American Scientist

To the Editors:

I agree in principle with Alan Pavlak’s argument in his Macroscope “Strategy Versus Evolution” (November–December) that a systemwide approach to carbon emission reduction is appropriate. But I believe Dr. Pavlak makes critical errors on important points. First is the remarkable omission of the most obvious opportunity to reduce emissions: conservation. Granted, this is a policy-based solution and not what Dr. Pavlak chooses to dabble in. But opportunities there make the engineering solutions much easier, maybe even attainable.

Likewise, he ignores the possibility that we could achieve further efficiency in electricity use and in transportation, again gaining ground on the goal of 83 percent reduction in CO₂ by 2050 without reinventing our entire energy complex. And his conclusion that nuclear energy will be the backbone (if not the entirety) of our electricity and transportation systems is troubling. Once again we would place ourselves in the full embrace of a technology that is based on a nonrenewable resource largely obtained from outside our borders.

If Dr. Pavlak were assigned this project, I believe his strategic plan would have to contain lots of the silver buckshot he casually dismisses. That includes conservation, efficiency, wind (surely less of a challenge to integrate into the grid than he opines), solar and other truly renewable sources.

Mark McClain
Salem, VA

Dr. Pavlak responds:

The main point I was trying to make is that we must start thinking strategically about clean energy systems or we will make big mistakes, charge down dead ends and invest in systems that will have to be discarded. We need simple architectural models of end-state system configurations to clarify which concepts can achieve sizable emission reductions. Wind power is a great example. People point to grid-scale storage, long-distance transmission and the smart grid as ways to increase wind penetration. It all helps a little bit. But as soon as we put numbers to it, when we conceptualize a zero-carbon grid based on what we know today, wind does not work. Mark McClain is quite correct to point to conservation and efficiency as high-return opportunities. Indeed we should have a metric such as a dollar-per-ton CO₂ emissions decrease to identify low-hanging fruit and to prioritize investments. But how much can we realistically expect to achieve with this? Based on actual emissions reductions to date (mainly from a onetime shift to natural gas), my hope is that conservation and improved efficiency can cap emission growth, even as the world’s GDP continues to grow. But an 83 percent overall reduction in CO₂ emissions is huge! It will require both an electric power grid and motor vehicle fuel that is zero-carbon (or not fossil fuel). This will require rethinking our entire energy complex.