The global shipping industry is responsible for about 3% of global GHG emissions and is considered a “hard-to-abate” sector. This means that electrification won’t work, and alternative solutions, such as biofuels or hydrogen are needed to achieve the emissions reduction targets of 40% by 2030 (with a baseline of 2008) and net zero by 2050. The problem with these solutions is that they are too expensive at present.
I didn’t think much about maritime emissions until I stumbled upon an article in the Economist magazine “A new age of sail begins”. The article argued that old and new wind-assisted propulsion systems (WASP) could substantially cut shipping emissions. The technology was first demonstrated in 1926, but was quickly made redundant by falling oil prices.
Today, the technology is experiencing a revival, as ship owners look for ways to cut emissions without breaking the bank. My search in Pitchbook INC came up with a spike in investment deals last year, reaching $57 mln - a clear sign of emerging interest from investors.
There are six main WASP technologies: rotors, kites, rigid sails, soft wing sails, turbines, and suction wings. Most require some free deck space for installation, and all can be retrofitted on existing vessels. Container ships are the most difficult retrofit, as they require space for cranes to work on loading and unloading.
Sails cannot fully replace engines but may cut fuel costs by around 20%. You still need to run your engines. Possibly, these could be made electric, with batteries for limited range and high-efficiency solar modules (like HJT modules) to top them up.
It is still too early to tell whether a new age of sail is upon us. Kites and all sorts of rotating turbines have been around in the wind energy industry for a long time, without delivering any value. But I would definitely recommend watching startups in WASP space closely. A simpler solution is always better than a complicated one (like hydrogen).
For a more technical introduction, check out this blog:
The Economist article is here (paywalled): https://www.economist.com/science-and-technology/2024/05/21/a-new-age-of-sail-begins