SciFi Future - Hydrogen Types defined

Its no secret that Hydrogen is expected to play a larger role as the squeeze on Fossil fuels continues.  Recall hydrogen does not exist on its own. Instead, it latches on to oxygen and carbon in compounds such as water (H2O), carbohydrates (sugar, wood, biomass) and hydrocarbons (oil, natural gas, biogas). It takes lots of energy to separate the hydrogen, which is stored until needed.  Pure hydrogen can be burned to produce heat in a furnace or engine, just like oil or natural gas. The hydrogen can also be channeled into a fuel cell to produce electricity. In both instances, water is the only byproduct.

Hydrogen is broken down by Color into Categories. There are three major types today - Blue, Gray & Green 

1) Blue - This type is made using non-renewable energy sources (e.g. nuclear). This meets the low-carbon threshold but is made from non-renewable sources. some say this is just a greenwash of Fossil fuels. Ranked as the second cleanest

2) Gray . AKA Fossil Hydrogen. Because it uses fossil gas, this way of making hydrogen does emit large volumes of CO2. This type accounts from roughly 95% of the hydrogen produced in the world today. 

3) Green - As the name might imply it is generated using renewable energy sources such as solar or wind.   Ranked as the the cleanest

There are two more colors Black and Brown but as you might guess from the names they are dirty and don't rank well

In summary, when you remove Gray you are left with two viable colors: green and blue. Choose wisely my friends