What is Hydrogen?

Hydrogen is an odourless, colourless and highly flammable gas, and is the lightest and most abundant element in the universe. It is an extremely effective energy carrier, and when used as a fuel in either hydrogen fuel cells or hydrogen adopted combustion engines, it only produces water vapour as a by-product.

Explore data for E-hydrogen and Blue hydrogen

stylised hydrogen ocean
E-hydrogen

Explore e-hydrogen readiness levels

stylised hydrogen ocean
Blue hydrogen

Explore blue hydrogen readiness levels

Advantages and disadvantages of hydrogen

  • Advantages
  • Disadvantages
  1. Zero emissions: Hydrogen has the potential to be a zero-emission, well-to-wake fuel if produced using renewable energy (e-hydrogen).
  2. Light: Hydrogen has a very high specific energy density (approximately 33.33 kWh/kg) and is considerably lighter than other fuels when storing the same amount of energy. 
  1. Storage requirements: Although hydrogen has a high energy density per unit weight, it has a low volumetric energy density and therefore poses storage challenges on-board as it requires either a significant amount of space or alternative storage methods, such as in liquid form in cryogenic tanks.
  2. Safety considerations: Hydrogen has unique safety considerations due to its flammability and potential for leaks, so stringent handling, storage and safety measures are crucial.
  3. Indirect GHG emissions: Whilst hydrogen is not considered a greenhouse gas emission in itself, if leaked into the atmosphere, it can react with other elements in the atmosphere to act as an indirect greenhouse gas emission. However, fuel cells are a closed energy system. Therefore, there should be no expected leaked hydrogen. 

Communities need educating on the wider benefits of renewable energy and to dedicate land use for these purposes, and investments in countries that are well-suited to providing renewable resources required for scale up of supply need to be de-risked.

Communities challenges

CCS for blue hydrogen is limited by availability of carbon storage, and evidence of high capture rates and lack of leakage from storage sites

Blue hydrogen challenges

Technology readiness needs to increase before trials can begin

Technology challenges