Photovoltaic cells were developed at Bell Laboratories in the early 1950s. Thin layers of silicon are impregnated with tiny amounts of other elements in order that when exposed to sunlight, electricity is produced.
What is an inverter?
An inverter is a power converter that converts low-voltage direct current (DC) into the alternating current (AC) power that is needed by lights and appliances. There are two types of inverters: central inverters (wall-mounted) and micro-inverters. Each microinverter attaches to the racking beneath the solar module and performs DC to AC conversions on a per-module basis. At Black Platinum Solar we install Enphase Energy microinverters, which provide customers with many advantages.
What is a grid-tied system?
Grid-tied systems do not use batteries at all. The panels work by producing DC power during sunlight hours, then converting it to AC power through the inverter. The inverter then feeds the energy loads required by the home, before pushing the AC power out to the grid through the "net meter." The net meter is provided by your utility company when you install the system. The net meter is a bi-directional electric meter that spins forward when you are using more power in your home than you are producing with your panels (at night, for instance), and spins BACKWARD when you are producing more electricity with your system than you are using in your home. This is how you generate credits with your utility company!
Do the solar panels need to face south?
South is best, but panels installed facing southeast or southwest still generate a very high percentage of possible power. It is usually more effective (and more attractive) to install the panels in the same plane as the roof direction, rather than build an awkward mount to angle them.
What happens if the panels are shaded?
In general, photovoltaic panels should be installed in areas where they get significant shade-free sun every day. Even small amounts of shade can very significantly reduce the output. Our designs and installations also seek to minimize the impact of any shade issues through selection of the proper equipment. With a central inverter system, minor shading on one panel will significantly affect the power output from the whole array. However, using microinverters, with each solar panel operating independently, the shading on one panel will only affect that panel.
What is Net Metering?
Net Metering is an electricity policy that allows utility customers to offset some or all of their energy use with self-produced, renewable energy. Net metering works by utilizing a meter that is able to spin and record energy flow in both directions. The meter spins forward when a customer is drawing power from the utility grid (i.e., using more energy than he/she is producing) and spins backward when energy is being sent back to the grid. At the end of a given month, the customer is billed only for the net energy used. Exact provisions vary with each state, but the effect is to allow you to generate excess power during the day, and use it at night, without needing batteries.
What maintenance is required on an installed solar power system?
Because they have no moving parts, they are virtually maintenance free. If you live in an area that doesn't get much rain, just keep them clean by spraying them off with a hose before sunrise or after sunset. Never spray hot solar panels with cold water.
If I sell my property, what effect does PV have on the sale price?
Energy conservation and renewable generation adds value to a home. Surveys have shown that for every $1,000 saved per year, $20,000 is added to a home's value. Solar energy can be one of the best home improvement investments you make. Arizona Public Service has estimated that a solar installation can increase the value of a home as much as $25,000 or more. (Note: No one should put in a solar system if they're thinking of selling their home in the next few years because there won't be enough time to recoup the cost of the system.)
How much does a typical residential solar system cost?
While system sizes can vary greatly, typical residential solar systems will have a post-incentives cost between $11,000 and $35,000, depending on the complexity of the system.
How long does a solar system take to pay for itself?
This depends on a number of factors including your current cost of electricity, the rate structure of your electrical service, the incentives available to you, and the cost of financing, if it's necessary. When paying cash, a typical residential system may see a simple payback in 8-12 years. If you are financing the purchase of your solar system, you may see immediate positive cash flow or you may initially see a slight negative impact on monthly cash flow when factoring the cost of the loan against the initial savings. As electrical rates increase, and with your loan payment staying fixed, you will eventually see positive cash flow, a break even point, and then a positive rate of return. Financed systems typically either see immediate positive cash flow or will attain positive cash flow within three years or so. See our Financing Your PV System page for more information.
Do the solar modules need to mount on the roof?
No. Though the roof is the most common location for mounting solar modules, they can also be mounted on the ground or in other architecturally integrated ways, such as in roof tiles or shade structures. Ground-mounted systems tend to cost more than roof-mounted systems because of the need for trenching, concrete footings, engineering and (typically) a steel sub-structure. Ground-mounted systems are, however, viable and common.
How long will a solar system last?
The solar modules are typically warranted for 20-25 years but have a design life of more than 40. There are modules still operating today that were manufactured in the 1970s. Central inverters are typically warranted for 10 years, and microinverter systems for 25 years. A conservative set of assumptions when considering the long-term financial performance of your Enphase microinverter system is to figure the performance at 30 years.
What kind of maintenance does a solar system require?
Washing the solar array with water a few times a year is a good idea but not strictly critical. Most good solar designers have factored the effect of seasonal dust on your projected system output over time. Occasional visual inspection of the array is wise in order to identify any serious soiling of the array such as significant bird droppings or other types of opaque soiling. Enphase Enlighten monitoring allows you to check the integrity of your PV components from your personal computer (or smart phone) 24/7
Will a solar system provide power during an electrical power outage?
Grid-tied solar electric systems do not provide electrical power during electrical power outages. As a requirement of a grid-tied inverter's safety listing, it must shut down in the event of grid power loss.
How do I plan for a solar system when building a new home?
You can have your new home, or addition, "pre-wired" for solar during the building stage. This provides an opportunity to easily install the system when you are ready. Many builders/developers are also going this route. If you are in the process of designing a new home, we can run conduit and pre-wire for solar at the rough-in electrical stage (before drywall goes in). This way, all wires are hidden in the walls, ready for use when it's time for your solar installation.
Where do I find the Federal Income Tax Residential Energy Credits (Form 5695)?