Safe Hydrogen, LLC is developing a hydrogen storage technology. It is an economical and safe hydrogen storage medium. When the hydrogen comes from electrolysis of water, electrical energy is stored. Safe Hydrogen uses a slurry of Magnesium/Magnesium Hydride particles with light mineral oil as a rechargeable medium. When the slurry is discharged, the particles are magnesium and, when the slurry is charged, the particles are magnesium hydride. The chemical equation is: Mg + H2 <--> MgH2 The two way arrow indicates that the reaction is reversible which makes the slurry rechargeable. The atomic weight of magnesium is 24 and the weight of hydrogen is 1. The weight of MgH2 is 26. Hydrogen is 2 out of the 26 or 7.7% by weight. We use a 50% mineral oil and 50% MgH2 mixture for the slurry. The slurry has 3.85% hydrogen by weight. It takes 12 kg of magnesium to store 1 kg of hydrogen. The 13 kg of MgH2 needs 13 kg of mineral oil to make it a slurry. Using today’s (Nov 2015) prices of $2.10 per kg of magnesium and $1 per kg of mineral oil, the raw material cost to store 1 kg of hydrogen is $38.20. One kg of hydrogen burned in a gas turbine will produce 15 KWh of electricity. Thus, the raw material cost to store 1 KWh of electricity is $2.40 per KWh. Assuming that the cost of processing the magnesium and oil into a slurry increases the cost to store 1 KWh by a factor of two, the capital cost to store one KWh of electricity is approximately $5.00. A capital cost of $5 to store 1 KWh of electricity compares extremely favorably with the capital cost of batteries which ranges from $200 to $500 per KWh stored.