We all know the scene in the National Lampoon’s Christmas Vacation movie where the switch is finally flipped on and Clark W. Griswold’s 250 strands of bulbs burst into light causing a rolling blackout.

Following Griswold’s calamity is a scene where a hand switches on the “auxillary” power plant which brings the city’s lights back to normal.

While the scenario of one house draining a city’s power is Hollywood shenanigans, holiday lighting does add a significant additional level of electricity demand during the start of winter when cold weather is already driving up load.

In New York alone, holiday lighting adds about 750 to 800 MW of additional energy demand to the Empire State, according to the New York ISO.

In other words, the amount of energy used for New York holiday lights would be enough to power roughly 800,000 homes.

But even though holiday lighting adds a little bit of extra demand during start of winter, overall electricity demand growth over past couple of decades has been relatively slow.

The Energy Information Administration estimates electricity demand growth has been 0.5% per year from 2000-2015. Further, EIA  predicts about 1% per year growth from 2015-2040.

Electricity demand growth has been closely linked to gross domestic product: if the economy does well, electricity demand grows with it, and vice versa.

Demand growth has also been slowed as the world has become smarter about how it consumes energy, with changes in the type of lightbulbs we use to more efficient appliances.

So if the economy picks up in the next few years, electricity demand could grow quicker than expected.

And who know, if Americans adopted the practice of lighting up houses for other holidays throughout the year, electricity demand could take off even faster.

Imagine houses lit up in green during St. Patrick’s day, red for St. Valentine’s Day or even orange for Halloween.

The Clark W. Griswolds of the world would be busy year round with lightbulb strands and th...