Hydrogen fuel used in fuel cell vehicles provides the potential for significant benefits from the perspective of greenhouse gas emissions, urban/criteria air pollutant emissions and energy security.  However, there are a number of methods for producing, distributing and refueling hydrogen that will affect the extent of these benefits. It is well understood that the costs, emissions and energy requirements for hydrogen infrastructure depend upon a number of important factors, including the choice of primary energy feedstock, type of production facility, and the methods for hydrogen delivery to refueling stations.  However, a number of other important factors influence the costs, emissions and energy use for hydrogen infrastructure, such as the specific geographic and demographic characteristics of each region or city, including the total city hydrogen demand, the physical size and density of the city, the cost of fuels and energy feedstocks and the emissions and energy efficiency of local electricity generation. 

In this study, we examine how each of these considerations affects the cost of providing hydrogen at refueling stations at various levels of market penetration of fuel cell vehicles.  We have developed a user-friendly, EXCEL-based analysis tool to estimate costs and environmental impacts for a variety of hydrogen infrastructure pathways, including production, delivery and refueling. The model is applied to estimate hydrogen infrastructure cost, delivered hydrogen cost and CO₂ emissions for the 73 largest urban areas in the United States, which encompass a range of different sizes and geographic and economic factors.  Given these inputs, we are able to perform a national case study for the United States that examines choices for hydrogen infrastructure supply and delivery modes and associated infrastructure investment and hydrogen delivered costs as a function of hydrogen demand. 

This analysis is based upon a model, called the Steady State City Hydrogen Infrastructure System Model, (SSCHISM) that uses US census data to determine hydrogen demand and an idealized city model to estimate the delivery system layout for trucks and pipeline delivery.  The model calculates the infrastructure capital cost and levelized cost of hydrogen for each city, as a function of the choice of hydrogen pathway, market penetration and average station size. The model determines the lowest-cost pathway for each city and allows comparisons of the cost, emissions and energy efficiency for a given hydrogen pathway for all cities.  The model allows users to select economic and technical assumptions from several sources, including the National Academies' Hydrogen Economy report, the DOE's H2A models or user-defined assumptions.

Model results show that early market hydrogen will be supplied by onsite natural gas SMR at the refueling station, while at high market penetration, hydrogen from central production (mainly coal and biomass) will dominate.  Hydrogen costs vary significantly between different parts of the country based on the size of production facilities, feedstock costs, size of distribution systems and electricity costs.  Emissions and energy inputs can also vary significantly among cities depending upon the composition of the local electrical grid, especially for electricity-intensive liquid delivery pathways.