Our Excellent Renewables Adventure

renewablesPut simply, society doesn’t know much about renewables. It’s a vast vacuum of information, which shouldn’t be surprising, because renewables are a total paradigm shift.

The New York Times added some to the confusion with a recent article that baldly states that renewables are universally burdened with serious water issues. The truth is that some renewables are burdened with serious water use issues. But others are not. And one must add that conventional coal, natural gas, and nuclear plants are all burdened by serious water issues, to the point of drawing as much water as irrigation in the US (about one third of all water use, each). We know that water issues for electricity production are endemic.

But the point here is not to throw stones at the NYT, which is doing a good job with renewables and is part of the solution to our serious knowledge gap. And it isn’t to make renewables just a little less black than conventional electricity on water use, but to explain that we have only begun our journey towards a correct understanding of renewables, and there are some great renewable options that essentially do away with water issues. These select renewables technologies not only meet our climate and energy security needs, they do it while freeing up water for other uses. Water use will be a strength of our renewables future (hardly what the Times implies, I am sad to say).

The message of the Times article is completely wrong: It is not all renewables that are tarred with the water use brush, but only particular ones, and even within those, they have choices. (For example, Brightsource towers do not cool with water.)

The negligible water-use renewables are wind and PV. Neither use any water for cooling (almost all the water use in thermal electric plants, conventional or solar). Either could meet our entire energy needs, and solar could do so many times over. We have no need for renewables that require as much water as conventional electricity.

But our excellent adventure with renewables goes back a little further. Remember corn ethanol? Remember hydrogen? Each has had its day in the sun and been pushed back into the pack for its Corn ethanolwarts. Renewables have warts – it is a matter of knowing them and how bad they are. Corn ethanol’s are fatal; food, fuel, energy payback, arable land. Hydrogen’s are not as bad, but nearly so – conversion losses to, and worse yet, from hydrogen to useful work. Burning hydrogen, which is essentially what happens in conversion, means you are back with huge turnaround losses that are avoided if you never have to make hydrogen in the first place. Using electricity in vehicles avoids almost all those losses, and since your non-CO2 source is wind or solar (or nuclear), you already have the electricity. Just transmit and use it in electric vehicles using batteries and electric motors, both of which have good efficiencies.

The last decade and the next are about getting to know renewables. Separating the wheat from the chaff. Seeing what the bad sides are and finding out if they are debilitating or not. Completing our excellent adventure.

The ones in the barrel for public examination now are wind, solar, and electric transport. They can do it all. Will they stand up to scrutiny?

Within solar, we are asking, is water too huge a challenge for solar thermal electric? And can that technology be as successful with air cooling as PV is without water? The Times also added drama to their story by wrongly saying that solar thermal plants are less costly than PV – that is no longer the case. Times have changed. Prices for large-scale solar PV in the coming decade will be in the $2.5/W range, as in recent announcements from First Solar and China.

By the way, we could also retrofit all those conventional coal, gas, and nuclear plants with air cooling, too.

Ken Zweibel