Hydrogen Production: Electrolysis | Department of Energy

The EU has started to make a move into making hydrogen as part of a larger strategy. Hydrogen, which has a diverse range of applications and can be deployed in a wide range of industries, can be produced in a number of ways. Over the last few years, a number of major businesses have become involved in projects centered around green hydrogen.

Spain’s Iberdrola and Sweden’s H2 Green Steel are to partner and develop a major facility that will produce green hydrogen, in yet another example of how companies are taking an interest in the much talked about sector.

In an announcement on Thursday, the firms said the €2.3 billion project would see them set up a green hydrogen facility with an electrolysis capacity of 1 gigawatt. Financing will come from a mixture of equity, green project financing and public funding.

Hydrogen, which has a diverse range of applications and can be deployed in a wide range of industries, can be produced in a number of ways. Electrolysis is the most common method and this can be used to refine steels and other metals as well. The companies are hoping to process 2 million tons of reduced iron each year.

The development by Iberdrola and H2 Green Steel will be situated somewhere on the Iberian Peninsula — no specific location has been announced yet — and is slated to commence production in 2025 or 2026.

To give this project some perspective the global electrolysis is about 300 MW so the scale of the project is genuinely massive. Among heavy industries, the iron and steel sector ranks first when it comes to CO2 emissions, and second when it comes energy consumption. The US steel production is dominated today by a fleet of minimills leveraging recycled metals. The EU move to a massive electrolysis suggests the US will take a good look at the ideas and there may well be some changes in the US heavy steel industry. The steel sector is currently the largest industrial consumer of coal, which provides around 75% of its energy demand.

Electrolysis is mature but the larger scale projects are demonstrating that here are advantages far beyond the immediacy of a supply of hydrogen. Hydrogen is a clean fuel for vehicles and power generation. Hydrogen does need a larger fuel tank which is a disadvantage. Hydrogen can even be used for home heating.

Long ago as a chemistry experiment I used nails and a 12V transformer in a beaker to explore the effects. Over time, one of the nails was corroded severely. The presence of hydrogen and oxygen suggests there was some industrial application with more study, Using a U shaped container would allow the hydrogen and oxygen to be captured easily. Changing the electrodes would eliminate the corrosion problem. Oxygen can be sold to hospitals readily. Cryogenic storage is mature so handling oxygen is easy. Hydrogen is slightly more demanding for cryogenic storage. Some of the ideas I looked at was making pure gold from alloys but the chemistry is complex. It is possible to separate gold from silver and even copper using aqua regia.

Liquid hydrogen is slightly more difficult than liquid oxygen. As for any gas, storing it as liquid takes less space than storing it as a gas at normal temperature and pressure. However, the liquid density is very low compared to other common fuels. Once liquefied, it can be maintained as a liquid in pressurized and thermally insulated containers. Liquid hydrogen also has a much higher specific energy than gasoline, natural gas, or diesel. Elemental hydrogen as a liquid is biologically inert and it’s only human health hazard as a vapor is displacement of oxygen, resulting in asphyxiation. Because of its flammability, liquid hydrogen should be kept away from heat or flame unless ignition is intended.

The goal of hydrogen is to replace fossil fuels to reduce the reliance on carbon. The US has studied hydrogen fuel stations to allow hydrogen based vehicles to travel the highways. These include the difficulty of developing long-term storage, pipelines and engine equipment; a relative lack of off-the-shelf engine technology that can currently run safely on hydrogen; safety concerns regarding the high reactivity of hydrogen fuel with oxygen in ambient air; the expense of producing it by electrolysis; and a lack of efficient photochemical water splitting technology. Hydrogen can also react in a fuel cell, which efficiently produces electricity in a process which is the reverse of electrolysis of water.

Prior to the development of natural gas supply and transmission—during the 1940s and 1950s in the United States and during the late 1960s and 1970s in the United Kingdom and Australia—virtually all gas for fuel and lighting was manufactured from coal. Town gas was supplied to households via municipally owned piped distribution systems. Originally created as a by-product of the coking process, its use developed during the 19th and early 20th centuries tracking the industrial revolution and urbanization. By-products from the production process included coal tars and ammonia, which were important chemical feedstock for the dye and chemical industry with a wide range of artificial dyes being made from coal gas and coal tar. Facilities where the gas was produced were often known as a manufactured gas plant (MGP) or a gasworks.

The UK has completed surveys and is preparing to start injecting hydrogen into the gas grid as the grid previously carried ‘town gas’ which is a 50% hydrogen-methane gas formed from coal. Auditors KPMG found that converting the UK to hydrogen gas could be £150 billion to £200 billion cheaper than rewiring British homes to use electric heating powered by lower-carbon sources. Excess power or off peak power generated by wind generators or solar arrays can then be used for load balancing in the energy grid. Using the existing natural gas system for hydrogen. Fuel cell maker Hydrogenics and natural gas distributor Enbridge have teamed up to develop such a power to gas system in Canada. Pipeline storage of hydrogen where a natural gas network is used for the storage of hydrogen. Before switching to natural gas, the German gas networks were operated using towngas, which for the most part (60-65%) consisted of hydrogen. The storage capacity of the German natural gas network is more than 200,000 GWh which is enough for several months of energy requirement. By comparison, the capacity of all German pumped storage power plants amounts to only about 40 GWh. The transport of energy through a gas network is done with much less loss (<0.1%) than in a power network (8%).

Hydrogen can also be made via high pressure electrolysis, low pressure electrolysis of water, or a range of other emerging electrochemical processes such as high temperature electrolysis or carbon assisted electrolysis. However, current best processes for water electrolysis have an effective electrical efficiency of 70-80%, so that producing 1 kg of hydrogen (which has a specific energy of 143 MJ/kg or about 40 kWh/kg) requires 50–55 kWh of electricity. The effective electrical efficiency of 70-80% is far better than any coal or natural gas power plant can achieve.

Graphene can store hydrogen efficiently. The H2 adds to the double bonds giving graphane. The hydrogen is released upon heating to 450 °C. This probably the best way to store hydrogen in smaller quantities. Cryo-compressed storage of hydrogen is the only technology that meets 2015 DOE targets for volumetric and gravimetric efficiency. Work is ongoing to overcome storage problems.

Due to its clean-burning characteristics, hydrogen is a clean fuel alternative for the automotive industry. Hydrogen-based fuel could significantly reduce the emissions of greenhouse gases such as CO2, SO2 and NOx. Three problems for the use of hydrogen fuel cells (HFC) are efficiency, size, and safe onboard storage of the gas. Other major disadvantages of this emerging technology involve cost, operability and durability issues, which still need to be improved from the existing systems. To address these challenges, the use of nanomaterials has been proposed as an alternative option to the traditional hydrogen storage systems. The use of nanomaterials could provide a higher density system and increase the driving range towards the target set by the DOE at 300 miles.

At present feeding hydrogen into the natural gas feeds is the best idea as the existing infrastructure is really available. Hydrogen can eventually displace natural gas as the production ramps up. Many Canadian cities use natural gas to heat homes. Converting to hydrogen would be of negligible cost. Wind and solar could create hydrogen for a feedstock. This is probably the best direction. The cost in minimal as well.