To contribute to creating a low-carbon society through the stable supply of high-quality, low-cost electricity, TEPCO promotes the best mix of power sources composed of nuclear power, a primary source of electricity provides excellent "environmental performance", "stability" and "economic efficiency", and a good balance of thermal power and renewable energies. Ongoing efforts are also made to increase the efficiency of power facilities such as increase thermal power generation efficiency.
CO2 emissions, emission intensity, and electricity sales
Lifecycle CO2 emissions for different types of power
Nuclear power generation is a highly effective countermeasure to global warming, as it does not emit CO2 in the power generation process. Based on the premise of ensuring safety and security, we are aiming to expand nuclear power use by increasing the facility utilization rates of nuclear power station and developing new power sources.
TEPCO's CO2 emissions increased drastically in FY2007 and FY2008 as a result of the prolonged shutdown of the Kashiwazaki-Kariwa Nuclear Power Station after sustaining damage from the Niigata-Chuetsu-Oki Earthquake in July 2007. In FY2009, however, nuclear facility utilization rate increased approximately 10 points from FY2008 to 53.3% as a result of the recommissioning of Units 6 and 7 at the Kashiwazaki-Kariwa Nuclear Power Station, and CO2 emissions dropped by approximately 11% to 107.5 million tons.
The operational status of nuclear power stations clearly has a large effect on CO2 emissions. Hypothetically speaking, each 1% increase in facility utilization rate at TEPCO's nuclear power stations would reduce yearly CO2 emissions by approximately a million tons.
Nuclear facility utilization rate and CO2 emissions
Nuclear facility utilization rates in major countries
Thermal power generation is important to ensuring the stable supply of electricity, as it can respond flexibly to changes in power demand.
We strive to minimize CO2 emission from thermal power generation by promoting LNG-fired thermal power generation, which emits smaller amounts of CO2 compared to other types of thermal power generation, and also by making ongoing efforts to increase thermal power generation efficiency.
TEPCO has introduced a 1,500℃ combined-cycle power generation system (More Advanced Combined Cycle (MACC) system) which provides one of the world's highest thermal efficiency level of about 59%, to the Kawasaki Thermal Power Station in 2007 and to the Futtsu Thermal Power Station in 2008. Furthermore, we are currently conducting an environmental assessment* toward introduction of a 1,600℃ combined-cycle power generation system (MACC II system) that would realize a thermal efficiency of about 61%. Operation of the system is slated to commence in FY2016 at the Kawasaki Thermal Power Station and in FY2020 or beyond at the Goi Thermal Power Station. We are reducing about 1.9 million tons of CO2 emissions per year for every 1% increase in average thermal power generation efficiency.
* Environmental assessment
The process of surveying, estimating, and assessing the possible impact of business activities on the environment. Assessment results are disclosed to the public to widely obtain the views of local residents and stakeholders.
TEPCO's thermal power generation efficiency (lower heating value)
International comparison of thermal power generation efficiency
Technological innovation is essential to achieving significant CO2 reductions in the future. We are therefore focusing our efforts on developing new technologies that would help reduce CO2 emissions.
Coal is available in abundance from diverse sources, and is an important resource to Japan, as a country that is largely dependent on imports for energy resources. In order to take advantage of the benefit of coal, which enables stable and economical supply of electricity, and to reduce CO2 emissions significantly, TEPCO is addressing to develop an integrated coal gasification combined cycle (IGCC) system. When commercialized, the system is expected to provide a high thermal efficiency of 48-50% (LHV standard; transmitting end), while emitting only the same amount of CO2 as oil-fired thermal power generation. We are presently conducting a demonstration test toward commercialization of the technology. In verification tests performed in 2009, we attained our target power generation efficiency of more than 42%, and verified the feasibility of using few types of coal. We will be carrying out further investigations to make sure the commercial system would provide the required performance, endurance, and economic efficiency.
The system could provide high-efficiency power generation by means of a combined cycle that gasifies and burns coal.
CCS is globally regarded as an effective technology against global warming, and is being researched and developed all over the world.
For its part, TEPCO is conducting research and studies on CO2 recovery technologies using a small-scale test plant. We are also working to identify issues in CCS implementation, and have launched studies aimed at assessing the feasibility of a system that incorporates the CCS technology in power stations as a means of solving those issues.
A process for capturing CO2 released from power stations and plants and storing it underground or in the sea for long-term isolation from the atmosphere.
CO2 separation/capture and underground storage technology