Solar power makes use of the most renewable energy source there is – the sun. Power generated by solar panels is produced without the risk of atmospheric emissions and, once a solar system is installed, energy costs are markedly lower than standard electricity from the utilities. Understanding the technical details of solar energy and power in general can be quite challenging to newcomers in the field, in particular the jargon, acronyms, and often confusing names that engineers and scientists have created over the years. Many of the units used to express the characteristics of a particular system are expressed as abbreviations. Some of these are straightforward; a photovoltaic system, for example, is often referenced by the letters PV, but the measurements of electricity are a bit more technical than that.
The terms AC and DC power are used in households and throughout industry. An alternating current, or AC, reverses direction at a regular basis and is commonly used by power grids because the voltage can be transformed to higher levels without much loss in energy. The current changes direction at a rate of 100 times per second at a frequency of 50 hertz, which is expressed as Hz. Solar power systems generate power in the form of direct current, or DC. This form is better suited for storage in batteries after it is produced by the solar modules. The size of the electric current is expressed in units called amperes; electricity may flow at currents of 20 or 30 A for example.
Voltage in power lines describes how much electrical pressure there is that enables the flow of electricity. Indicated by the letter V, it is multiplied by the amperes to calculate a measurement of total electrical power called watts, or W. A kilowatt (kW) is a thousand watts, while a megawatt, (mW) is a million. These units of energy often serve as measurements for how much power is used by consumers or which a utility provides. A kilowatt-hour (kWh) defines the use of 1,000 watts over an hour and utilities often use this measurement when billing customers.
The use of gas, oil, and coal to produce energy adds CO2 to the atmosphere. This is carbon dioxide, which is produced in such large quantities by power plants that it is part of the process of global warming. Just how solar energy contributes to climate protection is sometimes expressed as the tons or kilograms of CO2 per kWh of fuel saved. The electrical power of a solar cell, depending on the radiation from the sun, is often expressed as the Maximum Power Point, or MPP. This value usually depends on the temperature of the solar cell and the voltage produced; it is tracked continuously because it changes on regularly with temperature and power output.
Other abbreviations specific to solar systems include BOS, which stands for Balance of System. The BOS accounts for the design costs, installation, operation and maintenance, as well as support structures and batteries that comprise a PV system. A Building-Integrated Photovoltaic, expressed as BIPV, is the combination of materials in a PV installation that make up building elements such as roofs, walls, and windows. In addition, the LCC is the Life-Cycle Cost of a PV system, which includes the costs of owning, operating, and disposing of it. Another abbreviation you may come across is PPA, which is the Power Purchase Agreement between a power producer and consumer. It defines the agreed-to rate at which the consumer purchases a pre-determined amount of power. (We’ve done PPA systems for Hongwanji Mission School and Lighthouse Outreach Church.)
Making sense of common electricity abbreviations, in relation to solar power systems, helps to understand how they work and just how energy savings can be achieved.
If you have any questions about these terms or anything else to do with solar, that’s what we’re here for – contact us today!