Renewable energy refers to energy produced from non-fuel sources--especially including energy from the sun or the rotation of the earth.
When sustainable agriculture is achieved many plant based processes can be classed as renewable. That can extend to ethanol and biofuels made from switchgrass or wood chips. Ethanol production from corn remains controversial because some feel that fossil fuel inputs predominate over grain inputs. A conventional power plant fueled with wood chips can be considered renewable if tree farm areas and tree growth rates are sufficient to sustain operation of the plant.
For a summary of wind energy equipment suppliers see the following: 
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