# Hydropower

## Hydropower

## Energy Conversion

* Solar radiation evaporates water
* Wind currents from solar air heating move evaporated water to locations where it falls as rain
* Gravity carries water down hill
* Hydropower uses this gravitational potential energy and kinetic energy of the water to spin a turbine
* The turbine is connected to a generator, creating electricity

### Ancient Power Technology

* Waterwheels have been used for centuries
* Modern hydropower technology has added large scale dams

### Energy basics

* We use the simplest model for the water as a mass at a height or elevation
* A mass $m$ lifted to a high $h$ has a stored gravitational potential energy of $$PE = mgh$$
* PE is in joules if mass is in kilograms, g = 9.8 m/s^2^ and the height is in meters

### Power

* How do we convert this to a power?

  $$energy = mgh$$

  $$\frac{energy}{time} = \frac{mgh}{time}$$

  $$power = \frac{m}{time} gh$$

  $$power = flow \cdot gh$$
* To get flow in mass per time we convert from volume per time

### Types

* Run of river
* Dams

### Hydropower is significant world wide

* <http://wdi.worldbank.org/table/3.7>
* 2010 Hydropower 15.9% of world wide electricity
* Coal 40.5%, Nuclear 12.8%
* Largest power station in the world is hydroelectric

### Three Gorges

* Largest power plant in the world
* Displaced millions of people
* 22 GW power continuous
* NYC - 10 GW

### Three Gorges

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/three_gorges.jpg)

### Three Gorges

[Three Gorges Satellite](https://maps.google.com/maps?ll=30.823056,111.003333\&q=loc:30.823056,111.003333\&hl=en\&t=h\&z=14)

### Grand Coulee

* Largest hydroelectric installation in US
* 6.8 GW capacity
* 21 Billion kWh annual energy delivered

### Building a dam

* What is the effect of a dam?
* How does the dam affect the overall flow of water?

### Advantages

* Once built, very cheap power
* Reliable technology
* Can be used as storage

### Disadvantages

* Fish migration
* Environmental impacts
* Seasonal variation affects electricity supply
* Water flow
* Sedimentation
* Increased seismic activity
* Risk of dam failure
* Methane production from vegetation decomposition

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/hydropower_issues.jpg)

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/dam_schematic.jpg)

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/dam_schematic_2.jpg)

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/hydropower_physics_1.jpg)

### Hydropower similarities to fossil generation

* Uses spinning generators just like combustion plant
* Doesn't use heat, unlike combustion plant

### Hydropower turbines

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/dam_turbines.jpg)

### Hydropower turbines

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/water_turbines.jpg)

### Hoover Dam

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/hoover_dam_1.jpg)

### Hoover Dam

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/hoover_dam_2.jpg)

### Scalability

* Hydropower can be produced at small scale

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/medium_dam.jpg)

### Hydropower

![](https://github.com/dsoto/ENSP-330-notes/tree/96b68808dd2f3fe643ba262a0ba80de1548dc592/figures/tiny_dam.jpg)


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