RENEWABLE ENERGY What it is & What it isn’t. Vocab Buzz Sustainable Renewable NonRenewable ...

RENEWABLE ENERGYRENEWABLE ENERGY

What it is What it is

&&

What it isn’tWhat it isn’t

Vocab Buzz

• Sustainable

• Renewable

• NonRenewable

• Organic

• Green

• Clean

Energy Waste & InefficiencyWhat’s the moral of this

story?• Conservation vs.

Efficiency

• 84% of commercial energy in US is wasted– 41% due to entropy

(2nd law of thermo)

– 43% unnecessary; inefficiency

• $570,000/min

How does energy get wasted?

• Net Energy Yield• Net Energy EfficiencyNet Energy Efficiency

– Combine efficiencies of all steps in energy conversion for the entire system

Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year.

Solar Energy

Passive Solar Heating and Cooling

How does it work?

Passive Solar Heating

http://www.livingonsolar.com/passive-solar-video.html

Passive Solar Heating

Passive Solar Heating

• ADVANTAGES

– HIGH net energy yield

– Free energy

– No pollutants

– Moderate cost

• DISADVANTAGES

– Is there enough available sunlight in all areas?

• Need 60% of the time• Needs correct

orientation

– Need heat storage or backup

Solar Cooling• Super-insulation• Block summer sun trees, awning, etc.• Good ventilation• Earth Tubes

– Soil ~5-13ºC– Moves cool, dry air in– Inexpensive

• Light colored roof• Reflective foil in attic• Earth sheltered building

Active Solar Water Heating

Active Solar Heating

•Solar collectors on roof

•Heat stored in insulated tanks of water, rocks, heat-absorbing chemical

•Used for heating and hot water

Active Solar

• ADVANTAGES

– No pollutants

– Moderate net energy

– Free after initial installation

• DISADVANTAGES

– Unattractive

– Is there enough available sunlight in all areas?

• Needs correct orientation

– Requires a backup hot water source

– Pump requires energy, maintenance

Solar cooker

Solar Thermal Plant

Parabolic (U-shaped mirrors) concentrate the sun’s rays onto a black pipe containing molten salts or oil.

This produces steam to turn a turbine and generator.

Pros and Cons

PROS

• Non-polluting, no carbon emissions

• High efficiency (~15%)• Operating costs are low

CONS

• Takes up a lot of land – 1 sq. mile or more

• Not always reliable• Slightly more expensive

than PV cells• New technology involved• Heavily location

dependent

Why do we waste so much?• Fossil fuels cheap• Few gov’t

incentives• Inaccurate pricing• Inequitable

subsidies• What are the

benefits to reducing?

Photovoltaic (Solar Cells)

Photovoltaic Cells

1. Sunlight strikes semi-conductor

2. Electrons move

3. Energy can be stored in battery

• Life is carbon-based for a reason

• Silicon atoms have the same capabilities

http://www.youtube.com/watch?v=K76r41jaGJg(1:07 mins)

Solar Cells

• ADVANTAGES

– No pollutants

– Safe

• DISADVANTAGES

– Expen$ive!

– Need large surface area

– Unattractive

– Is there enough available sunlight in all areas?

– Requires a backup electricity source

Hydrogen Fuel Cells

• How it Works:– Combines H with O to

produce energy

– Can be fueled by anything with H in it

• Natural gas, alcohol, gas

– Gives off water

http://www.pbs.org/wgbh/nova/sciencenow/3210/01.html(12:49 mins)

Hydrogen Fuel Cells

• ADVANTAGES

– H is abundant

– Non polluting

• DISADVANTAGES

– Not very efficient to produce

• Takes electricity to split water and produce H

– Expensive

– Needs to be stored at high pressure

Energy Types:Can you match and discuss the +/- ?

• Chemical• Electrical• Mechanical• Light (EM)• Nuclear• Heat

• Clean• Renewable• Sustainable

• Wind• Hydrothermal• Active Solar• Biomass• Passive Solar• Coal, Oil, Natural Gas• Hydrogen Fuel Cells• Hydroelectric• Tidal

Slide Bank

Use renewable energy!

• Benefits of shifting to local, renewable energy sources– More reliable source– Improve national security– Reduce trade deficits due to importing oil– Reduce greenhouse gases and other air pollution– Creates jobs– Saves $ in the long run

Hybrid, Plug-in hybrid, Electric

• Hybrid Car Flash Animation– Prius Hybrid Synergy Drive

• GM Volt (2010)– http://gm-volt.com/about/– http://www.chevrolet.com/electriccar/

• The EV-1– http://ev1-club.power.net/

• The Tesla– http://www.teslamotors.com/

• http://www.fueleconomy.gov/feg/• http://www.nrel.gov/vehiclesandfuels/hev/

More on Batteries

• Carbon-Zinc – 1st Duracell

• Lead-Acid – Car batteries

• Nickel Cadmium – consumer electronics

• Nickel-Metal Hydride

• Lithium Ion – notebook computers

• Lithium polymer – newest development

3 types of Heat Transfer

TRADE-OFFS

Passive or Active Solar Heating

Advantages Disadvantages

Energy is free Need access to sun 60% of time

Net energy is moderate (active) to high (passive)

Sun can be blocked by trees and other structures

Quick installation Environmental costs not included in market priceNo CO2 emissions

Very low air and water pollution

Need heat storage system

Very low land disturbance (built into roof or windows)

Active system needs maintenance and repair

High cost (active)

Active collectors unattractive

Moderate cost (passive)

What IS a Battery?

• Energy Storage System!

• As easy as a clock spring or a log

• Is that potential or kinetic?

What IS a Battery? -aka cell

• Changes chemical energy to electrical

• Voltaic cells (cells that can transfer voltage)

• Electrons collect on the negative terminal of the battery

• Flows between the positive and negative terminals if a conductor (or wire) is present

http://www.howstuffworks.com/battery.htmBattery video

What is Energy?

• “The Ability to do Work”

The world is made up of MATTER & ENERGY.– Which one cycles and which one flows?

• The 2 classes are Potential & Kinetic• The 6 types are:

– Chemical, Mechanical, Nuclear, Light (EM), Heat, Electrical

Where are we now?

Coal Gasification

Where might we go?

Hydrogen Fuel Cells

What’s the bridge to get there?

Photovoltaic Cells