipment, small lights, etc. In most cases it is more economical in the long run to provide PV power than to install conventional power if there is not a conventional power source within a reasonable distance. An added benefit is, once the PV system is paid for you continue to produce free power for many years which can save a significant amount of money.
Grid Connected PV
Government subsidies, tax rebates/exemptions, the time of day value of summertime PV power, the enhanced value of "Green" power to a utility, has made PV systems practical in California and Arizona.
Grid connected PV systems can be of two major types, grid connected (non-interactive), and grid connected (interactive). An interactive system uses inverters that are capable of converting the DC power from a PV system into AC power. That power can be fed back into the utility system providing it meets the power quality required by utility companies. A non-interactive PV system can only use utility power to supplement the PV system and is not capable of feeding power back into the utility electric grid.
Net Metering
Net metering is a practice offered by some electric utilities to help encourage PV system interconnection. With net metering the homeowner can offset some of the costs of purchased electric power by feeding surplus electric power back to the utility. This is an interactive PV system as described above. The net period can be monthly or annual (depending on applicable laws, regulations, and utility policy). Typically a PV system produces more power during the peak sunshine period of the day than the home can use at that time. In a grid connected system with net metering, the value of the excess power that is fed back into the utility system is deducted from the customers billing invoice. This is generally an offset to the purchased power such as nighttime use when the PV system is not producing power.
COMMON QUESTIONS
How Much Does a Solar System Cost?
Currently installed cost is about $8 to -$9 per watt, before incentives. Incentives can include rebates, State tax credits, State sales tax exemption and in some cases Federal tax credits and accelerated depreciation, all of which significantly reduce the overall cost of a photovoltaic system.
What is the Payback Time?
With a solar PV system you are buying power at a known fixed cost of today's market. Payback can be calculated by the estimated future energy cost which is impacted by supply, inflation rates, and other market factors. The other variable is how the system is financed and the cost information listed above. Our company offers a variety of financing options.
Can the Meter Spin Backwards?
Yes, if more energy is generated than used, it is fed back into the utility grid. The owner of the PV system is compensated by having the cost of the power generated deducted from their monthly utility statement. It is common for the utility company to settle up at the end of each 12 month period. The compensation rate depends on the utility company and State requirements and law.
What size system do I need?
There are several variables that determine what size system you need and in the end, what size system you will be able to install.
Determining what you need:
If you install a PV system in California the utility company will “credit” your account for energy produced each month. You will receive a statement each month that shows where you stand. You may produce more than you use during the long days during the months of summer, then produce less than you use during the short days of winter. On the end of each twelve month period a settlement statement is sent. At this time, if you have produced more power than you have used during the 12 month period, you do not receive any money for it. The cycle simply starts over again from zero. There are Legislative Initiatives being considered that may someday require utility companies to actually buy any excess power that is produced by individuals. However, for now we want to prevent overproduction so we go through the following steps to design a system that is right for you. We first request a spread sheet from the utility company that shows at least 12 months of kW hours billed to you. That figure is divided by twelve to give us an average per month. We then size your system to produce the same or slightly less than the average amount of power previously used. We strive to design systems that come as close to meeting all of our customers needs as possible without “giving” additional power to the utility company to sell to someone else. You do not want to pay for something that will not be of direct benefit to you. However, all of our PV systems can be added to at a later date. So, if Legislation is passed that requires PV owners to be paid for excess power produced, our customers can add to their systems if they choose to produce and sell excess power to the utility company.
Determining what size system you can accommodate:
On occasion we find that a customers needs are for a larger system than they have room for.
Solar systems should be installed so as to face true south with a tilt of approximately 30 degrees for optimum power production. Minor deviations from these ideal conditions will usually reduce power production by 5% or less. However, shade issues can substantially reduce production. It is important that you have an installation location that is as free of shade as possible and allows a southern facing installation. If your solar array location is not within acceptable parameters, the production will not justify the cost. This is a very important factor in realizing an acceptable payback period for your investment.
Typically solar systems are installed on roofs, patio covers, carports, and on ground mount systems. However, you may not have enough space to install the size system you need. Many of the newer homes have many pitches and angles making it very difficult to fit a properly directed system large enough to meet the household needs. If this is the case, you may opt for a smaller system that will still significantly lower your utility bill. Or, if you have the room, our general contractor can build a variety of patio covers or ground mount racks that will accommodate a solar system. Our photo gallery will give you an overview of typical installations that we have done.
