Blog Action Day 2010: Water Supply, Water Quality and Energy Use

I was surprised to learn recently that 3% of total electricity production in the United States is used by the municipal water and wastewater sector.  That’s a large number.  And that amount of electricity translates to about 45 million tons of greenhouse gas emissions.  These statistics are no doubt typical of water systems in other developed countries.  All in all, the amount of greenhouse gas savings that could be achieved by reducing water system energy consumption is not insignificant.  

Where can we achieve those efficiencies and emissions reductions?

One part of the solution is to design and build infrastructure that is more efficient.  Water and wastewater infrastructure are energy intensive systems.  Energy is consumed in pumping potable water, wastewater, treatment sludge, and treated wastewater; aeration of treatment sludge; lighting; water clarification; chlorination; etc.  Further, poor maintenance can contribute to system inefficiency (e.g., scaling inside pipes reduces flow capacity, thereby requiring heavier pumping).  Existing facilities can be retrofit with more energy efficient equipment (e.g., motors, blowers, pumps), and new facilities should be held to design standards that take into account energy consumption over the lifetime of the facility.  Implementing these energy efficiency solutions is a challenge and requires the right incentives for utilities to adapt energy efficient practices and the right technical/engineering support. 

The U.S. Environmental Protection Agency just announced a policy to support increasing the sustainability of water infrastructure across the U.S. 

As part of this policy, EPA intends to work with states at the infrastructure planning stage to encourage water utilities to consider not only traditional planning issues (public health, water quality, rates, service levels), but new issues — climate change, energy efficiency and the merits of “green infrastructure” practices (e.g., rain gardens, porous pavements, green roofs, rainwater harvesting, etc.).  This policy could be made more rigorous by providing clear financial incentives to utilities, but it is a good example of the kinds of policies necessary to support sustainable infrastructure.

Energy-related greenhouse gas emissions can also be reduced at water and wastewater facilities simply by reducing the amount of water that is consumed.  The relationship between the volume of water that goes through the system and the system’s energy consumption is complex, but it is generally true that the less water means less energy consumption.  Public policies should support collaboration among utilities and their consumers to reduce water consumption.  Further, many communities can achieve energy savings in their wastewater systems by reducing the amount of stormwater that is captured in the wastewater system through “green infrastructure” (green roofs, open space preservation/restoration, porous pavement, rainwater harvesting, etc.).  At least 2 major U.S. cities (Philadelphia, PA and New York, NY) are well along the way in developing “green infrastructure” to manage their stormwater runoff.  Cities like these that embark on “green infrastructure” development will realize enormous energy savings due to reduced water treatment demands, but also substantial environmental benefits (urban heat island mitigation, improved air quality, reduction in stormwater volume and pollutants, enhanced groundwater recharge, etc.).  
    
Water, energy and climate change are inextricably linked, and it will be an on-going challenge to meet our increasing demands for water and energy while at the same time reduce our impact on the environment. 

Guest blog post from: Jane Kozinski, Senior Policy Advisor, British Consulate-General, New York, NY USA