Water critical for renewable energy
Nov 19, 2007 11:28 AM,
By Jim Langcuster
Auburn University
If you think water is a precious commodity now, just wait until the nation becomes more deeply invested in renewable energy.
That’s when water will become an especially valued and critical commodity, according to one expert.
“It doesn’t matter whether you’re talking about hydropower, nuclear power or bioenergy, you’re talking about lots and lots of water,” says Jim Hairston, the Alabama Cooperative Extension System’s water coordinator and Auburn University professor of agronomy and soils.
Biofuels are a case in point. Contrary to widespread opinion, people have been using biofuels or things strikingly similar to it for generations. And anyone involved in this process knows that it requires water, lots of water, Hairston says.
“Anytime you talk about growing a crop in the field, especially if you’re only harvesting the reproductive part of the plant such as corn kernels for fuel, you are going to encounter huge water demands for energy,” Hairston says.
In fact, Alabama farmers’ recent struggles with corn production during the prolonged drought speak volumes about this issue.
“An annual plant like corn has to have water in ample amounts at critical times of the year for it to be produced into biofuel sources, because if you don’t have the grain on the plant, you’re not going to have the bioenergy to produce the ethanol,” Hairston says.
These types of crops are different from another form of bioenergy crop, known as cellulose or biomass. With cellulose, the whole plant is converted into biofuel rather than only part of the plant — the case with corn, in which only the kernels are converted.
As Hairston sees it, “you just can’t separate energy security from water, no matter how hard you try.
“No water, no biomass. It’s as simple as that.”
But the same principle applies to renewable sources of energy in addition to corn and other bioenergy crops. Nuclear energy, a controversial renewable energy source that has earned a measure of respect in recent years as the nation struggles to move beyond fossil fuel-related sources, also depends heavily on water.
“You can’t just build a nuclear power plant anywhere, you have to have huge volumes of water for cooling towers,” Hairston says, adding that these nuclear plants consume considerably more water than conventional hydropowered electric plants consume.
In fact, Hairston even can imagine a time when an energy-strapped United States begins building nuclear power plants on the ocean to ensure a readily accessible water source for production.
The close connection between water and most renewable energy has not been lost on many policymakers as they prepare the rest of the nation for the transition to large-scale renewable energy production.
The new generation of biofuels known as cellulosic ethanol possibly could alleviate some of this water demand, though they would be far from a panacea. And this raises the question: As demand for renewable energy, particularly in the form of energy crops, increases, where will the water come from to grow them?
It’s precisely this concern that accounts for why Hairston and an informal coalition of university professors throughout the state have been touting the need for better stewardship of the state’s water resources in preparation for Alabama’s likely conversion into a major source of energy crop production.
“We’re in good shape in the Southeast, and it’s simply because we have all the water,” Hairston says. “But we’ve got to use common sense in the way we manage this water.”
One solution would involve the construction of off-stream reservoirs. Water generated during periods of heavy rainfall could be trapped and stored in these reservoirs during periods of heavy rainfall and then used later during those parts of the year when water is critical for growing bioenergy crops.
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