The Energy Problem

• How will society meet growing energy demands in a sustainable manner?

• Fossil-fuels currently supply ~80% of world energy demand.

Two Key Problems with fossil fuels

• availability (non-renewable resources)• Pollution from combustion of fossil fuels

How much longer can we depend on fossil fuels?

• Because they are fossil fuels they DO have a life expectancy

• “Oil has 40 – 50 years left”• In 1960 they said this too! – what has

happened is that we have found new reserves of oil and new technology has made the oil we use last longer

Alternative Resources

Types of Alternative Energy

• Nuclear Energy • Solar Energy • Hydroelectric Energy• Wave farms • Biomass• Geothermal Energy

1. Nuclear Energy

• A. fission:– Splits atoms and releases lots of energy – Pros:

• Release a lot of energy with no air pollution

– Cons• Dangerous radioactive wastes• Long term storage needed in isolated places• Accidental release of radiation

• Discovered in 1938• When the nucleus of the atom is split by

an incoming neutron • When this happens some mass is

converted to energy

• http://www.classzone.com/books/earth_science/terc/content/visualizations/es0702/es0702page01.cfm?chapter_no=visualization

• http://www.youtube.com/watch?v=qe7mbv7v9Zg&feature=related– Nuclear fission from National Geographic

Solar Energy• Energy received from the sun in the form

of radiation• Renewable resource• Can be used to heat homes, generate

electricity

• Solar collectors are dark colored boxes that have glass or plastic tops used to heat water in pipes running through it

Solar Power Generation

• located in desert/high intensity/long sunlight hours• parabolic mirrors reflect/focus sun’s rays onto metal

water pipe located along focal axis of mirrors.• High temperature produced - steam - electrical power

generated

• Pros: – doesn’t pollute– Renewable

• Cons– Weather– Time of day– expensive

Hydroelectric

http://www.youtube.com/watch?v=tSBACzRE3Gw

Wind Power

• indirectly connected to solar energy because wind is caused by unequal heating of air

• Windmill that drives electric generator

Offshore Wind Turbines

http://www.youtube.com/watch?v=K6BkPmKBJ9Y

Offshore Wind Cluster Features

• Larger average wind speed than onshore

• Easier planning consent

• Technical expertise exists from oil rig experience• Suitable location

Biomass

Bio-diesel

• Made by transforming animal fat or vegetable oil with alcohol .

• Fuel is made from rapeseed (canola) oil or soybean oil or recycled restaurant grease.

• Directly substituted for diesel either as neat fuel or as an oxygenate additive

Air Concerns/soil concerns

• Biomass processing technologies and biofuels use have the potential to increase emissions of ozone precursors

o Increase in Nox emissions

o Excessive inhalation of ethanol is harmful

• Burning biomass deprives local eco-systems of nutrients

• Increased use of pesticides and fertilizers to produce energy crops contaminate ground and surface water

Environmental Benefits

• Reduction of waste

• Extremely low emission of greenhouse gases compared to fossil fuels

• Ethanol is Carbon neutral and forms a part of the carbon cycle

• Growing variety of crops increases bio-diversity

Landfill Gas

• http://www.ctcleanenergy.com/innoflash/#/landfill/more

Geothermal Energy Sources Hot Water Reservoirs: These are reservoirs of hot underground water.

There is a large amount of them in the US, Space heating rather than electricity

Natural Stem Reservoirs: In this case a hole dug into the ground can cause steam to come to the surface. Rare in the US.

Geopressured Reservoirs: In this type of reserve, completely saturated with natural gas in stored under pressure from the weight of overlying rock. Can be used for both heat and for natural gas.

Advantages of using natural sources of energy

• They are inexhaustible – they will always be available – they are renewable

• They are clean and will not damage the Earth

• There are several types – so one or more of them is present in each country

• Most natural sources can be used on a small scale and serve local needs therefore cutting costs of transmitting the energy