Situation and outlook of solar energy utilization in Tibet, China

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Abstract

The near-exponential rise in tourist numbers and accelerating economic growth have challenged Tibetan energy supply and threaten its peculiar environment and valuable ecosystem. Exploitation of pollution free solar power may medicate this demand for energy. Here we shall provide a review of solar power development in Tibet. This region has a near inexhaustible source of solar energy due to its average annual radiation intensity of 6000–8000 MJ/m2, ranking it first in China and second after the Sahara worldwide. Currently, Tibet has 400 photovoltaic power stations with a total capacity of nearly 9 MW. In addition, 260,000 solar energy stoves, passive solar house heating covering 3 million square meters, and 400,000 m2 of passive solar water heaters are currently in use in Tibet. Although Tibet places first in applying solar energy in China, solar energy faces big challenges from hydroelectric power and the absence of local know-how. The new power generation capacity in Tibet's “11th Five-Year (2006–2010)” Plan focuses primarily on hydropower, PV power stations being relegated to a secondary role as supplementary to hydropower. Here it will be argued that this emphasis is incorrect and that solar energy should take first place in Tibet's energy development, as it is crucial in striving for a balance between economic development, booming tourism, and environmental protection.

Introduction

With an average altitude over 4000 m, unique ecological and geographical features, rich wildlife and water resources, Tibet has been called the “Roof of the World” and the “Third Pole of the Earth”. It is not only the “Asia's water tower”, but also the “starter” and “regulating area” of the climate of China and indeed of the Eastern Hemisphere as a whole. Tibet has a peculiar environment and a valuable ecosystem [1].

Rapid economic growth and booming tourism have challenged the Tibetan ecosystem. Tibetan economy has maintained development growth above 12% for seven consecutive years [2]. In addition, the completion of the Qinghai-Tibet railway has promoted local tourism. Regional authorities estimate that by 2010 the number of tourists will double from the 2006 total of 2.5 million [3] (total population in Tibet is 2.68 million in 2006 [4]). Accelerating economic growth and the soaring tourist trade are inevitably accompanied by increasing energy consumption and increasing pollution, putting great pressure on the precious ecosystem of Tibet.

Tibet is short of fossil energy resources. The theoretical reserves of coal resources are less than 50 million tons. The verified reserves of oil and gas are few [5]. In 2006, the output of coal was less than 30,000 tons [6]. Until now, most of the coal, oil and gas have been transported by road or pipeline from at least 1000 km away. Coal is mainly used for the cement industry, oil for transportation, and gas for cooking.

Energy consumption in Tibet is dominated by traditional biomass, such as cattle dung, firewood and crop straw, due to the long transportation distance and high cost of fossil energy. In 2003, the total energy consumption amounted to about 2 million tons of standard coal equivalent (tce), the share of traditional biomass utilization being nearly 70% [7], [8]. Most biomass is directly burned as fuel for cooking and heating. The rarified Tibetan atmosphere and use of outdated stoves, result in a very low burning efficiency, utilizing less than 10% of the potential energy of biomass [9]. Biotic energy sources are becoming overused with the rapid urbanization, and excessive depletion of biotic energy sources has become a main factor responsible for deforestation, land desertification, soil erosion, grassland degradation and soil fertility reduction in Tibet [7], [8], [10], [11], [12].

On account of the near-exponential rise in tourism and rapid economic development, Tibet has no choice but to develop a non-polluting and renewable energy supply to sustain development while protecting its precious and fragile ecosystem.

Solar energy is obviously environmentally advantageous relative to any other energy source, and the linchpin of any serious sustainable development program. It does not deplete natural resources, does not cause CO2 or other gaseous emission into air or generates liquid or solid waste products. Concerning sustainable development, the main direct or indirectly derived advantages of solar energy are the following [13], [14]:

  • No emissions of greenhouse (mainly CO2, NOx) or toxic gasses (SO2, particulates);

  • reclamation of degraded land;

  • reduction of transmission lines from electricity grids;

  • improvement of quality of water resources;

  • increase of regional/national energy independence;

  • diversification and security of energy supply;

  • acceleration of rural electrification in developing countries.

Section snippets

Solar energy resources in Tibet

Tibet is the main parts of the Qinghai-Tibet Plateau located in the southwest border area of China between 78′25–90′06E longitude and 26′50–36′53N latitude, the last latitude being similar to that of Algiers. Its annual average sunlight ranges between 1600 and 3400 h, the highest in China [15]. The average annual number of days with 6 h of sunshine is 275–330. Direct irradiation accounts for 56–78% of the total yearly solar radiation, and for 71–88% of the total solar radiation in summer. The

Solar thermal utilization

A large number of applications exist in which solar energy is utilized directly by exploiting its heat characteristics. These applications include cooking, heating and cooling of buildings and heating water for domestic and industrial applications. Such technologies are comparatively simple, relatively low cost and easy to adopt and are crucial in reducing the use of precious forest resources as fuel wood. Solar thermal utilization is the technology of choice to avoid deforestation, land

Hydropower challenge

As mentioned above, there are more solar power generators in Tibet than anywhere else in China, with total generating capacity nearly 9 MW. However, the generation of electricity from solar power is unlikely to become widespread for the time being as it is challenged by hydroelectric power.

There are many rivers in Tibet and they form a rich water resources (see Fig. 3). According to the reinvestigation on national water resources, the gross theoretical hydropower potential and annual average

Conclusion

Solar energy is a renewable energy source nearly inexhaustible and pollution-free. Solar energy application can increase clean energy supply and reduce pollutant emission, which is helpful to establish a sustainable energy system necessary to maintain the socio-economic development in Tibet. Tibet is affluent in solar resources and has a high development potential for solar energy applications. Meanwhile, Tibet's precious and fragile ecosystem is confronting gigantic challenges because of the

Acknowledgements

The authors gratefully acknowledge the anonymous referees for their helpful suggestions and corrections on the earlier draft of our paper, on which we have improved the content. We would also like to thank Professor Bernard de Jong for linguistic support.

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