PHOTOVOLTAIC CONNECTIONS TO A UTILITY GRID AND NET METERING

Although some homeowners have only a photovoltaic system attached to their home, many solar-powered homes and businesses are connected to transmission power lines outside their homes and businesses. The transmission lines are part of a grid system owned by a utility company. Using grid-connected photovoltaic power can have economic as well as environmental advantages for the homeowner. 


Because such homeowners are using much of their electricity from their own photovoltaic system, the amount of electricity they have to purchase from the utility company each month is reduced. In this cooperative arrangement, the homeowners get some of their power from their photovoltaic systems and some from the utility company’s grid.

What Is Net Metering? 

Net metering is a simple way of metering the energy consumed and produced at a home or business that has its own renewable energy generator, such as a solar energy system. 

Net metering enables homeowners to use their own generation of electricity to off set their consumption over a billing period by allowing their electric meters to turn backward when they generate electricity in excess of their demand. Th is program means that customers receive retail prices from their electrical utility company for the excess electricity they generate. A retail price is the price at which a utility company sells the electrical power to a homeowner or other consumer. 

Without net metering, a second meter is usually installed to measure the electricity that flows back to the provider, a utility company that purchases the power at a rate much lower than the retail rate. As of 2010, net metering for homeowners is available in 42 states. 

John F. Mongillo
A Student Guide to Energy 
Copyright 2011
Greenwood Publishing Group
Volume 2 Solar Energy and Hydrogen Fuel Cells


(For solar energy solutions and supplies visit our website: www.eastgreenfields.com or email us at inquiry@eastgreenfields.com)   

A BRIEF HISTORY OF SOLAR ENERGY

The early Greeks and Romans used passive solar energy to warm up the rooms in their homes. The Romans covered south-facing openings in the inside walls with glass or other transparent materials to keep in the heat, particularly during the winter months. 

In the 1830s the British astronomer John Herschel used a solar box, similar to today’s solar oven, on a trip to Africa to cook his food during his stay. Later in the 19th century, European scientists developed large cone shaped collectors that were used to boil ammonia for use in refrigeration plants and for other products. 

In the United States, John Ericsson did much research to harness solar power. He designed the parabolic trough collector, which operates much like the parabolic trough collectors we have today. (Parabolic trough collectors are discussed further in chapter 2.) 

William Adams used mirrors and the energy of the sun to help power a steam engine during the 1870s. His design, called the power tower concept, is still in use in the 21st century. (Solar power towers are discussed in chapter 2.) 

In the 1950s Gerald Pearson, Calvin Fuller, and Daryl Chaplin of Bell Laboratories (now AT&T Labs) discovered the use of silicon as a semiconductor. 

In the 21st century, Silicon, an element, is utilized as a major ingredient in the production of solar cells and solar panels. In 1953 the same three scientists developed the first silicon solar cell. Th e cell generated small measure of electric current. In the 1950s and 1960s, satellites and spacecrafts used solar panels for electricity. In the early 21st century the photovoltaic market is growing by 30 percent per year, as the costs of manufacturing the cells decrease.

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John F. Mongillo
A Student Guide to Energy 
Copyright 2011
Greenwood Publishing Group
Volume 2 Solar Energy and Hydrogen Fuel Cells