Below, we offer a few short definitions and explanations of key terms that tend to be tossed around in discussions about solar and electricity and EVs and PHEVs.
As elsewhere on our pages, our primary aim is to help push solar-charged driving into the mainstream, by reducing, as much as possible, the perception of solar-charged driving as something only “techno-geeks” can figure out and do.
electric grid (“the grid”): the power deliver system that brings electricity to homeowners, businesses, etc. Power stations and high-tension wires draped over large metal towers are among its most visible components.
energy payback time: the amount of time it takes for a single solar panel to produce as much energy as it took to make that solar panel in the first place. Typical energy payback time for an individual solar panel is 18 months to three years.
EV (Electric Vehicle): an EV is a vehicle completely powered by electricity stored in a battery pack located in the EV. The battery pack can be recharged by plugging it in.
feed-in tariff: a government instigated financial incentive system designed to encourage the adoption and use of solar energy. Requires utilities to pay customers for solar-generated electricity at above-market rates set by the government. Germany has perhaps the most well-known feed-in tariff system, though many other countries have seen feed-in tariffs instigated in certain states, cities, counties, etc. This includes some locations in the United States.
grid-tied vs. off-grid solar system: a grid-tied solar system produces electricity that can flow back into the general electric grid; it requires living in a location that allows for net-metering. An off-grid system is a stand-alone solar system not connected to the general electricity distribution system. It typicallyrelies on a battery pack to store electricity for use when sunlight is low, or non-existent.
grid parity: the point at which the total cost of electricity produced by renewable means is equal to, or cheaper than, electricity produced by other energy means (fossil fuels, nuclear, etc.)
kW (kilowatt): a kilowatt equals 1,000 watts. A watt is a standardized unit of power in the International System Units used to measure rate of energy conversion. One watt equals one joule of energy per second. Joules are the fundamental energy unit in the International System of Units measurement system.
kWh (kilowatt hour): a standardized unit of measurement to gauge electric energy output. One kilowatt hour equals 3.6 “megajoules.” Joules are the basic energy unit in the International System of Units measurement system. The kilowatt hour is often used by electricity providers for billing purposes, as it conveniently measures the energy consumption of residential consumers. One kilowatt = 1,000 watts. If a 100-watt light bulb is on for one hour per day for 30 days, the energy used is – 100 watts x 30 hours = 3,000 watt hours = 3 kWh.
lithium-ion batteries: lithium-ion batteries (sometimes abbreviated Li-ion batteries) are a type of rechargeable battery in which lithium ions move from the anode to cathode during discharge, and from the cathode to the anode when charged. This movement produces energy, which then can be tapped for a variety of purposes.
miles per kWh: the number miles an EV or PHEV in battery mode can travel on kilowatt hours. Typically, EVs (and PHEVs in battery mode) get 4 miles per kilowatt hour (kWh).
net metering: with net-metering, one’s electricity meter records energy use in both directions – outflow when one’s home solar system is over-producing, and inflow when it is “under”-producing (for instance, at night). In the U.S., net-metering is available in 44 states and the District of Columbia. However, it is not necessarily universally available within these states.
photovoltaic cells (PV cells): PV cells convert energy from the sun into electricity. PV cells produce DC (direct current) power which must be converted into AC (alternating current) power by a solar inverter. PV cells differ from solar thermal collectors, which are used to heat water for hot-water heaters, swimming pools, etc. In contrast to PV solar systems, solar thermal collectors do not convert sunlight to electricity. Instead, they heat fluids. One can often tell if a home has a PV system or a solar thermal collector by the appearance of the panels. PV solar panels typically are smaller, and thinner, are less likely to be on tilt poles, and are typically characterized by a series of rectangular grids bounded by thin metallic-looking “lines”.
PHEV (Plug-in Hybrid Electric Vehicle): a hybrid car with a battery-pack system that allows the car to run fully on energy stored in the battery pack over a given distance before the car switches to combustible engine mode (which then works to recharge the battery).
solar inverter: a type of electrical inverter that converts the DC (direct current) electricity produced by a PV solar system into the AC (alternating current) required to power electrical appliances and, in cases of a grid-tied PV solar system, to send excess energy generated by the system back into the general electric grid.
PV (solar) module/panel: an interconnected grouping of PV cells, often referred to as solar cells. Solar installations intended to produce significant electrical power capacity require an installation of several modules or panels. This is called a photovoltaic array.
solar-charged car: an EV or PHEV whose batteries have been partially or fully charged by solar panels located on a home, building, garage, solar carport, on a metal frame in a field, etc.
solar-charged driving: describes the activity of driving an EV or PHEV whose batteries have been partially or fully charged by solar panels located on a home, building, garage, solar carport, on a metal frame in a field, etc.
solar-powered car: a broader term than solar-charged car. It can describe both a solar-charged car whose batteries have been partially or fully charged by solar panels located on a home, building, garage, solar carport, on a metal frame in a field, etc. and/or cars which have solar panels on them.
solar-powered driving: a broader term than solar-charged driving. It describes the activity of driving an EV or PHEV whose batteries have been partially or fully charged by solar panels located on a home, building, garage, solar carport, on a metal frame in a field, etc. and/or the activity of driving an EV or PHEV that is partially powered by solar panels located on the car itself.
solar system capacity: the maximum amount of energy a given solar system can produce.
solar system monitoring: the ability to monitor one’s solar system through computerized software. Many solar companies offer computerized system monitoring – but they typically charge extra for it, and, unfortunately, it can be rather expensive.
Sun Miles™: SolarChargedDriving.Com uses this term to refer solar-powered miles driven by an electric vehicle (EV) or plug-in hybrid electric vehicle (PHEV) whose batteries have been charged using solar energy.
watt: a standardized unit of power in the International System Units used to measure rate of energy conversion. One watt equals one joule of energy per second. Joules are the fundamental energy unit in the International System of Units measurement system.