Consecuencias psicológicas de los desastres naturales

$/m3

Incremental availability

Billion m3

Steel: dry de-dustingNo till rainfed Power: wastewater reuseMunicipal leakage

New showerheads

Wastewater reuse in commercial buildingsSteel: wastewater reuse Others: waste other reuse

Integrated plant stress mgt. (rain-fed) New faucets Integrated plant stress mgt. (irrigated)

Irrigation scheduling Genetic crop development (irrigated)

Seawater direct use

Dam & reservoir - large

Efficient sprinkler irrigationImproved fertilizer balance (rain-fed) Pipe water conveyanceOn-farm canal lines

MulchingGroundwater pumping - deep Rainwater harvestingFresh water transfer – intra-basin Drip irrigation

Wastewater reuse – municipal/industrial Rain water harvesting – roof top

Fresh water transfer – inter-basin New toilets Desalination (RO)

Desalination (thermal) – co-located with power plant New laundry machines Power: Dry cooling

Retrofit toilets No till (irrigated)

Retrofit showerheads

Supply/demand gap in 2030 = 201 billion m3 Total cost to fill gap = - USD 21.7 billion

Local water conveyance

Desalination Thermal - standalone

140 220 240 100 0 0.6 200 60 40 120 0.8 1.4 -8.2 -3.4 -0.4 0.2 -0.2 0.4 80 160 260 20 180 Exhibit 24 Agricultural Supply Industry

Although agriculture still makes up more than 50 percent of the total demand, industrial and urban water use are the fastest growing uses of water (at more than 3 percent per annum). China can curb this rapid growth in a cost-effective way by instituting aggressive, water-conscious “new build” programs that encourage the technical measures we have identified. If it does so, the cost to fill the gap in 2030 is negative (including annualized capital and net operating expenditures), implying net annual savings of approximately $21.7 billion. The incremental investment capital needed in 2030 to close the gap amounts to $7.8 billion annually.

As the cost curve shows, these savings are almost entirely achieved by adopting industrial efficiency measures. These have the potential to close a quarter of the gap and result in net savings of some $24 billion in 2030. They are distributed among the thermal power, wastewater reuse, pulp and paper, textile, and steel industries. Their savings potential comes mainly from the significant reduction in operational expenditures that they yield. Other factors besides economics need to be taken into consideration, as implementation can face strong barriers and incentives to adopt efficiency are low; thus companies would not invest in them by themselves. In these cases, China faces the tradeoff between diverting businesses’ resources to water efficiency measures that may impede growth in the short term yet sustain and fuel growth in the longer term, versus supporting water use that is unsustainable in the long term, but allows for greater growth in the short term. Yet sustain and fuel growth in the longer term. Such opportunities arise where market growth in related sectors in turn helps develop new technologies and new local industries in water efficiency—for example where water treatment and reuse is growing to address increasing water pollution.

While China as a whole faces severe water scarcity problems rooted in rapid industrialization, solutions need to be explored at the basin, or sub-basin, level. In Daqing, for example, the solution involves curbing growing demand and leveraging alternative supply. In the Yangtze Basin, the solution will be built off capturing the region’s plentiful rainfall. In Hai, although there is a significant south-north transfer in progress, the solution still involves significant efficiency measures.

China’s solution to the water problem reflects its geographic expanse and extreme regional differences. Nowhere is this clearer than in supply. Supply levers can provide 37 percent of the solution in 2030 with an initial capital investment of around $2.3 billion per annum. Unlike more homogenous countries, different basins will use different levers. Surface water levers— those that can help capture a plentiful resource—will dominate in the Yangtze and Pearl basins where there are sufficient surface runoffs. Groundwater levers will be the main drivers of supply in the Northwest and Song Liao basins, although over-extraction in the Northwest is currently putting pressure on groundwater supplies. The most water-scarce regions, the Hai, Huang, and Huai Basins will require significant water transfers, wastewater reuse, and sea water usage to fill the demand gap.

Assuming accelerated economic growth beyond that modeled in the base case, the pressure on water resources rises further. The gap would increase by more than 25 percent, to a total

In any scenario, though, meeting growing water demand fueled by rapid industrialization and urbanization will require a balanced solution of agricultural, supply, industrial, and municipal levers. This solution, however, must be considered alongside China’s burgeoning energy demand. This “water-energy nexus” adds an important layer of complexity to China’s future—as China (and other countries) adopt new energy sources, these are likely to require significant amounts of water. The energy sector is already the largest industrial water user in China and is increasingly exposed to the risk of water scarcity.

Opportunities exist for energy- and water-saving measures to go hand-in-hand. Implementing ultra super-critical processes in thermal power, boosts plant efficiency and reduces energy costs by $3.9 billion. At the same time, it lowers water-cooling needs, reducing water withdrawals and saving $8.20 per m3_{. The cost savings per unit of actual consumption (the difference between} withdrawals and return flows) is substantial, although water withdrawal savings also reduces the return flows which were previously available for other uses, thus decreasing the total impact on water demand. Similarly, coke dry-quenching leads to heat recovery in the form of steam in a waste-heat boiler—saving water and generating steam for electricity production, while driving considerable savings—$3.40 per m3 _{of incremental water availability.}

Balancing cost, energy production, carbon emissions, and water demand will be no easy task. In order to solve China’s water and energy challenges conjointly, measures with a balanced performance should be prioritized. Strong penetration of overly water-intensive energy-savings measures and power plants (such as solar CSP, and coal-to-liquids), on the other hand, would need to be avoided—as would widespread adoption of overly energy-intensive water-savings measures such as desalination. Instead, growth in both sectors should focus on technologies that minimize the combined footprint. As a consequence, renewable technologies such as solar, wind, and hydropower that reduce consumptive water use may offer an important opportunity not only to the energy sector, but also to the sustainable management of water resources.