by Chieh-Hsin Chen
Taiwan being an isolated island country, one of the most important concerns is energy security. To enhance Taiwan’s energy security, there is interest by the Taiwanese to produce energy on their own. In addition to the energy security issues, climate change is also one of the serious challenges that Taiwan is facing. There has been a significant increase in hurricanes and storms hitting Taiwan since 2007, potentially the result of CO2 induced climate change. As the 25th largest CO2 emissions country, Taiwan has expressed a willingness to reduce CO2 emissions and to mitigate global warming climate shift. Kung et al. (2013) analyze the use of biofuel with standard of CO2 emission, fertilizer use, and land use change. The Modified Taiwan Agricultural Sector Model (MTASM) is used for economic and environmental analysis in this study, and shows that Taiwan would increase its energy security from bioenergy production, but net greenhouse gases emission would also be increased; fertilizer use and land use changes also have significant impact on the greenhouse emission offset.
Being limited in energy security, Taiwan is willing to induce biofuel production as a solution; however, with land area of 14,000 square miles and 67% of that land being mountainous, land use become a very important factor. Participation in World Trade Organization (WTO) and being a less competitive sector in agriculture, Taiwan was able to increase available land from 68,000 hectares to 280,000 hectares for bioenergy use.
Expanding bioenergy production in Taiwan may secure energy as well as reducing GHG emission; the authors examine Taiwan’s bioenergy production from ethanol, conventional bioelectricity and pyrolysis-based electricity, and the GHG emission offset by utilizing current land with the consideration of the emission from fertilizer and land use change. MTASM consists of multiple complicated equations taking account of economic and environmental variables that calculate the effects of this expansion.
The result indicates that when Taiwan develops bioenergy, the net GHG emissions are more likely to increase, especially when GHG price is low. The results show that the emissions of GHG from fertilizer and land use change is much higher than the emission reduction from bioenergy when the GHG price is low, but when the price is high, it is possible to reduce more GHG emission when the gasoline price is lower. When gasoline price is low, the feedstock will be used in ethanol and electricity production but when the gasoline price increases, most feedstock will be converted into the ethanol production, which may cause the amount of emission offset to be reduced.
The authors looked into various sources of bioenergy including ethanol, conventional bioelectricity, and pyrolysis-based electricity. The result indicates that most electricity is generated through pyrolysis. Pyrolysis produces three outputs: biooil, biogas, and biochar, all of which can be used to generate electricity. Biochar is found to enhance and restore carbon in cropland in a more stable form, thus it is better used as soil amendment. When biochar is used as an energy source, it is unlikely to provide net GHG emission offset; the results suggest that only when the GHG price reached to a point, and while gasoline price is also high, using slow pyrolysis, which yields more biochar, will create significant offset on the GHG emission; if GHG price is low, ethanol production is high and fast pyrolysis dominates over slow pyrolysis.
The study suggests several factors and effects that will influence the implication of bioenergy policy. The authors noticed that bioenergy production is heavily impacted by the GHG price, thus an effective trading system of GHG is necessary for the policy to be validated. Also the production of bioenergy requires long term planning, the simulation results only show that it can solve energy security issue, however, requirements for land use change and consequence of higher GHG emission will need a better solution.
Kung, C.-C., Xie, H., Wu, T., Chen, S.-C., 2014. Biofuel for Energy Security: An Examination on Pyrolysis Systems with Emissions from Fertilizer and Land-Use Change. Sustainability 6, 571-588.