Plausibility of Modern Coal Powered Ships and Heaters?

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?
 

Riain

Banned
Maybe if the coldry process takes off and we can easily and cheaply make black coal equivalent from brown coal.
 
What size would 1970s steam turbines with the same power output be in comparison with diesel engines? Can they be fitted in even nearly as small a space? I am asking because just a couple days ago I visited the engine room of a former steam passenger ship that was built in 1960 (becoming one of the last modern steam ships in the passenger traffic between Finland and Sweden) and then fitted with what then was modern steam machinery, with turbines. In the late 80s, the steam engines were replaced with two Wärtsilä diesels with a similar output allowing the same cruising speed (c. 16 knots).

The end result was that there is now a ridiculous amount of free space in the engine room, what with the engines themselves being much smaller (one of them was previously trialled on a railway loco) and the space previously needed by the boiler now occupied by just the ship's two Caterpillar generators and a lot more free space.

Had the ship originally been designed with the diesels, it could have carried a lot more passengers and have many more cabins for that same size, thus of course becoming more economical for the company operating it.
 
Your going to need a lot of coaling plants around the world, thats a huge investment. Oil just needs a tank farm or a refueling barge a hose and a pump. Coal needs big hoppers, cranes or elevators, a rail link or a lot of diesel engined Lorries to move it from the mines to the port and makes a hell of a mess.
 

Delta Force

Banned
Your going to need a lot of coaling plants around the world, thats a huge investment. Oil just needs a tank farm or a refueling barge a hose and a pump. Coal needs big hoppers, cranes or elevators, a rail link or a lot of diesel engined Lorries to move it from the mines to the port and makes a hell of a mess.

What about using coal to power ships that transport coal or go to major coal trading ports?
 
Coal is less practical a fuel source relative to Liquid fuels

More difficult to store

More difficult to move from where it is stored to where the boilers are compared to pipes and pumps etc

More difficult to 'refuel' to vessel

And more difficult to move around the country from the Coal mine to the Port

It would have to take a lot of POD to make this happen
 
What about using coal to power ships that transport coal or go to major coal trading ports?

What if the ship goes to a country with no major trade in good quality coal. Its a bit limiting my local port Liverpool used to import a lot of low grade Brown Coal (from South America iirc) and apparently it was absolute muck and would turn into mush if it got too wet and if it got too dry dust would blow everywhere and householders up to a kilometer away had to keep the windows shut. The local Power Station Fiddlers Ferry had to burn three times as much of the mucky stuff as the good hard Coal from Yorkshire it had burnt previously but it was about a quarter of the cost so it made sense to an accountant but not the poor souls who lived near the docks and the power station.

If you could design a furnace that burnt the cheap stuff that wasnt the size of a Basketball Court it might work but would need a big bunker. The Queen Elizabeth Battleships were designed in 1910 to burn Welsh Steam Coal which has one of the highest energy contents of any coal in the world. The design had 4,500 tons of bunkerage which would have given a range at 12 knots of 4,000 nautical miles, the final design had 3,400 tons of Oil for a range at 12 knots of 5,500 miles, the engine room crew was cut by 150 as you dont need lots of men to swing shovels.

Its doable but going to take a massive turnaround by the shipping companies and a lot of Countries are setting emissions laws for ships. Even with Bunker Oil A or B the Sulphur and Nitrous emissions are going to mean heavy and expensive exhaust gas scrubbing equipment will have to be fitted, Bunker Oil C is going to be legislated out fairly soon.
 
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Based upon fuel density, we already see a stratification among fuel consumers. This stratification will continue as the cost of fossil fuel increases.
We will still see plenty of stationary generating plants powered by coal. These stationary plants will always be situated beside railroads or harbours. Automated loading equipment vastly reduces the labour cost of loading.
As the cost of high-density fuels (liquid petroleum) increases, more and more stationary plants will convert to coal or freshly-grown biological fuels. Short range ships (e.g. ferries) will be next to convert to coal. Long-range ships will be the last ships to convert to coal but they will only serve ports located near coal mines.

Airplanes will be the very last to wean off of petroleum, simply because weight is so precious on long-haul flights. Airplanes will only wean themselves off of petroleum when it is no longer available. For example, airplanes powered by piston-engines disappeared from revenue service as fewer and fewer refineries produced high-octane gasoline. In many remote areas (e.g. Canadian high arctic) 100 octane, low lead gasoline has to be special ordered.
At the other end of the scale, several companies are developing electric (battery) powered airplanes for flight schools where a typical lesson lasts 1 hour. Once they produce reliable electric-powered trainers, they will start producing short-range electric-powered airplanes for short-range missions like banner-towing, glider-towing, skydiving, crop-dusting, commuting, etc. As the cost of batteries decreases and the cost of petroleum increases, electric-powered airplanes will fly longer and longer routes but trans-oceanic flights will still depend on petroleum.

Returning to the OP, new-built ships will slowly convert to coal-fired steam turbines as the cost of petroleum increases. ..... Because the cost of flying a ton of coal is 1/1000 the cost of flying a ton of coal. Shipping is still by far the least expensive way to move bulk commodities.
 

marathag

Banned
even with pulverized coal, the most efficient way of burning it, you still need larger area for combustion than you do with oil, and you still get bottom and fly ash to deal with.
 

Delta Force

Banned
What if the ship goes to a country with no major trade in good quality coal. Its a bit limiting my local port Liverpool used to import a lot of low grade Brown Coal (from South America iirc) and apparently it was absolute muck and would turn into mush if it got too wet and if it got too dry dust would blow everywhere and householders up to a kilometer away had to keep the windows shut. The local Power Station Fiddlers Ferry had to burn three times as much of the mucky stuff as the good hard Coal from Yorkshire it had burnt previously but it was about a quarter of the cost so it made sense to an accountant but not the poor souls who lived near the docks and the power station.

If you could design a furnace that burnt the cheap stuff that wasnt the size of a Basketball Court it might work but would need a big bunker. The Queen Elizabeth Battleships were designed in 1910 to burn Welsh Steam Coal which has one of the highest energy contents of any coal in the world. The design had 4,500 tons of bunkerage which would have given a range at 12 knots of 4,000 nautical miles, the final design had 3,400 tons of Oil for a range at 12 knots of 5,500 miles, the engine room crew was cut by 150 as you dont need lots of men to swing shovels.

Its doable but going to take a massive turnaround by the shipping companies and a lot of Countries are setting emissions laws for ships. Even with Bunker Oil A or B the Sulphur and Nitrous emissions are going to mean heavy and expensive exhaust gas scrubbing equipment will have to be fitted, Bunker Oil C is going to be legislated out fairly soon.

According to the EIA, around a billion short tons of coal are exported per year around the world (source here). The majority of that coal is imported in Asia (source here). That's a massive amount of trade, and ports in Asia, Australia, South Africa, Canada, and the United States could have it onsite.
 

Delta Force

Banned
As for coal ships, they would be bulk carriers like the MS Ore Brasil. That's the largest in the world, but it can carry hundreds of thousands of tons of bulk cargo, and do it with a much smaller powerplant than 80 megawatts. Ore Brasil only needs a 30 megawatt plant. The difference is probably because bulk transport isn't time sensitive, while Emma Mærsk is more time sensitive refrigerated storage. The smaller power plant reduces the total benefits of switching to coal, but if a ship is already carrying coal it could be something to consider.

Another thing to consider is that a ship could be equipped with a larger coal fired power plant to achieve higher speeds. Because coal is cheaper than petroleum it would still have lower fuel costs, but the ship could potentially transport more cargo in the meantime. A coal fired ship could be twice as fast as a petroleum fired ship and would consume four times as much fuel, but it would have only 60% the fuel cost. Ships are expensive to operate and time is very much money for them, so there could be a niche for fast bulk transports.
 
Depending on what pollution rules apply and how they're enforced, dealing with fly and bottom ash would also be a major problem for coal powered ships.
 

Delta Force

Banned
Depending on what pollution rules apply and how they're enforced, dealing with fly and bottom ash would also be a major problem for coal powered ships.

How was it historically dealt with on ships? Did the coal powered steam ships just retire or convert to petroleum before that became a concern?
 
How was it historically dealt with on ships? Did the coal powered steam ships just retire or convert to petroleum before that became a concern?

Fly ash was never a problem before pollution controls, as it was ejected out of the exhaust stack. Bottom ash was stored in either specialized holds or emptied coal bunkers, but as there was much less of it by volume compared to fly ash, it generally wasn't an issue.

More than anything else, it's the pollution controls that kills coal powered marine propulsion. With diesel and gas turbines water and urea injection is pretty much all you need, but with coal you need at minimum electrostatic filters to catch the soot and fly ash, flue gas desulfurisers to catch the sulfur oxides (which means you have to store the sulfuric acid somehow). Using anthracite may alleviate these issues, but anthracite isn't that much cheaper than Bunker 6 these days.
 
Given the high cost of what the EPA mandated from the late 1970's on in the USA to reduce oxides of sulfur and particulate emissions, I think coal-fired ships would be a non-starter by the early 1980's.

People forget that the well-known BlueTEC diesel emissions technology that Mercedes-Benz unveiled for its diesel-powered automobiles in 2005 have been around for a number of years for industrial diesel engines--selective catalytic reduction (SCR) by injecting urea gas to break down NOx gases since the early 1960's, and diesel particulate filters since 1980. As such, by 1990 diesel engines used for ships are actually quite quite clean in terms of air pollution, and because fuel storage and delivery is much cheaper with diesel engines than coal-fired steam engines, no wonder why most modern ships are powered by gigantic diesel engines.
 

Delta Force

Banned
Capital costs would be pricey, but coal might still be practical under certain scenarios.

A diesel generator cost $371 per kilowatt of capacity in 2003 (PDF page 9 here, around $480 today), while an advanced coal fired power plant currently costs $3,246 per kilowatt (PDF page 44 here).

An 80 megawatt diesel propulsion system would cost around $38,400,000. A coal system with all the modern emission control technology would cost $259,680,000.

In 20 years a diesel ship would consume $211,480,280 to $223,675,540 of fuel (fuel costs of $10,574,014 to $11,183,777 for year for fuel oil and diesel, respectively), while a coal ship would consume $8,034,520 to $29,842,540 of fuel (fuel costs of $401,726 to $1,492,127 per year). Total system costs would be $249,880,280 to $262,075,540 for diesel and $267,714,520 to $289,522,540 for coal.

It actually looks like 20 years is around the break-even point for a coal fired ship with the most advanced scrubber technologies. An important caveat for this is that I based the 30% capacity factor on the capacity for nuclear powered submarines. Naval ships don't usually operate at flank speed outside of war conditions, especially submarines which must be sneaky, so they might use less of their power under general peacetime conditions than a commercial ship does in routine operations. The more a ship is used and the higher the capacity factor of its propulsion systems, the more competitive coal is compared with petroleum.

As is clear from the example, capital costs would dominate for a steam ship powered ship. Iif the ship doesn't use advanced coal technology for some reason, such as it being earlier or not being required for ships, the capital costs would obviously decrease. A case could be made for lower pollution requirements for ships, as they are mobile and don't spend as much time near land. Before power plants were equipped with modern pollution controls, the air quality and pollution tended to be localized. A tug could push coal powered ships out of port prior to activating the steam engine, and/or fuel oil could be used for more sensitive portions of the trip. Many coal fired power plants actually have some fuel oil to help start the plant.
 

Delta Force

Banned
Also, there's the question of the coal powered heaters. I posted this thread last night because I remember reading a biography in which someone talked about how when they were growing up in the 1920s they had to purchase coal to heat their home. Petroleum is used for home heating in the Northeastern United States, so could coal be used as a less expensive alternative?
 
Some posters already mentioned pulverized coal but there is also this:
Coal-water slurry fuel is a combustionable mixture of fine coal particles suspended in water. It can be used to power boilers, gas turbines, diesel engines and heating and power stations.
That solves at least the engine size problem in form of coal slurry powered diesel engines. I am not sure however if this is/can be made economic thou.
 
I think that Wind Power will be the next thing. There are designs now that are getting close to motor vessels in speed and efficency. It will take time and a lot more research but there are improvements coming all the time. For non time restricted cargoes a wind power ship can already compete its the capital costs of construction where the older tech wins out.

Spare power from the wind can be used to make electricity which can then be used to make Hydrogen from sea water, this can be stored and used to fuel a power plant when approaching land.

Wing sails
jamda_shin_aitoku_web_large.jpg


Flettner Rotors
35-researchersa.jpg
 
Also, there's the question of the coal powered heaters. I posted this thread last night because I remember reading a biography in which someone talked about how when they were growing up in the 1920s they had to purchase coal to heat their home. Petroleum is used for home heating in the Northeastern United States, so could coal be used as a less expensive alternative?

I live in New Hampshire in USA where there is not much natural gas available. Many homes around here are heated with either fuel oil or propane or wood. Oil and propane are cheap right now but those prices wont last forever. Oil, propane and natural gas are very convenient. Even natural gas I feel will not stay cheap for long given that many natural gas export terminals are being built to export this commodity.

There already is a niche of homeowners that use coal for home heating. Like posted here, the economics of coal in price per BTU make it popular but like all solid fuels, it requires work in terms of loading in and ashing out. Also needs a storage area for solid fuel.

If I had to burn solid fuel as a cost savings measure, I would pick coal in a heartbeat over wood. Coal contains nearly twice as many BTUs as wood. If you are going through the hassle of dealing with a solid fuel, then pick the superior one. Sure wood is "green" etc etc... but when you are trying to heat a house in the winter, the time and cost savings of coal vs wood are appreciated.

Wood is a tremendous amount of work too. You could get split firewood delivered but there is a cost to that. Many people I know either fell and transport their own trees or have long logs delivered. After that, the wood needs to be cut into lengths, split and stored for 1-2 years. You will probably move the wood a few times as it comes out of storage and gets to your house for burning. You will most likely have a chainsaw, a log splitter and a truck to take care of and fuel up not to mention the hazards of dealing with said equipment. Vs coal where you get a multi-ton delivery and be done with it.

My buddy has a coal stove and can keep a fire going for 24+ hours on one load; try that with wood. This is a fuel I am giving serious consideration to in the future if I end up buying a house that will be expensive to heat.
 
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