* Greater distances from shore create challenges from increased water depth, exposure to more extreme open ocean conditions, long-distance electrical transmission on high-voltage submarine cables, turbine maintenance at sea and accommodation of maintenance personnel.
* A primary challenge for offshore wind energy is cost reduction. Developing the necessary support infrastructure implies one-time costs for customized vessels, port and harbor upgrades, new manufacturing facilities, and workforce training. In general, capital costs are twice as high as land-based, but this may be partially offset by potentially higher energy yields -- as much as 30% or more.
* As was experienced with land-based wind systems over the past two decades, offshore wind costs are expected to drop with greater experience, increased deployment and improved technology. To make offshore wind energy more cost effective, some manufacturers are designing larger wind turbines capable of generating more electricity per turbine. Several manufacturers are considering 10-MW turbine designs, and programs, such as UpWind in the European Union, are developing the tools to allow these larger machines to emerge.
The report went on to look at the technologies needed for deep water wind platforms. The three concepts for floating platform designs, including the semi-submersible, the spar buoy, and the tension-leg platform, each of which use a different method for achieving static stability
According to the report: "Although it is not yet known which of these designs will deliver the best system performance, designers seek platforms that are easy to install and minimize overall turbine loads. To determine this optimized design point, advanced computer simulation models need to be developed and validated. Most of the projects now reside in shallow water, and only two projects to date use transitional structures. One Norwegian demonstration project, Hywind, uses a deepwater floating design."
Looking for a major new ways to harness wind, solar and other evolving renewable energy, the DOE last month issued a call for advanced large-scale energy storage system technology. The DOE said the goal of its solicitation is to identify and prove new concepts for applied research in materials chemistry, battery components, battery designs and any technologies that will lead to breakthroughs in grid energy storage.
Such technology will be focused on novel materials, electrodes, electrolytes, membranes and other components, along with new concepts for ultra-low cost, high efficiency and long lasting energy storage systems. Emphasis is placed on highly innovative research proposals in areas that have the potential to have strong impact on large-scale energy storage in the future, the DOE stated.