Benchmarks

The 50 hertz market is poised for growth as the 60 hertz market levels off.

 

The savvy traveler considers three things when taking electronic equipment abroad: the voltage of the outlet, the type of plug needed, and the power frequency of the destination country. Builders of power plants and their suppliers, however, need concern themselves only with the latter of the three.

The power cycle frequency determines the very design of the combustion or steam turbine as well as the generator. This is because the turbines spin at the frequency of the power system. Today there are two power cycle frequencies in use world wide, 50 and 60 hertz. The reasons for this are both technical and historical.

Alternating currents won out over direct current systems by the end of 19th century because of greater practicality. Thereafter, the range of useful cycle frequencies was determined by both the characteristics of the human eye (flickering of light bulbs) and technical considerations. In a historical process of parallel invention and competition, American engineers under the leadership of the Westinghouse Co. eventually adopted 60 cycles per second as the frequency standard, while in Europe the dominant German AGE electric company settled on 50 hertz.

During the 20th century, countries around the globe adopted either 50 or 60 hertz for their grids. World frequencies still bear the mark of the political influences of Europe and the United States during the past century (see Figure). For power equipment manufacturers that seek a forecast of worldwide power plant additions, it is important to know not just the expected volume of orders but also the cycle frequency and the size of the units. Combustion turbines illustrate why the frequency is so critical to the design of power-generating equipment.

A frequency of 60 hertz, or 60 cycles per second, corresponds to a rotational turbine shaft speed of 3,600 rounds per minute. The number and the pitch of the turbine blades are designed to pull a certain amount of air through the turbine. The power of the turbine is approximately proportional to the amount of air that passes through the turbine every second, so if the same turbine were to spin at 3,000 rpm (50 hertz), less air would enter and exit the turbine, and power output would drop. Therefore, a combustion turbine designed for 3,600 rpm (60 hertz) cannot be used in a 50-hertz market without major modification. For that reason, all big turbine manufactures offer different turbines for the two world cycle frequencies.

In Platts Research & Consulting's new strategic guide to global power markets, WorldCap 2003, our forecast of global power markets goes beyond market-by-market demand/supply balances to provide a detailed 10-year forecast of needed power generating equipment by plant type, unit size, and frequency. At the beginning of 2003, 59.2 percent of the world's installed generating capacity operated on 50 hertz and 40.8 percent on 60 hertz. As markets such as Southeast Asia and China, which run on 50 hertz, begin to surpass traditional markets in capacity additions, this balance will shift even further toward