The Nov 2021 edition of Towpath Talk reports on the successful trials of HVO by the Inland Waterways Association in Britain, as a viable alternative to diesel and the dramatic reduction of carbon emissions.  It is deemed an alternative fuel for boat propulsion, cooking and heating. 

HVO (Hydrotreated Vegetable Oil) is a second generation bio-fuel which appears to have all of the necessary requirements:  it mixes well with other diesel fuels, is already approved by most engine manufacturers, has none of the diesel bug issues that have plagued first-generation biodiesel, is stable when stored, reduces CO2 emissions by 88%, remains free flowing to -25°C and brings a 10% drop in fuel consumption.

The article points out that there are still some supply and tax issues to be solved.  The IWA campaign is documented at Green Boating on Canals and Rivers.  The Canal and Rivers Trust in their Boaters Update section discuss Going Green on your Boat. There has also been some interesting discussions by members of the Barge Organisation (DBA) on their blog regarding usage and pricing.  Tests are complete or underway for a variety of engines that represent a wide range in age, including a Bolinder, Gardiner, DAF and Beta. 

Until electrical or hydrogen solutions are practical and cost effective for boats, HVO with solar energy, may be the immediate solution to reducing CO2 emissions from private and hire boats.