How sustainable is ferry travel....?

This is an interesting one. The issue of how "carbon hungry" ferries are first came to my attention when I was asking the former CEO of Veolia (Chris White), how expensive it was to run our diesel trains. I did some research and found the following:

Cost of fuel to run Auckland's public transport. % of mode operating costs.
Mode Rail Bus Ferry	% of Operating Cost 3% 11% 30%

You can appreciate how much it costs to push a ferry through the sea, compared to the low rolling friction of a train, with steel wheels running on steel rails whose gradients are usually not more than 2%. But a train is a very heavy thing - when it's full of passengers the total weight hardly changes.

Now we have a "free weeks ferry and bus" ticket being offered by ARTA and Fullers. This is good. But it is helpful to understand what we are promoting here....

There is a fantastic link I recommend if you are interested in growth strategy and intensification and stuff. It's a blog: Agenda 21, Auckland, Intensification, and Sustainable Urban Development, by Manish Udar. You can find it here:
http://sustainability.rediffiland.com/blogs/2007/05/21/Agenda-21-Auckland-Intensification-and-3.html

Here's a quote:

".....Public transport is an area of considerable energy wastage. It is quite commonly believed that commuter trains are the most sustainable form of urban transport, followed by fully occupied buses followed by fully occupied cars and that the least sustainable form of urban transport is an empty commuter train followed by an empty bus followed by a single occupancy car. But these common assumptions are not borne out by facts, if energy consumption and CO2 emissions for various transport modes are examined....As is shown by the following table, urban transport also contributes heavily to the greenhouse effect if it consists of petrol, diesel or gas driven buses, or if coal or gas is used in the production of electrical energy to power public transport trains. It also shows that vehicles with a high occupancy rate are less likely to contribute to the greenhouse effect. If a lot of people are packed together in a given space, they are more likely to be able to find a group of persons to occupy their vehicle to its optimum capacity. This seems to suggest that an intensified city will lead to lower greenhouse emissions. Whether this is borne out by experience needs to be examined....."

Carbon dioxide emissions in terms of kg per passenger kilometer
Mode Electric car (2 seater, 2 people) Average bus Quickcat ferry (rush hour) Suburban diesel train 4.0 litre Jaguar XJ8 (2 people) Electric Inter City 225 train Internal air flights Jet Raider ferry (average)	Carbon 0.02 0.08 0.08 0.13 0.16 0.17 0.26 0.45	Occupancy 100% 20% 65% 22% 40% 50% 65% 20%

That old Jet Raider ferry is seriously hungry.
Because those partly filled trips really chew through the diesel.
Wonder how the Kea does?