15 Must-Know PV Solar Terms
Photovoltaic (PV) solar energy has its own language and terms and understanding them can be confusing to anyone who is not part of the daily operations of solar energy. To help you understand the terms, acronyms, and phrases regularly used when purchasing or using solar energy, Uptown Energy Solutions has created this handy reference guide. Here you’ll find valuable information allowing you to comprehend the various terms used concerning solar energy effectively.
The flow of electrical energy (electricity) in a conductor, measured in amperes (a.k.a. Amps, abbreviated as simply A). In order to better understand the difference between electric current and electric voltage, it can be helpful to imagine a water hose - current is the flow of water (representing the flow of electrons in this analogy), and voltage is similar to the water pressure in the hose which is driving the flow. The amount of current (flow) for a given voltage (pressure) is determined by the amount of resistance being applied to that flow (i.e., the size of the hose).
Alternating Current (AC) vs Direct Current (DC).
Alternating current is a type of electrical current, the direction of which is reversed at regular intervals or cycles. In the United States, the standard is 120 reversals or 60 cycles per second. Most electricity transmission networks use AC because voltage can be controlled with relative ease, and power loss over a given conductor length can be minimized. Before it can be used for certain applications such as charging a battery for your cell phone or automobile, AC must be converted to direct current, its opposite. Direct Current is a type of electric current which flows in only one direction through the conductor, usually at a relatively low voltage and high current. Before it can be used for typical 120 volt or 220-volt household appliances, DC must be converted to alternating current.
A kilowatt is a standard unit of electrical POWER equal to 1000 watts. A watt (W) is equivalent to one ampere under an electrical pressure of one volt and is calculated as the product of voltage (Volts) and current (Amps) [so, 1 W = 1 V x 1 A, and 5 kW = 500 V x 10 A].
A kilowatt-hour is the most common way we measure electrical ENERGY production (or consumption) and is equal to 1,000 Watts acting over a period of one hour. This energy measurement is calculated by multiplying the amount of power consumed (Watts) by the length of time that power is being consumed in hours [so, 1 kWh = 1,000 W x 1 hr, and 600 kWh = 600 W x 1,000 hours]. If you were to look at your electric bill, you should easily be able to find how many kWh of electricity you consumed over your billing cycle and what tariff rate your electricity provider is charging you (look for a number in the form of $0.XX / kWh).
Photovoltaic (PV) Solar Cell.
The smallest element within a PV module which performs the immediate conversion of light into electrical energy, also simply called a “solar cell”. Each PV solar module (a.k.a. solar “panel”) is creating by connecting many individual solar cells (typically 60 or 72 cells) and laminating them together. Photovoltaic solar cells produce electrical energy in the form of DC current and DC voltage.
Crystalline silicon solar cells.
A type of photovoltaic cell made from a slice of single-crystal (a.k.a. “monocrystalline”) silicon or multi-crystal (a.k.a. "polycrystalline") silicon.
Thin Film solar cells.
Solar cells made from a layer of semiconductor material, such as copper indium diselenide (CIDS) or gallium arsenide, which is a few microns or less in thickness. Thin-film solar cells and modules are typically less efficient than crystalline silicon products, but in some cases can operate at a lower overall LCOE due to economic or environmental factors such as operating temperature. Thin-film solar products can be found in either flexible or rigid form-factors.
Building-Integrated Photovoltaics (BIPV).
A term for the design and integration of photovoltaic (PV) technology into the building envelope, typically replacing conventional building materials. This integration may be in vertical facades, replacing glass or other facade material; into semi-transparent skylight systems; into roofing systems, replacing traditional roofing materials; into shading "eyebrows" over windows, or many other building envelope systems.
Standard Test Conditions (STC).
Conditions under which a module is typically tested in a laboratory or factory setting. Specifically, STC testing is typically performed by controlling lighting (incident radiation) and operating temperature conditions while recording power output. These test conditions are useful for creating a baseline which we can use to compare different solar cells/modules/arrays manufactured by different companies, but are not necessarily equal to the amount of power or energy being produced under real-world conditions.
A device that converts direct current (DC) electricity to alternating current (AC) electricity. For PV solar applications, the two primary forms of inverter are String inverters and Microinverters. A String inverter is a device which will take in DC electric energy from multiple PV modules connected together and convert it to AC electrical energy all at once. A Microinverter is a device which will take in DC electric energy from a single PV module and convert it to AC electric energy to then be joined with the AC electricity being produced by all the other microinverters in the solar array. Since microinverters are only used for converting the energy from a single PV module, they are much smaller than string inverters and can be installed directly onto the back of the module. String inverters will typically feature higher efficiency ratings (~99%) than microinverters (~95%) since they are usually able to operate at lower temperatures; however, microinverters can be advantageous since they allow the rest of the modules in an array to continue operating at full capacity even after a single module or microinverter has failed.
An electronic component which controls the DC voltage coming from a photovoltaic module to tune the output to match the performance of the other modules in the array and achieve maximum power production. DC optimizers are similar to microinverters in that they are small devices installed directly onto the back of the module; however, they do not invert the DC electricity to AC electricity. Rather, DC optimizers are typically used in conjunction with string inverters with the desired effect being “best of both worlds” performance.
A billing mechanism that credits solar energy system owners for the electricity they add to the grid. For example, if you have a PV system on your home's rooftop, it may generate more electricity than your home is consuming during daylight hours. If the house has a bi-directional meter installed, the electricity meter will run backward to provide a credit against what electricity is consumed at night or other periods when your home's electricity use exceeds the system's output. In this way, customers are usually only billed for their “net” energy use; however, some utilities can only credit their customers’ accounts for a small fraction of the value of the electricity they export to the grid. In these situations, it can be advantageous to consider installing an energy storage device (battery) for the home or business.
Net Zero Energy Building.
A building with zero net energy consumption, meaning the total amount of energy used by the building on an annual basis is equal to the amount of renewable energy created on the site. These buildings consequently contribute far less overall greenhouse gas to the atmosphere than similar non-ZNE buildings. They do at times consume non-renewable energy and produce greenhouse gases, but at other times reduce energy consumption and greenhouse gas production elsewhere by the same amount. These are not the same as “off-grid” buildings, which are completely disconnected from the larger electricity distribution network and never consume energy which is not produced on-site.
Some residential customers, and many commercial and industrial customers pay electric bills that have two primary components: energy charges and demand charges. Energy charges are based on the total amount of energy used during a billing period (typically one month long), and these are calculated on a $/kWh basis. Demand charges, however, are based on the peak instantaneous power a customer will draw during a billing period and are typically measured on a 15-minute interval. The “high water mark” for a customer’s power draw sets the demand charge for the entire billing period, and Demand charges are billed on a $/kW basis.
Levelized Cost of Energy (LCOE).
The cost of each unit of energy that is produced by an electric generator, whether that generator is fuelled by renewable sources such as wind or solar energy, or by non-renewable fuel sources such as coal, natural gas, or nuclear. In each case, LCOE is calculated by considering the system's total lifetime cost (including construction, operations and maintenance expenses), and its lifetime electricity production.
If you’re looking for the best full-service solar energy brokers in Orlando, FL, reach out to the experts at Uptown Energy Solutions. We offer our services across Orlando, Windermere, Lake Nona, Lake Mary, Doctor Phillips, Tampa Bay, and Melbourne, FL. We know that everyone’s project conditions and requirements are different, so we’ve created a no-conflict solar company where we put our clients’ best interests first. We’ll provide you with a solar expert, specifically trained in the state of Florida, to act as your personal guide through the industry so you can stay focused on the things you know and love, and still invest with confidence.