ost of electricity generation and transmission is a problem. So the direction is right, these are all important to consider, but it is a matter of degree.
CWT: China has the fastest growing renewable capacity of any country in the world. Wind power and solar photovoltaic (SPV) are two bright spots of the new energy economy. Water is not a bottleneck for them—on-site water use is negligible and life cycle water consumption is only 1/7 to 1/5 of the most efficient coal-based technology. Reliability and grid accessibility, rather, are obstacles for wind and SPV.
Nuclear power, on the other hand, is among the most water-intensive energy generation technologies at 2.7 m3/MWh. Various sources indicate that China will significantly expand its nuclear power capacity in the coming decade, and at least 30 GW is expected to be completed by 2015. Though all existing Chinese nuclear power plants are based in the coastal region and use sea water for cooling, proposals on building inland nuclear units have been on the rise. In fact, three Yangtze provinces, Hubei, Hunan, and Jiangxi, are reportedly competing over the first permit from the central government. According to the Medium and Long-term Development Plan for Nuclear Power, several provinces facing water shortages (e.g., Henan and Gansu) are also on the list of potential sites. For those areas, a careful evaluation will be needed to ensure sustainable water supply for cooling, without sacrificing agricultural, human, and environmental water needs.
Likewise, some emerging and future energy generation technologies do pose a challenge for water availability. One example is CSP. Combined with thermal storage systems, this technology could be smoothly integrated into the current grid and even enhance its capacity to accommodate a larger share of variable energy sources. But solar thermal’s cooling water need is exceptionally high – considerably higher than that of nuclear (closed-loop) and almost double that of pulverized coal (PC) per unit of energy generation. Since China’s Sun Belt also overlaps with a water scarce region, water withdrawal and consumption will be a consistent challenge.
Another example is carbon dioxide capture and storage (CCS). Based on the findings from our research, current CCS technologies could capture 90 percent of carbon dioxide from a power plant’s emissions, plant-wide water consumption increases by more than 90 percent. When designing new PC plants with CCS, water availability, as well as the presence of geologic formations needed to promote secure storage, will need to be carefully evaluated.
CWR: Estimates are that an additional 350 million people will move to cities by 2030. What will this mean for energy consumption and the country’s water resources?
PJZ: A larger urban population of course means higher consumption of energy and water; new infrastructure, cleaner water and therefore more electricity use. Today’s rural population enjoys limited infrastructure and therefore uses less energy and consumes fewer resources. Urbanization, though, is a natural course with or without a specific policy because of the income gap between urban and rural communities.
In the coming two decades, China’s total installed power generation capacity is expected to double from the current level, and coal is projected to still be the dominant energy source. Thanks to modern technologies, future coal-fired power plants will be more efficient and environmentally friendly than they are today. For example, supercritical (SC) and ultra-supercritical (USC) units and dry-cooling could reduce water consumption per unit of power generated to different extend, at a commercially feasible price. Integrated gasification combined cycle (IGCC), though more expensive today, could drastically reduce wastewater discharges and cut GHG emissions. Clean coal technology, together with renewables, can help minimize water/carbon footprint of China’s power sector.
CWR: What part does water-pricing play in the discussion of the water-energy nexus?
CWT: Regarding water pricing, China is gradually 