nature.

There are numerous technologies contributory to global warming countermeasures that have yet to spread widely or are still far from commercialization but are quite promising for the future. For example, waste heat generated from industrial plants, power stations or waste incinerators is relatively widely utilized within these facilities. In Denmark and some other countries, waste heat is being utilized on a much wider scale. For instance, Copenhagen has completed the regional heat supply system for the total piping extension of 1,500 km, with about 500,000 residents connected to the regional heating network. About 60% of heat sources for the heat supply system are cogeneration plants using fossil fuels or biomass as fuels, with 20-30% coming from waste heat from waste incinerators. In Japan, the heat-carrying distance in heat supply operations is only about 2 km at most at present, far limited compared with cases in Europe or the United States. However, given that utilization of thermal energy as heat offers high energy efficiency and there is a large quantity of heat not utilized at the moment, expectations are high that infrastructure for utilizing waste heat will be improved going forward and effective utilization of waste heat makes headway in Japan as well.

In overland traffic in the traffic and transportation sector, in addition to electric vehicles already in practical use, we may be standing at the doorstep of an era when we see hydrogen automobiles and vehicles powered by fuel batteries running on urban streets as common scenes. Among vehicles powered by internal-combustion engines, aircraft and ships, on top of automobiles, are also seeing the wave of innovation coming toward them. Oceangoing vessels that carry large quantities of goods used to be powered by wind in the Age of Geographical Discovery. Going forward, they may be again powered by “renewable energy” like wind power and sunlight. A private-sector project launched in April 2008 envisioned the Eco-ship (Figure 2-4-12), which employed fuel cells instead of conventional diesel engines burning fuel oil, and also used wind power and sunlight. With clues from sharkskin, special coating was applied to the bottom of the ship to mitigate the resistance of water. The Eco-ship can reduce carbon dioxide emissions by 69% more than conventional containerships. The same project aims for

Figure2-4-12 Example of the Eco-ship Concept

Photo: Nippon Yusen Kaisha (NYK Line)

the development of a zero-emission ship, which emits no carbon dioxide, by 2050.

At present, solar light and biomass are already being utilized as energy sources to replace fossil fuels. Among things that have not yet reached the stage of commercialization is oil production from botryococcus and other microalgae. Oil productivity of microalgae is far greater than corn and other oil-producing plants. If demand for oil is to be met by oil produced from corn, we would need an area 14 times larger than all arable land on the earth. In theory, however, microalgae can satisfy all demand for oil with only 1.8-4.2% of all arable land on the earth. Further, as the ultimate renewable energy technology, we may be generating electricity in outer space by utilizing sunlight by around 2050. Departing from an era when we have to use limited resources on the earth savingly, that is the technology to utilize inexhaustible and clean solar energy in a stable manner without worrying about weather conditions. Electricity produced would be sent to the earth using microwave and laser. This might sound incredible, but it is not a story that would only come true several hundred years down the road. In fact, the Japan Aerospace Exploration Agency, an independent administrative institution, seriously expects that this “technology” may become applicable around 2033.