Turbines: Wind & Hydropower

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Turbines: Wind & Hydropower


NAICS: 33-3611 Turbines and Turbine Generator Set Units Manufacturing

SIC: 3511 Steam, Gas, and Hydraulic Turbines, and Turbine Generator Sets

NAICS-Based Product Codes: 33-36110836 and 33-36110856


Turbine Basics

Turbines are rotary motors in which motion is imparted to the motor's central shaft by a fluid capable of being put under pressure. A simple windmill illustrates the basic principles of a turbine. The wind—in a technical sense, a fluid—engages the blades of the mill and causes them to move. They move, rather than simply resist the pressure of the wind, because they have curvature and are oriented at an angle to the wind's direction, acting like sails on a boat. The blades are attached firmly to a shaft. As the blades move, so does the shaft. Inside the windmill the motion of the horizontal shaft is transferred to a vertical shaft by gearing and then does whatever work the windmill is supposed to do. The fluid a turbine uses may be the wind, steam, water, hydraulic liquids, or exhaust gases from combustion. In the case of wind turbines, the blades are huge in order to capture as much energy from the wind as possible. In the case of other turbines, the blades, referred to as vanes, are inside the chamber of the turbine and the chamber itself is designed in such a way that the fluid passes through it and transfers as much of its energy to the vanes as possible before leaving the turbine.

The fluid that imparts energy to the turbine must itself have energy. Wind gets its energy from solar radiation; heat from the sun causes high and low pressure weather systems to develop which, interacting with one another, cause the atmosphere to move. When water is used to drive a turbine, it must be under pressure. In hydropower applications, that pressure is provided by gravity; water is contained above the turbine and then released to flow down through it. Alternatively the pressure may be produced by the tides, thus in part by the gravitational pull of the moon. Steam turbines work because fuels have been burned to generate steam. Hydraulic turbines depend on compressors that pressurize the fluid before it is permitted to release its pressure by moving the turbine's vanes.

The general public, hearing the word turbine, may think of jet engines on aircraft. These turbines receive their energy from the combustion of fuels. Very energetic combustion generates powerful pressures when the exhaust gases are contained and channeled to drive a turbine. In turn the turbine compresses air flowing into it. Exhaust gases and pressurized air are then ejected with such force at the rear of the turbine that they produce thrust sufficient to lift the aircraft and then, once it is airborne, to keep it aloft. Jet engines differ from all other kinds in that the force is deployed to produce thrust rather than rotary motion. Such turbines also generate electrical power, and this by means of rotary motion, is needed by the aircraft to operate. Flying machines are complex because thrust itself would be insufficient if the plane's wings were not themselves artfully shaped as lifting vanes, causing air passing their surfaces to lift them.

Turbines classified under NAICS 33-3611 are typically used to generate electricity. Aircraft engines, be these turbines or other, are classified by the Census Bureau under NAICS 33-6412, Aircraft Engines and Engine Parts Manufacturing. The focus of this essay is on a minute part of NAICS 33-3611—equipment supporting the emerging new activity associated with alternative energy supply.

Wind Turbines

Wind turbines are placed on top of tall towers, and they power generators to produce electricity. They are classified as under 100 kilowatt (kW) for use in small applications at a single site or as 100 kW or greater. The larger devices are deployed in wind farms. In the latter case, the combined generation of many turbines is collected and passed into the electric grid. The kilowatt rating is for operation per hour, but only when the wind blows hard enough to turn the turbine at its designed speed. While electric demand is constant the wind blows only occasionally. A fundamental limitation of wind turbines, therefore, is that they cannot be used as the sole source of electrical energy. They may, however, supplement the electric demand when the wind is blowing, in effect substituting solar energy for power generated by fossil fuels or nuclear power devices.

The average household, for example, consumes 10,654 kilowatt hours (kWh) of electricity a year. A 5 kW turbine's maximum annual capacity is 43,830 kWh, derived by multiplying 365.25 days by 24 hours and then by 5. It would thus seem that the 5 kW turbine would be more than sufficient. But turbines also have a rating factor based on how frequently and fast they turn. A typical range is 20-30 percent of the time. At a rating of 24.3 percent, the 5 kW turbine will produce 10,654 kWh in the year, but this production may be taking place only in the windy season. During that time it will produce too much energy for consumption and in the off-season not enough.

Based on these considerations, the use of wind turbines is ideal in combination with fuel-based electrical generation, be the wind-driven devices grouped into wind farms or standing alone. Stand-alone units hooked into the electric grid, feeding their excess production to others on the grid, can replace a farmer's or homeowner's demand on the utility and earn him or her credits for supplying energy. Wind farms linked into the grid work in the same way, but on a larger scale. The utility can scale back generation when the wind is brisk.

Hydropower Turbines

Turbines used in hydropower electrical generation are placed in the path of falling or flowing water. The water engages the vanes, blades, or propellers of the turbine and, moving them, translates its energy into motion. Turbines in this application depend on the pressure exerted by the water, its volume and speed of flow, and combinations of these two aspects. The height of the water above the turbine (in a dam, for instance) is referred to as the head of the water. A high head may be a water held 500 feet above the turbine. Water of high head, released, falls with great velocity. When water flows rapidly and in large volume, it produces great pressure.

Turbines are designed to take advantage of velocity (head) or pressure (flow) or both in combination. Impulse turbines are designed for high velocity and relatively low flow volumes. An example is the Pelton, a turbine which receives its water flow in a curved duct that surrounds the actual moving element, the runner. Stationary nozzles direct the water in sharp jets at the runner. The runner carries spoon-shaped vanes or buckets. Variations on this general design are on the market; types are known as Turgo, Crossflow, Ossberger, and Michell-Banki turbines.

Reaction turbines are used in situations where larger flows of water are appropriate but the head is lower. The turbines are placed in the flowing stream itself. Propeller type turbines are the most common and come in different types. They may be pictured by imagining a propeller mounted inside a tube through which water is flowing with force, turning the propeller. Bulb type turbines submerge the generator along with the turbine in water. Francis turbines have two stages, an impulse and a reactive stage, and are a hybrid but classified as reaction turbines. Kinetic turbines are used in rivers and derive their energies from the river's own flow. Other types are Kaplan and Tyson turbines.

Turbines are also rated by electrical power capacity in kilowatts or megawatts (MW). The U.S. Department of Energy (DOE) classifies hydroelectric plants as large (30 MW or greater), small (100 kW up to 30 MW), and micro (less than 100 kW). DOE also classifies facilities as impoundments, diversions, or pumped storage facilities. Impoundments are what the public thinks of as dams that create extended basins of water upstream from the dam in a river. All of the water is held behind the dam until deliberately released, either to generate electricity or, bypassing the turbines, to release the water when the basin's level rises too high. The Hoover Dam on the border between Arizona and Nevada is a famous example of an impoundment. Diversion facilities are produced by rerouting a portion of a river's flow to generate power at a site where the river has a large vertical drop anyway. The hydroelectric facilities at Niagara Falls, New York, are an example of a diversion. Pumped storage facilities are artificially created elevated lakes or impoundments fed their water by pumps from a near-by river or a lower-lying body of water. Pumping takes place when electrical demand is very low, for example, late at night. The water is released from the storage basin at times of peak electrical demand. Kinetic turbines are sometimes used in flowing river waters to augment electrical requirements at river-side facilities. Tidal hydroelectric facilities are a variant of impoundments and pumped storage. Daily tides substitute for the pumping. In such facilities, gates are opened before the inflowing tide begins and are closed at high tide, preventing the seawater from flowing back into the ocean. Instead, the water is released under human control and while driving turbines.

Wind, Hydro, and Renewable Energy

In all of the cases of hydropower, natural gravitational forces supply the energy that is ultimately turned into electricity. The DOE's Energy Information Administration (EIA), however, typically excludes pumped storage from its definition of renewable energy facilities because the pumping action is supplied by electrical power generated by burning fossil fuels. With the exception of pumped storage, therefore, wind and hydroelectric power are two categories of renewable energy. Others are energy generated from biomass, geothermal sources, and solar energy.

Biomass may be wood or wood waste, industrial and municipal solid waste, or other biological wastes such as agricultural wastes, sludges, and the like. Energy from municipal solid waste may be generated by burning the waste and converting it, by the intermediate form of steam, into electric power, or by capturing methane gases generated in landfills and using that gas as a fuel. Geothermal energy relies on volcanic sources of heat, thus heat closer to the Earth's core. Solar energy is captured by solar panels that capture the sun's heat and hold it in liquids or photovoltaic systems that use semiconductors built into solar panels to convert sunlight directly into electricity.

By far the largest contributor to electricity from renewable sources is hydropower. In 2005, measured as electrical generating capacity in place, hydropower represented 81.6 percent of all renewable electric power. Second in rank was wind power, with 10.1 percent of renewable electricity. The remaining sources were biomass (5.6%), geothermal facilities (2.3%), and solar power (0.4%). These applications exclude other utilization of these sources, thus as sources of routine space heating.


Sizing the Markets

One picture of the market for wind and hydropower turbines in the United States is provided by looking at future generating capacity likely to be provided by wind and hydroelectric power. The U.S. Department of Energy provides projections into the future on an annual basis, including electrical power generation from renewable sources. Based on the DOE's Annual Energy Outlook 2006, and taking its projections out to 2010, installed capacity for electrical generation by conventional hydropower barely changes between 2005 and 2010. In 2005, hydropower generating capacity stood at 79.97 gigawatts (GW); ten years later, capacity was estimated to stand at 79.99 GW. Installed generating capacity for wind turbines, however, stood at 9.62 GW in 2005 and was projected to increase to 16.97 GW by 2010, indicating a substantial growth (12%). These data are shown in Figure 220, with geothermal included for comparison. Geothermal shows a moderate growth of 1.5 percent per year between 2005 and 2010, as analysts at the DOE estimate.

Estimating the market using such data involves applying dollar values to the increases in capacity. Increases in capacity are captured by private sector as well as governmental surveys, such as those conducted by the American Wind Energy Association and the DOE's own. Based on DOE estimates, capital investment in hydropower ranges between $1,700 and $2,300 per kW of capacity whereas corresponding investment for wind energy ranges from $750 to $1,000 per kW. The lower ranges represent less powerful turbines in both cases.

Examining the dollar estimates associated with wind energy in the United States and across the globe, by organizations like the Global Wind Energy Council (GWEC), shows that in the wind turbine category it is customary to assume that each kW of capacity added is valued at $1,000. This is a rule of thumb but one that is commonly employed. Using this approach, the market for turbines in the United States was $970 million in 2004, $2.65 billion in 2005, $2.63 billion in 2006, and $4.17 billion in 2007. If the DOE's projections hold, the market will be approximately $17 billion in 2010. This last figure assumes that costs per kW will not drop though costs have been trending down.

Using data collected by the GWEC on new capacity installed worldwide, the global market for wind power turbines was approximately $8 billion in 2004, having grown at an annual rate of 15.8 percent since 1999.

When it comes to hydropower the same approach cannot be applied because hydroelectric capacity was almost flat in the 2000 to 2005 period, increasing by a mere 601 MW (in comparison with an increase for wind in the same period of 7,240 MW). Assuming that each kilowatt of addition to hydropower capacity costs $2,300, the 601 MW yields $1.38 billion for a five-year period or, on average, a market for new equipment of around $276,000 per year. Based on global data, however, the market must be larger. Data published by Alstom, the multinational French power equipment company, the global market for power generation in all categories in 2005 was $125 billion of which $45 billion was spent on upgrading and retrofitting existing turbines and generators. Alstom argues that, in 2005, one-third of all power plants installed the world over were 30 years or older, creating a substantial market for service and retrofit. Applying this estimate to the U.S. context, approximately $915 million were expended by the U.S. hydroelectric sector on upgrading existing equipment or replacing turbines. This value results because, according to the Energy Information Administration, U.S. capacity represents 25 percent of world capacity and hydroelectric is 8.13 percent of U.S. capacity. If expenditures for new equipment are added to this derived total for replacement and upgrading, the hydropower market in 2005 was around $1.19 billion.

The 2002 Economic Census, conducted by the Census Bureau, provides no insight into this market at all. Industrial codes recognize the categories, as shown above, but in reporting its results the Census Bureau has suppressed data both for hydraulic turbines and wind turbines. Data suppression is mandated by law when numbers reported might reveal the identity of actual producers. In the 2002 Economic Census, the estimated wind turbine market was still too small for Census reporting without suppression (approximately $550 million) and new hydropower turbine sales were also minimal or nonexistent (no capacity additions were detected by DOE).

Market Determinants

The accelerating growth in wind energy is stimulated in part by economics and in part by environmental concerns. Using DOE figures from the Energy Information Administration, the cost of wind energy ranges between 4 and 6 cents per kilowatt hour. Residential costs from all sources, but predominantly from fossil fuel powered plants, ranged between 5 and 16.7 cents across the United States. Moving from West to East, examples are California at 12 cents, Kansas at 7.71 cents, Minnesota at 7.65 cents, Texas at 9.16 cents, New York at 14.31 cents, and Florida at 8.55 cents. The economic logic comes from the fact that capital costs of wind-power installations are declining and stand at approximately $1,000 per kW whereas alternatives are higher, with nuclear plants coming in at approximately $4,000, fossil-fuel plants at approximately $1,500, and hydroelectric plants at minimally $1,700 per kW. The only type of electrical generation plant that beats wind turbines is gas turbine plants coming in around $500 per kW. All of wind's competitors, excepting only hydroelectric plants, have fuel costs in addition, and in gas turbine installations the fuel costs are by far the highest. At the same time, as already noted, wind energy is not free-standing in the sense that wind farms must always operate in conjunction with conventional generation of electricity to account for the intermittent character of wind activity. For wind, therefore, the driving forces are economic—a way to supplement more expensive energy in regions favorably located. These factors not only account for the projected growth but, with likely rising conventional energy costs a high probability, they guarantee it.

Hydroelectric power has higher capital and maintenance costs than wind power, with costs ranging from 5 to 11 cents per kWh. But hydroelectric plants located in areas of sufficient water flow, in climates where freezing does not significant interfere with operations, is a much more independent source of electricity than wind turbines. Big dams, however, represent a major disturbance to established ecosystems and to the societal arrangements around them. Their use impacts water distribution, land use, and down-river ecologies. The very scale often demanded for a successful new hydroelectric project guarantees long lead times to development and tends to generate energetic public opposition. For this reason the DOE does not anticipate the addition of any new capacity until after 2020—and this despite some 5,700 identified sites capable of adding 30,000 MW of capacity to the nation's electrical power grid using hydroelectric power.


Hydropower Turbines

Large turbines dominate the hydroelectric industry. Major players operate globally and, more significantly, are suppliers of electric turbines and generators for all power generation applications, not just hydroelectric. World leaders include Alstom Power (France), American Hydro Corp. (United States), Andritz VA Tech Hydro (Austria), General Electric Hydro (United States), Hitachi Hydro Turbine (Japan), Mitsubishi Heavy Industries (Japan), and Voith Siemens (Germany). The top three companies in hydropower turbines appear to be Alstom, GE, and Voith. All three, for instance, are participants in the largest current hydroelectric project in the world, the Three Gorges Dam in China, which is in process of completion. The companies are also participants as turbine and generator suppliers in most countries with extensive hydropower capacity. Andritz is a relatively new name in this industry in that Andritz—a major equipment supplier to the steel, pulp and paper, and other process industries—acquired VA Tech Hydro in 2006.

The hydropower industry, however, has a much more difficult-to-see micro segment made up of quite small turbines providing 100 kW capacity on down. This segment displays a state of activity similar to wind power. A great deal of promotional activity is underway, spearheaded by environmental groups and promoters of renewable energy. Use of small hydroelectric installations by private individuals, on farms or in communal settings far from cities, are the object of these promotions, with case studies cited by many. Micro uses of hydropower are also of interest by industry in plant-level energy generation. In the United States alone, scores of companies offer micro turbines and related planning, engineering, and installation services. One promotional web site, for instance, www.Microhydropower.net, provides a list of 95 suppliers from all over the world, including eighteen U.S. producers. Another Web-based source, Source Guides, lists the following twenty-six companies offering small turbine equipment. The list is not exhaustive.

  • Alternative Energy Systems Co. of Mississippi
  • Big Frog Mountain
  • Bishop Enterprises
  • Canyon Industries, Inc.
  • Continental Field Systems
  • H & H Enterprises of Montana, Inc.
  • Harris Hydroelectric
  • Hydro Consulting & Maintenance Services, LLC
  • Hydro Green Energy
  • Hydro Technology Systems Inc.
  • Hydro West Group, Inc.
  • The James Leffer & Company
  • Lil Otto Hydroworks
  • Nautilus Water Turbine
  • North American Hydro
  • NWHydro
  • Pyramid Solar
  • Reliant Electric Inc.
  • Renewable Electricity Solutions
  • Rentricity
  • SoL Energy
  • SolarElectric.com
  • Southern Energy Solutions
  • Veterans Energy Technologies Inc.
  • Water Alchemy Enterprises
  • Windpower Unlimited LLC

Wind Turbines

The market leaders worldwide in wind energy turbines are Vestas Wind Systems A/S (Denmark), with a 27.9 percent share in 2005, GE Wind (United States) with 17.7 percent, Enercon GMBH (Germany) with 14.2 percent, and Gambesa Energy (Spain), with 12.9 percent. General Electric holds the dominant market share in the United States, with more than half of installed capacity according to the American Wind Energy Association. Vestas is the second-largest U.S. supplier. Vestas was already a leader before it increased its dominance in 2004 by acquiring NEG-Micon, another important wind turbine producer also a Danish company. Enercon is the top German producer, but Germany also fields three other companies that make the top ten: Siemens with a 5.5 percent share of the global market, REpower Systems AG with a 3.1 percent share, and Nordex Energy GMBH with a 2.6 percent market share. In addition to Gambesa another Spanish company, Ecotécnica, is also in the top ten. Ecotécnica had a 2.1 percent share in 2005. India's Suzlon Energy is a leader with a 6.1 percent share. Finally Mitsubishi Heavy Industries is a participant in the world's top ten with a 2 percent share. Share data listed here were calculated by Enercon GMBH from installed capacity worldwide.

In the case of hydropower turbines and in the wind energy industry, major global companies account for the majority of large installations but a large number of small or mid-sized companies participate in the micro segment of the market. In the case of wind energy, such installations serve a single facility such as a farm, a home, or an enterprise. The American Wind Energy Association lists, from among a large number of such companies, those shown below. The American Wind Energy Association (AWEA) labels these producers as "Commercial proven U.S. equipment providers," commenting further that they are "Certified or qualified by recognized agencies as meeting established standards and recommended business practices … and/or determined by AWEA's Small Wind Turbine Committee as commercially available with multiple publicly accessible operational installations in the U.S."

  • Abundant Renewable Energy
  • Bergey Windpower Co.
  • Entegrity Wind Systems
  • Energy Maintenance Service
  • Lorax Energy
  • Northern Power Systems
  • Solar Wind Works
  • Southwest Windpower Co.
  • Wind Turbine Industries Corp.


Turbines in general are steel-based precision industrial products of the heavy category. Hydropower turbines are typically massive because they are high capacity, intended for dams, and must withstand very substantial weight and pressure of water. Wind turbines are made as light as possible because they must be hoisted on towers for exposure to wind at optimum flow levels, but the forces impinging on such turbines are also considerable. Wind turbines must hold up to very powerful storms even as they turn with the greatest of ease in the lightest winds. Thus they must combine great strength with light weight.

Raw or semi-finished iron and steel product (forgings, fabricated metals, bars, shapes, and plates) represent the largest materials groupings purchased by the industry and further processed in manufacturing, representing approximately 23 percent of inputs. Fluid power devices, generators, and generator subcomponents are acquired in finished form and account for 5 percent of purchases. Census data on materials consumed fail to disclose the value of non-ferrous forgings, shapes, and forms, possibly because these are associated with wind turbines—for which all data are withheld. Sixteen of eighteen other major categories of finished inputs are all predominantly steel or aluminum products, the exceptions being fabricated plastic products and rubber and plastic hosing and belting, representing a tiny fraction of total inputs. Turbines fall under the general category of heavy industrial machinery and display the supply chain logistics of that class of products. They are typically made in major centers of heavy manufacturing, ideally in the vicinity of steel supplies and foundries.


Wind and hydropower turbines are sold directly by producers to the ultimate consumer, typically a utility, be that utility in the private or the public sector. The buying agency publishes a request for proposal (RFP) or sends such a request to a list of pre-qualified sellers. Usually after consultations, the seller prepares a proposal and submits it to the buyer. A process of review takes place. In the case of large projects, sellers usually make one or several presentations to the buyer, followed by frequently extended negotiations taking place on two levels: technical and commercial. The buyer reaches a decision and awards a contract to the successful seller.

In the power generation industry, buyers and sellers usually have ongoing relationships. Producers' sales engineers call upon utilities regularly; and utility engineers actively keep track of technological developments by personal study and attendance at trade fairs and technical shows. At the upper end of both wind and hydropower activity, where the producers are typically global operators, the companies maintain sales/technical offices in major buying regions from which they gather intelligence and conduct outreach operations. Trade associations participate indirectly in distribution by organizing regional and national meetings and acting in an information brokerage capacity as well.


Based on data published by the Idaho National Laboratory, the Federal government dominates the U.S. hydropower sector being the owner of 51 percent of all hydro-electric installed capacity in 2006. In order after the federal government are private utilities (24%), non-federal public agencies (22%), private non-utility operators (2%), industrial operators (1%), and cooperatives (less than 1% of installed capacity). In terms of number of facilities (rather than capacity) public utilities operate the largest number (735). Next in order are private non-utilities (642 plants), non-federal public bodies (577), industrial operators (226), Federal agencies (171), and cooperatives (37 facilities). Within the dominant Federal sector, the three largest operators are the Corps of Engineers (45% of the Federal sector), the Bureau of Reclamation (33%), and the Tennessee Valley Authority (17%).

Key users of wind turbines, operators of wind farms, are predominantly private sector electrical utilities. The largest operator of wind farms in 2005 was FPL Energy, a major utility which derives 30 percent of its energy from wind power, second only to natural gas fired plants (49%). FPL operates forty-seven wind farms in fifteen states and is four times the size, in wind power, than its nearest rival, PPM Energy. PPM, a Portland, Washington utility, operated nine wind farms in 2005. Other leaders, based on data assembled by Emerging Energy Research (EER), are The AES Corporation, Goldman Sachs-Horizon Wind Energy, Invenergy, Mid-American, and Shell WindEnergy.


Markets adjacent to wind power are other forms of solar energy, most notably photovoltaic power (PV), a technology that, using solar panels of special design, is capable of transforming sunshine directly into electrical current. Photovoltaic installed capacity was tiny in 2005, amounting to 30 megawatts (compared with 9,615 MW for wind), but photovoltaic was growing at a projected rate of 27 percent per year by 2010 based on DOE estimates. By 2010, however, DOE projects PV to be only 100 MW in installed capacity, still very small in the greater scheme.

Adjacent to hydropower is geothermal energy, a well-established technology that is highly dependent on local access to deep-lying thermal energy sources. Geothermal energy accounted for 2,284 MW of installed capacity in 2005 and was projected to be growing at a rate of 1.5 percent per year to 2010—faster than hydropower which, according to DOE estimates, was growing at a mere 0.005 percent per year.

Adjacent to both of these markets is conventional power generation using coal, gas, diesel, natural gas, and nuclear power. Electrical generation by these modes represented 89.6 percent of all installed capacity in 2005, some 819,800 MW. The efficient operation of wind power depends on this conventional capacity, which is always available. Conventional generation is projected by DOE to be increasing at a slow rate, 0.6 per year to 2010, repre-senting, in that year, 89.2 percent of all installed capacity, renewable source the rest. The most rapid growth within the conventional segment is predicted for so-called combined cycle generating plants, those that use both a fossil fuel and modernized techniques whereby exhaust gases are used more efficiently to generate additional power. The dominant form of electrical generation will still be coal-generated current.


A major area of research in wind energy is to develop turbines that operate efficiently in those areas of the country where wind speeds are low. The DOE has developed the Wind Energy Resource Atlas of the United States; similar atlases are available for other regions of the world as well.

The DOE provides seven classes based on average wind speed. Prevailing wind speeds (in meters per second) are translated into equivalent energy potential measured in Watts per square meter of surface. In the United States areas in the central Midwest fall into Classes 3 and 4; the Northeast is generally classified as Class 2, the Southeast as Class 1. Class 7 and 8 areas, the most desirable, coincide with the Rocky Mountains or are scattered in limited areas elsewhere. Operation of wind turbines in areas of Classes 1 to 3 are not economical unless equipment improvements can be achieved and tested. Larger rotors, taller towers, and generating equipment able to operate at low speeds without much higher costs are the goal of research. Once these aims are realized, wind energy can expand into much larger areas than at present. A good deal of other developmental effort is also underway directed at such issues as noise reduction (noise being a source of complaint by those who live near wind farms) and protection of migratory birds often injured by the gigantic turbine blades.

In the hydropower sector, R&D is largely centered on mitigating ecological problems caused by dams, including turbine designs able to accommodate fish migrations as they pass through turbines. Studies are focused on fluid dynamics, computer simulations, and development of testing methods, including so-called sensor fish, dummies, in other words, designed to capture the stresses and strains that fish undergo in passing through turbines. Other research is aimed at improving efficiency in equipment analogous to the same efforts underway in the wind turbine industry, thus turbines able to operate with water under less pressure and/or falling from lower heights.


The most notable trend in the entire renewable electrical energy sector is the very energetic growth in wind energy followed, at a distance, by expansion in photovoltaic power. The trend is global and fueled by global competition for energy resources and technological improvements in generating equipment, not least substantial on-the-ground experience with large scale installations. Also present, although much more difficult to track because statistical reporting is not yet in place, is ferment at the micro level both in the wind and hydroelectric sectors. Small scale systems are being installed at what appears to be high rates, but evidence for this activity tends to be anecdotal or offered in special proprietary studies only.

An analogous trend created by the very success of wind energy is growing concern about the impact of large wind farms on bird populations that are occasionally harmed in their migrations by the whirling blades of modern energy initiatives.


In both the hydropower and wind power segments of renewable energy, the industry is divided between producers of large turbines and small. A few companies offer the entire range of equipment. Those that do pursue two very different markets: the large institutional buyers by means of procurement contracts, and the private buyers through specialized consulting and advisory firms that do project packaging for small concerns or individual buyers. The size of the equipment, in effect, defines its market, with 100 kW and smaller machines targeted at the individual buyer likely to purchase a single turbine and the larger machines aimed at major projects typically purchased by large institutions.


Wind energy is developing rapidly in most parts of the world, hence, many countries have their own national associations for wind energy. Listed here are leading countries and regional or world organizations. Only U.S. hydropower organizations are listed.

American Wind Energy Association, http://www.awea.org

Association of State Dam Safety Officials, http://www.damsafety.org

Canadian Wind Energy Association, http://www.canwea.ca

Danish Wind Industry Association, http://www.windpower.org/en/core.htm

The European Wind Energy Association, http://www.ewea.org

German Wind Energy Association (BWE), http://www.wind-energie.de/en

Global Wind Energy Council, http://www.gwec.net

National Hydropower Association, http://www2.hydro.org/hydro/index.php

Northwest Hydroelectric Association, http://www.nwhydro.org

World Wind Energy Association, http://www.wwindea.org/home/index.php


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