The effect of PHEV battery range distributions on competitiveness: Implications for design strategy and energy-efficiency policy

Paper in proceeding, 2011

Electric vehicles have the potential to contribute to increased energy efficiency. However, competition is fierce among designs, energy carriers, and powertrains; electric vehicles must be economically viable from a consumer point of view. Batteries are still expensive; short of a breakthrough, the energy battery will constitute a considerable share of the vehicle cost for the foreseeable future. Economically efficient battery use is therefore very important. Plug-in hybrid electric vehicles (PHEV) constitute a response to this efficiency requirement. PHEVs rely on a relatively small battery, while still allowing a considerable share of the driving to be powered by electricity. In previous studies, we investigated optimal battery sizes, from the individual consumer’s perspective. In reality, only a limited number of battery sizes will be available. Understanding the relationship between a limited choice of battery sizes and the potential for PHEVs should be of value to car manufacturers, in constructing battery range strategies, as well as to policymakers, in formulating policies for encouraging the introduction of electric vehicles. Here we investigate this relationship by analyzing how various battery range strategies influence PHEV viability, efficiency, and potential. We use a data set on car use from a mid-size Swedish town covering 201 individual cars for 100 days. The results are presented in terms of the possible loss in net revenue, electrification potential, and energy efficiency for different distributions of battery ranges, which reflect a limited number of optimized sizes and a modular design. We apply our analysis to current conditions and a range of possible future techno-economic and recharging conditions, making it possible to estimate the importance of the different strategies in a variety of future scenarios. For the investigated non-optimal battery strategies, the estimated loss in average net revenue is up to 20-25% of the battery cost, the possible loss in fleet electrification potential is at least up to 10% of the distance driven, and the potential loss in average vehicle energy efficiency is also around 10%.