Hydrogen can be generated at a central facility or on-site by a number of production methods.
Current Hydrogen Production Methods:
- Steam Methane Reforming – High-temperature steam is combined with methane in the presence of a catalyst to produce hydrogen. This is the most common and least-expensive method of production in use today, Figure 2.
- Electrolysis – An electric current is used to “split” water into hydrogen and oxygen.
- Gasification – Heat is applied to coal or biomass in a controlled oxygen environment to produce a gas that is further separated using steam to produce hydrogen.
Hydrogen Production Methods In The Research And Development Stage:
- Renewable Liquid Reforming—Ethanol or biodiesel derived from biomass reacts with steam to produce hydrogen.
- Nuclear High-Temperature Electrolysis—Heat from a nuclear reactor is used to improve the efficiency of electrolysis, again splitting water to make hydrogen.
- High-Temperature Thermochemical Water-Splitting—Solar concentrators are used to split water.
- Photobiological Microbes—Certain microbes produce hydrogen as part of their metabolic processes. Artificial systems can encourage these organisms to produce hydrogen through the use of semiconductors and sunlight, improving their natural metabolic processes.
- Photoelectrochemical Systems—These use semiconductors and sunlight directly to make hydrogen from water.
http://www.window.state.tx.us/specialrpt/energy/renewable/h2.php
Electrolysis of water can use low-carbon energy sources including renewables to make hydrogen generation essentially zero emissions. Hydrogen is not an energy source, but an energy carrier because it can be oxidized in a fuel cell to generate electricity. The fuel cell combines hydrogen and oxygen to form water and oxygen. That is hydrogen generated from water during electrolysis produces water in the fuel cell, i.e., water to water. This is as clean as it gets.
Hydrogen fueled cars reportedly get an average of 60 miles per kg of hydrogen. The high efficiency of these vehicles tends to compensate for the high retail price of hydrogen, making it competitively priced gasoline. The industry is close to a price structure twice that of gasoline, at which point hydrogen starts to have a price advantage, according to Poppe.
To understand what 60 miles per kg of hydrogen means in terms of gallons of gasoline, a value called energy equivalents is used to compare different fuels. Energy equivalent is the amount of an alternative fuel it takes to equal the energy content of one liquid gallon of gasoline. For example, a typical gallon of gasoline has an energy content of about 114,000 BTU per gallon. Using standard conversation formulas, 114,000 BTUs equals 33.4 kWh (kilowatt hours). This means that one gallon of gasoline is equivalent to 33.4 kWh of electricity.
In a similar way, the energy content of one kilogram of hydrogen gas converts to 33.4 kWh. Therefore, one kilogram of hydrogen gas (33.4 kWh) has the same amount of energy as one gallon of gasoline (33.4 kWh), i.e., 1 Kg of H2 gas = 1 gallon of gasoline. (Note, it is happenstance that both 1 kg of hydrogen and one gallon of gasoline equal 33.4 kWh.)
Using this relationship, 60 miles per kg of hydrogen equals 60 miles per gallon (mpg) of gasoline. (The energy content of 60 kg of hydrogen equals the energy content of 60 gallons of gasoline.) Therefore, a hydrogen car rated at 60 miles per kg requires 4 kg of hydrogen to go 240 miles between fill ups. In the same token, a non-hybrid gasoline car rated at 25 mpg traveling 240 miles requires about 10 gallons of gasoline. The difference between 4 kg of hydrogen and 10 gallons of gasoline to go the same 240 miles is due to the higher efficiency of a fuel cell versus and internal combustion engine. The gasoline car wastes 6 gallons of gasoline and loses 684,000 BTUs of energy to go the same 240 miles.
With federal incentives drying up on the fuel side of the value chain, a powerful way to incentivize FCEV market is through cap-and-trade programs employing carbon credits. The evolution of a viable cap-and trade program in the U.S. goes back to 2006 with California’s Global Warming Solutions Act. The Act calls for a ten percent reduction in the carbon intensity (CI) of transportation fuels by 2020, where CI is in grams of carbon dioxide equivalents (gCO2e) per unit energy (MJ) of fuel.
Then In 2009, the California Air Resources Board (CARB) adopted the Low Carbon Fuel Standard (LCFS) program. The program, implemented and enforced since the beginning of 2011, is a performance-based regulation enacted to meet the statewide reductions in greenhouse gas emissions (GHG) specified by California’s Global Warming Solutions Act of 2006.
Finally, in January 2012, California launched a refined cap-and-trade program with enforceable compliance obligations in 2013. This program makes a grand leap towards California’s ability to meet their ultimate goal of reducing GHG emissions to 1990 levels by the year 2020 and an 80% reduction from 1990 levels by 2050.
The cap-and-trade program is a flexible market-based standard implemented using a system of credits and deficits. Transportation fuels that have higher carbon intensity values than the compliance schedule yield deficits. Fuels that have lower carbon intensity values generate credits. Regulated parties are required to have a net zero balance of credits and deficits annually. Credits can be banked and traded without limitations. Credits do not lose value.
Credits and deficits are calculated and expressed as metric tons of CO2 equivalent. Each credit represents 1 metric ton of carbon dioxide and only carbon offset credits issued by California Air Resources Board (CARB) are considered compliance offset credits.
The following five-step process adopted by the State of Oregon determines the amount of carbon credits or deficits due a regulated entity. The process is in two parts: an explanation of the “Methodology” used to determine credits or deficits and an example “Calculation” using the output of a theoretical hydrogen fueling station.
