Full stream ahead: how the shipping industry is lowering emissions

Posted on 11 Nov 2022 by Joe Bush

Driven by investor, regulatory and public demand, a variety of new technologies will be required to decarbonise the world’s shipping industry. Joe Bush reports.

The drive towards net zero is not only forcing manufacturers to look inwardly at energy consumption and the efficiency of their own processes, but it is also vital that sustainability is considered up and down the supply chain; beyond the boundaries of an individual manufacturing site, commonly referred to as Scope 3 emissions. In other words, it is no longer enough to have energy efficient processes in place to manufacture a product if the raw materials used, or the method of transporting them to customers, is carbon intensive or causes pollution – and the shipping industry is key to this.

As an island nation, shipping and the maritime sectors are among the most important industries to the UK economy. Manufacturers rely on shipping to import their raw materials and to export their finished goods, and last year a total of 445.5 million tonnes of cargo was handled at all UK ports.

Silverstream tech
Shipping is one of the world’s most polluting industries, exacerbated by the fact that maritime trade volumes are set to triple by 2050

According to The Organisation for Economic Co-operation and Development (OECD), 90% of traded goods are carried around the globe via the oceans. As such shipping is one of the world’s most polluting industries, exacerbated by the fact that as demand for global freight increases, maritime trade volumes are set to triple by 2050.

Current state of play

It is perhaps understandable that the emissions from shipping have flown (or sailed) under the radar of the public conscience. We see and hear road and air freight on a regular basis; we watch it fly overhead and drive past it on the motorway. However, unless you live near Dover or Felixstowe (or other such ports), maritime freight may well be a case of out of sight, out of mind.

Despite this, the shipping industry accounts for approximately three to four percent of global CO2 output which is comparable to a country the size of Germany. And of course, demand is growing; more countries are requesting more goods. Therefore, in the last decade, regulations around shipping have increased significantly.

While the industry has historically been a little slow to move towards newer technologies, better ships and reducing emissions, it is something that is very much on the radar now. The Energy Efficiency Design Index (EEDI) focuses on the efficiency of how new ships are built, and the Efficiency Existing Ship Index (EEXI) is a framework for determining the energy efficiency of in-service vessels. In addition, there is further regulation on emission targets from the EU and the International Maritime Organization (IMO).

Ship owners and charterers are also beginning to feel the pressure from consumers and large retail chains who want to source products from sustainable suppliers and no longer accept the transport of goods using highly emitting fuels. So, not only is there a transition towards better, more efficient ships, but also greener fuels that are emitting less or no CO2.

Catching the tailwind of this trend is London-based Silverstream Technologies, a specialist in air lubrication technology for large ships, which reduces frictional resistance between a vessel and the water by deploying a ‘magic carpet of air’ in the form of millions of tiny bubbles, which coat the vessel’s hull and can cut fuel burn and CO2 emissions by an average of five to ten percent net, depending on vessel type.

“The shipping industry today uses mainly heavy fuel oil (HFO) which is the most efficient for the sector but is also extremely polluting,” said Silverstream Founder and CEO, Noah Silberschmidt. “HFO has the highest calorific value. A new fuel like green methanol emits less CO2, but the mileage in one tonne is less than in one tonne of HFO.”

In short, a ship running on HFO will be able to travel further than one using a more sustainable alternative. Therefore, by moving into greener fuels, which will be more expensive, a ship will need to be even more efficient to be able to sustain the same mileage (unless tank capacity is increased which would negate the increased efficiency from the greener fuel).

The challenge of deploying greener fuels

The fuel currently used in shipping is rarely deployed in any other sector. For the most part it is an unwanted, unloved, thick, nasty substance. This has created an artificially low price for the fuel which has been a benefit to shipping for decades.

As industries of all kinds navigate towards greener fuels, there will be an increase in demand, meaning that shipping will have to compete on a pricing level. Sectors like aviation will have more money to spend on greener fuels, and therefore are more likely to be an early adopter.

In addition, there is a further question around manufacturing capability. Ship owners need to have the supply chain in place, have it working and get production facilities built. “In my opinion, it’s great that we’re discussing new, greener fuels, but it’s not going to happen overnight,” added Noah. “It’s going to take a lot longer for the supply chain to be in place and for adoption by ship owners.

“The media is discussing greener fuels like they’re happening tomorrow – it’s true that some ships are built to incorporate alternatives and we are working with owners who are looking into methanol for example, but we’re forgetting that over the next decade we will still have the same issues around burning traditional high emitting fuels. The reality is that all decarbonisation pathways will rely on fossil fuels as part of the fuel mix for some time yet, so right now, we need to reduce emissions, and apply as many technologies as possible to do that.”

Air lubrication technology

Silverstream’s technology is fuel agnostic and can be deployed on any type of vessel, be it a cruise ship, tanker or rollon/ roll-off (RORO) car carrier. There is evidence of air lubrication in literature over 150 years ago; the concept of introducing air around the hull of a vessel (the boundary layer), creating a thinner substance than water.

Frictional resistance between the hull and the water represents the biggest energy cost to a vessel’s operation. Reducing this frictional resistance is therefore essential to improving operational efficiency, regardless of fuel type. Deployed effectively, air lubrication enables a vessel to glide more easily through the water, achieving a higher speed from the same propulsion power, or maintaining the same speed while reducing the propulsion power and using less fuel.

Noah added: “Silverstream is the first company that has been able to find a solution to air lubrication technology that’s commercially viable. And we don’t just state on our website that we’re saving 5-10% net in CO2 emissions; we have a testing protocol that’s agreed with customers, industry and third-parties (such as Lloyd’s Register in the UK) which verifies the results.”

The Silverstream System fundamentally changes the interaction between water and a vessel. It shears air from air release units (ARUs) in the hull to create a uniform carpet of microbubbles that coat the full flat bottom of a vessel. As a result, frictional resistance is decreased – dramatically reducing fuel consumption and associated emissions.

Silverstream works with MSC, Maersk, Shell, Carnival and Grimaldi, among others, and the company’s growing orderbook illustrates the traction the technology is establishing in the industry – from three installations in 2018, to 90 orders today, and an anticipated 500 by 2025. In one such case study the Silverstream System is saving the world’s largest container shipping company, MSC, 1.6 million tonnes of CO2 – equivalent to the annual emissions of 350,000 cars.

“Air lubrication is one of the proven technologies that can help ships to achieve fuel savings and reduce energy losses. With the right hull design, the substantial reduction in carbon emissions that the Silverstream System can offer perfectly matches our ambition to fit our fleet with the latest technologies available, helping us move closer to a zero-carbon future,” said Giuseppe Gargiulo, Head of New Buildings at MSC’s ship management company in Sorrento, Italy.

New build and retrofit

Eighty percent of Silverstream’s customer base is new build vessels, however, there are currently around 90,000 ships that are already registered in the IMO database, 15,000-20,000 of which are commercially large tanker vessels that are relatively new. This represents a portion of the addressable retrofit market Silverstream is targeting.

A vessel will typically enter dry-dock every five years for a minimum of two weeks, essentially serving as the shipping equivalent of an MOT. Noah added that during this time, Silverstream can fit its system in as little as six days.

“Everything on a ship requires regular maintenance because the sea is such a harsh environment; nothing is fit and forget. Therefore, it’s extremely important for there to be service availability globally. As such we have linked up with companies that are helping us service our technology, for example, the air compressors and blowers that are producing the air.”

A key focus for Silverstream currently is how to service customers after installation; the after-sale service component, making sure spare parts are available when needed, while also focusing on the data element which is vital in verifying savings to customers.

A global standard

Global demand for lower energy consumption, increases in regulation and rapidly rising energy costs mean that the opportunity is there for air lubrication technology to be installed on all new build ships, aided by the fact that Silverstream’s technology is fuel agnostic. “We are in something of a perfect storm,” continued Noah.

“We have a technology that is trusted by customers and was proven many years ago. We also have the backup from third-parties, but also very well-known industrial companies. With a focus on reduction of energy it would be strange not to install a system like ours, which is relatively simple to implement in the new build process.

“We expect the Silverstream System to be installed on around 500 of the 800-1,000 new ships built each year. And of the existing 90,000 ships, of which 20,000 are relatively new, there’s no reason not to have at least 500 ships a year also installing our system. To do this we are planning to link up with a variety of local organisations. In Japan, for example, we have partnered with a very large conglomerate called Mitsui, and we have linked up with a large dry-docking yard in Malaysia. The plan is that we create the capability for our system to be installed on licence everywhere, either during a new ship build or while repair work is taking place.”

Noah added that although the technology is currently performing well, the company has also started working with machine learning and AI technologies, using data points and the information gathered by the system to optimise its performance. Taking into account varying journeys, weather, wind, wave and operational patterns, these automated solutions can help the system increase or reduce air to optimise net savings for the vessel owner.

Silverstream’s technology is certainly no silver bullet and Noah stressed that to fully decarbonise, the shipping industry will need a variety of new and emerging technologies working together. “In shipping, there are currently few new technologies that are verified,” he said.

“In the last 12 years since I’ve been part of the industry, there have been companies that have made bold claims who are no longer around. But I’m hoping there’ll be more verified technologies coming online, because the industry will need five to ten technologies like our system that can save 5-10% net to be able to reach a total of 40- 60% emission reduction.”

The clock is ticking for marine decarbonisation and maximising vessel efficiency, irrespective of fuel choice. As shipping moves towards the adoption of future fuels that enable it to meet its emissions targets, these fuels will be more expensive to handle and consume. It is therefore critical to incorporate proven, clean technologies in shipping’s decarbonisation journey.

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