Solar photovoltaic (PV) technologies convert the sun’s radiation to an electrical current that can be used to power a home or business. For customers that are connected to the electrical grid, these systems will push excess power onto the grid for which the owner receives a credit.
For homes without grid power or those looking to have a more secure power supply, PV systems are connected to batteries that store excess electricity. The electricity generated by a PV system can power lighting, household appliances, mini-split heat pumps, electric vehicles, and countless other electrical consumers.
Grid-tied solar electric systems utilize PV modules and inverters to deliver clean electricity. These systems first provide electricity to the electrical loads in the home or business. If the system generates more electricity than is being consumed, the excess is delivered to the grid. The utility measures the amount of electricity that the PV system delivers to the grid and provides a credit to the owner’s utility bill. In Maine, we have 12 months to use this excess electricity. Owners are not compensated for any surplus electricity that is generated during the 12-month cycle.
Grid-tied PV systems avoid the need for batteries, which create additional expense and maintenance. The tradeoff with a grid-tied system is that there is no stored energy in the home – at night, on a cloudy day, or during times of high use, electricity is purchased from the grid.
Battery storage can be incorporated with a grid-tied system to provide electricity when there is a power outage or to best utilize time-of-use electricity rates.
It is possible to install a system that offsets all of your electricity consumption through the net metering arrangement described above. Since these systems are modular, a smaller system can be installed based upon your budget or site limitations.
Off-grid PV systems utilize batteries to store electricity when there is sufficient solar radiation to satisfy the electrical demands in the home. The systems, also known as “standalone” systems, range from small systems for running emergency signs and lighting to systems that satisfy the full demands of a home or business. These systems are typically utilized in places where access to the grid is impractical or expensive. These systems are commonly used for seasonal cabins and homes located away from existing electrical infrastructure.
Some off-grid systems are supplemented by a generator that provides consistent power even when there is limited access to the sun. The demand for a generator depends upon the storage capacity of the battery bank, the electricity demand, and the ability for the PV modules to recharge the battery bank.
Due to the need for electrical reliability, the design process for off-grid system is very detailed and requires an accurate assessment of the electrical use at the site.
We provide the design and installation of certain off-grid PV systems and generators. Typically, our off-grid clientele are those who are looking for whole-house systems or larger camp systems. Due to the economics of designing and installing small off-grid systems, it is often difficult for us to attend to the design and installation of systems of one or two solar modules. If you are looking for guidance on a system to satisfy small electrical loads, we are willing to connect you with good resources for doing so successfully.
Sample some of our solar photovoltaic (PV) projects: