[From May Issue 2014]
Kyoritsu Electric Corporation
The Great East Japan Earthquake of March 2011 has affected our lives in numerous ways. In particular, power shortages caused by damage to the nuclear power station inconvenienced a huge number of people. By complying with power saving measures that continue to this day, many people have discovered the importance of electricity. As a result, the debate about how to generate a safe and stable supply of electricity has heated up.
In addition to standard hydraulic, thermal and nuclear power, recently more and more energy has been generated using methods that harness natural power like wind and sun power. In recent years, “wave power generation” has been a big topic of discussion. As Japan is surrounded by ocean, it’s the most suitable method of generating power. With this in mind, Kyoritsu Electric Corporation of Shizuoka Prefecture is conducting research and development in cooperation with Tokai University and other private companies.
Wave power generation technology is diverse and includes the overtopping device, the oscillating water column and floating devices. Kyoritsu Electric is working with overtopping devices. Executive Director NISHI Nobuyuki explains enthusiastically, “An oscillating water column turbine can’t generate any power under bad weather conditions. The downside of floating devices is that they don’t generate much power. The overtopping wave device is still in development, but I think we’ll be able to maintain a certain level of power regardless of weather conditions.”
Nishi and his team are developing the overtopping wave device; for this, piles drilled into the offshore seabed are fitted with equipment such as ramps, reservoirs, water discharge pipes and power generators. The method involves storing water that has surged over the ramp, when it descends it turns a propeller to generate power. “It’s particularly unique, in that compared to other methods of wave power, its effect on the environment is limited and it operates reliably,” says Nishi outlining the merits of the overtopping wave device.
Nishi says, “Our research indicates that one meter of coastline can generate enough electric power for ten households. Compared to sun and wind power, the cost per kilowatt is low.”
The lower cost isn’t the only advantage of overtopping wave power generation. Currents created by the revolution of the turbine propeller, dissolve oxygen into the seawater. Oxygen rich seawater promotes the growth of marine life. In other words, it’s known to have a positive effect on the fish farming and fishing industry.
It takes a tremendous amount of money, equipment and raw materials to generate electricity. However, since Japan is an island country surrounded by ocean, wave power is constantly available for almost all coastal regions. As Japan is a country that is poor in natural resources, wave power that harnesses the abundant raw energy of the ocean is seen as a way for Japan not to lose out to foreign competition.
Text: ITO Koichi