Hydrogen is the first element on the Periodic Table of Elements and is comprised of a single proton and a single electron. It is literally the fuel that powers the sun and is the most abundant element in the universe. While hydrogen gas (H2) is rare on earth, it can be extracted by various means from chemical compounds such as water (H2O) and ammonia (NH3). One of the most common ways to extract hydrogen is with a device called an electrolyzer, which passes an electrical current through water, splitting apart the hydrogen and oxygen atoms. These two gases can then be stored for various uses.
Hydrogen is an energy storage medium similar to a battery, but unlike batteries, which eventually lose their ability to hold a charge, hydrogen gas can be stored indefinitely.
Perhaps the best argument in hydrogen's favor is that when it is burned for heat, or passed through a fuel cell to make electricity, the only byproduct is chemically pure water.
When integrated with renewable energies like solar and wind power, hydrogen can offer a superior energy storage alternative to batteries with the added benefit of chemically pure water and oxygen as the only byproducts.