A future hydrogen economy would interact with and influence the electricity grid in numerous ways. This paper presents several concepts for understanding a hydrogen economy in the context of the co-evolution with the electricity sector and lays out some of the opportunities and challenges. H2 and electricity are complementary energy carriers that have distinct characteristics, which lead to more or less utility in different applications. Despite their differences, it is possible to understand a future hydrogen economy using some of the same techniques as electricity system analysis. Hydrogen pathways will lead to additional electric demands that will influence the structure, operation and emissions in the electric sector. Examples of convergence between these sectors include a number of options for H2 and electricity co-production and interconversion.

This report assesses technology requirements for reducing greenhouse gas (GHG) emissions in California to 80% below 1990 levels by 2050 as required by Executive Order S-3-05 (2005). Details of this analysis, assumptions and data are to be found in forthcoming reports, including a detailed analyses for specific energy technologies. The present document serves to synthesize the results and present the major findings.

The challenge of meeting these GHG emission targets is large:•    By 2050, California’s population is expected to grow from the 2005 level of 37 million to 55 million. Even with moderate economic growth and business-as-usual (BAU) efficiency gains, we will need roughly twice as much energy in 2050 as we use today.•    To achieve the 80% reduction goal, California’s greenhouse gas emissions will need to fall from 470 MtCO2e/yr (million metric tons of CO2 equivalent per year) in 2005 to 85 MtCO2e/ yr in 2050, with most of those emissions (77 MtCO2e/yr) coming from the energy sector. Accomplishing this will require a reduction from about 13 tons CO2e per capita in 2005 to about 1.6 tons CO2e per capita in 2050.

This study has developed a set of energy system “portraits”, each of which meets the challenge of providing the energy needed for future growth while striving to achieve the required greenhouse gas emissions reductions. We use the term energy system portrait to mean a set of energy sources, carriers and end-use technologies that meet all the energy needs of Californians projected for 2050. An energy system portrait describes an end-state or target energy system that could be a goal for California. This study connects related sectors of the energy system in order to account for trade- offs and inter-relationships. For example, if vehicle electrification is chosen as a strategy to reduce emissions, we also have to account for the emissions produced by the generation of the additional electricity needed for the vehicles.

Concerns regarding air pollution, energy dependence, and, increasingly, climate change continue to motivate the search for new transportation solutions. Much of the focus is on light-duty vehicles, as they account for approximately 60% of transportation energy use and greenhouse gas (GHG) emissions. Battery-powered, electric-drive vehicles (EVs), such as plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs), are among the most promising of the advanced vehicle and fuel options that have been proposed to help reduce fuel usage and GHG emissions from light-duty vehicles.

The development of a hydrogen infrastructure has been identified as a key barrier to implementing hydrogen as for a future transportation fuel. Several recent studies of hydrogen infrastructure have assessed near-term and long-term alternatives for hydrogen supply [1-2]. In this paper, we discuss how advances in material science related to hydrogen storage could change how a future hydrogen infrastructure is designed. Using a simplified engineering/economic model for hydrogen infrastructure design and cost, we explore some potential impacts of advances in storage materials, in terms of system design, cost, energy use, and greenhouse gas emissions.

The development of a hydrogen infrastructure has been identified as a key barrier to implementing hydrogen as for a future transportation fuel. Several recent studies of hydrogen infrastructure have assessed near-term and long-term alternatives for hydrogen supply. In this paper, we discuss how advances in material science related to hydrogen storage could change how a future hydrogen infrastructure is designed. Using a simplified engineering/economic model for hydrogen infrastructure design and cost, we explore some potential impacts of advances in storage materials, in terms of system design, cost, energy use, and greenhouse gas emissions.

Proceedings of the National Hydrogen Association Annual Hydrogen Conference (NHA 2005), Washington, DC, March 29 - April 1, 2005

Hydrogen offers a wide range of future environmental and social benefits, when used as a fuel for applications such as light duty vehicles and stationary power. These potential benefits include significant or complete reductions in point-of-use criteria emissions, lower life-cycle CO2 emissions, higher end-use and life-cycle efficiency, and a shift (with respect to transportation fuels) to a range of widely available feedstocks. Despite the potential benefits of a hydrogen economy, there are many challenges as well. One of the most critical is the tremendous cost and investment associated with developing and transitioning to an extensive transportation network based upon hydrogen. The widely-discussed "chicken and egg" problem focuses on the difficulty in building vehicles and hydrogen supply to meet a small and growing demand. While many current studies of the 'Hydrogen Economy' present a steady-state portrait of a mature energy system including H2 production, distribution and utilization, the transitional issues that are embodied in the chicken and egg problem are not addressed. Modeling the transition to a hydrogen economy is more complex than these static analyses because of dynamic nature of the problem. The transition costs will be determined by the size of the production, distribution and other infrastructure components and the economies of scale associated with these components and with the major shift in the transportation sector. Some analysts believe that in the near-term, infrastructure will be built up by means of distributed production of hydrogen at refueling stations by fuel processors or electrolyzers, which will lessen the initial infrastructure investment. These systems take advantage of existing energy distribution infrastructure (natural gas and electricity) reducing the capital expenditure requirements for hydrogen infrastructure. Only after significant maturation and market penetration of vehicles will the hydrogen demand be large enough to take advantage of the economies of scale associated with a dedicated infrastructure with large centralized hydrogen energy production plants and hydrogen pipeline distribution. In general, there is a trade-off between production costs and distribution costs that impacts a decision when to move from distributed to centralized hydrogen production. One key question that this analysis will explore is when and under what circumstances this transition could occur.

Hydrogen delivery is a critical contributor to the cost, energy use and emissions associated with hydrogen pathways involving central plant production. The choice of the lowest-cost delivery mode (compressed gas trucks, cryogenic liquid trucks or gas pipelines) will depend upon specific geographic and market characteristics (e.g. city population and radius, population density, size and number of refueling stations and market penetration of fuel cell vehicles). We developed models to characterize delivery distances and to estimate costs, emissions and energy use from various parts of the delivery chain (e.g. compression or liquefaction, delivery and refueling stations). Results show that compressed gas truck delivery is ideal for small stations and very low demand, liquid delivery is ideal for long distance delivery and moderate demand and pipeline delivery is ideal for dense areas with large hydrogen demand.

Hydrogen delivery is a critical contributor to the cost, energy use and emissions associated with hydrogen pathways involving central plant production. The choice of the lowest-cost delivery mode (compressed gas trucks, cryogenic liquid trucks or gas pipelines) will depend upon specific geographic and market characteristics (e.g. city population and radius, population density, size and number of refueling stations and market penetration of fuel cell vehicles). We developed models to characterize delivery distances and to estimate costs, emissions and energy use from various parts of the delivery chain (e.g. compression or liquefaction, delivery and refueling stations). Results show that compressed gas truck delivery is ideal for small stations and very low demand, liquid delivery is ideal for long distance delivery and moderate demand and pipeline delivery is ideal for dense areas with large hydrogen demand.

Many past studies of the 'Hydrogen Economy' have presented a steady-state portrait of a mature pathway from hydrogen production and distribution through utilization. One of the key problems surrounding the hydrogen economy is the large cost of building the infrastructure. The desire to reduce these costs associated with hydrogen infrastructure development leads to models and analysis of the dynamics of how a hydrogen supply infrastructure might grow over time, as demand for hydrogen increases in the transportation sector. To fully model hydrogen transitions is immensely complex, involving not only matching hydrogen supply and demand, but also how hydrogen interacts with the rest of the energy system, the economy, the environment and policy.

As a first approach to understanding transitions, we are developing a simplified model of the hydrogen economy – including alternative feedstocks, production technologies, distribution modes and demand scenarios. This model will be used to estimate infrastructure transition costs as a function of relatively small number of parameters for various demand scenarios. We plan to study how transition costs depend on factors such as the size and geographic density of demand, the market penetration rate, resource availability and technological progress. The goal is provide insights into low cost paths for moving our transportation fuel infrastructure from its current state to one based on large-scale use of hydrogen fuel. In this paper, we describe our overall approach and present initial results.