Environmental Implications of Battery Powered Cars

Carnegie Mellon University scientists, Lester B. Lave, Chris T. Hendrickson and Francis C. McMichael, of the Green Design Initiative have put together a very interesting paper on the implications of battery powered cars.  I find it facinating that with the push toward greener and newer technologies important information such as their paper get losst in the gloss.

This is more from their paper:

Introduction:

Several states have mandated the sales of "zero emissions" vehicles to improve local air quality; several manufacturers are now marketing battery powered vehicles. Battery powered vehicles produce no air pollution at the point of use. If the electricity is generated in a distant place, these cars are a means of switching the location of, and possibly reducing, emissions.

We are examining the current and near term life cycle consequences of producing and reprocessing lead-acid batteries to power electric cars. Smelting and recycling the lead for these batteries will result in substantial releases of a neurotoxin, leading to reduced cognitive function and behavioral problems. Even at low blood levels, environmental discharges of lead are a major concern. For example, eliminating tetra-ethyl lead (TEL) from US gasoline greatly reduced the blood-lead levels in children.

Lead-Acid Battery Powered Vehicles

The large weight of batteries needed to supply energy means that electric cars will be heavier, will cruise at lower speeds, and will have much less range than an equivalent gasoline vehicle. We estimate annual lead losses from the lead-acid BPV fleet, F, from four factors: F = ABC/D where A is lead mass in a BPV, B is the vehicle fleet size, C is the fraction of lead released to the environment over the battery life cycle per kg. of lead used in the battery (a measure of environmental management) and D is the average lifetime of a BPV battery pack. Lead releases to the environment from production and recycling are uncertain. The best estimate of the current discharges is that primary lead processing releases about 4% of its production to the environment,secondary or scrap production releases about 2%, and the manufacturing sector releases about 1% of the lead processed.

There is wide disagreement on the quantity of lead released to the air per unit of lead handled. In its 1992 national air emissions inventory, the EPA reports total lead air emissions to be 0.36% of the total demand for lead in the US, and 0.04% based on primary lead production and 0.03% based on secondary production. Using the 1992 SARA III Toxic release inventory for lead and lead compounds, the EPA reports air releases of lead and lead compounds from all manufacturing sectors to be about 0.06% of total US demand.

Effects of One Million Battery Powered Vehicles

We examined the environmental implications of having 500,000 battery powered vehicles (BPV) in Southern California and another 500,000 in the New York City area. Using standard ambient air quality models and the expected emissions of the new low emission vehicles that ZEV would replace, we find that peak ozone levels would decrease about 1 ppb in Southern California and less than 1 ppb in New York City; having 5% of the fleet be BPV would reduce ozone levels by less than 1%.

In contrast to the small ozone related benefits from BPV, the potential environmental problems are considerable. Mining, smelting, and recycling more than 500 kg of batteries per vehicle would result in lead releases 80 times greater per vehicle mile than a gasoline powered vehicle with a current starter battery. We estimate total lead discharges to be 6.5 Gg to 14.6 Gg with 1,625 to 1,625,000 kg emitted to the air. Stringent regulation presumably could lower these discharges. Another way to compare the effects of BPV is that 500,000 lead-acid BPV would reduce regional ozone levels by 1 ppb while increasing national discharges of lead into the environment by about 20%.

Policy Implications

We conclude that 1998 lead-acid BPV are a potential environmental liability compared with the new, ultra low emission GPV. Introducing an unappealing technology on the grounds that it is "transitional" makes even less sense due to the higher environmental and economic costs. ZEV may play an important role in attaining ozone standards in the future, especially in large urban areas. Advanced technologies, such as fuel cells or advanced batteries, or old technologies, such as bicycles, may be attractive. We are examining some other propulsion alternatives.