Wind turbine manufacturers design, test, manufacture, and assist with the operation and maintenance of wind turbines. Important choices facing them include turbine design (generator type, gearbox vs. gear-less, materials) and how much control to maintain over component supplies (internal vs. external). They must be concerned with maintaining their extensive fleets of operating turbines while at the same time developing newer and ever-larger models. The largest wind turbine manufacturers are based in Denmark, Germany, Spain, India, and the US. Wind farm developers develop and sometimes own and operate wind farms. This involves purchasing or leasing land, installing meteorological equipment to quantify the wind resource, and securing transmission, power sales, turbine supply, construction, and financing agreements. Some small wind farm developers, lacking the "muscle" and financing necessary to secure major turbine supply contracts, will develop a project in order to "flip" it and sell to larger developers such as
wind power managing owners. Wind farm construction companies construct and sometimes assist with the
operation and maintenance of wind farms. Wind farm operation and maintenance companies (also called "wind O&M contractors", or simply "wind operators") are a rapidly growing industry segment. They assist with the
operation and maintenance of wind farms, under contract with (other) companies which own those wind farms. O&M contracts typically focus on the maintenance of the turbines, towers, and blades. They haveresponsibility for the generation of electricity (conversion of mechanical energy to electricity), but usually are not responsible for the actual transmission of this electricity to the grid through
electrical substations which are located at or near the wind farms. Note: some of these companies are also
wind power managing owners (see below), at certain wind farms where these companies are not contractors, because the same company owns and operates those wind farms directly. Wind farm finance companies sell loans and other financial products to wind farm developers and wind turbine manufacturers. Most of these companies are large banks with experience in providing financing to other large industrial projects.
Wind power consulting companies offer consulting services to the wind power industry, including wind turbine design and certification, technical Due Diligence (or acting as the "Owner's engineer"), wind resource maps,
wind resource assessments, wind power forecasting, and wind turbine power performance testing. Most of these companies maintain financial independence (no ownership stake) from wind farm projects in order to guarantee unbiased service to their clients. Wind power research organizations provide research and development to the wind power industry. They are usually part of government agencies or universities and conduct research on aspects of wind power that are currently cost-prohibitive for the private industry to invest in. Wind power managing owners are responsible for the
operation and maintenance and administration of wind farms which they develop or acquire. All or part of these responsibilities may be subcontracted to third parties. Wind power managing owners, along with other financing parties and equity partners, typically sell the electricity generated from wind farms to
public utilities under long-term
power purchase agreements (PPAs) where they receive a fixed price for the electricity. ==Recent trends==