Future transportation will need hydrogen
It is required 53 KWh to produce 1 kg of hydrogen at a pressure of 300 bar. A medium sized passenger car with fuel cell will be able to drive approx. 100 km per kg hydrogen. A car that drives 15,000 km per year will thus need 15,000 km/100 km = 150 kg of hydrogen per year. An annual production of 53 KWh x 150 = 7,950 KWh = 7.95 MWh is needed to keep a car with clean fuel.
The westerlies in the southern hemisphere
If we move this turbine to the southern westerlies, where the annual average wave energy is over 100 KW per meter wavefront, the calculation would be as follows: An 11.5 meter buoy would be affected by 11.5 meter wavefront. If the average energy potential is 100 MW per meter, it will be affected by 100 KW/m x 11.5 m = 1 150 KW = 1.15 MW.
But the turbine can only capture 14.4% of this energy, according to the table. Thus we ar left with 1.15 MW x 0.144 = 0.1656 MW. In one hour, it produces 0.1656 MWh and in a year 0.1656 MWh x 8640 = approx. 1 430 MWh. We saw above that each car will need 7.95 MWh. Then each subwave unit will produce energy corresponding to the need for 1 430 MWh/7.95 MWh = approx. 180 cars each running 15,000 km/year.
It is, however, not easy to produce energy from waves in the southern west wind belt. The main problem is that it is far offshore, and in most places the sea is very deep, 4000-6000 meters. If this should be possible, we must assume that facilities must be kept in place, not by means of anchoring, but dynamically with machine power. And the energy should come from the waves. This will of course be at the expense of the energy for hydrogen production. Researched is needed to find out how effective this can be done. But for the sake of this example, let us assume that 30% of the energy will be needed for this. Then we are left with 70% for hydrogen production. From each Subwave turbine we will then get a net energy yield equivalent to the need for 180 cars x 0.7 = 126 cars.
What are the petrol costs for an annual mileage of 15,000 km? A reasonable estimate would be EUR 800 (0.5 liter/10 km and EUR 1,1 per liter). A Subwave turbine in this ocean will thus produce hydrogen for a street value of EUR 800 x 126 cars = about EUR 100,000.
It will not be appropriate to deploy a single turbine in distant and demanding waters. Instead, a larger number would be deployed. Let's envision a field containing 30 x 30 units 75 meters apart. This will be 900 units distributed in an area of about 5 square kilometers. The yearly value of this production would be about EUR 90 million.
At this stage we are not able to give any meaningful assessment of the cost of such a project. Caption costs, operating costs, transportation costs and distribution costs would have a number of similarities with the offshore oil and gas industry. These environments have made such calculations for decades and gained a lot of experience. A competent cost analysis would be the first priority in assessing this vision.