Flexible hydrogen pipeline systems for distribution & transportation

Despite the production costs associated with green hydrogen, the gas has many attractive properties as a future fuel source. With over three times the energy of petroleum per unit of mass and zero carbon emissions, hydrogen works well when used in conventional combustion engines but also as a source of heat for homes. 

Unlike electricity, hydrogen distributed production is possible wherever renewable energy and a water source are present. Hydrogen can fill gaps in the renewable grid when stored in high-pressure tanks when solar or wind farms cannot produce energy.

There are a wide variety of ways to transport hydrogen. As a liquid, it can be shipped via insulated tube trailers by road, rail, or water in the form of a carrier substance — typically methanol or ammonia. However, pipelines have the highest energy efficiency and lowest distribution costs of any delivery system, supplying ten times the energy of a typical twin overhead power line at over ten times less cost.

Green hydrogen is made by splitting water into its separate hydrogen and oxygen molecules using electrolysis. The resulting hydrogen (technically dihydrogen, or hydrogen h2) can be shipped or stored as needed, with the only byproduct being oxygen. Electrolysis requires large amounts of electricity, which for the hydrogen to be classed as 'green', must come from renewable energy sources such as solar or wind farms.

Green hydrogen can be blended with natural gas and either piped directly to home heating systems or used in municipal plants. When stored in fuel cells, hydrogen makes a viable alternative to batteries and electric motors, especially in larger applications such as coastal ships and long-distance trucks, as hydrogen can be injected into modified combustion engines and replenished at fueling stations in a similar manner to petroleum. 

As well as being used for fuel cell vehicles, hydrogen can be transported to power stations and used directly as a fuel to create electricity, which can then be distributed through local power grids.

By blending pure hydrogen into existing natural gas supplies, it will be possible to significantly reduce the CO2 emissions from home heating and cooking without residents having to radically alter their boilers or cookers. In the UK, for example, a 20% hydrogen blend is being trialed, which has not impacted gas users or required large-scale infrastructure changes.

On the one hand, hydrogen's low density means it flows at three times the velocity of methane. Conversely, methane has three times the calorific energy of hydrogen. This means that overall, existing pipelines should be able to deliver a very similar capacity of energy at a given pressure. 

Demand for hydrogen is rising as we transition to a cleaner energy grid. In the United States, hydrogen production is building momentum, which could lead to a 400 times increase in capacity during this decade. Closer to home, The European Commission has stated that by 2050, hydrogen should form 12-14% of the EU's energy supply. The Hydrogen Council suggests that countries go even further, pushing for 18% of total energy to come from gas.