Hydrogen technologies: Powering the race to net zero

The race to net zero is on, and to cross the finish line by 2050 industry needs to shed the burden of fossil fuels. But which energy sources have the power to replace them?

Although electricity is the undisputed front-runner when it comes to cleaner energy alternatives, electrification falls short in parts of the world that are isolated or lack solid electrical infrastructure. And this is without mentioning all the “hard-to-abate” sectors such as steel industry or intensive mobilities.

That’s where hydrogen steps in. The gas is already used as a chemical reagent in industries such as oil refining and agrochemicals, to the extent of 90Mt a year. And now a boom is on the cards, with demand predicted to increase by a factor of 4 to 6 by 2050. Production from water electrolysis would then account for over a quarter of the global power demand!

Decarbonizing hydrogen

But just how virtuous is hydrogen? Its production processes vary wildly in their environmental impact, leading to the informal and sometimes bewildering hydrogen rainbow classification system. The vast majority of hydrogen today comes from fossil fuels via high temperature steam reforming of methane, with 10kg of CO2 emitted for every kilogram of H2. This type of production is responsible for 2-3% of global CO2 emissions, on a par with air-travel!

Making hydrogen is also possible using electrolysis. This process, that splits water molecules into oxygen and hydrogen, is energy-intensive – 50-60 kWh generates 1kg of hydrogen. But when the electrolyzers are connected to renewable energy sources, very low-carbon hydrogen can be achieved.

However, its low density at room temperature means it must be compressed at high pressures – up to 700 bar – or cooled to a very low temperature – -253°C (20K) – to turn it into a liquid that can be transported and stored.

Furthermore, the carbon intensity of hydrogen produced by water electrolysis depends on the energy mix of the electricity source. In some countries with lots of coal power plants, the carbon footprint of electrolysis process could be more detrimental than steam methane reforming.

High-pressure challenges

New applications for hydrogen are springing up in the fields of energy and mobility. But to ensure the boom doesn’t run out of gas, big changes must be made over the whole lifecycle.

This starts with production. For hydrogen to truly contribute to a net zero emission world, the energy used for the electrolysis must come from renewable sources such as onshore or offshore wind and solar farms which Nexans already connects. This will have a direct impact on hydrogen’s price tag, which will then be driven by the costs of electricity and capital investment in farms and electrolyzer units.

Once it has been produced, all this hydrogen still has to reach the end user, and the right storage and transportation solutions could mean the difference between success and failure. Just one kilogram of hydrogen takes up 12m³ at atmospheric pressure, and very high pressures (up to 700 bar) are needed to bring this volume down to manageable levels.

The solution? Liquefy hydrogen. This has been a practice in aerospace for decades, and new applications for liquefied hydrogen (LH2) are emerging, such as:

• Overseas transportation of energy between production and consumption places. The Hystra project – producing hydrogen in Australia and shipping it by cargo to Japan – was a world first, enabled by Nexans high-flexibility cryogenic transfer lines. Projects aiming at deploying the infrastructures for maritime transportation of LH2 are now starting in key maritime ports to prepare the forthcoming worldwide trade of LH2.
• Aeronautics. Airbus is aiming to fly the first commercial plane fueled with LH2 in 2035. This will mean a complete change of airport infrastructures to supply hydrogen, electricity and sustainable aviation fuels, in places where safety and floor space are major stakes.

Innovation at every stage of the game

Nexans is contributing new technology and business solutions all the way down the hydrogen value chain.

• On the production side, we provide solutions for optimizing the operating and capital expenses of producing renewable energy. Applied to electrolyzing units, our unique know-how on grid design could help achieving optimized hydrogen production facilities
• On the storage and distribution side, Nexans has long been a pioneer in supply infrastructures for cryogenic fluids. Our vacuum-insulated flexible transfer lines offer easy-to-install, safe and reliable solutions for tank-to-tank transfer of LH2. Their “plug-and-play” installation is as easy as laying a power cable and beats conventional rigid piping systems when it comes to speed of implementation. We recently equipped the world first loading systems for ship-to-shore transfer of LH2 in Kobe, Japan, with long length, high flexibility cryogenic transfer lines capable of high flow rates, numerous bending cycles and minimal boil-off.

The future is hybrid

If smartly combined, electrification and hydrogen will team up to contribute to more efficient low-carbon energy supplies. Pushing forward the complementarity between the two energy vectors, we are currently developing new concepts of hybrid lines able to vehiculate both hydrogen and electricity in the same system, including:

• Subsea umbilical systems to transfer hydrogen, data and electricity between offshore production units, such as wind farms or energy islands, and land;
• Superconducting systems combining LH2 transfer and superconductivity for hybrid energy highways that can transmit impressive amounts of power over long distances and help modernize power grids.

Ultimately the transition to net zero will require a shrewd combination of many interlocking energy sources and technologies. Together with electrification, Nexans is empowering hydrogen to become a safe, effective, economically and environmentally viable contributor to the energy supply of tomorrow.

Floating technology is a hot trend in the world of renewables. We examine the drivers and discover how Nexans is helping to turn the dream of floating offshore wind – and solar – into a reality.

Offshore wind generation has seen tremendous growth over the past decade. Global offshore capacity has now reached 35 GW – an almost nine-fold increase since 2011. An additional 235 GW of offshore capacity is expected by 2030, taking the global total to 270 GW.

Turbine technology has made huge strides since the first wind farms appeared in our oceans more than twenty years ago. Today’s turbines are bigger and more efficient than ever, with rotor diameters in excess of 200 metres and power ratings of 10 MW and more. These advances have played a critical part in driving down the cost of offshore wind.

Almost every offshore wind turbine in existence today depends on bottom-fixed foundations, which are a good solution in relatively shallow waters – those up to 60 metres deep. These foundations are steel and concrete footings that attach the turbine structure directly to the seabed.

The vast majority of oceans and seas have waters that exceed 60 metres in depth – and this is where the highest and most consistent winds are found. In Europe, for example, 80% of the wind resource occurs over waters with a depth of 60 metres or more. Conventional foundations are not cost effective in these situations. So there are large areas where wind resources are untapped.

New horizons for offshore wind

Floating wind turbines overcome the problem of providing foundations in deep water. Instead of being rooted to the seabed, turbines are mounted on a floating substructure that is tethered with mooring lines and anchors.

All of this is a game changer for offshore wind. Rather than being restricted to a depth of 60 metres, floating turbines can be deployed in waters up to 1000 metres deep – and potentially much more.

This has exciting potential to expand the geographical reach of offshore wind. The northern part of the North Sea basin is one example. The depth of waters here typically far exceeds 60 metres, putting them beyond the reach of conventional foundations.

Hywind Scotland in the UK – the world’s first floating wind farm – highlights what can be achieved. Sited about 30 km offshore in waters up to 120 metres deep, Hywind has been in service successfully since 2017. Hywind has the highest capacity factor for any wind farm in the UK: in 2020, it set a new UK record, achieving an average capacity factor of 57.1%. This compares to an offshore wind average in the UK of about 40%.

The technology behind floating wind is set to have an impact far beyond the North Sea, particularly in geographies where the sea gets very deep, very near the shore. Examples include the Mediterranean basin, the west coast of the United States, South Korea and Japan – all of which have huge offshore wind resources waiting to be tapped. Floating wind can also be deployed in shallow waters where seabed conditions prevent the use of conventional foundations.

Currently, floating wind accounts for just 0.1% of the offshore wind total. But that is set to change. Forecasts by the Global Wind Energy Council suggest that by 2030, floating wind could account for 6.1% of all new installations with an estimated 16.5 GW of new capacity added within the next ten years. Robust, cost-effective technologies hold the key to achieving this.

One of the big technical challenges with floating offshore wind is exporting the electricity they generate. There are three factors in play. First, cable links between wind farms and the shore are longer because turbines are typically sited further out to sea. Second, the power levels that must be handled are increasing as turbines grow in size. Third – and most importantly – dynamic cables are required. These must be capable of accommodating movements of the floater structure caused by currents, tides and wind. Resilience is critical.

Smarter dynamic cables

Nexans’ track record in high-voltage submarine cable systems and dynamic cables means the company is ideally placed to support the development of floating wind. Indeed, Nexans supplied dynamic cables for the Hywind Demo and Hywind Scotland floating wind projects. The company’s experience has deep roots: Nexans developed its first dynamic cable back in 1983.

Today, the innovation continues. The focus is now on developing HV dynamic cables that can handle more power and greater voltages than ever before. This new generation of cables will be lighter and more flexible than traditional subsea cables. They will also be smarter, thanks to the integration of optical fibre elements to provide real-time monitoring – providing critical information on various parameters of the cables and ensuring years of reliable operation.

Utility-scale floating solar power is one of the fastest-growing renewable technologies. Photovoltaic arrays are mounted on rafts anchored out in open water, with subsea cables to channel the power back to the land.

The most challenging aspect of the project from a cabling point of view is handling dynamic loading, caused by movement of the platform in response to wind, waves and tides. Nexans is utilising a three-core cable design of a type well-proven in offshore wind farm and fish farming installations. The 5 km cable is being manufactured at our Rognan plant in Norway.

The beauty of floating solar is that it dramatically expands the potential area available for siting solar arrays – without the need to acquire land. Growth in the floating solar sector is strong. Almost 10 GW of new floating capacity is expected to be deployed by 2025.