Power Electronics

Wind Will Power Component Development Too

The demand for alternative energy sources is making an impact on the power electronics industry, spurring development at both the system and component levels. Wind power provides one example that should become increasingly significant in the years to come. As wind turbines continue to appear on our landscapes and seascapes, there will be pressure on manufacturers to improve their performance, which in turn will inspire component developers to better theirs.

Data released earlier this year by the Global Wind Energy Council (GWEC) illustrates how the installed base of wind-power plants across the world is growing rapidly.[1] According to the GWEC, the total installed base of wind-power capacity in 2005 was 59,084 MW, which represents a 24% increase from the previous year. Put another way, last year the world added 11,531 MW of energy generating capacity through new wind-power installations and that was a 40.5% rise from the previous year's added capacity, reports the GWEC.

In the United States, the installed capacity for wind power has reached 9149 MW, which ranks third behind Germany (18,428 MW) and Spain (10,027 MW). All over the world, governments are creating incentives (like the U.S.'s production tax credit) and drafting laws to encourage use of wind energy.

In February, President Bush recognized the importance of wind power in his Advanced Energy Initiative, noting its potential to supply up to 20% of the U.S.'s electricity needs.[2] And last month, the American Wind Energy Association (AWEA), together with the U.S. Department of Energy and the National Renewable Energy Laboratory announced they would develop a plan of action for reaching this 20% goal.[3] Despite the rapid growth in wind power, 20% represents a challenge given that wind power currently accounts for less than 1% of the nation's electric supply.

All of this activity has implications for turbine manufacturers[4] and those making the parts that go into them. According to the GWEC, the total value of power-generating equipment installed globally last year was more than $14 billion. Power electronics represents a modest but significant slice of that pie as power converters are required to regulate the voltage and frequency of the electricity produced by the turbines.

The Darnell Group reports that variable frequency power converters used in wind turbines are expected to account for $1.21 billion in global sales this year. In just five years time, Darnell forecasts that sales figure will jump to $2.39 billion, which represents a compounded annual growth rate of 14.5%.

Capacitor manufacturers are among the suppliers benefiting from the spread of wind turbines. For example, ultracapacitors are being used to control the pitch of windmill blades. These components provide energy storage that can be tapped to turn the blades away from the wind in the event that wind speed rises too high. To a lesser extent, ultracapacitors are also used as electric shock absorbers, filtering the energy produced by the turbine.

One supplier, Maxwell Technologies, reports that its 350-F D-cells are used for controlling the blade pitch. In addition, this vendor's 2600-F cells are combined into large banks for the filtering application.

Meanwhile, lower value capacitors with high voltage ratings are used in newer turbines built with double-fed induction generators and synchronous generators. These turbines employ IGBT-based ac-ac power converters that need high-voltage capacitors for dc filtering and decoupling.

For dc filtering, one vendor, AVX, supplies oil-filled capacitors with values up to 48 mF and voltage ratings as high as 6 kV. It also builds resin-filled power film capacitors as high as 27 mF with ratings approaching 2000 V. For IGBT decoupling, the company's metallized polypropylene capacitors offer as much as 3 µF and 3-kV voltage ratings.

Because of the extreme performance and ruggedness required of these types of components, vendors who produce them can demand a premium. This fact bodes well for the electronics industry as efforts to mine wind power continue for years to come.

References

  1. Record Year for Wind Energy: Global wind power market increased by 40.5% in 2005, Global Wind Energy Council, press release issued February 17, 2006, available online www.gwec.net

  2. Advanced Energy Initiative, President's Letter, February 21, 2006, available online at www.whitehouse.gov/stateoftheunion/2006/energy/index.html.

  3. “Energy Department, Wind Industry Join To Create Action Plan To Realize National Vision Of 20% Electricity From Wind”, American Wind Energy Association press release issued June 5, 2006, available online www.awea.org

  4. For rankings of wind turbine manufacturers, energy installations by state, largest wind farms, and other statistics relating to US wind energy usage, see “Annual Industry Rankings Demonstrate Continued Growth Of Wind Energy In The United States,” American Wind Energy Association (AWEA) press release issued March 15, 2006, available online http://www.awea.org/

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