Ship propulsion by renewable energies available at sea: Innovations for utilisation of wind and waves

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1 Ship propulsion by renewable energies available at sea: Innovations for utilisation of wind and waves Dr. rer. nat. Jörg Sommer Januar 2013

2 Preliminary remark 1 The next-but-one generation of vehicles will be driven by hydrogen The BMW path: Hydrogen driven combustion motors The Mercedes-Benz path: Hydrogen fuel cell electric motor Prototype for ferries of the future: Alsterwasser Alsterwasser: Ferry for 100 passengers, Hamburg 2008, driven solely by hydrogen.

3 Preliminary remark 2 The hydrogen driven vehicles exist already but not the infrastructure: We have to look for intermediate steps. One of them could be to produce hydrogen aboard. This is the initial point of my further considerations.

4 1. Sun alone isn t enough Negative advertizing A press release: The huge freighter capable of carrying 6,400 automobiles is equipped with 328 solar panels at a cost of 150 million yen (1.68 million dollars), the officials said. The solar power system can generate 40 kilowatts, which would initially cover only 0.2 percent of the ship's energy consumption for propulsion, but company officials said they hoped to raise the ratio. Auriga Leader, Japan 2008, 60,213 gross tons

5 33 PS or 32 hp for a superyacht (31 m = 102 ft) Even a special design for maximal use of sun power results in disappointing performance. Despite the fact, that this is one of the most beautiful solar ships ever built. The Tûranor Planet Solar (loa 31m) was entirely new designed for maximal use of sun power, with 537 square meter solar panels. Nevertheless she has to manage with only 24 kw (32 hp).

6 2. Energy by sails isn t storable but they are the most effective wind propulsors, especially the newly developed wing sails. A wind turbine can do both: 1. Drive the boat or 2. produce storable energy. But for (1) you need a gear and a screw, which have friction- and transmission losses, and for (2) you need a generator, a device to store electrical energy, and a motor to drive the screw, also with conversion losses. BMW Oracle America's Cup boat Relevation II

7 3. The developement of mobile wave energy converters is Fins: Not a good solution! Suntory mermaid II reaches only pedestrian mean speed Orcelle: performance not known, but most likely insufficient. insufficient Suntory Mermaid 2 (Hiroshi Terao) Orcelle (Wallenius Wilhelmsen)

8 Conclusion: All or none! If you really want to promote the use of renewable energies for ship propulsion, you have to Use all sources available on sea, Make a new design, Take care of storing energy.

9 Primary energy and effective power facts & figures about sun-, wind-, and wave energy Example: Eco-Trimaran with realistic scenarios for method and location of operation

10 Eco-Trimaran The broad roof is covered with solar cells. Wind turbine of type H- Rotor. In a newer version the two rotors are side by side (interlocking) and not twisted. The floates can move about their horizontal cross axis (used for wave power conversion) and about their vertical axis (necessary for steering, avoiding of torsional stress and minimazation of drag) Technical data: LOA = 24.6 m, displacement: 61 m 3

11 The movements of the floats in the waves (upper animation) are at first converted into hydraulic pressure (lower animation) and then into electric power (not shown) the same principle as at Pelamis.

12 Pelamis is a stationary wave power convertor. Several machines of this type deliver electrical power since years. The Eco-Trimaran uses the same principle. The only difference: His floats lie side by side and not in a row.

13 The same principle of wave power conversion may be realized by other types of ships

14 Back to wind power: How to combine the benefits of a wind turbine (energy storage + ship propulsion) and wing sail (direct propulsion without storage- and transformation losses)?

15 Using a wind turbine as sail Requirements: H-rotor (vertical axis) with 2 vertical blades (not twisted). Bracket for wind turbine. Step motor, which may turn the rotor together with its bracket in any position of a 360 circle. Every blade is pivotable about its own longitudinal axis by a step motor. Process computer to steer the step motors and a special software.

16 Change of operation from wind turbine to wingsail 1. Stop the wind turbine by its bracket 2. Turn the rotor together with its bracket in a position which a) is optimal for using the blades as sails and b) minimizes shadowing of solar panels on the roof 3. Turn each blade in an optimal sailing position 4. Enlarge the area of the blades and give them a sail profile. How the latter is achieved is shown on the next frame:

17 From wing sail to blade and vice versa hinge State as wing sail State as blade in a H- Rotor (wind turbine)

18 Topview

19 As sail: Some further benefits of this construction Fully automatic sail trimm Minimization of shadowing the solar panels As wind turbine: Gain in efficiency by adaption of the blade angle to wind direction (traditional H-rotor has fixed blades)

20 Sun: Global radiation and effective power Primary energy Northern scenario (North Sea) Effective power E = 900 kwh P 1 = 0.10 kw P 2 = kw P 3 = 2.26 kw = 3.0 hp = 3.1 PS Sum of radiation energy per year and 1 m 2 (horizontal plane) P 1 = E / 8760 h Mean radiation power per 1 m 2 (8760 is the number of hours per year) P 2 = P 1 * 100 m 2 Mean radiation power arriving at 100 m 2 solar cells P 3 = P2 * 0.22 Power output of 100 m 2 solar cells is their efficiency coefficient Primary energy Southern scenario (Mediterranean) Effective power E = 1800 kwh P 1 = 0.20 kw P 2 = kw P 3 = 4.52 kw = 6.1 hp = 6.2 PS

21 Wind: Speed and effective power Primary energy Northern scenario (North Sea) Effective power v 1 = 8 m/sec. V 2 = 6.2 m/sec. P 1 = 148 W P 2 = 4.8 kw = 6.4 hp = 6.5 PS mean wind speed in a defined hight, e.g. 50 m (wind maps) mean wind speed in hub height of 9.5 m v 2 = v 1 *(9.5/50) 0.12, where 0.12 is a roughness coefficient for open sea Wind power per m 2 P 1 = 0.61 * v is half air density wind power of a wind converter with an effective area of 111m 2 and degree of efficiency of 0.29: P 2 = P 1 * 111 * 0.29 /1000 Primary energy Southern scenario (Mediterranean) Effective power v 1 = 7 m/sec V 2 = 5.7 m/sec. P 1 = 115 W P 2 = 3.7 kw = 5.0 hp = 5.0 PS

22 Primary energy Waves Northern scenario (North Sea) Effective power T = 5.5 s HS = 3.3 m P 1 = 30 kw P 2 = 106 kw = 143 hp = 147 PS Significant wave hight H s and Period T (as registrated by detection buoys for defined sea areas) Wave power per 1m wave crest P 1 = 0.5 * T * H s 2 (kw) power output of a wave line converter with frontal width of 6.45 m, a degree of efficiency of 0.7 (wave to wire) and a free course relative to wave fronts: reduction factor P 2 = P 1 * 6.45 *0.7* (kw) Primary energy Southern scenario (Mediterranean) Effective power T = 3.0 s H s = 1.29 m P 1 = 5 kw P 2 = 18 kw = 24 hp = 24 PS

23 Comparison: Waves are by fare the best energy source! Scenario Source North South best unit Sun 2,3 4,5 5,5 kw Wind 4,8 3,7 6,7 kw Waves 106,0 18,0 319,1 kw Sum kw PS But all things concidered: Is that enough for a super yacht (25 m = 81 ft)?

24 Critical considerations Sum kw PS This figures are Means. There are days with higher energy input, but also days with less. We must also take into account the power consumption aboard. a southern scenario like the mediterranian is a very favored region for superyachts not every owner likes strong winds and high waves. Is there annother source of energy?

25 The forth source: Stored energy The mooring times may be used for energy storing. Especially super yachts have long mooring times in many cases 90% of the year! Hydrogen is proposed as storing medium; so we take future proceedings into account. We have a bridge Technology to the next-butone generation of eco vessels.