For centuries, humankind has harnessed the energy of falling water to provide mechanical energy. The ancient Greeks used water wheels that were turned by the current of moving water. The motion of the water wheels turned stones that ground wheat into flour.

Hydropower as we know it is electricity generated by the movement of water that pushes blades in a turbine. The turbine spins a generator that produces electricity. We use this electricity in our homes, schools and businesses.

Renewable EnergyHydropower is known as a renewable energy source since the water isn’t “used up”. The water that spins the turbines flows though the facility and is returned to the river. Every year snowmelt or rain provides the source water that makes its way through rivers.

Wind and solar power are also ex-amples of renewable energy sources.

By way of contrast, non-renewable energy sources include coal and natural gas which are burned in the process of electrical generation.

Hydroelectric power provides one-fifth of the world’s electricity. In Colorado, about 4 percent of our electricity comes from hydropower.

Watershed Defenders was developed by the Colorado Foundation for Agriculture (www.GrowingYourFuture.com) with support from the Colorado Nonpoint Source Program and Colorado Department of Public Health and Environment, Water Quality Control Division. ©2011 Colorado Foundation for Agriculture.

This edition of Colorado Kids was created by the Colorado Foundation for Agriculture (www.growingyourfuture.com) with support fromTri-State Generation & Transmission Association. ©2014 Colorado Foundation for Agriculture.

HydroPOWERTransforming kinetic energy to electricity

Kinetic energy is the energy of motion.The first hydroelectric power plant was built at Niagara Falls in 1879. This plant converted the energy of falling water to create electricity. In 1881, street lamps in the city of Niagara Falls, New York, were powered by hydropower.Turbines in the Hoover Dam on the

Colorado River generate electricity.

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When we talk about energy, we commonly think about making our cars move or heating our homes, but energy is everywhere. Our bodies require energy. Plants require energy. Phones and electronics require energy. Energy is life.

There are two types of energy: potential and kinetic. Potential energy is stored energy and kinetic energy is the energy of motion. For example, think of a spring. When you compress and hold a spring, it has potential energy. When you release that spring, the potential energy becomes kinetic energy. Similarly, when we hold water in a reservoir, it represents potential energy. When we release the water from the reservoir, the potential energy becomes kinetic energy.

Energy can also be described in other ways—thermal (heat) energy, light energy, sound energy, chemical energy, electric energy and gravitational energy. Energy has basic rules:

1. Energy can be transformed from one form to another.

When you use a flashlight, potential energy stored in the batteries becomes electric energy and then light energy.

2. Energy cannot be created or destroyed.

The energy we use has always existed and will continue to exist, but not in the same form.

3. You cannot achieve 100 percent energy efficiency.

While energy is conserved (rule 2), some of the energy always go into a non-useful form. Think about dropping a basketball and letting it bounce until it stops. The first bounce will be the highest and each subsequent bounce will be smaller until it stops bouncing altogether. Useful energy is lost with each bounce.

Understanding Energy we commonly think

about making our cars move or heating our homes, but energy is everywhere. Our bodies require energy. Plants require energy. Phones

There are two types of energy: potential and kinetic. Potential energy There are two types of energy: potential and kinetic. Potential energy is stored energy and kinetic energy is the energy of motion. For example, think of a spring. When you compress and hold a spring, it has potential energy. When you release that spring, the potential energy becomes

Understanding Energy

Math Challenge

If a 100 watt light bulb is left on for 10 hours,

how many Btu are consumed?

Answer: A 100 watt bulb left on for ten hours uses 1 kilowatt-hour of electricity. One kilowatt-hour equals 3,412 Btu.

Powerful VocabularyMechanical Energy Mechanical energy is the sum of potential

energy and kinetic energy.

Fuel A substance consumed to make energy.

Fossil Fuels Fuels formed by ancient (fossilized) plants and animals (coal, oil and natural gas).

Force Sometimes called “push or pull,” force is an influence that causes something to speed up or slow down. Gravity and electro-magnetic force are two examples.

Power The work done in a set amount of time.

Energy Efficiency A measure of the useful energy compared to the total amount of energy required to do useful work. One example would be evaluating two cars based on their fuel economy (miles per gallon).

Energy Conservation Choices that lead to less energy consumption.

Lumens? Watt? We are incredibly dependent on electricity. From our computers to cell phones, from refrigerators to home heat and from the water we drink to possibly the cars of the future, we are dependent on the reliable production of electricity.

Since the early days of indoor lights, we’ve chosen light bulbs based on their wattage. For instance, a common bulb in your house was 60 watts. With the shift to CFLs and LEDs, watts don’t serve us as well, so these lights are measured in lumens. A lumen is a standard unit of light as perceived by the human eye. A watt is a measurement of energy consumption or output.

The 60 watt light bulb is equivalent to 750 - 850 lumens. On average, an LED bulb produces as much as 110 lumens per watt. An incandescent bulb by comparison, averages 12-17 lumens per watt. The LED bulb is a good example of an improvement in energy efficiency and an energy conservation strategy.

How do we measure energy?Measuring energy can seem pretty messy. We use different units for heat energy, mechanical, and electrical energy.

The energy content of fuels is measured in terms of the heat it can generate. The term is British Thermal Unit (Btu). One Btu is the amount of energy required to raise the heat in one pound of water 1 degree Fahrenheit. Alternately, a calorie is the amount of heat needed to raise one gram of water 1 degree Celsius. Food calories are actually kilocalories (1,000 calories).

When measuring electricity, we use kilowatt-hours (1,000 watt-hours), but we can find equivalents:

1 Btu equals 252 calories

1 kilowatt hour equals 3,412 Btu

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Blue Mesa Dam on the Gunnison River in Colorado houses two turbine generators and produces an average of 264,329,000 kilowatt-hours each year.

Hydroelectric Dam

Water Turbine Hydropower—A Closer LookA hydroelectric power plant depends on gravity to move water through the system. In the example above, the dam holds back the flow of the river creating a reservoir. Some of the water is allowed to move through the dam to the powerhouse through what is called a penstock. The flow of water pushes against the panels of the turbine (detail at left). The shaft of the turbine then turns and causes a magnet to spin inside a generator. The magnet is surrounded by copper windings. The spinning of the magnet inside the copper windings transforms the mechanical energy to electrical energy. The electricity leaves the power plant and the water is returned to the river.

How much electricity can be generated depends on how far the water drops and the volume of the water that moves through the system. The electricity can be transported via long distance transmission lines. Engineers can regulate how much electricity is produced by controlling the flow of water into the system.

Potential energy is stored energy.Potential energy is also called the energy of position. Thanks to gravity, the water stored in a reservoir has potential energy. When it flows, the potential energy becomes kinetic energy.

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Now is an exciting time for hydropower. New technologies are creating an opportunity for small-scale projects to be economically

built in conjunction with existing infrastructure. In particular, Colorado’s system of irrigation diversions and ditches may see significant hydropower development in the near future.

All methods of electrical generation have ‘pros’ and ‘cons.’ Hydropower is desirable for a number of reasons. In the United States, hydropower is the cheapest way to generate electricity. Once the generation equipment is in place, there is very little cost to generate electricity. Water supplies are self-renewing and the process doesn’t consume any of the water. Engineers have a high degree of control over the power generation by controlling the water. In addition, reservoirs can have added benefit providing recreational opportunities and wildlife habitat. The flows from reservoirs can also be used to benefit downstream wildlife.

The creation of new reservoirs for large-scale hydropower can be a divisive issue. While enhanced water storage creates opportunities, it can also have a negative impact on existing ecosystems. The releases of water from reservoirs can have a detrimental influence on oxygen levels in a river and the temperature of the water can also be a concern.

Other Methods of Generating Electricity Renewable Energy SourcesOther sources for renewable energy are solar, wind and biomass. Solar energy involves collecting energy from the sun. Wind energy uses the power of the wind to create energy. Biomass energy involves burning renewable fuels.

Non-Renewable Energy SourcesIn Colorado, most of our electricity comes from coal-fired power plants. The coal is burned to heat water and create steam. This steam spins turbines connected to generators. In this process water is also used for cooling. Natural gas is becoming increasingly important in Colorado and is used much the same as coal. While both coal and natural gas are naturally occurring and abundant, they are considered non-renewable because they can’t be replaced. El

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Energy Resources

Bringing Electricity to Your Home

The electricity leaves the power plant and moves to facility where the voltage is stepped up for transmission.

Voltages in the transmission lines can be as much as 345 kilovolts.

Close to where the energy will be consumed, substations step-down the voltage.

Some industrial users require higher voltages, but the power that reaches your home is available as 120 volt or 220 volt.

Kilowatt vs. Kilowatt-HourThe kilowatt (kW) is a measure of electrical capacity. The kilowatt-hour (kWH) is a measure of consumption. The average Colorado household requires 3 kW of capacity and consumes 740 kWH per month. This average cost is 11.6 cents per kWH—about 1 cent below the national average. Do the math: What is the average cost on annual basis?

Math Answer: 740 kWH * $0.116 * 12 = $1,030.08

• Coal • Natural Gas• Wind • Hydro • Biomass • Solar

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