Date: 12/19/2013

Source: Seanica Otterby, National Association of Farm Broadcasting News Service

Audio with Jordan Macknick, National Renewable Energy Laboratory energy and environmental analyst. (MP3 3.9 MB). Download Windows Media Player. Time: 00:04:15.

Each year, the power sector withdraws more freshwater than any other sector in the United States. National Renewable Energy Laboratory Energy and Environmental Analyst Jordan Macknick researches water impacts of the electricity sector, including how wind energy compares to other technologies. Macknick says there are two types of water metrics: water withdrawal, where water is used and returned to the system, and water consumption, where water is used and then evaporates. Both have their risks and vulnerabilities, but water consumption is the most concerning, he says.

Different technologies use water differently, Macknick says. For instance, many coal, natural gas and nuclear thermal electric power plants are located on large bodies of water and utilize once-through cooling systems that take in water and then release it back into the environment at much higher temperatures. The amount of water this system takes in can range from 20,000 gallons per megawatt hour of electricity generated to 60,000 gallons per megawatt hour generated. Macknick says non-thermal technologies—like wind—don't require any water for operations.

"This provides a benefit for these non-thermal technologies, such as wind, in the sense that they are not dependent upon reliable sources of water to operate. When you compare technologies, if you look at how many gallons of water would I need for every megawatt-hour of electricity that I generate, by far and away, the clear winner in the water world is wind. Wind requires very little water for production, for manufacturing, as well as for site development, and it requires no water for operations. It's when we start looking at thermal power plants, such as coal, natural gas, and nuclear, that we see large water requirements both upstream for fuel production, as well as at the actual power plant with all the water that's required for cooling."

Macknick has explored different electricity pathways through 2050. He looked at where producing electricity is most cost effective and where there are constraints that could hinder development. For this research through 2050, Macknick looked at how a lack of water resources could impact four different scenarios.

"The first is what we call our business-as-usual scenario, and that looks at if we just went with the lowest cost solution right now, what would happen? Under our second scenario, we really looked at high renewable penetration. So we looked at, let's try to maximize the amount of renewable electricity we can get onto the grid while still ensuring the grid operates properly, and see what the impacts are from that. The third scenario is a high nuclear, as well as a coal and natural gas with carbon capture and storage scenario. In that scenario, we looked at achieving levels of lower carbon dioxide emissions using nuclear and coal with carbon capture and storage technologies. And then the fourth scenario, we really looked at what would be the impact if we employed a lot of energy efficient technologies to really reduce the overall amount of electricity that we'll see."

The most important thing Macknick notes from this research is that although national level values of water consumption may increase or decrease, water consumption is a local issue and will have different impacts in different areas of the country.

"Wind energy technologies play an important role in not only improving the cleanliness of our energy industry, but then also in reducing some of the vulnerabilities associated with water resource stress, which can plague thermal generating stations, like coal, natural gas, and nuclear stations. We have had, in the past 5 to 10 years especially, a number of power plants each summer that have had to curtail generation or cut their power down because either water was too warm or there was not enough water available in that water body for them to use.

Macknick says water consumption is an important issue that energy managers are beginning to recognize, especially the fact that it causes concerns about stability and whether or not power plants have to shut down in critical times, such as the summer when electricity demand is at its peak.

Macknick says wind energy is a unique technology that fits in very well with agricultural areas because once wind turbines are up and running, they don't need water to operate.

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