Hydrogen Energy Storage and Distribution
- Overview
The development of hydrogen infrastructure is slow and holding back widespread adoption. Hydrogen prices for consumers are highly dependent on how many refuelling stations there are, how often they are used and how much hydrogen is delivered per day. Tackling this is likely to require planning and coordination that brings together national and local governments, industry and investors.
Hydrogen is versatile. Technologies already available today enable hydrogen to produce, store, move and use energy in different ways. Hydrogen can be transported as a gas by pipelines or in liquid form by ships, much like liquefied natural gas (LNG). It can be transformed into electricity and methane to power homes and feed industry, and into fuels for cars, trucks, ships and planes.
There are tradeoffs between centralized and distributed production to consider. Producing hydrogen centrally in large plants cuts production costs but boosts distribution costs. Producing hydrogen at the point of end-use -- at fueling stations, for example -- cuts distribution costs but increases production costs because of the cost to construct on-site production capabilities.
Government and industry research and development projects are overcoming the barriers to efficient hydrogen distribution. Learn more about hydrogen distribution from the Hydrogen and Fuel Cell Technologies Office.
- Hydrogen Storage
Hydrogen storage is a key enabling technology for the advancement of hydrogen and fuel cell technologies in applications including stationary power, portable power, and transportation. Hydrogen has the highest energy per mass of any fuel; however, its low ambient temperature density results in a low energy per unit volume, therefore requiring the development of advanced storage methods that have potential for higher energy density.
Small amounts of hydrogen (up to a few MWh) can be stored in pressurized vessels, or solid metal hydrides or nanotubes can store hydrogen with a very high density. Very large amounts of hydrogen can be stored in constructed underground salt caverns of up to 500,000 cubic meters at 2,900 psi, which would mean about 100 GWh of stored electricity electricity. In this way, longer periods of flaws or of excess wind / PV energy production can be leveled. Even balancing seasonal variations might be possible.
- Hydrogen Distribution
Most hydrogen used in the United States is produced at or close to where it is used -- typically at large industrial sites. The infrastructure needed for distributing hydrogen to the nationwide network of fueling stations required for the widespread use of fuel cell electric vehicles still needs to be developed. The initial rollout for vehicles and stations focuses on building out these distribution networks, primarily in southern and northern California.
Currently, hydrogen is distributed through three methods:
- Pipeline: This least-expensive way to deliver large volumes of hydrogen is limited as only about 1,600 miles of U.S. pipelines for hydrogen delivery are currently available. These pipelines are located near large petroleum refineries and chemical plants in Illinois, California, and the Gulf Coast.
- High-Pressure Tube Trailers: Transporting compressed hydrogen gas by truck, railcar, ship, or barge in high-pressure tube trailers is expensive and used primarily for distances of 200 miles or less.
- Liquefied Hydrogen Tankers: Cryogenic liquefaction is a process that cools hydrogen to a temperature where it becomes a liquid. Although the liquefaction process is expensive, it enables hydrogen to be transported more efficiently (when compared with using high-pressure tube trailers) over longer distances by truck, railcar, ship, or barge. If the liquefied hydrogen is not used at a sufficiently high rate at the point of consumption, it boils off (or evaporates) from its containment vessels. As a result, hydrogen delivery and consumption rates must be carefully matched.
Creating an infrastructure for hydrogen distribution and delivery to thousands of future individual fueling stations presents many challenges. Because hydrogen contains less energy per unit volume than all other fuels, transporting, storing, and delivering it to the point of end-use is more expensive on a per gasoline gallon equivalent (per-GGE) basis. Building a new hydrogen pipeline network involves high initial capital costs, and hydrogen's properties present unique challenges to pipeline materials and compressor design. However, because hydrogen can be produced from a wide variety of resources, regional or even local hydrogen production can maximize use of local resources and minimize distribution challenges.
[More to come ...]