Delta Force
Banned
Coal has a low cost per unit of energy relative to petroleum and coal fired power plants (a ship's machinery is akin to a power plant) are about as thermally efficient (to calculate divide 3,412 by the BTU per kilowatt hour; lower is better) as par with petroleum fired power plants. Of course, coal is not as energy dense and twice as much weight of coal is needed as fuel oil for the same amount of energy (I can't find energy density per volume), but that might not be an issue for certain roles.
Of course, one of the reasons why ships historically moved away from coal was because it took days to fuel a ship and large engine crews were required. That seems to be less of an issue with modern coal power plant technology (an average American coal plant employs 0.18 people per megawatt of capacity), but it would still likely lead to larger crews. For example, an 80 megawatt coal system for a ship (equivalent to a Wärtsilä-Sulzer RTA96-C diesel engine) would require 15 or so crew members, but the RTA96-C powered Emma Mærsk usually only has a crew of 13.
Assuming the 80 megawatt unit operates at a capacity factor of 30%, a total of 210,240,000 kilowatt hours of energy would be generated per year. That's equivalent to around 717,368,656,949 BTU, or 717368.656949 million BTU. With a cost per million BTU of $0.56 to $2.08, a coal powered ship would have a fuel bill of $401,726 to $1,492,127 per year. A ship powered by $14.74 per million BTU fuel oil or $15.59 per million BTU diesel would have a fuel bill of $10,574,014 to $11,183,777 per year.
At least for fuel costs, the economics seem to work out for coal powered ships. Coal would have similar advantages over heating oil (commonly used in the Northeastern United States) and a smaller advantage over natural gas (not suitable for propulsion except on LNG tankers due to its propensity for boiling off). Given this, how plausible would it be for there to be modern coal powered ships and heaters? Could they have returned in the 1970s or even be a feasible option in the present?
Of course, one of the reasons why ships historically moved away from coal was because it took days to fuel a ship and large engine crews were required. That seems to be less of an issue with modern coal power plant technology (an average American coal plant employs 0.18 people per megawatt of capacity), but it would still likely lead to larger crews. For example, an 80 megawatt coal system for a ship (equivalent to a Wärtsilä-Sulzer RTA96-C diesel engine) would require 15 or so crew members, but the RTA96-C powered Emma Mærsk usually only has a crew of 13.
Assuming the 80 megawatt unit operates at a capacity factor of 30%, a total of 210,240,000 kilowatt hours of energy would be generated per year. That's equivalent to around 717,368,656,949 BTU, or 717368.656949 million BTU. With a cost per million BTU of $0.56 to $2.08, a coal powered ship would have a fuel bill of $401,726 to $1,492,127 per year. A ship powered by $14.74 per million BTU fuel oil or $15.59 per million BTU diesel would have a fuel bill of $10,574,014 to $11,183,777 per year.
At least for fuel costs, the economics seem to work out for coal powered ships. Coal would have similar advantages over heating oil (commonly used in the Northeastern United States) and a smaller advantage over natural gas (not suitable for propulsion except on LNG tankers due to its propensity for boiling off). Given this, how plausible would it be for there to be modern coal powered ships and heaters? Could they have returned in the 1970s or even be a feasible option in the present?