100 Blackout!-Low

Blackout! FOCUS Question What are blackouts, and why do they occur?

Lights Out! What do you do if the power goes out? Light candles? Carry a flashlight It can be kind of exciting when the electricity is out for a few minutes but imagine if it goes out for days or even weeks! A long-lasting widespread power outage is a blackout, and it gets old pretty fast. Some blackouts are caused by severe weather that takes down power lines. Other blackouts happen due to periods of high demand for electricity. Computers that run power systems are also vulnerable to technical glitches and cyber attacks. A cyber attack happens when a computer virus is used to shut down or disable one or more power plants. During a blackout, an entire country can lose power.

Blame It on the Grid The system that delivers electricity to your home is called a grid. Electrical grids are made up of power plants that produce electricity and countless miles of power lines, or transmission lines. To get from the power plant to your home, electricity traveling through the grid is high voltage. Transformers in the grid raise the voltage so it can travel long distances. Transmission lines deliver the electricity to additional transformers that lower the voltage and make it safer for neighborhoods. Distribution lines carry the electricity to houses. The trouble with many power grids around the world is that they are getting old, but the demand for electricity is rising. When parts of a grid fail, blackouts can occur. Word Wise Voltage is the force of an electrical current.

Blame It on the Weather Some of the worst blackouts are caused by huge storms. Strong winds, heavy rains, and falling tree limbs can knock down power lines. After Hurricane Katrina in 2005, electricity was out for more than three weeks in several U.S states. In 2012, Hurricane Sandy left people from Maine to Virginia without power for nearly two weeks. Winter storms can also cause blackouts. Snow and ice coat power lines, and the added weight can bring them down. Ice storms in the United States in 2008 caused blackouts from Maine to Pennsylvania and even as far south as Louisiana. A 2011 snowstorm left people in Connecticut and Massachusetts without power for more than a week. It takes time for utility crews to repair power lines and restore electricity.

Intentional Outages Sometimes electric companies cause blackouts on purpose by shutting off small sections of the grid, one at a time, to prevent a failure of the entire system. These are called rolling blackouts. In 2011, during a rare cold snap in Texas, people were using a lot of electricity to heat their homes. This high demand led to rolling blackouts for two days. Brownouts happen when the electricity continues to flow but the voltage drops. This causes lights to dim and can affect other electric devices. Electric companies use brownouts to reduce the load on power plants and prevent blackouts, but sometimes brownouts occur because of storms or system glitches.

A Year of Big Blackouts In August 2003, six states and parts of Canada went dark in the Great Northeast Blackout. High electricity use on a hot day caused a wire in a transmission line to heat up. The line's covering melted and weakened, then it snapped when a tree limb hit it. An alarm meant to alert workers of the outage never went off, so the same thing happened to other lines. In the end, fifty million people were without power for about two days. In September of that same year, parts of Switzerland and much of Italy lost power. Storms damaged a transmission line that brings electricity from Switzerland to Italy. Suddenly, there was increased demand on the lines that were still working. They became overloaded and failed as well.