AUDUBON, MONTGOMERY COUNTY -- It may not look like much from the outside, but PJM Interconnection outside Philadelphia helps keep your lights on and keep you cool.
PJM Interconnection serves 65 million homes and businesses and is the nation's largest electric grid. The place monitors power usage in Washington D.C. and 13 states, including Pennsylvania.
As temperatures get hotter, employees work to make sure we stay cool this summer.
An important part of the equation at PJM is the staff meteorologist -- Penn State graduate Elizabeth Anastasio.
"I'm primarily using my meteorology background to forecast how much electricity demand we're going to meet every day," Anastasia explained.
Employees usually see peak usage of electricity during the summer when people start using their air conditioning. Meteorologists anticipate another warmer-than-average summer.
"We've seen some really long stretches. I don't know if I would say yet that it's unusual, but we've seen some long stretches of hot weather, but I feel that we're very well prepared for it."
The power companies monitored by PJM can generate up to 185,000 megawatts at a time. Last summer, demand on their grid peaked at 150,000 megawatts on August 11.
Employees say one reason they had no trouble meeting the demand that day is more energy-efficient lights and appliances in businesses and homes.
Employees say the spring and fall months are usually pretty quiet because that's when temperatures are moderate, but severe weather is always a concern at PJM.
"Pop-up summer thunderstorms, you might know that they're going to happen somewhere in your area, but you're not exactly sure where. When it comes to reacting to that sort of scenario, that's definitely a real-time issue. Something like a hurricane, like Hurricane Sandy, that's something we can be more prepared for."
To make sure PJM Interconnection is prepared for whatever Mother Nature has to offer, employees are constantly going through disaster training.
"We do a lot of looking at what the load has been over the last several years, but as it continues to change, it's an interesting problem to work on. We always have to come up with new methods to improve our forecasting process," Anastasio added.