Scrubbers: an evolving story

Many in the shipping and bunkering industry see exhaust gas cleaning systems (scrubbers) as a temporary technology.

However, according to Anders Skibdal, CEO of scrubber manufacturer PureteQ,  this perception is changing “as it becomes evident that we neither have the energy nor the capacity to produce e-fuels at scale for many years to come”.

Whatever the perception, the installation of SOx scrubbers continues. Almost 20% of all newbuildings from Chinese shipyards are being equipped with scrubbers. Retrofitting of scrubbers in Europe is also ongoing.

Scrubbers have existed for more than 100 years and remain a viable technology with numerous applications. The first scrubbers in shipping were inert gas scrubbers for tankers, followed by exhaust gas recirculation (EGR) scrubbers to reduce NOx emissions from larger marine diesel engines, and then SOx scrubbers to reduce sulphur and particle emissions. The next evolution of the technology involves absorption towers and desorption towers for carbon capture, as well as scrubbers for unwanted emissions from new e-fuels.

According to Skibdal, scrubbers are here to stay in one form or another “and they do not pollute – combustion of fuel does”.

He notes: “Predicting future ship fuel has become nearly impossible, prompting ship owners to find ways to secure the needed capacity. However, only a fraction of the required green fuels seems to be available, necessitating a focus on future-proof seaborne logistics that are cost-effective and, at the same time, comply with stricter global regulations. The low-hanging fruit is energy optimisation in any form, and this seems to have taken the headlines, replacing the wonders of methanol and ammonia. Additionally, we see an ever-growing interest in Onboard Carbon Capture & Storage (OCCS).”

“At PureteQ, we do not find this relevant until some of the uncertainties in the value chain are resolved, such as legislation, infrastructure, classification, safety, measurements, etc. The “minus C” in the EEDI/EEXI and CII must be defined and measurable to ensure a level playing field for owners, operators, and technology providers,” says Skibdal.

Recently, scrubbers have come under attack from NGOs and politicians in Scandinavia while Denmark intends to ban emissions from scrubbers within a 12 nautical mile zone. If implemented, this means that vessels transiting through Danish waters can still use open-loop scrubbers, but vessels bound for Denmark will have to use compliant fuel and switch off scrubber systems.