|
Image Credits: OFC Pictures/shutterstock.com
There are several different types of energy that can be generated by solar panels, the first of which includes passive solar energy, which can be accessed directly, such as when sunlight enters a window and warms the interior of the house. Active solar energy instead captures the energy from the sun and enhances it through various mechanical systems. While active and passive energy can both be incorporated into a building’s design, active solar energy is commonly discussed when referring to electricity generation.
The two primary systems capable of converting sunlight into active solar energy include photovoltaic (PV) and thermal solar energy systems. Solar thermal energy systems often utilize thermal collectors, which are often in the form of flat panels or tubes located on building rooftops, and a pump to deliver converted solar energy as heat to a water storage tank. The heated water within this tank is connected into the building or home’s main water system and can be easily accessed as needed. By reducing the need to use boiler or water heaters in the home, residents are able to benefit from significantly lower utility bills.
In PV systems, sunlight is directly converted into electricity through the use of numerous solar cells that combine to form larger solar panels. PV technology can provide electricity for both residential and commercial buildings, such as by providing power for security lights and air conditioning. In addition, PV cells can also generate power for pumping water, electrifying fences or aerating ponds. This article primarily discusses PV technology applications.
Why Use PV?
The sun generates enough clean energy in one day to provide a year’s supply of energy for your home or office. Why not tap into this abundant resource of clean energy? By utilizing PV technology, the earth's finite fossil-fuel resources-coal, oil, and natural gas sources are preserved while simultaneously reducing air and noise pollution that is often associated with the extraction of these energy sources. Consumers and businesses can also benefit from PV technology, particularly because of the cost-efficiency of this electricity alternative.
Recent technological breakthroughs, combined with federal and state programs and incentives, have greatly reduced the cost of PV ownership. PV system reliability and durability are outstanding; in fact, typical PV systems are expected to last 30 years with minimal maintenance.
What are the Different Types of PV Systems?
There are three different types of PV systems, which include grid-tied, grid/hybrid and off-grid systems.
Grid-Tied Systems
A grid-tied solar panel system involves connecting solar panels directly to the electrical grid of the home or building. While this type of system does not include a battery for energy storage, users can selectively acquire their energy from the solar panel system during sunny days or from their electricity grid on cloudy days or at night.
The main components used for grid-tied solar systems include a grid-tie inverter (GTI) or micro-inverters and a power meter. Like all solar inverters, GTIs regulate the voltage and current received from the solar panels, as well as synchronize the phase and frequency of the electrical current to easily fit into the building’s internal grid. Micro-inverters work in a similar manner; however, these components are often more efficient and more expensive than traditional GTIs. Additionally, power meters are used to measure the power that is entering and leaving the grid.
Off-Grid Systems
Off-grid solar panel systems require the use of a battery storage system, as well as a backup generator for individuals living off-the-grid. For these types of systems, the battery banks are typically very complicated to operate, expensive to purchase and must be replaced after 10 years of use. For these reasons, off-grid solar systems are rarely incorporated into residential homes.
Hybrid Systems
Since most people are working outside of the home during the day, they are often unable to benefit from solar energy that has been acquired through grid-tied solar panel systems. By combining the technologies of both grid-tied and off-grid solar systems, hybrid systems, which can otherwise be referred to as a grid-tied solar system with additional battery storage, are often less expensive than off-grid solar systems.
The main components that are incorporated into hybrid solar systems include a charge controller, battery bank, an additional DC disconnect cord, a battery-based GTI and power meter.
How Can I Use PV in my Home or Business?
Today's PV systems can be incorporated into virtually any type of building ranging from homes to commercial buildings. Additional uses for PV systems can be found outdoors for powering security lighting in gardens, parking lots, and bus shelters. Inside family homes or high-rise office buildings, PV systems can be used for the operation of all electrical systems, including lights, cooling systems, and appliances.
PV systems should be sized according to the electricity needs and budget of the applied building. In general, PV systems in buildings are sized in a way that ensures the solar system can either fully or partially meet the load of the building.
If a home or building is already connected to a power line, users may be able to get credit for their “net” electricity; which is the amount of power consumed from the utility subtracted from the power generated by your PV system, through an arrangement known as “net metering” that has been made with local electric utility companies.
What does a typical PV system look like?
A typical PV system consists of solar cells connected electrically to form a module that can measure two to four feet wide and four to six feet long. Some solar modules look just like traditional roof shingles. Many interconnected PV modules are called an array. An array is often mounted on the roof of a building, facing the sun (south in the northern hemisphere – north in the southern hemisphere) at an angle, so that the modules receive the maximum amount of sunlight. You can also mount the array on a tracker so that it moves to follow the sun, allowing the modules to capture the most sunlight over the course of a day. Other typical features of a PV system are an inverter, which changes your electricity from direct current to alternating current so it can be used by most standard appliances and computers. Batteries may also be added for emergency backup in the event of power outages or in cases where your PV system is not connected to utility power lines.
How can I use PV in my home or business?
Today's PV systems can be incorporated into virtually any type of building ranging from homes to commercial buildings. Additional uses for PV systems can be found outdoors for powering security lighting in gardens, parking lots, and bus shelters. Inside family homes or high-rise office buildings, PV systems can be used for the operation of all electrical systems, including lights, cooling systems, and appliances.
PV systems should be sized according to the electricity needs and budget of the applied building. In general, PV systems in buildings are sized in a way that ensures the solar system can either fully or partially meet the load of the building.
If a home or building is already connected to a power line, users may be able to get credit for their “net” electricity; which is the amount of power consumed from the utility subtracted from the power generated by your PV system, through an arrangement known as “net metering” that has been made with local electric utility companies.
Is My Home or Office Building a Good Place for a Solar System?
A PV system requires unobstructed access to the sun's rays for most or all of the day, throughout the year. Since PV modules are relatively unaffected by severe weather, it is not imperative to factor climate into the decision to install solar systems. In fact, some PV cells have been shown to actually work better in colder weather. PV modules are angled to catch the sun, not snow; therefore, any snow that does collect will quickly melt.
Most residential systems require as little as 50 square feet, which is typical for a small starter system, to as much as 1,000 square feet for larger systems. While this may be true, it is important to remember that an energy-efficient building will require a smaller PV system. For example, a typical one-kilowatt system would occupy from 80 to 360 square feet.
Although PV systems can be installed on any type of roof, some roof types are simpler and cheaper to work with than others. For instance, if the roof of a building or home is older and will need to be replaced in the near future, it may be worth considering replacing the roof at the same time of installing the PV system in order to avoid the cost of removing and reinstalling the PV system.
How can a PV dealer help?
PV dealers can help homeowners and building managers to:
- Ensure that panels will access the most amount of sunlight available in a given geographic location
- Determine the kind and size of PV system a building will require
- Provide cost analyses of PV systems compared to traditional utility systems
- Install and maintain PV systems throughout their lifetime
- Assist with permitting issues, such as building and electrical permits
How Much Does a PV System Cost?
The price of any PV system will depend on a number of factors, some of which include the system’s size as well as the energy efficiency of the residential home or office building. As of January 2019, the average solar panel cost was $3.05 USD per watt. Since the average solar panel system used in the United States is around 6 kilowatts (kW), the average solar panel system would amount to approximately $13,000 USD, after the customer received tax credits for their purchase. PV system sizes can range from 2 kW to as much as 25 kW.
Before determining the adequate system size, it is recommended that individuals interested in purchasing a PV system for their home or business first try to reduce the energy consumption of their respective building by making it more energy efficient. Ultimately, both commercial and residential PV system costs will depend on the system's configuration, equipment options, and other factors, such as how the customer will incorporate the PV system into the building's architectural design. Local PV suppliers can provide customers with accurate estimates or bids during this process.
What Incentives are Available to Help Reduce the Cost?
Depending on the location, certain states and municipalities have incentives available to help offset the cost of PV systems, or otherwise, make them easier to finance. These incentives may include tax credits, state grants and/or low-interest financing packages. Additionally, some businesses may be entitled to a federal tax credit and accelerated depreciation on the PV system. These tax benefits can substantially reduce the effective cost of a PV system, and should, therefore, be thoroughly investigated. It is recommended that individuals interested in purchasing a PV system for their home or business contact their local energy office to determine what grants and incentives are available.
How Can I Finance the Cost of my PV System?
Depending on the location, several financing options are available for individuals interested in purchasing a PV system, of which include new state and federal programs, as well as tried-and-true financing approaches, such as mortgage loans. Mortgage financing options include a primary and/or secondary mortgages, such as a U.S. Department of Housing and Urban Development Title 1 loan, or a home-equity loan that is secured by your property. If mortgage financing is not available, other sources of financing may also be available, such as conventional bank loans. Since any type of PV system is a long-term investment, the terms and conditions of a given PV financing agreement will likely to be the most important factor in determining the effective price of your PV-generated power.
|