What Are Alternatives for Using and Creating Hydrogen Fuel?
by Bob Shively, Enerdynamics President and Lead Facilitator
In our December 2019 Energy Insider we wrote that after electric storage, green hydrogen may be the next big thing in energy. To help you understand what is involved in making the transition to green hydropgen, let's examine the current and future markets for hydrogen and the technologies for creating hydrogen. The we'll discuss how the desire to decarbonize the energy sector may lead to future adoption of low-carbon hydrogen.
Current and future markets
An estimated 76 million tonnes of hydrogen were produced worldwide in 2019. Most of this was used for petroleum refineries and ammonia production. Currently almost all hydrogen is produced from fossil fuels, meaning that the current uses contribute to greenhouse gas emissions. But with the potential to create low- or zero-carbon hydrogen in the future, new markets may arise as hydrogen becomes a key tool in climate change initiatives. Potential new markets include:
||Fuel for passenger electric vehicles using fuel cell technology and fuel for light and heavy-duty trucking using fuel cell technology or liquid synthetic fuels formulated from hydrogen
||Long-duration storage coupled with low-cost electricity generation by excess renewables or excess nuclear power
||Fuel for combined-cycle gas turbines, peaking turbines, and/or fuel cells
|Industrial heat process
||Fuel for industrial process heating
||Replacement for high-carbon hydrogen in ammonia production and refining, and displace coal in steel production
Fuel for traditional combustion furnaces and combined heat and power system
Hydrogen production technologies
Today almost all hydrogen used in industry is produced from fossil fuels. An estimated 75% is from natural gas, with most of rest from coal or oil. Less than 2% of hydrogen is produced using electricity to drive electrolysis. Here are four key processes that can be used to produce hydrogen:
Steam methane reforming (SMR)
|Natural gas is heated to high temperatures in the presence of steam and a catalyst resulting in production of hydrogen gas and carbon monoxide. In a subsequent process, the carbon monoxide and steam are reacted using a catalyst to produce carbon dioxide and more hydrogen. The hydrogen is then cleaned to create a pure hydrogen stream. An undesirable by-product is carbon dioxide, a greenhouse gas.
|Steam methane reforming with carbon capture and storage (SMR with CC&S)
||The SMR process is used, and the carbon dioxide is captured and placed into long-term geologic storage. This can eliminate about 90% of the greenhouse gases produced by the SMR process. Hydrogen created this way is called Blue Hydrogen.
||Coal is reacted with oxygen and steam under high pressures and temperatures to form synthesis gas, a mixture consisting primarily of carbon monoxide and hydrogen. Then, like in SMR, the carbon monoxide and steam are reacted to produce carbon dioxide and more hydrogen. The hydrogen is then cleaned to create a pure hydrogen stream. Like with SMR, an undesirable by-product is carbon dioxide, a greenhouse gas. The volume of greenhouse gases produced by coal gasification is about twice that of natural gas SMR without CC&S.
||Electricity is used to split water into hydrogen and oxygen in a device called an electrolyzer. Electrolyzers consist of an anode and a cathode separated by an electrolyte. Different technologies include Polymer Electrolyte Membrane (PEM), alkaline, and solid oxide electrolyzers. The greenhouse gas emissions associated with the process depend on the source of electricity. If renewables are used, there are no greenhouse gas emissions. Hydrogen created with renewable electricity is called Green Hydrogen.
The future for hydrogen fuel
Hydrogen fuel will likely be a key component in world governments' or markets' efforts to reduce greenhouse gas emissions. Initial development is already occurring. According to Wood Mackenzie, a total of 252 megawatts (MW) of green hydrogen projects were in production by the end of 2019, and by 2025 an additional 3,205 MW will be deployed. Current green hydrogen projects are being implemented in numerous countries including Austria, Belgium, Japan, the Netherlands, the United Arab Emirates, and the United Kingdom.
Numerous countries also are implementing pilot projects to inject hydrogen into natural gas distribution systems to create a blended fuel. Countries with such projects include Austria, France, Germany, Italy, and the United Kingdom. Many in the electricity industry envision that hydrogen storage for renewable generation is critical to operating grids with high percentages (greater than 70%) of renewables. While batteries may be more appropriate for short-term storage, it appears that hydrogen may be best for long-duration storage when pumped hydro is not available. So, while it is premature to say a new hydrogen economy is here, there are certainly signs that it is on the rise.
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