Substitution strategies for cooking energy: To use gas or electricity?

The Chinese government has called for clean and effective energy substitution for cooking in rural areas. This paper assesses the environmental and economic impacts of various types of cooking fuels and stoves. According to the assessment results, the environmental impacts are highly influenced by the types of fuels and the efficiency of stoves used for cooking. Using biogas, liquefied petroleum gas (LPG), and natural gas for cooking instead of solid fuels can significantly reduce environmental emissions. To provide 1 megajoule (MJ) of useful cooking heat, the environmental costs of lump coal, honeycomb briquettes, and straw are the largest, estimated to be 80.4 yuan/MJ, 73.1 yuan/MJ, and 71.4 yuan/MJ, respectively. In addition, the economic assessment results show that the most expensive source of cooking fuel is LPG, with an average annual cost of 1700 yuan, while the cost of straw and firewood is the cheapest, at less than 100 yuan. The average annual cost of electricity is higher than that of natural gas. Regarding the substitution effects, using natural gas for cooking is better than using electricity. The environmental benefit of electricity substitution is only 10%-20% of natural gas substitution, and the corresponding increasing cost for residents is 1.5 times that of natural gas substitution.

Impact of energy technology and structural change on energy demand in China

Facing significant pressure from growing energy demand, China needs to identify specific, effective, and targeted policies that can effectively control this demand. In the past, both technological progress and structural change have been shown to reduce energy demand. However, extant studies on this lack sufficient evidence to support effective policies as these look broadly at technological progress and do not narrow this to the energy field alone. Moreover, heterogeneity in energy technology along with internal changes in specific industries have been overlooked. To address these gaps, this study investigates the effects of energy technologies and structural change on China's energy demand. Using a provincial panel dataset from 2000 to 2016, the results show that although energy technological progress is effective in controlling demand, different technologies offer significantly different results: utilitarian energy technologies, focused on energy conversation, are more effective than technologies aimed at energy substitutions. In addition, technologies developed by enterprises show a significant and positive effect on energy demand, while those developed by higher education institutions and individuals do not. Analysis of the regions indicates some significant regional differences as well. The implication is that China should design energy policies that support funding for enterprises developing utility-focused energy technologies.

PET bottles recycling in China: An LCA coupled with LCC case study of blanket production made of waste PET bottles

A large number of polyethylene terephthalate (PET) bottles are discarded daily after usage. Thus, plastic bottle recycling has elicited considerable attention in recent years. In this context, this study aims to quantify the environmental and economic impacts of blanket production from 100% recycled waste plastic bottles in China through a life cycle assessment coupled with life cycle costing method. In addition, the environmental impact of replacing coal with natural gas and solar energy was evaluated. Results show that impact categories of global warming and fossil depletion have significant influence on the overall environment. Carbon dioxide, water, iron, coal and chromium (VI) to water are the main contributors to the overall environmental burden. The internal and external costs are $6433/metric ton and $370/metric ton, respectively. Analysis results indicate that the optimization of organic chemicals, recycled polyester filament and steam production processes can reduce environmental and economic burdens substantially. Energy substitutions with natural gas and the use of solar photovoltaic in steam production and electricity generation are effective measures for decreasing environmental impacts. Finally, suggestions based on research results and the current status of waste plastic bottle recycling in China are proposed.

Carbon costs and benefits of France's biomass energy production targets

BACKGROUND

Concern about climate change has motivated France to reduce its reliance on fossil fuel by setting targets for increased biomass-based renewable energy production. This study quantifies the carbon costs and benefits for the French forestry sector in meeting these targets. A forest growth and harvest simulator was developed for French forests using recent forest inventory data, and the wood-use chain was reconstructed from national wood product statistics. We then projected wood production, bioenergy production, and carbon balance for three realistic intensification scenarios and a business-as-usual scenario. These intensification scenarios targeted either overstocked, harvest-delayed or currently actively managed stands.

RESULTS

All three intensification strategies produced 11.6-12.4 million tonnes of oil equivalent per year of wood-based energy by 2026, which corresponds to the target assigned to French wood-energy to meet the EU 2020 renewable energy target. Sustaining this level past 2026 will be challenging, let alone further increasing it. Although energy production targets can be reached, the management intensification required will degrade the near-term carbon balance of the forestry sector, compared to continuing present-day management. Even for the best-performing intensification strategy, i.e., reducing the harvest diameter of actively managed stands, the carbon benefits would only become apparent after 2040. The carbon balance of a strategy putting abandoned forests back into production would only break even by 2055; the carbon balance from increasing thinning in managed but untended stands would not break even within the studied time periods, i.e. 2015-2045 and 2046-2100. Owing to the temporal dynamics in the components of the carbon balance, i.e., the biomass stock in the forest, the carbon stock in wood products, and substitution benefits, the merit order of the examined strategies varies over time.

CONCLUSIONS

No single solution was found to improve the carbon balance of the forestry sector by 2040 in a way that also met energy targets. We therefore searched for the intensification scenario that produces energy at the lowest carbon cost. Reducing rotation time of actively managed stands is slightly more efficient than targeting harvest-delayed stands, but in both cases, each unit of energy produced has a carbon cost that only turns into a benefit between 2060 and 2080.