What's the Weather? —Warm Weather Hazards Return | Direct Energy Blog

What’s the Weather? —Warm Weather Hazards Return

Possibly the biggest factor effecting your electric bill is the weather. It not only directly influences how much you use to heat or cool your home but also effects the demand, supply, and ultimately the price of energy on the wholesale markets. In our What’s the Weather? series, we’ll track weather forecasts and events to see how they impact your energy bills and how that information can help you save.

What's the Weather? —Warm Weather Hazards Return | Direct Energy Blog

Warm Weather Hazards Return

When warm weather returns, every one looks forward to the sunshine, the blue skies, and outdoor fun. But warmer temperatures also bring the chance for violent storms. In April 2017, storms battered Texas, Missouri, Arkansas and Mississippi with tornadoes and floods tearing down power lines before rolling eastward to cause more storm damage in western PA.

The US sees about 100,000 thunderstorms each year and with any thunderstorm, the chief danger is lightning. In the first millionth of a second in a common lightning strike, a negative charge probes downward from the cloud. At the same time, a positive charge probes skyward. When they connect, up to one billon watts of electricity blasts upwards, turning the air into a 50,000°F plasma, ten times hotter than the surface of the sun.

When lightning strikes a home or building, it can enter by following wires and pipes that go into the ground. It can also travel through metal reinforcing wire or bars in concrete and explode. Lightning causes 4,400 home structure fires every year. To learn how to protect your home, check out the National Weather Service’s Lightning Safety website.

When lightning strikes power lines, it sends powerful electrical surges through electrical and phone lines. Less than one third of such transient voltage surges come from lightning strikes (either nearby or direct hits) — but they are usually the most powerful. Without protection, these can burn out appliances and other electronics.

Storm damage to power lines, meanwhile, from direct strikes, downed trees, or from the onslaught of the wind itself is expensive. With our economy more dependent on computer networks and online connectivity, storm-caused power outages are costing everyone. In 2008, FEMA estimated the repair costs per pole to be around $6,000. Repairs to transmission lines following the April 2011 outbreak of 153 tornadoes in the seven southeastern states served by the Tennessee Valley River Authority cost $200 million in lost power generation, sales and repair expenses. Overall, storm-related outages cost the US economy between $20 billion and $55 billion annually coming in the form of damaged electrical equipment, lost business due to power blackouts, and lost production.

What's the Weather? —Warm Weather Hazards Return | Direct Energy Blog

Teetering Reliability—Taking the Heat for High Demand

It’s not just violent storms that can threaten the electrical grid but also the combination of hot transmission wires and a hot afternoon. Even the best electrical wires possess a certain amount of electrical resistance, which produces heat. Strung out for miles and miles, a transmission line’s resistance can eat up a significant percentage of the electricity running through it. That can be thousands of volts all being converted to heat; it’s known as “line loss”. Power transmission companies must push more power through the lines to overcome the electrical resistance and to make sure that the required power makes it to the other end of the transmission line. In other words, it takes extra energy to transmit energy.

The trouble is, the higher the temperature of the wire, the higher the electrical resistance and the more power lost to more heat. So, during high electricity demand, transmission lines can get really hot from the electric load they are transmitting. Plus, on really hot days, not only is the sun baking everyone who wants to crank their air conditioning but also miles and miles and miles of electrical transmission lines. Again, hot lines mean higher electrical resistance, which raises the temperature of the lines even higher. In these cases, the transmission cables stretch and begin to sag towards the ground. If the line has too much tension between the towers, the heat and sag will cause it to snap and cause a power outage. If the line continues to sag, it could come in contact with tree tops or a structure and cause a short-circuit that would also result in a power outage. Over time with continual stressing and expansion, transmission cables will permanently stretch (called “creep”), which adds to the likelihood of their eventual breaking.

How bad can it get? On a hot summer’s day in August, 2003, the Great Northeastern Blackout was triggered when several sagging 345 kV lines came in contact with nearby trees. The cascading power failures knocked out power to 50 million people in eight US states, including all of New York City, and two Canadian provinces.

What's the Weather? —Warm Weather Hazards Return | Direct Energy Blog

What To Do When the Power Fails

Most often, power outages from storms or power lines events are sudden and unexpected. The best way to deal with them is to know what you should do when the lights go out.

  • Take out the flashlights. Using candles should be avoided due to the potential for fire. While they’re handy, they should NEVER be left unattended.
  • Use a battery-operated radio. This way you can stay informed about the size of the power outage and maybe find out how long it will last.
  • No flashlight? Most cell phones have a built-in flashlight so you’ll be able to find your way around your home.
  • Report the outage to the local utility. They need to hear from their customers to find out what areas are affected.
  • Turn everything off. Sometimes, voltage spikes occur when the power comes back on. It’s also a good idea to unplug TVs, computers, and other expensive electronics just in case.
  • Keep your refrigerator closed. Only open it when you absolutely must. Without power, an unopened refrigerator will keep food cold for about 4 hours.
  • In summer, it’s important to stay cool and hydrated. Open the windows of your home to encourage cross ventilation. In really hot weather, it might be necessary to head out somewhere that is air conditioned such as a theater, mall, or emergency public cooling center.


Vernon Trollinger is a writer with a background in home improvement, electronics, fiction writing, and archaeology. He now writes about green energy technology, home energy efficiency, the natural gas industry, and the electrical grid.

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