Until battery cost is cut down to $100/kWh, the majority of US consumers for battery electric vehicles (BEV) will be better off by choosing an electric vehicle with a range below 100 miles, according to a new study by Oak Ridge National Laboratory (ORNL) researcher Zhenhong Lin.

The research, published in Transportation Science, a journal of the Institute for Operations Research and the Management Sciences (INFORMS), suggests reconsideration of the R&D goal that battery electric vehicles should have a driving range similar to that of conventional vehicles. It also implies that the focus of policy and R&D should be on continued reduction of battery costs to make short-range BEVs more price-competitive.

The focus should also remain on deployment of charging infrastructure to improve usability of short-range BEVs that attract more potential buyers.

In the study, Lin proposed a framework for optimizing the driving range by minimizing the sum of battery price, electricity cost, and range limitation cost—referred to as the “range-related cost”—as a measurement of range anxiety.

The objective function was linked to policy-relevant parameters, including battery cost and price markup; battery utilization; charging infrastructure availability; vehicle efficiency; electricity and gasoline prices; household vehicle ownership; daily driving patterns; discount rate; and perceived vehicle lifetime.

The electric driving range of a BEV was optimized separately for each of 36,664 sample drivers representing US new car drivers. Key results were the distribution of optimized BEV range among US consumers and the change of such a distribution in response to battery cost reduction and charging infrastructure improvement.

The quantitative results strongly suggest that ranges of less than 100 miles are likely to be more popular in the BEV market for a long period of time. The average optimal range among US drivers is found to be largely inelastic. Still, battery cost reduction significantly drives BEV demand toward longer ranges, whereas improvement in the charging infrastructure is found to significantly drive BEV demand toward shorter ranges. The bias of a single-range assumption and the effects of range optimization and diversification in reducing such biases are both found to be significant.

The results of the study explain the dominance in the BEV market of products with an electric range below 100 miles, the author said.

Before the introduction of the Nissan Leaf (certified with a 73-mile electric range) in December 2010, BEV ranges were often assumed to be between 150 and 200 miles. Now, eight out of the ten BEV products on the US market are equipped with an electric range below 100 miles, Lin said.

The paper further discusses the policy and R&D implications of the found distributions of optimal BEV range, providing insights for BEV-related policies and market strategies. The paper also includes sensitivity analysis and quantifies the significance of the optimization approach.