Why is China building the world’s biggest dam? - The Climate Question podcast, BBC World Service

Key Concepts

• Hydropower: Electricity generated from the energy of moving water.
• Mega-Dam: Extremely large-scale hydroelectric dam projects, often with significant environmental and geopolitical implications.
• Climate Resilience: The ability to prepare for and adapt to the effects of climate change, including altered rainfall patterns and water availability.
• Baseload Power: Reliable, continuous electricity supply, unlike intermittent sources like solar and wind.
• Intermittency: The variable nature of renewable energy sources like solar and wind, dependent on weather conditions.
• Silt/Sediment: Fine particles carried by rivers, crucial for ecosystem health and river fertility.
• Fish Ladders: Structures designed to help fish migrate past dams.

China’s Mega-Dam: A Climate Resilience Project?

Introduction

This discussion centers on China’s ambitious plan to construct the world’s largest hydroelectric dam, a project estimated to cost $167 billion. The program explores the motivations behind this massive undertaking, its potential benefits and drawbacks, and its implications for regional water security and climate change adaptation. The conversation draws on insights from the BBC’s China correspondent, Laura Bicker, and experiences from existing dams, such as the Bhumibol Dam in Thailand and the Grand Ethiopian Renaissance Dam.

The Scale of the Project

The dam is being built in Tibet, within the Himalayas, along a 2,000-kilometer river that descends 2,000 meters over 30 miles. Rather than a traditional dam structure, the project utilizes a tunnel system to harness the water’s energy. This scale dwarfs existing dams; the Three Gorges Dam on the Yangtze River currently powers 40 million people, while this new dam is projected to provide electricity for three to four times that number. The project aims to deliver power to highly populated and industrialized regions like Guangdong, Macau, and Hong Kong, which are major manufacturing hubs (“the factory of the world”).

Motivations and Official Justification

The Chinese government frames the dam as a crucial component of its climate resilience strategy. Historically reliant on coal, and currently importing oil and gas, China is aggressively investing in renewable energy sources – installing approximately 100 solar panels per second in May of this year. The dam is intended to contribute to energy self-sufficiency, reducing dependence on foreign fossil fuels. While still building coal-fired power stations, China is simultaneously becoming the world’s largest investor in renewables, including hydropower (currently providing 18% of China’s electricity). The official narrative emphasizes benefits for Tibet, including job creation and economic development.

Regional Concerns and Geopolitical Implications

The dam’s location near the borders of India and Bangladesh has sparked significant regional concerns. Neighboring countries fear China could potentially control water flow, creating droughts downstream – a concern described as a “water bomb.” This echoes anxieties surrounding the Mekong River, where existing Chinese dams have been accused of disrupting sediment flow and impacting fisheries. The disruption of silt (“the rivers brown”) is a key concern, as it’s vital for maintaining river ecosystems and supporting fish populations. China has dismissed these concerns, characterizing the project as an “ecological project” with benefits for all.

Lessons from Existing Dams: The Bhumibol Dam Case Study

The discussion highlights the experience of the Bhumibol Dam in Thailand, initially hailed as a “miracle dam” for its transformative impact on the economy through electricity generation, flood control, and irrigation. However, over time, the dam has faced challenges due to unpredictable rainfall and drought, reducing its electricity output and irrigation capacity. This led to a project to divert water from another river through a mountain tunnel to replenish the dam, illustrating the complex and expensive solutions required to address water scarcity.

Hydropower as a “Battery” and the Role of Baseload Power

The conversation explores the potential of hydroelectric dams to function as “batteries” by pumping water back uphill during periods of excess energy (from solar or wind) and releasing it to generate power when needed. This addresses the intermittency issues associated with renewable energy sources. Hydropower’s ability to provide consistent, “baseload power” – similar to fossil fuels, geothermal, and nuclear – is emphasized as a key advantage. The experience of physically witnessing a turbine being activated, providing instant power, underscored this point.

Recent Developments and Global Trends

Ethiopia’s recent completion of the Grand Ethiopian Renaissance Dam, a $5 billion project, demonstrates a global trend towards large-scale hydropower development. However, this dam, like the Chinese project, is also controversial due to its potential impact on downstream countries (Egypt and Sudan) and their access to Nile River water.

Impact on Electricity Prices

Laura Bicker reported that electricity bills in some regions of China are decreasing, ranging from 2% to 11%, with Guangdong province experiencing an 8% reduction in the past year, attributed to the increasing contribution of renewable energy sources.

Fish Ladders and Environmental Considerations

The discussion touched upon the use of “fish ladders” to facilitate fish migration past dams, acknowledging their limitations and the importance of maintaining sediment flow for healthy river ecosystems. The analogy of a “cat fish flap” was used to playfully illustrate the concept.

Conclusion

China’s mega-dam project represents a significant investment in renewable energy and a strategic effort to achieve energy self-sufficiency and climate resilience. However, the project raises complex geopolitical concerns regarding water security for neighboring countries and potential environmental impacts on river ecosystems. The experience of existing dams, like the Bhumibol Dam in Thailand, underscores the challenges of adapting to changing rainfall patterns and the need for long-term planning. While hydropower offers the advantage of baseload power, its sustainability depends on ensuring a reliable water supply in a changing climate. The project highlights the intricate balance between economic development, environmental protection, and regional cooperation in the pursuit of a sustainable energy future.