03241 Energy Inventory

In the "developed" countries, at least, the large problems occur because all of us live in ways that are either partly wrong or almost entirely wrong. It was not just the greed of corporate shareholders and the hubris of corporate executives that put the fate of Prince William Sound into one ship; it was also our demand that energy be cheap and plentiful. — Wendell Berry

The goal of your Energy Inventory is to track your household’s energy consumption so you know how much fossil fuel and other energies it takes for you and your household to live. If you can extend this observation backwards, for example with utility company records, this will be help your understanding of your situation.

I keep a spreadsheet with monthly records going back to 2004, with a few months from 2003 for my primary house utilities of natural gas and electricity. I started keeping my records from my utility bills in late 2005, and got the earlier years’ information from the website of my electrical utility. We don’t have natural gas service now, but we did before late 2005, and I have two years records of our household’s natural gas consumption, which I got from the Oklahoma Natural Gas website.

I have recently started to keep track of the monthly actual usages and average daily use of the primary resources I consume — electricity, water, propane, gasoline, firewood, garbage.

If you live in a college dormitory, or some other kind of group living, get figures for the energy used in your entire building so you can figure out your per capita share. The good news is that because of the density of the housing, dormitory living is energy conservative on a per capita basis.

After setting up the spreadsheet, this activity takes about five minutes/month. I have separate areas in the spreadsheet for each type of household energy — in our case, electricity (hot water, cooking, ventilation, AC, lighting, communications, entertainment, backup heating), propane (for cooking), and wood (backup heating). I don't report solar energy, because the sun, our primary heat source, is unmetered and free.

In the spreadsheet, if you have a personal automobile, you need two sections — one for household operating energy, and one for transportation. In the household operating energy section, you need columns as follows:

Date — most people pay energy bills on a monthly basis, so organize my records on that calendar basis.

Types of energy and amounts used — this will be kWh of electricity, cords or ricks of wood (a rick is 1/3 of a cord), gallons of propane, and dekatherms or cubic feet of natural gas, whatever the fuel is and its typical measurement.

Total Price — include the taxes and fees.

Price per unit, which is the total price divided by the units used.

Heating and Cooling degree days. You’ll have to go to a weather service climate observation site for your geographical area to find this information. It is useful to have so you can study how the weather impacts your energy consumption. For example, you could convert the energy required to run your house or apartment (heating, cooling, cooking, hot water, entertainment, communications, etc.) to BTUs and divide that number by the heating or cooling degree days for that month. If it’s a spring or fall month, you might have heating AND cooling degree days in the month, in which case, add them together. This gives you the BTUs you use per degree day. So if your bills are much higher this July than last July, you can figure out if the problem is that the people in your household are burning more energy, or if it was simply a lot hotter this year than last.

Comparison columns. I compare current use to each previous year’s usage, in a column. So I have two columns for 2010 over 2009, 2009 over 2008, 2008 over 2007, etc. One column shows the change in units used (kWhs etc.), the second shows the percentage change. I put formulas in these columns so they are automatically calculated when I enter new data.

Because the number of people in my household has varied over the years, I calculate the amount of fuel used “per person.”

The second section of your energy inventory is for transportation.

At its simplest, this can be a record of the date, amount bought, price per unit, and total price of the transportation fuels you use in your vehicle. If you have more than one vehicle, you need to track each vehicle and then total your figures.

You could keep track of your mileage based on purpose (school, work, fun, shopping, etc.) This is a minute amount of additional work that can be useful in your ongoing observation of your life.

This observation develops the base line of your energy usage. Once you know where you are, you can start developing design ideas to reduce your total energy consumption.

Besides raw energy, you need to get a handle on how much stuff you go through. One useful statistic is the amount of garbage you produce. Measure the volume of your garbage. If you have a municipal garbage container or containers that you put out for pickup, this will be a matter of determining the volume of the container(s) and how many containers you put out each week. My Oklahoma City garbage cart has its volume stamped on the side — 90 gallons.

The documents on materials and cycling have a number of questions about stuff, waste, and resource cycling that should be answered as part of your observations.