The promo video claims a 60m Mirage sail can provide 400kW of power.
Accounting for weather, berthing, and efficiency, let's assume the sail can provide that power for 4 hours of every 24 hour period - that's 1,460 hours/year .
Each Mirage sail might therefore provide 584,000 kWh per year of useable power.
A gallon of bunker fuel is worth 11.0 kWh/kg [1]
So, a Mirage sail can compensate 53,090 kg of bunker fuel per year.
Bunker fuel is priced around $600 USD / metric ton. [2]
Therefore - the expected value of each Mirage sail may approach $31,850 per year. Assume a 10 year service life. Each Mirage must have an installed cost of $318,500.
If you triple the assumption of 4 hrs/day to 12 hrs/day efficiency, the value scales linearly to $955,500.
Edit: Outsail's website lists the fuel offest to be 2,000 metric tons per year. Let's assume fuel is converted at 50% efficiency, we can say that they're looking for the sail to return 11,000,000 kWh per year. That's 27,500 hours of sailing per year. There are only 8,760 hours per year... oops.
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Perhaps, let's look at it another way.
24 hours x 400 kW x 365 = 3,504,000 kWh
2,000 ton x 1,000 kg/t = 2,000,000 kg
3,504,000 kWh / 2,000,000 kg = 1.752 kWh/kg assumed fuel value
We couldn't fully explain that 400kW number in the video, but our video says "average power" and it was based on a standard transpacific route. The 400kW already takes into account the times the Mirage is not being used, both for bad weather and time at port. Depending on the wind speed and direction we can provide a lot more than 400kW. Using 24 hrs/day we get an maximum install cost of 1.9 million!
So if 400kW average, on 21 day journey, we get 201,600 kWh which is 18,300 kg of bunker fuel, which costs approx. $11,000
If you are directly offsetting fuel consumption and helping shippers meet their efficiency goals, you have a break even at approximately $11,000 per Mirage per journey, or $523 per day.
Assuming 100% bookings, each Mirage has an annual revenue floor of $190,895
Accounting for weather, berthing, and efficiency, let's assume the sail can provide that power for 4 hours of every 24 hour period - that's 1,460 hours/year .
Each Mirage sail might therefore provide 584,000 kWh per year of useable power.
A gallon of bunker fuel is worth 11.0 kWh/kg [1]
So, a Mirage sail can compensate 53,090 kg of bunker fuel per year.
Bunker fuel is priced around $600 USD / metric ton. [2]
Therefore - the expected value of each Mirage sail may approach $31,850 per year. Assume a 10 year service life. Each Mirage must have an installed cost of $318,500.
If you triple the assumption of 4 hrs/day to 12 hrs/day efficiency, the value scales linearly to $955,500.
[1] http://www.cmar.hk/contoil_flow_rate.pdf [2] https://shipandbunker.com/prices
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Edit: Outsail's website lists the fuel offest to be 2,000 metric tons per year. Let's assume fuel is converted at 50% efficiency, we can say that they're looking for the sail to return 11,000,000 kWh per year. That's 27,500 hours of sailing per year. There are only 8,760 hours per year... oops.
-------
Perhaps, let's look at it another way.
24 hours x 400 kW x 365 = 3,504,000 kWh
2,000 ton x 1,000 kg/t = 2,000,000 kg
3,504,000 kWh / 2,000,000 kg = 1.752 kWh/kg assumed fuel value
Oops again...