# How Much Is Your Electricity Bill?

The most common question people ask about Oly Lightstravaganza is “how much is your electricity bill?!?”, assuming we spend bazillions of dollars to power the display. Not so, owing in large part to the display being composed primarily of LED lights, which are far more efficient than traditional incandescent lighting.

We could just give you the answer to the cost question in dollars and cents, but what fun would that be? Instead, let’s complicate things by taking a trip down memory lane to high school physics.

Here’s how we figured out the cost to run the 2012 display:

• Determine Energy Used (Watts). Our 2012 light display was powered by two receptacles using a total of 2478 watts (1725 watts for one, 753 watts for the other). We used a power meter to figure this out.
• Convert Watts to Kilowatts. Electricity is charged by the kilowatt hour, so we need to divide the consumption (2478 watts) by 1000. We get 2.478 kilowatts.
• Calculate Kilowatt Hours. We then need to calculate the number of hours the energy was used per day. The display was on from 4:45 pm to 10:00 pm daily, or 5.75 hours per day. To find the kilowatt hours we multiply the kilowatts used (2.478 kilowatts) by the time (5.75 hours). We get 14.2485 kilowatt hours used per day.
• Calculate Cost. To convert the kilowatt hours of energy used by the display to dollars and cents we need to multiply the kilowatt hours by the electricity rate. Puget Sound Energy’s (PSE) current green power electricity rate is \$0.09 per kilowatt hour. Multiply \$0.09 by our 14.2485 kilowatt hours, and we get our answer – \$1.28 to power the display each day. For 2012 the display was on for 36 days, costing us a total of \$46.17.