Energy conservation is on many people’s minds these days, and that’s a good thing. Thinking about the problem, doing some research and listening to what people are saying about the various manifestations of energy usage helps us to make better decisions as individuals.
But it’s not helpful when the terms aren’t defined. So let’s take the example of the washing machine. Many manufacturers make machines which reduce the direct energy required by 30-40%. Some of the front loader machines will also reduce water consumption by 80%.
But water consumption has only an indirect impact on energy, unless you want to analyze the energy cost of water treatment and all it’s input components. As it turns out, water treatment is very efficient and I have paid 2.96/1000 gallons recently. That takes all the costs into account, including delivery.
The direct energy used by the washing machine is hard to get at. The maximum power service needed by the machine is 10 Amps at 120 Volts AC or 1200 watts, although the machine rarely uses anything like that. My washer is a top loader with a 3/4 horsepower AC inverter motor. So its using about 560 watts except when it starts up with a full load. Maybe it takes about 1.5KW per load to do wash.
If it takes 1.5KW to run a load of wash, and we do 10 loads a week, we run about 750KW a year and at 11.5 cents per kilowatt we would pay about $86.25 in direct cost. A 30% saving is $25.88 cents.
Add to that a 10 gallon per wash load cost for water, or about 5000 gallons of water a year doing the wash. That’s 14.80 cents with a potential saving of $11.84. A combined saving of $37.42 a year in water and electricity.
A new $1600. washing machine with a 20 year life expectancy will cost me $80/year (and I hope it will last that long with no service costs). More that twice the cost of the amount saved. So I am losing $42.58 a year on my investment.
I have no disagreements with energy savings and conservation. I think electric cars are the future. I joined that industry in 1994, before there was an electric car industry. Its just taking longer.
I have a big issue with conversations that obscure the economics. There is a real risk of engaging in large scale energy projects without discussion of the system payback. The choices we make as individuals are our own business and privilege in a free society. But when government money is involved, there is a responsibility to disclose what the investment cost, payback and return on investment of the public funds is going to be. And it needs to be real.