The most abundant element in the universe appears like the answer to every energy question.

It can be produced anywhere there is electricity and water. It can generate either heat or electricity. Unfortunately, hydrogen has not received the same limelight as some of its counterparts - especially in transportation applications.

What is hydrogen fuel?

Hydrogen is a clean and abundant fuel, that when consumed in a fuel cell has a by product of only water.  Hydrogen can store, transport and deliver energy produced from other sources such as coal. Hydrogen can be produced from a range of resources including solar, wind, biomass, natural gas and nuclear power. It is an attractive fuel source as it utilised in applications such as housing, portable power, vehicles and transportation.

Hydrogen fuel production:

The most common methods today of production include:

  • Steam reforming
  • Gasification
  • Electrolysis
  • Photolytic
  • Biological reactions

Hydrogen production technologies:

Thermochemical Processes

Thermal processes use energy from resources such as coal, natural gas and biomass to release hydrogen from their molecular structures. In combination to heat, some thermochemical processes use closed chemical cycles to extract hydrogen. Some of these processes include:

  • Natural gas steam reforming
  • Coal gasification
  • Biomass-derived liquid reforming
  • Solar thermochemical hydrogen
  • Biomass gasification

Electrolytic Processes

Using the process of electrolysis, electrolyses use electricity to split water into hydrogen and oxygen. This method to extract hydrogen is efficient and popular.

Solar water splitting processes

Hydrogen can also be produced through photolytic processes, sometimes referred to as direct water splitting, uses light energy to split hydrogen and oxygen. The potential of this process is a low environmental impact, but these processes are in early stages of research and their long term potential for sustainable hydrogen production is not yet known.

Solar water splitting processes include:

  • Photo-electrochemical
  • Photobiological.

Biological processes

Hydrogen can be extracted from microbes such as bacteria that produce hydrogen through biological processes. A sustainable, low carbon method of hydrogen production which is achieved using sunlight or organic matter. Examples include:

  • Photo-biological
  • Bacteria/microbial biomass conversion

Hydrogen fuel cells:

Fuel cells are often classified by the electrolyte that they contain. Classifications determine the cells capabilities and characteristics such as electro-chemical reactions that occur in the cell, catalysts required, operating temperatures and fuel required. Fuel cells have advantages and disadvantages which determine their potential applications.

Fuel examples of fuel cells include:

  • Phosphoric acid
  • Molten carbonate
  • Solid oxide
  • Reversible
  • Polymer electrolyte membrane
  • Direct methanol
  • Alkaline

Why are hydrogen fuel cells so expensive?

Fuel cells require expensive raw materials such as platinum and complex manufacturing procedures which result in a high purchase price.

Hydrogen fuel cells are expensive for two major reasons:

  • Raw material cost
  • Low market penetration - high manufacturing cost

Hydrogen for transportation:

What are fuel cell electric vehicles (FCEVs)?

A hydrogen fuel cell electric vehicle (FCEV) is a vehicle powered with electricity generated from chemical reactions of on board hydrogen between oxygen, which drive an electric motor. In comparison, a traditional electric vehicle (EV) is powered with electricity which is stored onboard via a cell, which is generally restored with a plug or regenerative braking.

Hydrogen fuel advantages and disadvantages:

Advantages

  • Low to zero emissions
  • Fuel cells are durable
  • Fits into current fuel pump infrastructure
  • Continually becoming more affordable
  • Refuelling time is lower than EV's

Disadvantages

  • Limited hydrogen refuelling stations/infrastructure - United States limited to California
  • Flammable - safety measures must be rigorous
  • EV's are more efficient overall with a battery energy source
  • Greenhouse emissions are still high - Fossil fuels are still used to produce hydrogen
  • Expensive to transport and store hydrogen

Does hydrogen-on-demand work?

A hydrogen-on-demand system (HOD) provides hydrogen for use by an internal combustion engine. HOD systems provide the possibility to convert traditional, fossil fuel vehicles to run on hydrogen power. Often, these systems utilise a process called hydrogen injection to create hydrogen using water and converting it into a gas.

The gas (HHO) is created by running an electrical charge (generated by the vehicles battery) through water and other chemicals. This is then fed into the engine through the intake manifold where it mixes with the fuel and is burned in the combustion chamber. Adding HHO gas to the fuel allows it to burn at a lower temperature, increasing efficiency and decreasing harmful carbon emissions.

The results also showed 10% increment in the gasoline engine thermal efficiency, 34% reduction in fuel consumption, 18% reduction in carbon dioxide, 14% reduction in HC and 15% reduction in NOx (EL-Kassaby, Eldrainy, Khidr and Khidr, 2016).

What is the range of a hydrogen cell?

Hydrogen competes with fossil fuels and battery-powered vehicles on driving range extremely well, with high efficiency. A full hydrogen cell will last approximately 480 kilometers, comparatively, an average petrol or diesel tank will last between 400 and 600km. Battery-powered vehicles are competitive in range, capable of driving long distances, but long charge times of 30 minutes to 12 hours are considered as their biggest disadvantage.

What is the current state of hydrogen fuel and what does the future look like?

Industrial demand of hydrogen has grown over 3 times that of 1975. Supply is often derived from fossil fuels, with 6% of global natural gas supply and 2% of coal supply used for hydrogen production.

Global spending on hydrogen energy research has been increasing over the past few years, but it is yet to return to its peak which was 2008. Governments are primarily looking at battery-powered electric vehicles as the solution and manufacturers have taken a similar stance with only Toyota pushing FCEV's.

In the future, fuel cells could power our cars, with hydrogen replacing the petroleum fuel that is used in most vehicles today. However, it is more likely that battery-powered EV's will have the greatest market share. Innovation in cell technology could change this.

International cooperation is pivotal in accelerating the growth and viability of hydrogen. A coordinated global push at a government level would increase awareness and investment into the technology which would bring costs down and increase availability as a viable fuel.

In 1970, a nuclear physicist named Lawrence W Jones presented a paper which noted 'The use of liquid hydrogen must be seriously considered as the logical replacement for hydrocarbons in the 21st century.' Since then, scientists have looked to hydrogen as a possible future solution for the worlds energy crisis.

As oil prices plummeted in the 1980s, hydrogen's appeal on the energy market vanished, only to come back around the start of the technology and internet bubble in the early 2000's. Low oil prices and bureaucracy has inhibited traction of hydrogen as a key player in the energy industry until now.

Researchers from UNSW Sydney have determined that Australia is in a good position to take advantage of its environment, with its solar resource to produce green hydrogen for export. Not using any energy from the grid - which uses fossil fuels for energy production, a method of using energy from solar cells to produce green hydrogen energy. With its spacious and sun abundant outback, Australia could envision itself become a key global player in the production of green hydrogen.

The pressing need for affordable, green hydrogen could not come sooner with California governor Gavin Newsom making a bold attempt of creating California a carbon neural state by 2045. The executive order, directs state agencies to develop regulations which ensure that all new passenger cars and trucks sold in the state are zero emissions by 2035 and heavy duty vehicles by 2045. This limits future sales to electric vehicles and hydrogen powered vehicles.

Environmental initiatives are sprouting as increasingly more attention is being cast on the environmental practices of states. This is likely to increase the pressure and incentives for the increased and greener production of hydrogen, resulting in competitive pricing to compete with future electric vehicles and traditional fossil fuels.