The Okinawa Electric Power Company, Incorporated (OEPC)
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R & D Information
The business environment of the electric power industry is becoming increasingly challenging due to a variety of laws and measures, such as the Kyoto Protocol and Special Measures Law Concerning the Use of New Energy by Electric Utilities (also referred to as the "RPS Law") to prevent against global warming in order to reduce CO2 emissions and increase the use of renewable energy. OEPC is conducting various studies aimed at finding effective solutions to these urgent issues.
Utilizing renewable energy sources
Although such renewable energy sources as wind and solar power have disadvan-tages in energy density and therefore generating cost, they are "clean" forms of energy that do not contribute to global warming through the release of CO2; and are thus coming under growing scrutiny as answers to society's energy needs. In April 2003, the RPS Law came into force in Japan, imposing an obligation on electricity retailers to use a certain amount of electricity from new energy according to the amount of their retailing electricity. OEPC is committed to the development and adoption of renewable forms of energy such as solar and wind power. As Of the end of March 2009, the Company has a total capacity of 18,158kW(including small hydroelectric generators) of renewable energy throughout the prefecture including remote islands.
Verification of introduction of off-grid renewable energy systems for remote islands
The Company is evaluating the impact on the normal power grid of the introduction of large-scale solar power systems to off-grid power systems on Miyakojima Island, Yonaguni Island, Kita-Daito Island, and Tarama Island, all of which have power systems of varying size. We are also conducting a field test("remote island micro-grid verification tests") to verify measures to stabilize the power supply. The capacity of the solar power systems will be 4,500kW in total, of which 4,000kW will be installed on Miyakojima Island, the largest of the four islands. The Company aims to stabilize the solar power supply in combination with storage batteries with the same capacity as the solar power facilities. With the knowledge obtained from this research, it will become more possible to use new energy sources to contribute to reduction of CO2 emissions. This study uses grants from the Ministry of Economy. Trade and Industry under its support program for off-grid renewable energy demonstration projects for remote islands (fiscal 2009).
Components of the Demonstration Research Facility
| Demonstration Research Location | Miyako Island |
|---|---|
| Percentages of Introduced Photovoltaic Power Generation | 8% |
| Distribution Net Work Scale | Approx, 50,000kW |
| New Photovoltaic Power Generating Facility | 4,000kW |
| New Storage Battery System | 4,000kW(NAS) 100kW(LiB) |
| New Photovoltaic Power Generating Facility Estimated CO2 Emission Reduction | Approx, 4,000t. per year |
| Existing Internal Combustion Generators | 74,000kW |
| Existing New Energy Facility | Wind Turbine Generation 4,200kW |
Biomass energy
OEPC conducted research on the use of woody biomass made out of construction and demolition waste, which, in Okinawa Prefecture, was mostly incinerated without being used effectively. Having confirmed that the biomass was perfectly usable based on the result of field tests conducted from June 2007 to October 2008 at the coal-fired Gushikawa thermal power station, we built a biomass distribution facility at the station, and on March 25, 2010, we started burning the biomass pellet (mixed with coal by three percent in weight). The successful utilization of the "carbon neutral" biomass fuel has enabled us to reduce CO2 emissions, curb our coal consumption, and make effective use of an untapped energy source.