5-6th Thermal and Fluids Engineering Conference, 2021
Much of the world believes that global warming can be mitigated through mandated de-carbonization of the atmosphere. Much of the policy effort has been focused on substituting wind and solar power generation for power produced by burning fossil fuels. If the goal is to have at least 24 hours of economical,utility scale, stored power in order to contend with wind and solar intermittency, we are not anywhere near meeting that goal. Today, even with deep pockets, 2 hours is the target. We, and others, propose an alternate option, similar to the proven LNG storage methodology,in order to store surplus “green” power. This approach would produce “green” hydrogen. Surplus renewable power would support the electrolysis of water. The released hydrogenwould then be liquefied and stored for future use as a fuel in generating power, initially by blending the hydrogen with pipeline natural gas and using the blended fuelin combustion turbines or larger combined cycle gas plants.Although electrolytic production of hydrogen is power intensive, even before considering the cost of liquefaction, it is viewed as a viable option for the use of “free” surplus renewable power. While the majority of hydrogen produced today is based on processing natural gas, a green option is technically possible using electrolysis. We have been operating NASA space flights for 50 years using engines fueled with liquid hydrogen and oxygen. Perhaps the ultimate “green” fuel, this approach produces no CO2 and when the Hydrogen is combusted, the only exhaust is water. Finally, another approach, announced by UK researchers, uses surplus renewable energy to liquefy, perhaps the most ubiquitous of all working fluids, air. Once produced, the liquefied air isstored and then re-gasified and used to generate power by feeding the high pressure air to turbo-generators during periods when wind and solar power are offline. Our proposal expands on the British approach by using distillation columns to remove CO2 from the liquefied air prior to storage. Multiple companies, including Air Products and Air Liquide have been using cryogenic distillation to supplyhigh purity oxygen, nitrogen and argon for the better part of a century.
3299 0