The Disparity in Water Efficiency Values

April 9, 2014
Availability & economics drive perception of water value

About the author: Robert McIlvaine is president of McIlvaine Co. McIlvaine can be reached at [email protected] or 847.784.0012.

Improving water efficiency through reuse, conservation or more effective treatment comes at a cost, which must be weighed against the value. The value, in turn, is a function of water scarcity, cost of energy and other aspects of treatment, as well as other factors. The result is that the right answer for China, for example, may be quite different than that for the U.S.

The relativity of water efficiency values is an important subject that heretofore has not been extensively addressed. Even though there are more than 1.3 billion cu km of water on the planet, less than half of 1% is readily available as fresh surface water for use by humans. This relative lack of readily usable water—coupled with growing demand—provides both huge challenges and huge opportunities. 

There are many arid regions of the world and even more semi-arid ones. These regions place a higher value on water than the rest of the world does. Surface and near-surface water per capita in China today is roughly a quarter of the global average, and it is distributed very unevenly. The north and northwest regions—which comprise about 380 million people (almost 30% of the national population) and more than half the country’s arable land—have about 7% of its surface water. That means its per capita resources are roughly 20% to 25% of the average for China as a whole, or 5% to 6% of the global average.

The Efficiency Value Disparity

 Many arid countries rely on reverse osmosis (RO) for their water treatment needs; however, RO consumes a lot of energy, which results in greenhouse gas emissions. In addition, they have embarked on massive construction of coal-fired power plants, and have not adopted the same priorities as the U.S. and Europe relative to CO2 and other emissions. The amount of greenhouse gas that a Chinese company is willing to generate in order to purify water is likely to be much higher than what an American company would find acceptable. One reason is that the U.S. places greater importance on greenhouse gas emissions. The other reason is that water is four times scarcer in China.

Every option for providing more water to a region has negative consequences. Whether it is RO to purify or desalinate water, or large pumps to transport water, large amounts of energy are consumed. This energy is created largely by processes that generate CO2. One can calculate the tons of CO2 generated by an RO system to produce one ton of water. Whether this ratio is acceptable or not varies considerably from country to country.

A Common Metric

This disparity needs to be addressed in a statistical way in order to make the best water efficiency decisions. Our research team has developed two common metrics to measure harm and good. One is straightforward and relates all harm in terms of equivalent tons of CO2. The second takes into account the disparity in values and is called Quality Enhanced Life Days.

The relationship between CO2 and various pollutants can be made simply by using the U.S. Environmental Protection Agency (EPA) guidelines developed in justifying cost of regulations. If EPA places the reduction of a ton of total suspended solids in the water at $5,000 and the  reduction of a ton of CO2 to the atmosphere at $50, then there is a 100:1 value ratio. Because EPA places a human life at $7 million, then a life is worth 350,000 tons of CO2.

These values vary from country to country. In areas with a water surplus, such as Canada, the value of a ton of CO2 is 1,000 tons of water, a ratio that assumes that the goals and aspirations are the same, and it is only water scarcity that causes values to differ. In reality, the goals and aspirations are equally important. 

The impact of climate change 50 years from now is less of a concern for someone who struggles with starvation on a daily basis. The way to determine value is to ask specific questions: How many days of your life would you be willing to sacrifice to save one polar bear? This can be rephrased to state: “The quality of my life will be enhanced by the equivalent of X life days if I can save one polar bear.”  

Whether it is resolution of water issues among governments or among individuals in a community, the disparity in water efficiency values should be recognized. This can lead to quicker resolution of disputes and better decisions.

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About the Author

Robert McIlvaine

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