Renewable energyRenewable energy

Alternatives to fossil fuelsAlternatives to fossil fuels

Which countries consume the most energy?

think: How much more energy do Americans use than Chinese?

Alternative energy Alternative energy sourcessources

SolarSolar WindWind GeothermalGeothermal NuclearNuclear TidalTidal HydroelectricHydroelectric BiofuelBiofuel

We are searching for We are searching for other sources of energyother sources of energy

Renewable resourcesRenewable resources will not run outwill not run out

Environmental impacts Environmental impacts could be much lesscould be much less

Solar powerSolar power Turning light energy into Turning light energy into

electricityelectricity Sun produces 10,000 x Sun produces 10,000 x

the amount of energy the amount of energy needed to power the needed to power the worldworld

Adv: Free, non-pollutionAdv: Free, non-pollution Dis: Expensive to build Dis: Expensive to build

and install the panelsand install the panels& don’t work at night/ & don’t work at night/

cloudycloudy

WindWind

Wind is the movement Wind is the movement of air caused by the of air caused by the uneven heating of the uneven heating of the Earth’s atmosphere.Earth’s atmosphere.

Pros: non polluting, Pros: non polluting, renewablerenewable

Cons: unreliable, many Cons: unreliable, many birds have be killed by birds have be killed by turbines, loud turbines, loud

Geothermal Geothermal Heat generated by the Earth’s coreHeat generated by the Earth’s core water is pumped deep into the Earth crust water is pumped deep into the Earth crust

where it turns into steam that turns a turbine where it turns into steam that turns a turbine generating electricitygenerating electricity

Pros: renewable, nonpollutingPros: renewable, nonpolluting Cons: not available everywhere, can use up Cons: not available everywhere, can use up

water reserves (unless reclaimed water is water reserves (unless reclaimed water is used) used)

Nuclear EnergyNuclear Energy Nuclear fission: splitting large atoms Nuclear fission: splitting large atoms

releases energyreleases energy Adv: plenty of fuel, no greenhouse Adv: plenty of fuel, no greenhouse

gasses, existing technologygasses, existing technology Dis: radioactive waste which causes Dis: radioactive waste which causes

cancercancer

Tidal powerTidal power Building a dam in a bay or estuary to use Building a dam in a bay or estuary to use

the tides to turn turbines the tides to turn turbines Adv: non polluting, renewableAdv: non polluting, renewable Dis: only available in limited areas, could Dis: only available in limited areas, could

harm sea life harm sea life

Think: how could tidal power harm sea life?

Hydro-Hydro-electricelectric Moving water Moving water

turns turbines to turns turbines to Most rivers are Most rivers are already dammedalready dammed

Causes problems Causes problems for fish, for fish, downstream downstream habitatshabitats

Biofuel Biofuel

Organic matter: food scrap, manure, corn Organic matter: food scrap, manure, corn ethanol, algae…ethanol, algae…

Pros: can be “carbon neutral” or decrease Pros: can be “carbon neutral” or decrease greenhouse gasses, can be a reuse of greenhouse gasses, can be a reuse of waste products, renewable waste products, renewable

Cons: can increase food prices, may use Cons: can increase food prices, may use up too much land or not generate enough up too much land or not generate enough energy to be cost effectiveenergy to be cost effective

Reducing energy wasteReducing energy waste All forms of energy All forms of energy

generation waste generation waste energyenergy

Power plants are only Power plants are only 35% efficient35% efficient

We need to reduce our We need to reduce our energy use energy use andand energy energy wastewaste

157 mpg car

Think: of 3 ways you can save energy.

Summary Review Summary Review 1.1. How much energy does the US use How much energy does the US use

compared to the world average?compared to the world average?

2.2. Make a chart of the alternative energy Make a chart of the alternative energy sources listed in this lecture of: what sources listed in this lecture of: what they are, how they are ‘harvested’, and they are, how they are ‘harvested’, and the pros and cons of each. the pros and cons of each.