July and August are "red alert" time for the Taiwan Power Company. As soon as the workday begins and electricity is switched on in factories and office buildings around the island, Taipower engineers start to hold their breath, fearing that system demand will go over the top and the load will be too great to bear.

Meanwhile, growing environmental awareness and strong feelings among the public about "not wanting a power plant built in my back yard" have caused the company to talk more and more about ordering cutbacks.

Lo Kuang-mei, chief of Taipower's environmental protection division, declared on May 10 that power cuts to handle the shortages will be "a certainty" by 1993. The main object of the cutbacks will be large industrial users.

Isn't there any way to save Taipower, industrial manufacturers, and the general public from threats of power shortages and to relieve the deadlock over building new power plants?

"They had a solution way back at the end of the nineteenth century," says Eric K. Y. Kang, director of the second division in the Ministry of Economic Affairs' Energy Committee, adding that the solution was cogeneration.

Ch'en Mo-hsing, director of the Energy Systems Research Center at the University of Texas, indicated during a visit to Taiwan this May that if cogeneration is promoted on Taiwan now, then Taipower need not order power cutbacks or build any new power plants for the next ten years.

What is cogeneration? Is it really so effective?

Chu Wen-chen, a professor of electrical engineering at the Tatung Institute of Technology, explains that in conventional generation, high-pressure steam produced by fuel combustion is used to drive the turbines that generate the electricity. The steam is then cooled by sea, river, or lake water and sent back to the furnace for heating. In this way a large amount of heat is lost to nature without being used, and the efficiency of the process is just thirty to forty percent, but for a power plant whose only purpose is to generate electricity, the loss is unavoidable.

Many factories, on the other hand, require a large amount of steam to drive machines and manufacture products, and the steam they use is often released as waste also. Making use of this steam to generate electricity would be equivalent to turning one dollar into two. Thus arose the concept of cogeneration.

"Cogeneration means taking steam (heat energy) and power (electric energy) and combining them both in a single fuelusing process," Dr. Chu explains.

In a steel or concrete factory, for example, where high-pressure steam is required in the manufacturing process, left-over steam can be used to drive a turbine to generate electricity for in-house use.

Use of cogeneration equipment dates back to the end of the nineteenth century and reached its peak during the Second World War. Later "due to the availability of cheap oil, cogeneration fell out of favor," Kang says. But during the energy crisis of 1976 cogeneration was resurrected from people's memories.

With an energy efficiency ratio of seventy to eighty percent, cogeneration is one of the most direct and effective methods of saving energy. The U.S. government strongly promoted it at the time and passed a law encouraging manufacturers to adopt it. By 1984 the U.S. had saved 67 million barrels of oil a year and spared power companies from building nine large generating stations.

Cogeneration has a long history on Taiwan too. During the Japanese Occupation, the Taiwan Sugar Corporation used high-pressure steam produced by burning sugar cane husks to generate electricity and then used the resulting medium- to low- pressure steam for making sugar.

The energy crunch was felt strongly on Taiwan, which lacks major energy resources. The Energy Management Law of 1979 stipulated that any industrial user that produced over 100 tons an hour of steam should install cogeneration equipment.

More recently the Energy Committee asked Dr. Chu and Chen Bin-kwie, a colleague of his at the Tatung Institute, to evaluate the potential for cogeneration on Taiwan. They found that there is already installed on the island 580,000 watts of cogeneration capacity and that if the government actively promotes it then, at a conservative estimate, another 1.66 million watts can be added by 1994, nearly the capacity of two nuclear generators.

As to businessmen with an eye for the bottom line, a flip of the abacus will show that cogeneration pays. By designing the most appropriate system for their factory, they can produce cheap in-house power and can recover the cost of investment in a few years.

This July 15 the Energy Committee, to encourage businessmen to install cogeneration equipment, announced that surplus power generated by private businesses could be sold to Taipower for distribution to the public. Also targeted for promotion of cogeneration are commercial users, such as hotels, hospitals, supermarkets, and office buildings.

"Cogeneration can't completely replace power plants," cautions Eric Kang, pointing out that even if industrial users become completely self-sufficient, they comprise only twenty to thirty percent of the capacity on Taipower's system and cannot solve other problems of expanding usage in the future.

Besides cogeneration, other ways to relieve the power crunch include peak load management, rationalized rate structures, off-peak storage, solar power, and waste heat generation.

Building new power plants is not the only answer to Taiwan's power shortages. A thorough solution depends on the cooperation of Taipower and the public; cogeneration only provides a buffer opportunity.

[Picture]

Power, heating, cooling, and hot water systems

System Flow Chart

Example of Commercial Cogeneration

[Picture Caption]

(Taken from a brochure of BBC, Switzerland)

Commercial applications of cogeneration include use in electric power, hot water, air conditioning, and heating systems. (photo courtesy of the Energy Commission, MOEA)

A cable at the Sanchung transformer station caught fire because of long-term overload. (photo by Ch'en Wu-you)

(Left) Cogeneration equipment in a papermaking factory in Taitung. (below) The central control room.

A cable at the Sanchung transformer station caught fire because of long-term overload. （photo by Ch'en Wu-you）

Commercial applications of cogeneration include use in electric power, hot water, air conditioning, and heating systems. （photo courtesy of the Energy Commission, MOEA）

Cogeneration equipment in a papermaking factory in Taitung.

（below） The central control room.