Sustainability through renewable energy

Biogas and other forms of biomass-based energy from solid (wood, pellets, rice husks) and liquid biofuels (bio-ethanol, bio-diesel) can replace fossil fuel, such as coal and natural gas, and nuclear energy. Biomass fuels have the big advantage of not being dependent on weather conditions like wind and solar power and thus are more reliable and stable. They can be stored and made available on demand more easily, and thus qualify as controllable basic supply services. This characteristic has not been fully recognized and, therefore, biomass-based energy remains underdeveloped and undervalued.

Following the best international models since 2005 - applied in Germany - research has been carried out at the Institute of Clean Energy and Environmental Engineering of Shenyang Aerospace University in Liaoning province to see if using agricultural and urban organic waste as sources for renewable biogas generation is possible. The average collection of biodegradable waste in the pilot areas, with 60-70 percent participation, was 80 kg per capita per year. The biogas generated from that 80 kg of biowaste will be enough to run a car for at least 600 km. But such waste is dumped into landfills at present.

Waste incineration does not generate the potential amount of energy from garbage. To get the potential amount of energy from waste it is necessary to separate "dry" and "wet" waste at source. This system was recently introduced in about 3,000 residential communities in Beijing, and in Shanghai, Guangzhou, Shenyang and Harbin. Dry waste can then be incinerated or converted into fuel energy. Wet waste consists mainly of biowaste and can be used to generate biogas.

Managing sustainable energy supply in China is very important. The still high demand for traditionally operated centralized power supply is confronted with a newly built decentralized distributed energy supply system, based mainly on local renewable sources with small generation units. The challenge is to combine 600-megawatt coal-power plants with some kilowatts from solar panels, smaller wind turbines and mid-sized biogas plants.

According to the National Development and Reform Commission's (NDRC) "Medium and Long-Term Development Plan for Renewable Energy in China in 2007", by 2020 at least 3-gigawatt grid-connected electricity should come from middle- and large-scale biogas plants.

The NDRC has acknowledged that 1 billion tons of coal can be replaced by biomass-based energy by 2050. It is to be hoped that the 12th Five-Year Plan enforces integrated concepts and the use of agricultural, municipal and industrial biomass for energy generation. Modern reliable technologies based on international standards can boost the development of this sector and the goals of China's national renewable energy agenda can be reached more easily and economically.

Biomass-based energy can even help replace nuclear power plants which, however we build and operate, will pose a serious threat to and create an unsustainable burden for future generations because of its radioactive waste.

The author is a professor at the Institute of

Clean Energy and Environmental Engineering at Shenyang Aerospace University and China Agriculture University. He is the director of the Sino-German GIZ Biomass Utilization Project of the Chinese Ministry of Agriculture.

(China Daily 05/10/2011 page9)