Advanced Wind Turbine Program Next Generation Turbine ... - NREL

2 Concept Studies
GE approached the design of its next generation turbine from the premise that any turbine concept
or technology that might yield improvements in COE should be considered for inclusion in
the design. As a result, at the onset of the project, GE chose not to focus all engineering efforts
on designing and developing a preconceived concept for an advanced technology wind turbine.
The company instead chose to identify a number of innovative concepts and technologies that
might be expected to produce improvements in COE. At project commencement, GE expected
to spend approximately 6 to 8 months conducting studies of these concepts and then, based upon
the results of these studies, to select the most promising, feasible, and mutually compatible technologies
to incorporate into the preliminary design of a POC turbine. As research and development
progressed during the NGT project, new concepts were continually proposed and concept
studies continued in parallel with the development of the POC and EMD turbines. As some of
the best concepts were refined, they were introduced into the POC and EMD turbine designs, as
explained in Sections 3 and 4 below.
GE Wind personnel and consultants have completed investigations of several wind turbine system
and component concepts. The purpose of these studies has been to determine the trade-off
between cost and improvement in energy capture resulting from each of the concepts. These
studies have focused on three broadly defined categories of concepts:
• electromechanical systems
• controls systems
• Rotor and structural design.
Each of these categories of concept studies is discussed in Sections 2.1 through 2.3.
The concept studies were initially conducted at a rated power of 750 kW so that the baseline
Z48/750 turbine could be used as a basis for comparison. As is noted in Section 3, the POC turbine
was developed at 1.5 MW. As a result, some of the concept studies conducted subsequent
to the initiation of the POC design were also conducted at 1.5 MW so that their results could be
compared to the POC turbine.
Because of market advantages and GE experience, it was decided from the outset that the NGT
design should favor the three-bladed, upwind, variable speed, and pitch-regulated configuration,
although some alternatives to this were briefly examined. Additional guiding principles
throughout the concept studies have been:
• Use of readily available (commercial off-the-shelf or COTS) components
• Modularity (i.e., distributed design)
• Simplicity and ease of operations and maintenance
• Manufacturability
• Transportability
• Scalability.
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