Hydropower Resources from the NEED Project

The following resources from the NEED Project can be used to introduce students to hydropower:

Wonders of Water Teacher Guide and Student Guide (elementary)

Energy of Moving Water Teacher Guide and Student Guide (middle)

Exploring Hydroelectricity Teacher Guide and Student Guide (high)

Energy and Our Rivers is a unit designed for middle and high school students to investigate the role rivers play in transporting energy sources across the country.  In Activity 2, Energy in Flowing Water, students learn that that the upper, middle, and lower courses of a river have different energy levels; this could lead into a discussion about how moving water provides energy and into the different types of hydropower plants.

Don’t forget that there is also a collection of graphics from NEED’s curriculum guides, including graphics that can be used to teach about hydropower.

Thermoelectric-power plants: water withdrawal versus consumption

Conventional Power Plants: Water withdrawal versus consumption

According the US Geological Survey (USGS), production of electrical power results in one of the largest uses of water in the United States and worldwide. In 2005, about 201,000 million gallons of water each day were used to produce electricity (excluding hydroelectric power) and surface water accounted for more than 99 percent of total thermoelectric-power withdrawals. While some of the water withdrawn provides water to drive the steam turbines and generate electricity, much of the water is used for cooling the power-producing equipment.

When evaluating water use by thermoelectric-power plants, a distinction needs to be made between that of water withdrawal and water consumption.  Water withdrawal entails the removal of water from a local water source; the withdrawn water may or may not get returned to its source or made available for use elsewhere. Water consumption refers to the use of water in such a way as to prohibit it being returned to its source, usually because it is lost to evaporation. While water withdrawal by conventional power plants can be high, consumption can be low if the withdrawn water is returned to lakes and streams.  In 2005, withdrawal of water by thermoelectric power plants for cooling represented 44% of water withdrawn nationally, and 6% of water consumed (Congressional Research Service, 2010).

Droughts and hot summers can influence water withdrawals by power plants as they adjust to low water supply levels and/or use warmer water for their cooling operations; a graphic from the Union of Concerned scientists (UCS) illustrating these scenarios is available.  And for power plants that return water to its source, the returned water, now warmer, can impact the aquatic ecosystem in which it is discharged, which is referred to as thermal pollution. Another graphic from the UCS indicates regions around the country that have encountered power production/water supply issues associated with hotter and drier summers.

To learn more about cooling water, cooling water systems at power plants and thermal pollution, the following resources may be helpful:

Thermoelectric Power Water Use, USGS.  This website includes graphics and a schematic of a coal-fired power plant that relies on a closed-loop cooling system.

Thermal pollution, Encyclopedia of Earth.  This website includes satellite image illustrating thermal pollution in association with a power plant.

Cooling water for energy generation and its impact on national-level water statistics, Food and Agriculture Organization of the United Nations, 2011 (pdf). This document includes graphics depicting once-through and closed-loop cooling systems, comparison of withdrawal and consumption for each type of system.

Energy’s Water Demand: Trends, Vulnerabilities, and Management, Congressional Research Service, 2010 (pdf).

Energy-water collision, Union of Concerned Scientists. This website includes graphics and links to supporting scientific publications.

How Much Water Does It Take to Make Electricity?

The Union of Concerned Scientists describes the various roles of water in the process of producing electricity from fuel extraction, production, refining, processing, and transport to electricity generation and emissions control at the power plant.  When comparing energy sources, one thing to keep in mind is the amount of water required for the entire life cycle of each energy source.

For example, I recently learned that natural gas requires the least amount of water to produce electricity when you consider the amount of water needed to produce 1000 kilowatt-hours of electricity.  This 2008 article from the Institute of Electrical and Electronics Engineers, How much Water does it take to make electricity, summarizes research that took place at the Virginia Water Resources Research Center, to quantify the amount of water consumed during the production of a dozen types of fuel. To learn more, visit the original publication here.

Waterfootprint.org has also calculated the water footprint for various renewable and on-renewable energy sources, concluding that “the water footprint of energy from biomass is 70 to 400 times larger than the water footprint of the other primary energy carriers (excluding hydropower).”

 

ChokePoint US: Energy Used in the Water Cycle

I recently learned about a project from Circle of Blue called ChokePoint: US, a four-month reporting project where journalists set out to better understand what is occurring in the places where rising energy demand collides with diminishing supplies of fresh water.  Check out the website for featured stories, multimedia and infographics about hydropower, coal, oil, tar sands, fracking, and renewables.

Check out the interactive infographic titled: Energy Used in the Water Cycle that details the amount of electricity that is needed to transport, distribute and treat the water we use in our homes and businesses as well as the industrial and agricultural sectors.  While electricity plays a role in many steps of this water cycle, most electricity use occurs with the end users – customers who heat water to bathe, cook, etc.

For those of you who take your students on tours of water treatment plants or waste water treatment plants, consider asking the plant operators to discuss the plant’s use of electricity to pump, move and treat water.

 

Myths and Facts About Electricity in the U.S. South

In December 2011, Marilyn Brown from the Georgia Institute of Technology in Atlanta, along with co-authors from the Nicholas Institute for Environmental Policy Solutions at Duke University released a paper titled Myths and Facts About Electricity in the U.S. South.  In this publication, the authors identify six myths about clean electricity in the southern United States and in doing so identify “new starting points for energy policy development” by evaluating these myths in the context of future energy policy scenarios.

One myth that is examined that is also of significance to helping today’s learners more critically evaluate future energy options is myth#6, which states that “power resource decisions have little impact on water resources.” The paper cites that 54% of freshwater withdrawals in the South are for thermoelectric generation; thus, water conservation through energy planning is significant for this region.  The paper describes the disconnect that often exists between a state’s energy planning and water conservation policies citing that “energy impacts on water usage is often ignored.” While recognizing that knowledge of this connection may not alter decision-making associated with power generation, the authors cite that the connection should not be ignored in light of growing populations and shrinking water resources.   This is just the kind of connection I want today’s students to be able to make!

It would be interesting to ask your students to examine their own myths around energy consumption; I am willing to bet that most students operate under the assumption that their energy consumption does not impact local water resources, for instance.  I imagine their myths would be very different from the ones identified in this paper; however, this exercise could serve to start a conversation about the myths and underlying belief systems that might be operating as future energy generation options as well as energy efficiency and conservation strategies are considered in your city or town.

Fact Sheet about Water and Energy

The Union of Concerned Scientists has created a factsheet titled The Energy-Water Collision: 10 Things You Should Know (pdf) that highlights the connections between water and energy usage.

“Energy and water are woven into our daily lives and strongly linked to one another. Producing energy uses water, and providing freshwater uses energy. Both these processes face growing limits and problems. In most power plants, water cools the steam that spins the electricity-generating turbines. Refining transportation fuels requires water, as does producing fuels—for example, mining coal, extracting petroleum, or growing crops for biofuels. Using water in our homes and businesses requires getting it there, treating it, heating it, and more. Because of these links between energy and water, problems for one can create problems for the other. In places where using energy requires a large share of available water, or where water resources are scarce or stressed by competing pressures (such as the needs of farmers or of local ecosystems or, increasingly in many parts of the United States, by climate change), the energy-water connection can turn into a collision—with dangerous implications for both.”

Visit the UCS website to read more as well as to see other, related information about:

• Power and Water At Risk
• How it Works: Water for Electricity
• Water Use in Biofuel Production

A Video that highlights the Water & Energy Connection!

This 20 minute video from the Surfrider Foundation   describes in a colorful, “Story of Stuff“-  style format, current water management practices and offers sustainable solutions to manage water in the 21st century energy.  I am posting this resource on an energy blog because I think the video does a great job of emphasizing the water & energy connection – that energy is used to pump, transport and treat water and that our current energy choices contributes to water pollution. Let me know what you think!

See a 2-minute trailer at: http://vimeo.com/9838297