The uptake of alternative fuels and green technologies is ramping up across the global shipping fleet, Clarksons Research says.

According to the analyst's Fuelling Transition report and monthly data, 4.3% of existing fleet tonnage is capable of using alternative fuels — an increase from 3.6% one year ago.

Newbuildings are making faster progress, managing director Steve Gordon said, with 34.8% of the orderbook by gross tonnage capable of using alternative fuels or propulsion. That is up from 27.7% a year ago and 10.3% five years ago.

But with increased activity, shipping’s carbon footprint is estimated to have edged up to 2.4% of global CO2 emissions in 2021.

Breaking down the orderbook shows that 30.6% of that tonnage is set to use LNG (573 vessels) while 95 units will use LPG.

The alternative fuels group includes about 150 slated for battery/hybrid propulsion, 21 likely to burn methanol, nine ethane, eight biofuels and five hydrogen.

In 2021, 33.8% of newbuild tonnage ordered was for alternative fuel-capable vessels (425 units), up from 209 in 2020. More than 259 ships in the fleet and 96 on order are designated "LNG ready", while there are 35 "ammonia ready" and four "hydrogen ready" vessels on order.

Energy-saving technologies — including propeller ducts, rudder bulbs, Flettner rotors, wind kites and air lubrication systems — have been fitted on more than 4,398 ships, accounting for 20.9% of tonnage.

Scrubbers are fitted to more than 4,568 ships, 24% of the fleet by gross tonnage. Retrofitting has slowed from around 300 per month in January 2020 to 10 in December 2021, but newbuild uptake has risen, with 231 orders for scrubber-fitted newbuildings reported in 2021, including 190 containerships.

"Eco" ships make up a growing share of the fleet — 27.1% of total gross tonnage — with implications for earning potential, asset values and increasingly "tiered" and complex charter markets, Gordon said.

Green port infrastructure is also expanding, with 143 LNG bunkering ports active and 93 planned, while more than 1,229 vessels are fitted, or set to be fitted, with shore power connections.