Documenting my attempt to cut my energy usage in half.

Thursday, February 24, 2011

My Half Project

Gary Reysa over at BuildItSolar had several articles published in Mother Earth News and Home Power Magazine several years ago about his Half Project to cut his energy usage and green house gas (GHG) emissions in half.  He has managed to do this and more without making any major changes to his families lifestyle.

Reading through what he has done has got me wondering where I'm at.  I'm not sure I can do a half program because there are a lot more options for providing solar energy to heat a house during the winter than there are to cool a house during the summer.  However, to understand where I'm going, I have to know where I'm at and where I've been.

I retrieved the data for the last 6 years worth of electric bills and totalled up the kwh usage for each year. My house has a ground source heat pump to provide heating and cooling so I didn't need to figure in any propane, natural gas, or heating oil usage.  I did calculate the fuel consumption for the three vehicles, however I don't have a way of finding per year mileage so I ended up taking the total mileage on the vehicles and using that to calculate a per year average.  I know this isn't perfect as my mileage has dropped off a bit in the last two years but it's a reference point.

I'm not sure how these numbers compare to other houses in the area with similar square footage and all electric for heating, cooling, cooking.  I've found gvmt estimates for electrical usage per house but that includes houses that use some other form of energy for heating/cooking other than electricity.  What I haven't found is a chart of household or per person energy usage that includes all sources of energy.

My household uses on average over the last 6 years:  75,133 kwh/year
Per person average:  25,044 kwh/year

I was also interested in knowing how many tons of CO2 I'm belching into the air each year.  To do this I need to know where my electricity comes from.  The EPA was kind enough to provide this.

From that I was able to get this information on emissions.  Note that this is just from the energy used by the house.  This does not include emissions from my vehicles.

To calculate the emissions from my vehicles I needed to calculate how many gallons of gas I use each year.  From my earlier calculations for energy usage I determined that I drive on average, 15,336/year.  I also average about 18 mpg across all three vehicles.  That gives me an average usage of 852 gallons of gas/yr.  Each gallon of gas produces 19.4 lbs of CO2.  852 * 19.4 = 16,528 lbs of CO2.

CO2 emissions of 53,265 from electricity + 16,528 from fuel = 69,793 lbs of CO2.  That's the number I need to reduce.  I realize that this is not going to be an overnight change.  Gary has made significant reductions in his GHG emissions but over 6 year period.  If I can knock of 5% per year I will be very pleased.  I also understand that some changes that I make up front may have dramatic affects and that improvements in the years following will be more difficult.

1 comment:

  1. Thanks for taking the time to take on the 'half project' and the nice details of your investigations!

    I conducted my own 'half project' while living in New Zealand ( I just returned to Canada and lived in NZ for 9 years) but the motivation was far different. Electricity costs were raising 10%/year there the whole time I was there. We marked spring by when the rate increases arrived in the mail! By the time I left, I was paying 0.28/kwh

    Anyway I find your numbers particularly interesting as I compare with my own numbers and experience. I only employed the simplest of techniques and I can say that by the time I left we were using a per person average of 4000kwh/year.

    So are your numbers high? I don't know but I assume you are in the US or Canada somewhere and I see these numbers and they seem astounding to me!

    I noticed in another post that your ghost consumption was 1.5kwh/day! Well, basically I had nothing running overnight except the refrigerator and the clock on the microwave. In NZ we have switches at every outlet and its usual to switch off at source when done for all appliances.

    If I calculate correctly, your background consumption alone is 13,000 kwh/year!

    With the consumption figures you have here, I would have had monthly electricity bills of $1750!
    I managed to keep my bills < 100 for most of the year but mainly by prudent use of appliances and keeping everything off when not needed (well, and of course CFLs - that wasn't even a question). As well the hot water heater was on a timer to prevent the full tank from being constantly heated, cooking multiple things on the stove/oven when it was heated up, etc.

    Mental exercise. Electricity costs 30c/kwh. Reassess what keeping things on is worth!