A big part of choosing the right power tool is choosing the right power supply. Your options include gasoline, diesel, plug-in electric, and battery power. There’s a right time and place for each of these options. For crushing stone, a gasoline engine is often the only tool that provides enough torque. But with oil prices skyrocketing, the costs of gasoline and diesel are going through the roof too. Fueling a leaf blower or diesel lawnmower often costs more than buying the machine. The engines themselves have many moving parts that can wear out, and these complex engines require special care and maintenance.
Electric tools are often the more cost effective choice for gardening. The upfront costs are about the same as gasoline and diesel tools, but electric mowers, blowers, and trimmers have lower operating costs. There are no spark plugs or air filters to replace. Electric tools cost only pennies to run. Electricity costs 8 to 12 cents per Kilowatt, while gas is heading towards $4 or $5 per gallon.
According to numbers from the Energy Information Administration, each gallon of 88 octane gasoline has about 36 Kilowatts of power. A gallon of diesel has slightly more power – equivalent to about 40 Kilowatts. Unfortunately, gas powered tools waste most of that power as noise, heat, and vibration. Because of these factors, gasoline motors are less than 30% efficient and many lawn mowers fall in the 10-15% efficiency range. Electric power tools are much more efficient than gas powered models. There are fewer moving parts, which means there’s less friction and reduced mechanical inertia. They also tend to weigh less, which is useful for self propelled models. Many electric trimmers and electric mowers offer 75 to 85% efficiency. This increased efficiency means that when you spend money on electrical power you get more value for your money – and electricity costs far less than gasoline.
To compare apples to apples, here’s a chart comparing gasoline prices and electrical prices. It assumes that electricity costs 15 cents/Kw, the gas mower is an efficient model (15% energy conversion ratio), and that the comparable electric mower is an inefficient model (75%).
Gasoline mowers also contribute to our dependence on oil. Each weekend, about 54 million Americans mow their lawns. Lawn care consumes about 800 million gallons of gas per year. Imagine if one household in a hundred switched from gasoline mowers to electric mowers. Such a switch would conserve more than 60 million gallons of refined oil a year – equivalent to roughly 3 million barrels (assuming 19.5 gallons of usable gasoline per barrel).
In other words, if a million people switch to electric lawn tools, we could make do without 2 supertankers full of fuel every year. Even small changes can make a significant difference in the price of gasoline. Part of the reason that prices have been running out of control is that our levels of consumption are very close to the available supply. If we can change the math, we can push down the cost of gasoline, but as long as demand outstrips supply, prices will continue to rise.
By reducing our dependence on oil, electric powertools also help the US economy. Power tools rely on domestic sources of energy, and American power companies create jobs for Americans instead of funneling money overseas. Oil is one of the United State’s biggest imports – in 2007, we spent $331.23 billion on crude oil. Keeping that money inside the country would do a lot of good.
When oil prices go up, they drastically increase our foreign trade deficit. This deficit harms the buying power of the US dollar. If you’ve tried to travel overseas recently, you may have noticed that the exchange rates are trending in a painful direction. Well, our trade deficit is partially to blame. High oil prices also hurt other countries that import oil, and these high prices can hurt the US economy because people that would like to buy our exports have less money to spend.
Choosing electric tools is also a great way to help the environment!