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.

Plastic is not good for the environment: everyone knows it and everyone makes efforts to avoid it, or at least to sort it better. However, it is still essential in many sectors. Indeed, it remains very important in the design of cables because of its exceptional properties: mechanical, dielectrical, processability, durability…

The problem lies in the poorly managed and uncontrolled plastic waste streams that endanger ecosystems around the world:

• Over 460 million tons of plastics were produced in 2019,
• Up to 50% of plastic waste was sent to landfill,
• Despite current initiatives and efforts, the amount of plastics in the oceans has been estimated to be around 75-199 million tons. According to the Ellen MacArthur Foundation, by 2050 and without action, there will be as much plastic as fish in the sea (1kg for 1kg).

To face the growing volume of plastic produced, used and dumped, industries have to evolve to a fully circular model in which end-of-life plastic products are not discarded but transformed to create value. Innovation, regulation and international collaboration are needed to enable this transition.

In addition to resource management and pollution issues, plastic materials have an impact on greenhouse gases. A kg of polyethylene produced in Europe for plastic manufacturing has a carbon footprint of roughly 1.8 kg of CO2 equivalent.

Plastic material: versatile and unavoidable

Industrial-scale plastics production began in earnest in the 1940s and rapidly increased in the 1950s. More than 8 billion tons of plastics have been produced worldwide since 1950, making it a widely used manufactured material (Geyer et al., 2017).

Plastics offer various benefits such as a high strength-to-weight ratio, and the ability to tailor their physical properties to be hard or soft as needed. This versatility and durability, combined with the low cost of plastic production, is the major reason why plastics are currently used in almost every sector.

Today, almost all plastic is derived from materials made from fossil energy (primarily oil and gas). This causes several problems:

• If dependence on plastics persists, it will represent 20% of annual global oil consumption by 2050,
• Greenhouse gas emissions for plastics will reach 1.34 gigatons per year by 2030 if it remains in its current form,
• The ability of the global community to keep temperature rise below +1.5°C or even +2°C by 2100 will be threatened.

According to OECD, “Plastic pollution is growing relentlessly as waste management and recycling fall short”. Indeed, it is estimated that only 9% of plastic waste is recycled, and 22% is mismanaged. Due to the durability and strength of the material, plastic waste remains in the environment and takes decades or even centuries to decompose naturally. It involves the loss of biodiversity and alteration of ecosystems (MacLeod et al., 2021).

Hopefully, a transition of plastic materials is possible:

• Recycling: although recycling is currently the simplest and most widely used solution to transform plastic waste into new products, efforts can be made in terms of sorting and separation. Among all the recycling routes, we differentiate: the simple reuse (direct wastes reuse within the manufacturing processes for example), the mechanical recycling (crushing/powderization after a sorting/separation for example) and the chemical one (with different routes: dissolution, depolymerization or conversion). These technologies make possible to approach the recycling of the wide family of plastics with different levels of complexity and quality.

• Eco-design: The principle of eco-design is about taking into account the entire life cycle of the product, from the materials used to its recovery and recycling and to take this into account at early stages, i.e. during the material conception. Meaning for example the use of recycled or biobased materials, increase the product lifetimes, select the materials to facilitate the recycling, decrease the weight of plastics used…

The major challenge of industrial activity is to drastically limit the impact on the environment. There are three main issues that are interconnected:

• the impact on greenhouse gases and the climate,
• the impact on resources, particularly copper and aluminum as well as plastic materials,
• the impact on biodiversity, which requires the substitution of certain additives (e.g. REACH substances) and the control of the entire life cycle in order to limit and eliminate pollution.

Environmental challenges are at the center of Nexans cable solutions development. We commit to reduce the environmental footprint of our cables thanks to the selection of materials. More than ever, Nexans aims to invent innovative materials that combine eco-design, performance, durability and recyclability.

Extend the use of recycled materials

The incorporation of recycled materials in new products is a challenge for all industries. Nexans has launched a company-wide initiative to use up to 30-60 % recycled plastics in different cable families across the electrification chain.

Recover our wastes

Nexans works to improve the recycling of end-of-life cables and offers to collect customers’ wastes through Nexans Recycling Services. Moreover, Nexans has an objective to recycle 100% of its production wastes by 2030, with a circular economy dynamic. Plastic wastes sorting and valorization are now at the center of several R&D projects to answer all the blocking points (e.g. legacy additives, plastic mix separation, crosslinked polymers recycling…).

Eco-design of our cables

The current valorization efforts of existing end-of-life cables highlight substantive problems linked to their complex designs or to their various components. New products are now created with a strong will of eco-design including:

• Limit and replace the use of hazardous substances,
• Development of plastic materials that are more easily recycled,
• Simplification of cable designs,
• Improvement of the cable lifetimes.

Innovation will be key to the transition from a linear to a circular model for plastics materials. It requires the development of specific technologies, but will also have to include supply chain and business model components that will be only possible through ecosystems.

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.

After more than a century in the shadows, Direct Current (DC) power could be set for a comeback.

The closing years of the nineteenth century saw a fierce battle to establish the best method for supplying electricity to consumers, with DC on one side (promoted by Thomas Edison) and AC on the other (backed by Nikola Tesla). DC lost, and the world has been dominated by AC ever since.

The story might have ended there but for two things. First, DC is remarkably efficient for long-distance bulk power transfer – indeed, it has been used in this role for decades. Second, more and more of the electrical devices we use are natively DC – everything from your mobile phone to LED lights and electric cars.

All of this is leading to a reappraisal of DC for transmission, distribution and even final consumption by electricity users. So how might this work in practice?

DC transmission

Transmission is the bulk transfer of electrical energy, typically over long distances. This is achieved using overhead transmission lines or underground (or subsea) cables. Using high-voltage DC (HVDC) for transmission instead of high-voltage AC has a number of advantages.

First, less material is needed. This is because DC requires only two conductors (AC needs three). Second, electrical losses are lower with DC because only active power is transferred (by contrast, AC transfers both active and reactive power). Third, the possible length of transmission links is much greater with DC thanks to the absence of reactive power.

HVDC is a proven technology – and it is getting better all the time. Recent developments include voltage source converters (VSCs) and improved transmission capacity for cables. This is achieved with higher voltages, higher operating temperatures, bigger conductor cross sections and the introduction of extruded technology. All of this means that the footprint and cost of HVDC projects is falling relative to the energy transferred. In short, HVDC transmission is becoming much more competitive.

A bright future for HVDC

Two important market trends are driving increased interest in HVDC transmission. The first is the growing demand for electricity interconnectors. These span oceans and link the grids of nations and regions. The second driver is subsea export cables for the growing number of offshore wind farms.

To date, some 15,000 km of HVDC submarine cables have been installed, using both MI (mass impregnated) and XLPE (extruded) cable technology. An additional 20,000 km of HVDC interconnectors are expected to be deployed by the beginning of 2030, not including offshore wind farm export cables. The installed base of extruded cables is expected to increase and equal the length of mass-impregnated cables by the end of this decade. Manufacturers of HVDC submarine cables are positioning themselves to capture the market by investing in more production and installation capacity.

Could DC be used for distribution as well?

Medium voltage (MV) and low voltage (LV) distribution networks, and power distribution within buildings, have long been dominated by AC. But a progressive shift to DC – achieved through the development of LV and MV microgrids – could bring energy savings, improved interoperability, easier renewable energy integration and greater sustainability.

Interest in DC microgrids is being driven by fundamental changes in the way that electricity is generated, stored and consumed.

First, power generation is becoming less and less centralised and moving closer to sources of demand. Rooftop solar photovoltaics and small wind turbines are examples. Solar photovoltaics are natively DC, as are some micro wind turbines.

Second, battery storage is becoming widespread. Uninterruptible power supplies (UPSs) are one example. These are used by businesses, such as data centres, to maintain supply security. There are also growing deployments of battery energy storage systems (BESSs) for grid balancing. On top of this, home energy storage systems are now becoming available. Last but not least, electric vehicle batteries have grid integration potential. A key point about battery storage is that most of it is distributed rather than centralised, and all of it is natively DC.

Third, on the consumption side, DC devices are now widespread and uptake is accelerating. As noted earlier, many commonly-used devices, from phones to LED lighting and electric vehicles, are natively DC. Today, all of these devices depend on adaptors to convert AC to DC.

All of this is creating an environment that is ripe for DC microgrids with generation and consumption in the same grid, backed up with battery storage – including electric vehicle batteries. One of the beauties of the DC microgrid model is that it removes the need to convert AC to DC, eliminating the need for adaptors – an energy saving in its own right.

How is Nexans enabling DC?

Nexans is a leader in the submarine HVDC market and the company continues to invest in growing its manufacturing and deployment capacity. In 2021, we launched Nexans Aurora, the world’s most advanced cable laying vessel. Nexans is well positioned to support the future needs of both transmission system operators and wind farm developers.

With DC deployments growing in the high-voltage transmission sector, the next step could be medium and low-voltage DC microgrids. These will need to utilise optimised cables, accessories and connectors to be technically viable. They will also need to be reliable and to meet the requirements for energy efficiency, sustainability and safety.