Generating, storing and consuming energy

The key idea of the project as a whole is to consistently utilise the most important sources of energy available at sea. Since this project is likely to be initially realised using a yacht, which for most of the year would lie at anchor, great stress is to be placed on storing energy. Wind and solar energy, in the least, are continuously available during mooring periods, and these can be converted into a form able to be stored. Compressed hydrogen gas is planned to be used for storage; the rea­sons for deciding on this medium are presented in the annex in the section entitled “Andere Speichermöglichkeiten” (at present only in German). In order to obtain concrete results, we proceed as outlined in the following. First, the amount of energy able to be generated on the vessel from the sun, wind and waves is determined. To do this, an operating scenario for the vessel is required, i.e. assumptions regarding: the proportion of  
mooring time to travel time; the average number of daily operating hours of the ship’s motors during voyages; and the areas where the vessel is likely to operate, since there is a great amount of variation among marine areas with respect to sun, wind and wave conditi­ons.
   Based on a survey of individuals familiar with the practical operation of large yachts, it is assumed that our vessel will be travelling an average of 42 days per year, while the rest of the time it will either be moored at a pier or lie at anchor near a beach. Such assumptions can be verified when large used yachts are sold. In such cases the number of hours of operation accumulated thus far by the ship’s motor is made public, and this figure can then be divided by the number of years of operation. Mooring periods then need to be further broken down into phases during which crew or passengers are on board. For a generous estimate of energy needs, the period withouta crew (i.e. non-use of the vessel) has, at 50 days per year, been intentionally assumed rather conservatively. All of the calculations presented below are based on
a proportion of 50 : 273 : 42 days (mooring time without crew : mooring with crew : travel time) with 6 hours of motor operation on each day of travel.
    Once the amount of available energy has been determined, energy requirements need to
be calculated. First, requirements are ascertained, i.e. energy necessary for the crew’s comfort (heating, air conditio­ning, lighting, kitchen appliances etc.) as well as energy needed for other equipment on board (electronic and electrical steering components, bilge pumps, position lights etc.). The energy surplus, i.e. the difference between available energy and board energy requirements, is consumed by the ship’s motor during travel and stored while mooring. During voyages the motors can thus run on the energy produced directly and additionally on stored energy.
energy mix

Generating energy

An annual total of 78 MWh is produced according to the northern scenario and 68 MWh according to the southern scenario. The graph shows the distribution of energy quantities among the three primary energy sources. Wind and waves predominate in relative terms in the northern scenario, while solar energy plays a stronger role in the southern scenario. Yet in each case wind is the major source. Seperate sections, entitled “Sun”, “Wind” and “Waves”, describe in greater detail how the share of each of these three types of energy are produced and a description of the “northern” and the “southern” scenario in detail.
Editorial remark:

This page represents the 2006 version of the project description. An exception is the page about wave energy, which is up to date (Dec. 2012). Therefore there are discrepancies in the figures for power conversion, especially that of wave power. The latter have turned out to be much higher than that calculated in 2006.
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