Plug In for Clean Air

As someone who has been enthusiastically watching and promoting plug-in hybrid electric vehicles, I was concerned that the headline of an article in USA Today (“Plug-in cars could actually increase air pollution,” Feb. 26) could lead to misperceptions about the environmental benefits of plug-in hybrid vehicles. The fact is that plug-ins are an important opportunity for reducing pollution.

Plug-in hybrid vehicles, which run part time on electricity supplied from power plants, are an extremely promising technology for reducing global warming pollution. Compared to conventional vehicles and today’s non-pluggable hybrids, they can run cleaner and use less gasoline, which helps reduce global warming pollution, slash oil dependence and save Americans money at the pump.

The environmental benefits of large-scale plug-in hybrid deployment have been detailed in Environmental Assessment of Plug-In Hybrid Electric Vehicles a comprehensive study jointly authored by the Electric Power Research Institute (EPRI) and NRDC (executive summaries of report: Volume 1 | Volume 2). The EPRI-NRDC report is especially relevant because it considers the evolution of the grid toward cleaner generation due to carbon constraints and existing regulations that tighten select criteria pollutant controls in the future. It evaluates the complex mix of generation resources used for vehicle charging in concert with rapid penetration of plug-ins into the market, and the study shows that plug-in hybrids reduce global warming pollution and provide modest, widespread air quality benefits.

Like many technologies, you can use plug-ins in the right way or the wrong way. Charging plug-ins with dirty coal power is the wrong way; these carbon-intensive sources make it harder for both the electric sector and transportation sector to meet our long-term global warming goals. Heavy reliance on the dirtiest technologies can also lead to localized increases in certain criteria air pollutants, such as particulate matter, also known as soot. Many of NRDC’s advocacy efforts are focused on preventing the wrong path: we are fighting against continued use of dirty coal generation, and we promote policies that encourage a cleaner grid mix.

The USA Today article focuses on the worst-case scenario where the oldest, dirty coal plants are the sole source of electricity for vehicle charging. Typically, this is not the case; the electricity grid is a mix of generation technologies that includes coal along with cleaner energy sources. Overlaying the mix, regulations cap the criteria pollutants that are primary contributors to smog and acid rain (including oxides of nitrogen and sulfur dioxide), and therefore electricity producers cannot increase these emissions in their efforts to meet the increased energy demanded from plug-in hybrids. Existing laws tighten these cap levels over time forcing power plants to get cleaner.

We already have a road map for the right way to deploy plug-in vehicles. As soon as the vehicles are ready for the market, they should be introduced in large numbers across the nation in areas where the public is assured that plugging in will not lead to localized air pollution problems. We need to also keep improving the efficiency of these and other vehicles, so we continually reduce fuel demand by maximizing fuel economy (both miles per gallon and miles per kilowatt-hour). Simultaneously, we should follow examples for controlling global warming pollution from electric sector set by California (AB32 Global Warming Solutions Act and SB1368 Greenhouse Gas Performance Standard) and the Northeast states (Regional Greenhouse Gas Initiative).

So let’s get started. It takes nearly fifteen years to turnover the fleet of vehicles on the road, and power plants can live for fifty years or more. Deploying plug-in vehicles smartly will put us on the path of clean, electrified transportation.