N Newman, Who said electricity and water don’t mix? Petroleum Review, November 2019, p 30

In the marine world, although ships account for about 2% of global CO2 while carrying about 90% of the world’s commodities, a marked reduction in emissions is vital since, for example, one large ship emits as much CO2 as 70 000 cars. Although the new ultra-low sulphur marine fuels will help, the future appears to favour electric propulsion. So far, most of today’s commercial batteries will move small vessels no more than 50 miles between charges. Furthermore, port operators globally will need to invest in expensive charging technology involving renewable energy.