PHOTON International - The Photovoltaic Magazine

Industrialized nations like Japan could say sayonara to coal, oil, and nuclear power with today's renewable technologies – at least, that's the main conclusion of a study published at the start of the year by the Institute for Sustainable Solutions and Innovations. For the most part, the study foresees PV as a solution primarily for covering midday energy peaks.


Japan solar: PV plays only a minor role in the renewable energy scenarios of the Greenpeace-financed study Energy Rich Japan.

Would today's technology be enough to allow a highly-developed industrialized country to completely cover its energy needs with renewable energy sources? A new study by the Aachen, Germany-based Institute for Sustainable Solutions and Innovations (ISUSI) says yes, and uses Japan as an example to show that it's possible to eliminate fossil fuels and nuclear power without reducing the quality of life. The study, which was financed by Greenpeace (as well as other unnamed companies active in the renewable energy business), not only says that it's possible, it also lists the initial steps needed to accomplish the switch practically. Yet the study doesn't take into account questions of costs, acceptance, or duration. »Those are factors that are primarily set by politics,« says author Harry Lehmann, thereby limiting the study's pretensions.

According to the study, Japan's total energy needs could be permanently satisfied with a mix of wind power, PV, hydroelectric, geothermal, and, for peak loads, pumped storage power plants. The biggest part of the switch will be energy-saving measures. The study estimated that in the future, household and transportation energy needs will be a third of what they are today, while industrial demand will decrease by almost two-thirds, or 63 percent. Researchers see plenty of room to save energy in heating and hot water generation.

Japan wasn't picked for the study for the purpose of developing a specialized solution for the island nations' energy problems. Rather, the highly-developed nation, which lacks raw materials, can easily be compared with other industrialized nations that for the most part must fend for themselves when it comes to energy. »If it can work here, it can work anywhere,« says Lehmann.

Using weather data and consumption statistics from 1999 for industrial sources and private households, the study develops six scenarios, three of which assume that Japan's population will decrease. Speculations about whether the Japanese economy will pick up again aren't part of the study's scope. Two scenarios that call for eliminating dependence on fuel imports foresee various solar energy technologies playing an important role.

60 percent of roof space is enough

In all six scenarios, PV plays second fiddle to technologies like solar thermal collectors and solar power plants with solar thermal. According to the study, heating from solar collectors alone can cover energy needs over the course of a year. Depending on the scenario, PV is foreseen as covering up to 10 percent of the total energy supply. But PV is still important, since sunshine and peak loads coincide during the summer. Furthermore, PV works well in combination with wind energy. A collector surface area of 806 m² sounds enormous, but if it's distributed evenly, the result is no more than 6.7 m² per inhabitant. Depending on the scenario, these collectors can be supplemented with an additional 3.2 to 6 m² of PV modules per capita. Altogether, that means just 60 percent of all suitable roof-surface area would be required for use with PV and solar thermal applications.

The models were developed by comparing demand and availability in order to ensure that the energy supply would suffice for every minute of an entire year. The system would be designed to completely eliminate electricity bottlenecks. To ensure the concept's feasibility, the study's authors provide a list of hints and tips, since without a political strategy renewable energy will remain at a disadvantage to conventional energy sources. Thus, the average citizen should be drawn towards renewable energy through tax incentives, education, and a high-energy prize covering external costs. Finally, building regulations should promote more efficient building insulation standards, public transportation should take priority over individual transportation, and investors in new energy should enjoy the necessary planning reliability.

And that's basically what Japan's new Minister of the Environment, Yuriko Koike, said when she assumed office in September – though at the same time, Japan plans to add new nuclear power plants. In an article in the Japan Times, Toshio Hori, chairman of Eurus Energy Holdings Corp., Japan's largest wind power company, said, that »a lot of people would buy energy from ecologically-sound resources if it didn't cost more. But Japan doesn't even have a political framework that supports such ideas."«

Kazzhico Wada, PV expert at prefabricated house manufacturer Hakushin, praised the study as »revolutionary and appealing,« though he doesn't foresee its implementation in the near future. At this point, few Japanese believe that it's possible to cover energy demand without nuclear energy, especially since up until recently, everyone felt they could control the technology. However, the study disregards one thing by propagating solar thermal technology: solar collectors, says Wada, are denounced as unaesthetic. And indeed, the big Japanese PV corporations advertise the »all-electrical ecological house,« where PV-generated electricity is even used for heating water. Moreover, the prevailing opinion is that the wind doesn't blow hard enough in Japan to exploit wind power – a reason why Japanese official targets for this technology and companies' activities are still very petite compared to Germany.

The study is available in Japanese or English at www.energyrichjapan.info