WHAT IS HYDROGEN?
Hydrogen is the first element of the periodic table.
It is the lightest chemical element that exists; the atom consists of one proton and one electron and is stable as a diatomic molecule (H2).
Under normal conditions hydrogen is in gaseous state, and is tasteless, colorless and odorless.
On Earth is abundant, it constitutes approximately 75% of matter in the universe, but is combined with other elements such as oxygen to form water molecules, or carbon to form organic compounds. Therefore, there is a fuel that cannot be taken directly from nature, but an energy carrier (like electricity) and therefore it must be “manufactured.”
HYDROGEN PRODUCTION
There are several methods to produce hydrogen from different raw materials, different energy sources and by different procedures.
Depending on the raw material and the energy source used to produce it, we may speak of processes 100% renewable, 100% fossil or hybrid processes in a certain percentage.
Hydrogen can be produced locally, at large central plants or in small distributed units located at or near the point of use (on-site production). This means that every community, even remote areas, can become an energy producer.
When produced using renewable energy sources and powering highly efficient fuel cells, the environmental benefits of hydrogen are even greater. Additionally, hydrogen can be produced and stored using off-peak energy produced by renewable energy technologies such as solar, wind, hydraulic…
One kilogram of hydrogen can release more energy than any other fuel (almost the triple of gasoline or natural gas), and to release that energy does not emit any carbon dioxide, only water vapor, so the environmental impact is zero.
HYDROGEN STORAGE
One of the most important applications of hydrogen is its use as energy storage. This is a key point for its introduction into the market and one of the main advantages and values of hydrogen as an energy carrier. Hydrogen is characterized by a high energy density per unit mass but not per unit volume so its mayor problem is that storage in normal conditions occupies much volume.
For this reason there are several ways to store hydrogen in different stages of development, including:
Compressed Gas
This is the most often used technique to supply hydrogen in pressures up to 700 bar. It is a generally available and low cost technique. Only relatively small amounts of H2 at 200 bar are stored nowadays and storage at higher pressure (700 bar) is still in a development phase.
Liquid hydrogen
Metal hydrides
Chemical hydrides
Carbon structureso
HYDROGEN APPLICATIONS
Hydrogen has been used safely for many decades in a wide range of industrial applications, including in the food, metal, glass and chemical industries. The global hydrogen industry is well established and produces more than 50 million tonnes of hydrogen per year.
With respect to energy, hydrogen can be used as a fuel for transport, and to generate electricity in fuel cells.
One kilogram of hydrogen can release more energy than any other fuel (almost the triple of gasoline or natural gas), and to release that energy it does not emit any carbon dioxide, only water vapour, so the environmental impact is zero.
A hydrogen internal combustion engine (ICE) vehicle uses a conventional internal combustion engine modified to burn gaseous hydrogen. Hydrogen ICE vehicles are typically about 30% more efficient than comparable fuel vehicles, and perform well under all weather conditions, including cold temperatures.
Hydrogen Refuelling Stations
A hydrogen refuelling station (HRS) is a storage or filling station for hydrogen.
It is a relatively new concept and it is intended in transportation is to use fuel cells to replace diesel or gasoline to hydrogen in HRS. It is expected that the stations will be gradually replaced from fossil fuels with petroleum-based to fuel cells or hydrogen.
Hydrogen fuel is intended to be an intermediary between renewable energy and the final user, avoiding the problem of discontinuity generation and mobility in the case of transportation.
Hydrogen stations can obtain hydrogen by electrolysis of water with surplus renewable electricity from wind farms or solar panels located in public parkings.