Short-term ways to reduce emissions
Behaviour change solutions
Cost: Low | Vessel downtime or installation needed? No
The quickest and most straightforward way to reduce ships’ emissions is by reducing fuel consumption, and a behaviour change service like Signol’s enables lower fuel usage during a vessel’s usual operations without requiring training or retrofitting.
Signol does this by identifying specific operational processes where fuel can be saved by modifying human behaviour and decisions – including main engine usage, engine maintenance, auxiliary engine usage and managing power demand on board.
Crew members are supported to make fuel-saving decisions with individual, realistic fuel-saving goals, behaviour change techniques delivered through a web app and email communications, and a detailed, personalised dashboard to track and understand fuel-saving progress.
Signol’s projects with maritime clients like Ridgebury Tankers, BSM and Young Brothers delivered over 5% fuel savings and emissions reductions in less than six months.
Since Signol uses the data collection and reporting processes already in place on vessels – from noon reports up to high-definition IIoT data – these emissions reductions are achieved without the need to install any additional technology on board. This makes Signol an affordable and quick-acting solution to reduce the cost of EU ETS compliance.
Scrubbers
Cost: High | Vessel downtime or installation needed? Yes
Scrubbing systems can be installed to treat exhaust from ships’ engines, removing the harmful components of emitted gasses (including sulfur oxides and nitrogen oxides).
As a result, harmful emissions can be reduced without lowering fuel consumption. Different scrubbing systems require more or less structural modifications to install and need different ongoing maintenance. But for all systems, installation and usage is a significant investment both in terms of expense and time and resource.
Fuel emulsion technology
Cost: Medium | Vessel downtime or installation needed? Yes
Another solution to produce ‘cleaner’ fuel consumption and combustion is fuel emulsion technology, which creates a stable emulsion of fuel with up to 30% water. The result burns more completely than fuel alone, which means fuel can be saved due to combustion efficiency.
It’s estimated that this can reduce fuel consumption by up to 7%. According to Tecnoveritas – one provider of fuel emulsion technology for shipping – the technology requires installation but no modifications to the engine or disruptions to engine operation.
Alternative power sources
Cost: High | Vessel downtime or installation needed? Yes
Replacing fuel with alternative power sources like wind and solar power will quickly reduce emissions produced, but inevitably making this transition requires significant modifications to vessels.
To date, solutions put into action are hybrid solutions – where solar, wind and electric power are used alongside fuel engines, including Carisbrooke Shipping’s use of solar panels and Cargill’s trial of wind power.
While it’s thought that wind power could potentially reduce fuel consumption by up to 30%, the industry currently relies on bold first-movers who are willing to take a risk and potentially make a loss on the investment – like Cargill, whose shipping business president acknowledged that the cost savings were unlikely to deliver positive financial returns on the investment.
Ship design modifications
Cost: High | Vessel downtime or installation needed? Yes
Modifying ships themselves can reduce the power needed to run the ship – which in turn reduces emissions produced. Innovations in ship design specifically aimed at reducing emissions include adapted hulls, propeller cones and aerodynamic superstructures.
Streamlining hulls is one of the most common approaches within sustainability-focused naval architecture, using fluid dynamics to design hulls which minimise water resistance and so “glide’ more efficiently through water.
Other modifications include installing propeller cones to reduce energy loss from propellers, which can improve fuel efficiency by 3-5%, according to engineering firms.
Recent research has explored the potential for aerodynamic superstructures on ships to improve energy efficiency by reducing aerodynamic drag. The innovation also harnesses fluid dynamics but is applied to airflow and pressure by designing superstructures with outwardly curved rather than squared edges.
Modifying ships in these ways – and others – can have an immediate effect on energy efficiency and reducing emissions, but requires significant structural modifications and vessel downtime.
Alternative fuels
Cost: High | Vessel downtime or installation needed? Yes
Using alternative fuels to power ships can significantly lower emissions compared to conventional fuels, but there are limits on the current opportunities to use alternative fuels.
Biofuels – derived from organic matter like plant oils and animal fats – produce significantly lower amounts of greenhouse gases, but current availability and projected availability based on production facilities is limited. In the absence of long-lasting trials of biofuels onboard vessels, experts also caution that a better understanding of biofuel compatibility with existing ship machinery is needed before it can be widely adopted.
Another promising area of development is the use of ammonia, which also produces significantly lower emissions than fuels like HFO and MGO. However, using ammonia can be significantly more expensive since its lower calorific value means more fuel is required to produce the same energy. Shipping companies (including charterers and managers) must also implement operational and design safeguards to protect seafarers from the safety hazards of using ammonia.
Liquified natural gas (LNG) produces less greenhouse gases and air pollutants than conventional fuel (up to 23% lower emissions), but also brings additional operational and safety challenges. Keeping LNG at the low temperatures required means that bunkering is not straightforward, although the LNG bunkering infrastructure is improving due to increased uptake. Using LNG onboard currently requires high investment for shipping companies, including engine modifications. Recent studies have highlighted the risk that investing heavily in LNG-capable vessels could result in significant losses and stranded assets.
Medium and long term ways to reduce emission
