Exploring Solar and Wind Energy Resources

Perpetual Resources

Resources like solar energy that are constantly available.

Solar Energy

The sun constantly provides light and heat, which we mostly take for granted.

Photovoltaic (PV) Panels

Convert sunlight directly into electricity and do not store energy—only work when the sun is shining.

Photovoltaic

Derived from photo (light) + voltaic (electricity).

Examples of PV Usage (Small)

Pocket calculators.

Examples of PV Usage (Medium)

Bus stops, emergency phones.

Examples of PV Usage (Large)

Rooftops of homes, schools, malls, and parking lots.

Examples of PV Usage (Huge)

Entire parking lots or building roofs like at high schools or shopping centers.

Energy Flow in Homes

During the day, excess solar power can be sold to the power company (net metering).

Energy Storage

Battery systems are expensive and have limited capacity.

Cost and Efficiency

Solar panels used to be expensive and only ~10% efficient; now they're cheaper and ~15-20% efficient.

Payback Time for Solar Panels

Dropped from 10+ years to around 5-7 years.

Buyer Beware

Some companies offer 'free installation' but retain ownership of the panels.

Power Generation Impact

Large installations can generate up to half a megawatt on a sunny day.

Solar Power in Southern California

On some sunny summer days, enough solar power is generated to meet all electricity needs during midday hours.

Solar Thermal Collectors

Use sunlight to heat water, not to generate electricity.

How Solar Thermal Collectors Work

A shallow box is painted black, with a copper pipe zigzagging through it, and a glass cover traps heat.

Benefits of Solar Thermal Collectors

Free hot water when the sun is out; often used for heating swimming pools.

Limitations of Solar Thermal Collectors

Doesn't work well for early morning showers unless you store the hot water.

Parabolic Trough System

Uses curved mirrors to focus sunlight on a pipe containing superheated oil.

Limitations of Parabolic Trough System

Takes up huge land area and only produces about 1/8 the electricity of a fossil fuel power plant.

Operational Limitation of Solar Thermal Power Plants

Only works in sunlight (not at night).

Power Tower System

A tower in the middle surrounded by thousands of mirrors (heliostats) that reflect sunlight onto a black box at the top of the tower.

Molten Salt

A substance inside the black box that absorbs a huge amount of heat.

Electricity Generation Process

Hot salt is pumped down to heat water into steam, which spins turbines to generate electricity.

Advantage of Power Tower System

Has a reservoir of molten salt, allowing it to store heat and generate electricity at night.

24-Hour Power Capability

Unlike typical solar systems, the Power Tower System can provide power 24 hours a day.

Ivanpah Solar Thermal Power Plant Location

Located in Ivanpah Valley, eastern California.

California Desert Tortoise

A federally endangered species that survives in harsh conditions by burrowing in sand and eating desert vegetation.

Legal Protection of Tortoises

Desert tortoises are protected by law, making it illegal to touch them.

Impact of Ivanpah Construction

The construction of Ivanpah disrupted the habitat of desert tortoises, likely violating the Endangered Species Act.

Bird Deaths - The 'Fried Chicken' Effect

Birds flying through intense beams of heat created by mirrors can get incinerated mid-air.

Intensity of Heat Beams

The heat beams can be 100 times stronger than natural sunlight.

Photovoltaic (PV) Solar Comparison

PV panels are becoming cheaper and more common, with large PV fields built near Ivanpah.

Environmental Concern of Solar Farms

Solar farms cover large areas of natural desert, affecting ecosystems.

Desert Ecosystems

Deserts are rich in biodiversity and important to the planet's health, contrary to the assumption that they are barren.

Sustainable Solar Alternatives

Placing solar panels on building rooftops or over parking lots to avoid destroying natural habitats.

Solar Power as a Perpetual Resource

The sun is inexhaustible and doesn't need to be renewed, but solar power must be part of a mix.

Wind as a Perpetual Resource

Wind is driven by the sun's uneven heating of the Earth, making it a renewable resource.

Historical Use of Windmills

Windmills have existed for centuries, using sails to catch wind and turn a horizontal drive shaft.

Milling Process

Gears convert the rotation of windmills into a vertical drive shaft that powers millstones to grind grains.

Watermills

Used the same principle as windmills but were powered by water.

Wind Pumps

Pumped water from rivers to fields, extensively used in the Netherlands.

Dutch Land Reclamation

Dutch built * to enclose areas and pumped water out with wind power, allowing for agriculture.

Dutch farmland

Much of Dutch farmland, including tulip fields, is now below sea level.

Modern Wind Energy

Wind turbines are today's version of windmills: Tall, narrow towers with fan blades that spin a generator to produce electricity.

Energy transmission

Energy can be transmitted over long distances by power lines, unlike historical windmills.

California's major wind farms

San Gorgonio Pass (near Palm Springs), Tehachapi Pass (east of Bakersfield), Altamont Pass (east of San Francisco, near Livermore).

High winds

These areas have high winds due to their locations in mountain passes.

Pros of Wind Farms

No fossil fuels or greenhouse gas emissions; Clean, sustainable energy source.

Cons of Wind Farms

Visual pollution, land disruption, noise pollution, and dust affecting air quality and human health.

Offshore Wind Energy

Wind farms are now being developed offshore, already built off Europe's coasts.

California's offshore wind goal

California's goal (2022): Offshore wind to power 25 million homes by 2050.

Inflation Reduction Act (2022)

Provides funding and incentives for wind energy development.

Floating wind turbines

New technology being developed for deeper waters, using vertical-axis turbines.

Wind as a resource

Wind is powered by solar heating and pressure differences in the atmosphere — it's a perpetual resource.

Bird Fatalities

Wind turbines do kill birds, particularly from collisions with the spinning blades.

Research Efforts on Bird Deaths

Scientists are studying turbine placement and design to reduce bird deaths.

Donald Trump's Comments

Trump has criticized wind energy, often bringing up bird deaths, especially eagles.

Cats vs. Wind Turbines

Cats kill over 4,000 times more birds than wind turbines.

What Are Tides?

Tides are the rising and falling of ocean levels, usually twice every 24 hours.

Cause of Tides

Caused by the gravitational pull of the moon (and to a lesser extent, the sun).

Earth's movement during tides

The solid Earth doesn't move, but water bulges toward the moon.

Tidal bulge movement

As the Earth spins, the bulge appears to move around the globe.

Cycle of Tides

The cycle of tides is actually about 25 hours, not 24, due to the moon's movement.

Tidal Range

The vertical difference between high tide and low tide.

Tidal Range in Southern California

Approximately 6-10 feet.

Tidal Range in Birch Bay, Washington

Approximately 15 feet.

Tidal Range in the Bay of Fundy, Canada

Over 40 feet, the largest in the world.

Why Tidal Energy Matters

Huge volumes of water move in and out of bays with the tides — a massive energy source.

Capturing Tidal Energy

The process of harnessing tidal movement for electricity.

Tidal Barrages

Dams that are built to capture tidal energy.

La Rance Tidal Power Plant

An example of a tidal barrage located in France.

Tidal Barrages Energy Output

Produces 240 megawatts, about ¼ of a modern fossil fuel plant.

Downsides of Tidal Barrages

Ecosystems disrupted: marine animals can't freely enter or leave the bay; permanent change to the coastal environment.

Underwater Turbines

Devices placed in natural channels where tidal flow is strong to capture energy without a dam.

Ecological Impact of Underwater Turbines

Less energy than a dam, but much less ecological damage.

Is Tidal Energy Perpetual?

Yes — It is a perpetual resource that can't be used up as long as the moon's gravity and Earth's rotation continue.

Flowing Water as a Perpetual Resource

Flowing water in rivers can be used to generate hydroelectric power.

Hydroelectric Power Generation

Building a dam to hold water and letting it flow through turbines to generate electricity.

Hoover Dam

Creates Lake Mead, which is 120 miles long.

Three Gorges Dam

The largest dam in the world located in China.

Benefits of Dams

Generate electricity, provide flood control, and store water supplies.

Environmental Drawbacks of Dams

Disruption of river ecosystems, flooding of land, and methane emissions from decaying plant material.

Sediment Buildup Example

Colorado River sediment settles in Lake Mead, which could become completely full in less than 100 years.

Norway's Hydropower

Rivers run through hard, ancient rock, leading to clean water and dams that may last thousands of years.