It exists in the stars. It is a gaseous, colorless, odorless and insoluble element in water. It's less dense than air and it's the lightest of all elements on the periodic table. It is… Hydrogen... and its stable molecular formula is H2!

In the last few months you may have heard about this humble “hero”. H2 has been used for many years, but now it is receiving more attention in several sectors, primarily in the energy sector. Hydrogen is indispensable to the decarbonisation of society and EDP has its sights set on this element's superpowers. 

H2: in search of its place in the energy sector 

The Roadmap for Carbon Neutrality (RNC2050) is a commitment that aims to achieve 100% decarbonization by 2050; an international goal that Portugal has taken on with many other EU countries, thus contributing to the reduction of greenhouse gas emissions around the world. 

Miguel Patena, who responsible for Innovation at EDP Produção, believes that we have entered a new and attractive stage for the energy sector. We have to consider not solely using electricity for energy, but also using green fuels. This combination is what could lead to the decarbonisation that society intends on. And why? 

In 2030, the objective is that more than 90% of the electricity generated by EDP is from renewable sources. The most efficient and inexpensive way to reach 100% in 2050 is with electrification of consumption in general, whether in electric mobility, air conditioning, industries, etc. Even so, there are sectors where electrification will be "unreachable", such is the case with heavy industry, air transport and navigation. Here comes hydrogen, more specifically green H2, which can be used to solve this problem. In addition, it has gained economic viability, and its use is increasingly accessible. That is why we can look at this element as a possible important tool in the fight against the climate crisis. 

“With great expectations comes great responsibility” 

With the global euphoria currently felt around hydrogen for the production of green energy, it is not only necessary to know all this element's powers, but also to be aware of its disadvantages.

H2 does not exist in nature in its pure state, so it has to be obtained through energy-consuming processes, to then be utilized in different ways, either in direct combustion or in fuel cells. The way it is produced can be “green” or not. The most common processes for producing electricity from H2 are:

• Reforming: it works by applying high temperatures where the steam reacts with a hydrocarbon fuel (natural gas, diesel, coal, etc.) to produce hydrogen. Today, about 95% of hydrogen is produced through vapor from natural gas. 
• Electrolysis: an electric current is used to separate water into hydrogen and oxygen. These processes occur with an electrolyser, which has the ability to create H2 from water molecules. 

The natural gas process gives rise to gray hydrogen, because it emits CO2. When the electrical energy, which powers electrolysis, is 100% renewable, we have green hydrogen - a process without any CO2 emission, from source to its final use. This is the goal in the very near future: completely clean and environmentally friendly production.
 

The electrolyser technology, with an installed capacity of 1 MW, works with membranes and protons, that is, what it does is the separation of hydrogen and oxygen in the treated water. Oxygen is used as a fuel or as a catalyst in other industrial processes and hydrogen as an energy vehicle, either by direct combustion to produce heat in boilers or to produce electricity from fuel cells. 

In the Ribatejo project, FLEXnCONFU, the production process will be one with a combined cycle. This technology is based on the simultaneous operation of a gas turbine and a steam turbine. Let's see how it works?

H3: How does the Combined Cycle work?

• Gas at high pressure, created by the combustion of natural gas or hydrogen, is used to move the gas turbine and produce electricity.
• The medium and low pressure gases pass through the recovery boiler, and release residual heat for the production of water vapor, activating the steam turbine. 
• The steam coming out of the turbine is condensed through cooling in the condenser. The water is redirected to the boiler to be vaporized again. The combined action of the two turbines sets the alternator in rotation, converting mechanical energy into electrical energy.
   

“What we are doing in Ribatejo is not green hydrogen, because the electricity that powers the electrolyzer is not 100% renewable, but this only is a pilot project. The future is renewable energy. Since we already have this installation, we want to proceed with the project, so that later we will have all the know-how to explore green H2 ”, says Miguel Patena.

It is with this component that it is possible: to produce electricity and produce green fuel. In addition, this is the only renewable energy source to date, that we have managed to store and even managed to transport. This is another hydrogen power that will help RNC2050. Storage will also be tested in the Central do Ribatejo project. 
Some of the current technologies allow us to store large amounts of hydrogen in:

• A liquid state at temperatures below -235ºC and stored in large capacity cryogenic chambers;
• Compressed under high pressure. This will be the method tested at the Ribatejo power plant with a storage capacity of 12 MWh.  

With the support of the European Union, EDP expects to have the construction phase of hydrogen demonstration and production ready in 2022. For EDP's Executive President, António Mexia, “Hydrogen is a clear option in the new world of energy. As leaders in this transition of energy, we are continuously evaluating and testing potential alternatives for energy production. Portugal can aspire to be at the forefront of hydrogen development over the next decade”.