2013. The ultimate goal of the project is to start business as a private entity in 2016 and to obtain necessary knowledge (Figure 4-2-9).

Offshore wind power generation technology is undergoing development on a global scale. As a result, technological verification from this project may bring about a dramatic expansion in the introduction of renewable energies around the world in the years to come.

(4) Potential of Accumulators and Future Development — Technology to Accumulate Clean Electricity

As described in Chapter 3, in response to the Great East Japan Earthquake, renewable energies (e.g., photovoltaic power generation and wind power generation) and next-generation vehicles (including electric vehicles) have gained attention as a way to improve energy security and reduce carbon dioxide emissions. It is known that accumulators can play a central role in leveling unstable output or accumulating excess power from solar and wind power generators. At the same time, high-end, low-cost accumulators are needed as a power source for electric and other next-generation vehicles.

Lithium-ion batteries have several advantageous features, including an extremely high energy density and charge-discharge efficiency, less self-discharge, rapid charge-discharge, and long life, hinting at a wide variety of device applications. Three applications in particular have drawn significant attention: massive accumulators for system stabilization in view of the vast introduction of renewable energy in the future and the establishment of smart grids and other new social systems; fixed accumulators for customers, such as households and business operators; and accumulators for electric and other next-generation vehicles.

Massive accumulators for system stabilization assume a key role in temporarily stabilizing the unstable volumes of electricity generated by renewable energy generators. Demonstration research has been launched as a key component in establishing smart grids.

Fixed accumulators installed on the customer side (e.g., households and business operators) can also be used as an emergency power source. For example, products combining a fixed accumulator with solar power generation or a fuel cell have been marketed by some manufacturers for private homes.

The performance of accumulators mounted in electric and other next-generation vehicles directly impacts automobile performance. Manufacturers have been making serious efforts to develop high-output, high-capacity lithium-ion rechargeable batteries with reduced size and weight. Another practical use for accumulators on a vehicle is to be used as a home accumulator. As an example, an electric vehicle equipped with a high-capacity 24-kWh accumulator can supply electricity to a house for about two days. An accumulator like this was developed by a Japanese company with support from the Ministry of the Environment.

As stated above, accumulator technology is the key to energy management for vehicles, industrial equipment, products, and electric power systems. Accumulator systems have great potential to bring dramatic changes to our daily lives and industry, including social conveniences, economic efficiency, environmental impact, and more (Figure 4-2-10).

During 2010, sales of lithium-ion rechargeable batteries in Japan amounted to 295.8 billion yen. This demonstrates that Japan is sufficiently competitive globally in this field; however, other countries have been making joint public- and private-sector efforts in recent years. It is therefore critical for Japan to establish technologies that focus on these fields: improving performance and safety while reducing costs to expand penetration of markets both domestically and abroad.

Figure 4-2-10 Energy Management Model Using Accumulator

Source: Agency for Natural Resources and Energy

# Technology for Using Microbes to Mitigate Environmental Impacts

Research on environmental technologies using algae and microbes has been developing rapidly. The purpose of these technologies is to apply the biological activities performed by algae and microbes (their metabolism and energy metabolism) to various aspects of resource supply and environmental impact mitigation (e.g., supplying biofuels, environmental purification, and GHG sinks using carbon fixation). Specific examples include research on power generation systems using microbial catalysts and the use of biomass energy through the hydrocarbons produced by a type of blue-green algae called Aurantiochytrium. In addition, advances in research on the microbe euglena, a well-known freshwater flagellate used in science experiments and observations, have been making rapid progress in recent years.

Euglena is a collective term for a genus of flagellates of the phylum Euglenophyta, which perform photosynthesis using chloroplasts and use their flagella to move around.

Euglena's photosynthesis is extremely efficient, and is capable of carbon fixation performance about eighty times more effective than that of rice plants. Because of its outstanding production capacity per area, euglena is expected to help supply biomass resources that do not compete with the food supply, and to help formulate a low load distribution food supply chain and material circulation cycle.

Moreover, euglena can grow prolifically in conditions where carbon dioxide is heavily concentrated. It is known that euglena can grow in exhaust gas from thermal power plants (usually containing around 15% carbon dioxide). These characteristics were used to conduct an experiment to verify the feasibility of euglena in practical use, in which pipes were connected to the smoke path of a power plant and the exhaust gas was vented into a euglena culture tank. It turned out that the euglena grew prolifically around seven days, suggesting that the microbe successfully performed carbon fixation.

Not many aspects of microbes have been scientifically identified at present. Future research may find environmental impact mitigation potential.