UC Davis Institute of Transportation Studies

Proceedings of the National Hydrogen Association Annual Hydrogen Conference (NHA 2006), March 12 - 16, 2006

The development of a hydrogen refueling infrastructure is a challenging proposition, especially in the transition where the number of hydrogen vehicles is low. These challenges include the high cost of producing and delivering hydrogen at a small scale to meet a limited demand and providing enough refueling stations and distributing them widely for consumers to feel comfortable about purchasing a fuel cell vehicle. The often-cited chicken-and-egg problem focuses on the early markets for fuel cell vehicles and the development of an early hydrogen refueling infrastructure. At very low market penetration of hydrogen vehicles (<5% of total vehicles), providing stations throughout a region to ensure adequate consumer convenience can be costly. These early stations will have significantly fewer customers and will sell much less fuel than typical gasoline stations. As a result, it will be difficult for these stations to benefit from the economies of scale that can be achieved with hydrogen infrastructure technologies. One of the key challenges for developing a hydrogen infrastructure is supplying hydrogen to small and growing markets at a reasonable cost.

Researchers at UC Davis have been developing a suite of systems models to analyze and better understand the design, economics, costs and benefits and consumer convenience of hydrogen production, delivery and refueling infrastructure. One key area that we have been focusing upon is the important issue of customer refueling convenience at low market penetration. This work continues to build upon previous models used to determine optimal station siting within specific urban areas in California.

In addition to the detailed city level model, we are developing high-level regional models that attempt to quantify the cost and environmental impacts of hydrogen infrastructure. In order to simplify these models, an alternative approach is taken with respect to determining the distribution and layout of refueling stations and the hydrogen delivery networks (trucks and pipelines) that supply them. "Idealized city" models are used to describe hydrogen delivery systems in relatively dense (i.e. urban/metropolitan) areas in terms of a few easily specified parameters and have been used to develop hydrogen delivery costs for many US cities. The idealized city model (ICM) is useful because it provides a quick and easy way to estimate delivery requirements of a range of city sizes. The goal of this study is to compare these two approaches in order to verify and improve the ICM.