Saving Energy Means Saving Water Too
The connection between energy and water, often referred to as the "energy water nexus" is collecting attention from business leaders, policy makers, and citizens alike. In short, this term refers to the close link between water and energy.
Water is used in nearly every aspect of energy production. So, saving energy will save water, and saving water will save energy. When we consider that demand for electricity is supposed to increase significantly in coming decades, it is clear that water consumption will also increase.
This links adequate water supply directly to the energy security of our country. Clean energy technology such as biofuels and carbon sequestration actually require large amounts of water to produce, so while they cut down on greenhouse gas emissions, they may actually contribute to water pollution and waste. Wind and solar power are the cleanest energy sources in terms of both water and carbon emissions.
Electricity, in particular, has a significant impact on our water supply. Fossil fuel generation, nuclear power, and hydroelectricity all consume large amounts of freshwater. It is estimated that fossil fuel generation alone comprises about 39% of all freshwater withdrawals in the US, which equals about 136 billion gallons of water per day. When you do the math, it turns out that every single kWh of electricity uses about 40 gallons of fresh water.
Water is also used intensively for extracting the fuels that generate our electricity. Coal, oil and natural gas all require a significant water supply to acquire, and, in most cases, contribute to fresh water pollution.
Hydraulic fracturing or "fracking" is one of the most controversial topics currently circulating in the energy sector. It is a hot topic because chemicals are mixed with water and injected into rock to release gas or oil. There is still debate over whether or not this practice seriously contributes to pollution of the water table.
On the other hand, clean water has a sizeable footprint when it comes to electricity. Electric power is used to treat and pump water supply to homes and businesses. In fact, the water industry consumes about 100 million MWH of electricity per year. This is equal to about 4% of all generated power and most of that energy is used by water pumps. The interconnection between water and energy means that conserving one will help conserve the other. By becoming more energy efficient we become more water efficient, and vice versa.
As energy efficiency and smart grid initiatives are more commonly adopted across the world, similar solutions to the problem of water efficiency may follow suit. The fact is that electricity demand in the US is rising, especially in regions typically strained for water supplies, such as the Midwest, which experienced serious draught last year. This means water supplies will need to be conserved as much as possible going forward and one way to help this happen is to become more energy efficient.
The energy water nexus reminds us that our resources are not isolated. We often don't remember how reliant we are on a good water supply. Water and energy also both contribute to operating expenses of business and industry. Enacting energy conservation methods in these sectors not only conserves resources, but can save money as well.
Jessica Kennedy, energy consultant, Energy Curtailment Specialists, Inc.