Green Hydrogen: Fuel of the Future?
Scientists are certain that without drastic countermeasures and new technology, global warming will continue to cause ever more disruptive environmental, economic and social disasters. Furthermore, current research emphasizes that to slow global warming and stem these consequences, society needs to go carbon neutral by 2050.(1) This means adopting new technology in every sector of our economy. The comparative advantages green hydrogen has, especially in transportation and energy storage, make it a promising energy source. With trillions of dollars committed to research and development, hydrogen could potentially power a significant portion of our economy in the coming decades.
Surprisingly, hydrogen is already used extensively in oil refining, fertilizer production and industrial manufacturing. In 2018, these sectors used 73.9 million tons of it, making hydrogen production a $135.5 billion industry.(2) However, currently, over 95% of hydrogen is produced by burning coal, natural gas or fossil fuels. As a result, analysis shows that the industry contributes more carbon emissions annually than the United Kingdom and Indonesia combined.(3) Growing investment in green hydrogen promises to decarbonize the process. Production of green hydrogen is carbon neutral and uses a different technique called electrolysis, whereby electricity from renewable energy sources is used to split water into hydrogen and oxygen.
Green hydrogen will contribute to achieving carbon neutrality by not only eliminating the carbon footprint of current production, but also by expanding into other highly polluting industries. For example, the transportation sector is ripe for a hydrogen revolution. Tesla and other car manufacturers have shown that electric cars are essential for reducing carbon emissions. However, the heavy weight and long charging times of batteries makes it difficult to implement outside of the personal vehicle market. Transportation and shipping by trucks, trains, ships and planes require light-weight construction and fast charging times; both of which batteries cannot deliver. Hydrogen fuel cells will likely be the solution to decarbonize these industries. The cells work by converting hydrogen back to water, which frees electrons in the process and creates a current that can be used to power electric motors. Importantly, hydrogen has 8 to 14 times the energy density of batteries, meaning hydrogen tanks are significantly lighter.(4) In addition, hydrogen refueling is much faster. Whereas a current battery powered car takes hours to charge, a hydrogen powered car with similar range refuels in under 5 minutes.(5) It is simply infeasible and inefficient for trucks, trains, ships and planes to carry heavy batteries and wait hours or even days to recharge. Recognizing the advantages of hydrogen, many companies, including Airbus and Toyota, are investing in hydrogen planes and trucks, while hydrogen trains and ships are already being tested in Europe.(6) Together, battery and hydrogen technology can electrify and decarbonize the transportation sector, which contributes 28.2% of global greenhouse gas emissions.(7)
Another important contribution green hydrogen can make to achieving carbon neutrality is providing cheap, long-term storage for renewable energy sources. A significant disadvantage of renewable energy is that it can often only be harnessed at certain times. For example, solar and wind power are completely weather dependent. This means that without sufficient storage capacity, shortages and blackouts are inevitable. Again, batteries and hydrogen will likely complement each other in providing much needed storage capacity. For short storage durations and small loads, batteries are cheaper and more efficient. However, hydrogen has a decided advantage in storing large capacities for long periods of time.(8) This is because hydrogen can be stored underground in salt caverns, aquifers and depleted oil fields, which reduces upfront investment costs. In fact, several underground storage systems are currently being built in the U.S. and Europe.(9) As society continues the transition to renewable energy, expanding battery and hydrogen storage will be central to building an efficient power grid.
Green hydrogen promises to help decarbonize the two most polluting industries, transportation and electricity generation; however it is not without its challenges. Currently, the production and distribution process are inefficient and costly. Since hydrogen is highly reactive, it only exists naturally in chemical compounds like water. Electrolysis breaks hydrogen apart from these compounds using electricity. Then, the hydrogen is stored so it can be converted back into electricity later on. In the end, the stored electricity is only about 80% of the electricity used to form the hydrogen.(10) This is far below the 99% efficiency rate of lithium-ion batteries and is a major contributor to the high production costs of hydrogen.(11) Additionally, hydrogen is corrosive, flammable and needs to be stored at high pressures or temperatures below -252.87 °C, meaning specialized and costly trucks, pipelines and short-term storage containers need to be built to handle widespread hydrogen use.(12) The facts illustrate that hydrogen is currently too expensive and the required infrastructure does not exist for mass adoption. It is important, however, to remember that high costs and low early demand have characterized the adoption of every energy source from coal and fossil fuels to solar power and batteries.(13) The trillions of dollars that many countries, universities and companies have committed to research and expansion is a positive sign that green hydrogen will greatly contribute to a carbon neutral future.
- www.forbes.com/sites/mitsubishiheavyindustries/2020/11/23/traveling-toward-a-hydrogen-economy-fueled-by-advances-in-planes-trains-and-ships; www.airbus.com/newsroom/press-releases/en/2020/09/airbus-reveals-new-zeroemission-concept-aircraft.html