storageparcial2

Which of these energy storage systems responds most quickly to grid instability?. Supercapacitor. b. CAES (Compressed Air Energy Storage). Flywheel. Battery.

In air liquefaction for LAES cycles: a. Liquid air is stored at high pressure (aprox 200 bar). b. The Linde cycle is usually employed. c. Very low-temperature cold from the regasification of liquefied natural gas can be utilized to improve storage efficiency. d. Moderate pressures (aprox 10-20 bar) are used.

The storage efficiency in LAES (without external heat or cold sources) is around: a. 55%. b. 35%. c. 90%. d. 75%.

In the Power Recovery Unit (PRU) in a liquid air energy storage plant, regeneration using a heat recuperator: a. allows reducing the necessary heat for pre-heating before the first expansion, and therefore increasing the storage system's efficiency. b. presents no advantages because the necessary investment is very high. c. allows increasing the power of the turbines and therefore increasing the storage system's efficiency. d. Heat cannot be recovered.

In supercapacitor systems for electrical storage: a. Their highest discharge power occurs when they are fully charged. b. They have better discharge response stability than Lead-acid batteries. c. Their nominal full-load voltage must be exceeded for charging. d. After 80% discharge, they suffer a sudden drop in discharge potential.

Hydrogen as an energy vector: a. Is currently produced mainly by water electrolysis. b. Can be transported in current natural gas networks without modification up to concentrations of 50% vol/vol. c. Presents many difficulties in both its storage and transport. In both cases, it implies a non-negligible energy consumption. d. Has a lower heating value per unit mass (LHV in MJ/kg) on the order of 4 times less than gasoline.

Which of these systems does not use Carbon as one of its fundamental materials?. a. Lead-Acid Batteries. b. Supercapacitors. c. Lithium-Ion Battery. d. High-speed Flywheel.

One of the main characteristics of supercapacitors is that: a. They are based on electrochemical exchanges. b. They are based on the accumulation of electrostatic charges. c. They are capable of storing a lot of energy to be discharged over hours. d. They are used for alternating current systems.

The production of e-fuels (electro-fuels or synthetic fuels) via power-to-liquids fundamentally consists of: a. around 20% of the energy is lost in their elaboration process. b. producing ammonia NH3 for fertilizers from hydrogen obtained by electrolysis and renewable energies. c. combining gray hydrogen and CO2 to obtain a hydrocarbon via the Haber-Bosch process. d. combining green hydrogen and captured CO/CO2 to obtain a hydrocarbon via the Fisher-Tropsch process.

Which of these elements cannot be considered an energy vector?. methane. ammonia. water. methanol.

The major advantage of alkaline electrolyzers is: a. They adapt very well to variable load, which makes them the main technology for hybridizing with fluctuating renewable energies. b. In general, the catalysts (nickel) are cheap, which means the specific cost of alkaline electrolyzers is reduced compared to other technologies. c. The ability to work at high pressures, which allows reducing the compression work of H₂ for its storage and/or transport. d. Obtaining H₂ directly in the gaseous phase, which makes it possible to dispense with an H₂/water separator.

An important disadvantage of PEM ("Proton Exchange Membrane") electrolyzers is: a. The high cost of catalysts, such as platinum, gold, or iridium. b. Their poor efficiency at partial and variable load, which makes coupling them with fluctuating renewable energies difficult. c. The need to separate H₂ from water at the cathode. d. Their very poor performance (aprox 45%).

In a flywheel formed by a solid cylinder, the maximum energy density (J/kg) that can be stored: a. Does not depend on the characteristic length of the cylinder. b. Depends on the speed of rotation. c. Is independent of the relationship between admissible stress and material density. d. Is solely a function of the material's admissible stress.