Single- vs. Multi platform
Traditionally fixed wind turbines have always had an individual
foundation and this property has also been adopted in the first designs of
floating wind turbines. The offshore wind sector has developed to such extend
that the research community have taken great interest in further optimizing the
system design in order to obtain higher a power efficiency for lower
investments. One of such innovations is the introduction of multi-turbine
platforms. These multi-turbine platforms have advantages, but when these
platforms are considered one also has to cope with a couple of disadvantages.
First of all a two concepts for multi-turbine platforms will be discussed, where after an overview is given of the description, status, advantages, and disadvantages for both single-and multiple-turbine platforms. At last an innovative idea for a multi-turbine floater is introduced.
First of all a two concepts for multi-turbine platforms will be discussed, where after an overview is given of the description, status, advantages, and disadvantages for both single-and multiple-turbine platforms. At last an innovative idea for a multi-turbine floater is introduced.
Concepts
One multiple-turbine concept consists of a single pontoon type floater (semi sub) with several turbine towers on it to share anchors costs and provide wave stability as seen in the figure.
Another multiple-turbine concept is to place an array of smaller turbines on a single tower and platform. In an analysis of the first concept, there is determined the cost would be very high and it was questionable whether the large structure could withstand extreme wave loading.
Because turbine spacing is poorly optimized, both multiple-turbine concepts require the floating structure to either yaw with wind direction changes or compromise energy production when the wind shifts off the prevailing direction. Systems consisting of multiple turbines on a single floater may prove to be more expensive than single-turbine floaters because of additional support structure required to connect several rotors or towers together. However, for very large systems (>20-MW per structure) it may be possible to lower overall system weight with multiple turbines due to cubic mass scaling laws.
Advantages & Disadvantages
The 'Wind hunter'
We like to bring you new technological ideas on energy before anyone else. Here’s an interesting idea for alternative energy that we’ve encountered. The windhunter concept is a portable system that allows a huge floating platform to travel the high seas and anchor in a windy spot. This is just in its concept advantages but could have potential. Most existing sea based wind turbines are fixed at the moment at an enormous cost and are only as effective as the wind present in that area.
Interestingly its creators also plan to produce hydrogen from the turbines. The developers of this idea say: “The Windhunter system concept is an offshore, floating system that uses several wind turbines for power output to produce hydrogen by electrolyzing water. This continuously manned, safe and stable system will be easily maintained on-board while relocating to the best wind conditions for the wind turbines. The produced hydrogen gas may be compressed and stored as gas or liquefied and placed in insulated tanks. The compressed or liquefied hydrogen may be transferred by helicopter, surface ships or by other means.”