Each week, TradeWinds’ print and e-reader editions carry estimates by Signal Ocean of the bulker and tanker sectors’ greenhouse gas emissions across the global fleet.

For 2022, the overall picture is not pretty.

In bulkers, dry bulk’s total CO2 emissions rose to nearly 192m tonnes, up from just over 188m in the period year. The tanker sector saw an overall rise to 128m from 120m tonnes, according to the data on page 28 of the upcoming edition.

But the data from Signal Ocean, the digital division of Greece’s Signal Group, showed a slip in carbon intensity in both sectors. Bulkers saw a dip from 3.59 grams of CO2 per deadweight tonne-nautical mile in 2021 to 3.53 last year, and a fall for tankers from 3.69 grams to 3.62.

The numbers are a reflection of the way that even as shipping increasingly adopts more efficient technology such as eco engines, deploys LNG fuelling and retires older ships, market factors continue to play a major role in the ups and downs of the sector’s carbon emissions.

And as Signal Group market analyst Maria Bertzeletou explained to Green Seas, how freight markets influence vessel speeds is a key parameter in the ups and downs of shipping emissions.

The carbon intensity picture brightens for 2023 so far.

Signal Ocean data to 20 February shows the carbon intensity of the bulker fleet has decreased by 5% so far this year compared to the same period of last year, while the tanker fleet’s carbon intensity dipped by 2.8%.

Total CO2 emissions in millions of tonnes

202120222023 to date2023 estimated

Source: The Signal Group

Bertzeletou said a major factor in the difference is vessel speed.

Tanker spot rates, particularly in the crude sector, have been on the rise, while bulkers have struggled at the start of the year. That is because bulkers are slowing down in slow markets.

Signal Ocean data shows average speeds of capesize bulkers so far this year are below those of the same periods of both 2021 and 2022.

“We have a different freight market dynamics that lead to a significant reduction in vessel speed,” she said. “In the tanker segment, they are not forced to apply that slow-steaming policy.”

VLCCs are moving faster in a stronger market. Photo: Piet Sinke/CC BY-NC-SA 2.0

The largest tankers — VLCCs — have started 2023 at higher average ballast speeds than January and February of the prior two years, continuing a period of faster steaming that started in the second half of 2022. Bertzeletou said the speed of ballast legs, which is when ships have no cargo, tends to swing more with freight market dynamics.

And how the market forces influenced vessel speed also played out between different segments.

Change in carbon intensity in start of 2023

Source: The Signal Group

For example, Signal Ocean estimates that supramax bulkers have seen their carbon intensity drop on average by 8.3% so far this year, compared to the same period of last year. This also compares to just 5% for panamaxes.

In tankers, suezmax crude tankers have seen robust spot rate improvements and their carbon intensity has slipped by just 0.3% compared to the beginning of 2022 but, in a less frothy product tanker market providing more incentives to slow down, carbon intensity has fallen 4.1% compared to the first several weeks of last year.

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But Bertzeletou pointed to changes in weight of speed in the years ahead as eco-design vessels and those with alternative fuels make up a larger share of the fleet.

She pointed to data from classification society DNV that shows the LNG-fuelled fleet will rise from 354 vessels last year to 876 in 2028. LPG-fuelled vessels will grow from 65 to 151. And by 2028, there will be an estimated 84 methanol-powered ships.

But for now, the impact of freight market dynamics on speed will remain a major driver in vessel emissions.


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