An Experiment in Lowering my Carbon Footprint - Part 2

In my last post I discussed an experiment I ran over the summer months of 2009 in Dallas, Texas where I attempted to reduce my carbon footprint. In this post, I discuss my attempt to determine how much CO₂ I prevented from being released into the atmosphere and contribute to climate change.

In order to do so, I had to first determine two pieces of information: 1) estimate how much energy I saved over the duration of the experiment; and 2) determine the sources of power being delivered to me and the amount of CO₂ they emit.

To get the first piece of information, I went to my account on the TXU website and compared my energy usage for the summer months in 2009 to what I used in 2008; TXU is the energy company that bills me for the electricity I use. I assumed all other factors are equal and the only major contributor to the differences in energy usage result from my experiment. Below is a summary of my findings.

Table I. Energy Usage Data

Month	2008 Energy Used, kWhr	2009 Energy Used, kWhr	Difference, kWhr
June	1,025	716	309
July	1,820	1,128	562
August	1,690	1,212	608
September	900	473	427
Total	3,529	4,750	1,906

As a result of my experiment, I saved approximately 1,906 kWhrs of energy. In order to determine the second piece of information, I first had to determine how the power that was distributed to me was being generated. There a number of ways in which power is generated and each emits carbon in different amounts in the generation process. I had to determine for example, what percentage of my power was being generated from a coal-fired plant, from a natural-gas plant, etc.

I first contacted TXU and inquired as to how the power being delivered to me was being generated. They referred me to Oncor as TXU provides metering and billing functions to their customers. I then contacted Oncor who referred me to Luminant as Oncor provides transmission and distribution services. I never got a response from Luminant, the power generating company that serves me. I went to their website and did some digging around. I found that Luminant generates electricity using coal-fired plants, natural-gas plants and nuclear plants.

I determined the power generating capacity from all their plants and then determined what percentage of total the type of plant represents; they are summarized in the table below.

Table II. Luminant Power Plant Data

Plant Type	Generating Capacity, MW	Percent of Total
Coal	6,396	38.27%
Gas	9,018	47.97%
Nuclear	2,300	13.76%
Total	16,714

I was able to find the amount of CO₂ released per thousand-Watt-hours (kWhrs) of power generation from various fuels used in power generation systems from the US Government's Energy Information Administration website; they are summarized in the table below.

Table III. CO₂ Emissions Per Fuel Type

Power System Fuel Type	CO2 Released, lbs/kWhrs
Coal	2.117
Natural Gas	1.314
Nuclear	0

Note that nuclear fuel used to generate electricity produces no CO₂; however, a small amount is released from processing the uranium that is used in the reactors. I decided to ignore that fact as it wouldn't be meaningful in my estimates.

I assumed the power delivered to me was generated in the percentages shown in Table II. I then calculated the amount of CO₂ I saved by the following:

CO₂ = ((2.117)(38.27%)+(1.314)(47.97%))(1,906) = 2,743lbs.

This is equal to 1.37 tons or 1.24 tonnes of CO2 not released. I think that's pretty good and in future posts, I'll try to comment further on this.

I believe there is increasing scientific evidence showing our burning of fossil fuels such as coal, oil and natural gas are contributing to climate change. Burning fossil fuels in generating electricity is responsible for 39% of all carbon emissions.

In 2007, the per capita emissions in the US was 19.1 tons/CO₂; this represents approximately 20% of the total emitted by all nations in the world. The average American in their daily routine emits roughly 9.44 tons/CO₂. Assuming I fall into the average camp, by my experiment over the summer, I reduced my CO₂ emissions by 14.5%. I'll provide more details and analyses in my next post.