How Much Energy is in the Holiday Season?

By Kolby Hoagland | December 20, 2013

With the holiday season upon us, many around the world will congregate with family and friends to celebrate our respective holidays around Christmas trees and Menorahs. And for this holiday blog, I’d like to put the season in a bio-energetic context. In this week’s DataPoints, we celebrate the holiday by quantify the potential energy in a Christmas tree and the candles on a Menorah. To accomplish this, numerous assumptions must be made and logical corners cut. By no means is this an attempt to portray a potential power, heating, or transportation market arising from wax or Christmas tree chips. Simply, I’d like to provide you all with fodder for you to use when the inquisitive relative asks how work is going and you’d do nothing more than not talk about our industry.

We will assume that our hypothetical conversion of a Christmas tree and candles into electricity occurs at a large commercial scale plant in order that economies of scale and commercial efficiencies can be achieved. The calculations below simply assess the energy content of a single Christmas tree and eight candles on a Menorah in the form of their lower heating value, intentionally neglecting the many other factors necessary in harvesting, transporting, processing, and storing biomass for conversion to electricity.

A 10’ 4” Christmas tree at my local tree lot weighed 74 lbs. Much of the weight in a freshly cut tree comes as water, up to 50%, while the rest of the tree’s weight is primarily made up of energy-rich lignin, hemicellulose, cellulose, and pitch. Assuming that the tree is chipped and dried to a moisture content of 15% and Btu energy content is around 7,000 Btu/lbs, the once Christmas tree possesses roughly 340,000 Btu of potential thermal energy. Converted to electricity in a commercial scale plant with a thermal-to-electricity efficiency of 33%, there is roughly enough energy in a 10’ 4” Christmas tree to power one average American house for one day.

Candles are often made from biogenic sources such as bee’s wax or tallow. A candle flame is fueled by vaporized wax that travels up a wick from the capillary action. The energy from a candle flame is in the form of heat and light. The heat released from a candle is roughly 273 Btu/hr. With up to nine candles aflame, Menorahs pump out 2,184 Btu/hr of energy at their peak. If we were to convert that heat to electricity assuming a utility efficiency of 33%, there would be just enough power to turn a ¼ horsepower electric motor with no load.

Christmas trees and Menorahs not only symbolize what we celebrate but also provide segue to change the topic of conversation away from work. When the inquisitive relative asks how “that renewable energy business” is going and you simply want to sip eggnog and enjoy the season, I hope you will call upon this week’s blog to lighten the conversation and provide a context of energy and the holiday.

I wish everybody a very merry holiday.