The hydrogen economy is the use of hydrogen as a low carbon fuel, particularly for heating, hydrogen vehicles, seasonal energy storage and long distance transport of energy.
The hydrogen economy is proposed as part of the future low-carbon economy. In order to phase out fossil fuels and limit global warming, hydrogen is being considered as its combustion only releases clean water, and no CO2 to the atmosphere. As of 2019, however, hydrogen is
mainly used as an industrial feedstock, primarily for the production of ammonia, methanol and petroleum refining.
Hydrogen gas does not occur naturally in convenient reservoirs. As of 2019 almost all the world’s hydrogen is produced by steam methane reforming (SMR). (Wikipedia)
But hydrogen can also be produced by electrolysis of water, acting as an energy storage, so that, when combined with renewables like wind, solar or hydro, it can successfully even out the intermittent nature of these energy sources be used in automotive, as well as stationary applications produce ultrapure water and heat as a by-products
One of the largest advantages to PEM electrolysis is its ability to operate at high current densities. This can result in reduced operational costs, especially for systems coupled with very dynamic energy sources such as wind and solar, where sudden spikes in energy input would otherwise result in uncaptured energy. The polymer electrolyte allows the PEM electrolyser to operate with a very thin membrane (~100-200 μm) while still allowing high pressures, resulting in low ohmic losses, primarily caused by the conduction of protons across the membrane (0.1 S/cm) and a compressed hydrogen output.
The polymer electrolyte membrane, due to its solid structure, exhibits a low gas crossover rate resulting in very high product gas purity. Maintaining a high gas purity is important for storage safety and for the direct usage in a fuel cell. The safety limits for H2 in O2 are at standard conditions 4 mol-% H2 in O2.
A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is a type of electric vehicle which uses a fuel cell, instead of a battery, or in combination with a battery or supercapacitor, to power its on-board electric motor. Fuel cells in vehicles generate electricity to power the motor, generally using oxygen from the air and compressed hydrogen. Most fuel cell vehicles are classified as zero-emissions vehicles that emit only water and heat.
So, providing the energy for production of Hydrogen comes from renewables, the only emissions are those embodied in the manufacture of the H2 production equipment, their storage and transport.
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from metals and their ions or oxides  that are commonly already present in the battery, except in flow batteries. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
Already several countries have launched their own industries on the path to H2 Fuel cells and production, and the diversification of the market, with Lithium batteries better suited for some applications and H2FCs for others, offer a broader range of choice than ever before, with real opportunities for investment in the whole supply chain. All that is needed is a co-ordinated effort between academia, industrial R&D and manufacturing, international bodies and institutions, national governments and commerce, to bring online a range of prototypes to demonstrate the advantages of replacing IC engines with H2FCs and electric motors for vehicles of every type, as well as between renewable generation equipment and Fuel and Electrolytic Cells manufacturers.
The launch of such an initiative would create multi-strand opportunities for industry, financial institutions and investors, and create a range and number of jobs in the manufacture of fuel cells, motors, H2 storage, H2 production, infrastructure, storage, delivery and distribution, not to mention education and training in the new technology, as well as in
the renewables industry to generate the hydrogen.
An intermediate stage towards the Hydrogen Economy may be to manufacture the elements necessary to adapt current fleets of internal
combustion vehicles. These would comprise of:
a motor, of a suitable type, size, shape and rating to replace an IC engine a Fuel Cell stack, with the necessary wiring and H2 feed pipes
a Hydrogen tank – of whatever type and size may best suit the vehicle’s configuration*
*These could be compressed H2, metal hydride or other solution.
Kits can only be installed by specially trained personnel, and undergo rigorous testing to ensure their safety, after installation, and only released with safety certification.
Erroneously termed “Al-air batteries” these units produce electricity from the reaction of oxygen in the air with aluminium. They have one of the highest energy densities of all batteries. Formerly considered impractical, because of the because of problems with high anode cost and byproduct removal when using traditional electrolytes, a British former Naval Engineer, Trevor Jackson, of Métalectrique has in fact developed commercially viable Al-Air FCs, and is now working with Austin Electrical Ltd. to produce the first Al-Air powered vehicle.