Natural gas has been touted as a “bridge fuel” which would allow us to transition towards cleaner alternatives in the future while leaning away from emission-heavy carbon based fuels. We looked at some of the atmospheric consequences for using natural gas last week, and this week we’re taking a closer look at water.
The EPA estimates that fracking for oil and gas consumes between 70 and 140 billion gallons of water each year, all of which becomes too polluted to reuse. If the natural gas extracted during this process is used to generate electricity, it may actually save water compared to coal-fired and nuclear power plants. According to a study by Climate Central, natural gas power plants use significantly less water for cooling than do coal-fired power plants. In 2005, coal-fired and nuclear plants used about 55 trillion gallons for cooling, which fell to 33 trillion gallons in 2012. That’s a big difference, but of course most of that water isn’t lost forever.
Coolant water for coal-fired or nuclear power plants is generally drawn from a local lake or river, then returned after being used to cool the plant. The amount of water actually lost (consumption) is far less than what is withdrawn. In 2005, about 1.8 trillion gallons of water were lost to evaporation and other processes out of the 55 trillion that were used for cooling plants. Consumption declined with withdrawals in 2012, with 33 trillion gallons withdrawn, and only about 1 trillion gallons consumed.
So while drilling and fracking have used up to 140 billion gallons of water each year from 2005 to 2012, the amount of water consumed during power generation has been reduced by 800 billion gallons of water per year. Much of the water lost during power production returns to the water cycle, but not before having an effect as a mild greenhouse gas, and contributing to a changing climate.
There are many other concerns associated with fracking, such as where the fluid is stored, what evaporates during well completion, and if condensate tanks leak into the air and water around communities. However, as far as fracking and natural gas are concerned, the permanent loss of water during these activities may be mitigated by the savings during power generation.