- An abundant and cost-free fuel supply: Rather than depleting fossil fuel sources and polluting the environment, putting readily abundant air through the liquefaction technology actually cleans the air used. Depending on its contamination levels, the air is taken through a cleaning process, liquefied, and released (after producing electricity) as clean, pure air.
- Cryogenic liquid production, distribution, and equipment are mature infrastructures: LNG (liquid natural gas) is the largest user of cryogenic systems and a mature “end to end” system used on a very large scale. The existence of this system is necessary for the introduction of liquid air as a large-scale stored energy solution.
- Storage is at low pressure, and there is no fuel combustion risk: Large scale storage and delivery systems are well developed as there are over 300 LNG tankers with a storage capacity in excess of 125,000 m3 each plying the world’s oceans at any given hour. Liquid air, having no fuel combustion or high pressure risks, would make its shipping and handling cost 5 to 15% less than that of shipping and handling LNG. Stored air poses no threat to the environment. Air is safe; it is what we breathe. However, there are some considerations when handling it as a liquid.
- Unlike pumped hydro or large-scale CAES (compressed air energy storage) systems, grid-based storage has no geographical constraints: Less than 1% of the world’s land (and no ocean) is suitable for pumped hydro or contains caverns large enough for compressed air to be viably transported and stored. However, over 99% of the world’s oceans are suitable for cryogenic transportation and storage of liquefied air. Liquid air would be first used in coastal cities with suitable berthing for cryogenic tankers. Within 5 to 10 years, the LNG industry will have its FSO (floating storage & offshore) facilities coming online which will open much of the world’s coastal ports to cryogenic storage and offloading capabilities.
- Cost competitive to fossil fuel technologies: Renewables have the advantage that their marginal fuel cost is close to zero once the capital expense of developing a grid-connected renewable facility is paid back. A floating offshore rim-driven wind farm mechanically producing liquid air without the need for electricity has an LCoE (Levelized Cost of Energy) of 4 cents/KWh. The LCoE of natural gas is around 6.8 cents/KWh. The higher the difference is between the peak and off-peak cost, the more economical this technology will be. The debate around grid balancing is usually presented in terms of the need for additional gas-fired plants to run when the wind drops or there are shortfalls in other means of energy. Furthermore, there is a powerful case for additional grid storage to absorb excess ‘wrong time’ energy and warehouse it for times when it is required, preventing it from being wasted and allowing power plants to run more efficiently – enter liquid air.
- The automotive industry would have tremendous incentive to produce electric cars if they were charged from renewable electricity. Today’s single biggest constraint facing the use of electric cars is their dependence on fossil fuel to charge their batteries.Liquid air also brings many advantages to the utility industry.
