Alternative Energy

Alternative Energy Sources90% of the energy used today isin the form of fossil fuels.

Forms of energy OTHER than fossil fuels are termed “alternative”energy sources.

Alternative energy sources can bedivided into two main categories.

1)Non-renewable energy sources-nuclear power-geothermal power

Geothermal Energy: heat energy from the Earth-the conversion of natural heat from the Earth’s interior to heat buildings and generate electricity.

-considered a non-renewable source when extraction rates are greater than supply.

High vs. Low temp GeothermalLow Temp: Use of groundwater, Whichis 55 F year round.

Deep wells (over 100 feet) are dug,and groundwater is used as a heatsource in winter, and as a coolantin summer. Initial costs are higher, but cost to run is much lower, and uses little fuel.

Outlook: excellent, low temp geothermalis becoming much cheaper to install,and the technology is already in placefor it to become successful.

High Temp. Geothermal: using hot water from the Earth as an energy source.

-uses water heated from features suchas geysers and volcanoes

-direct heating of buildings, as well as electricity generation.

-steam generated within volcanic areasis used to turn turbines, which generateelectricity. Outlook: Limited, because areas with enough volcanic activity are not widespread. Great success in areas where geothermal activity is high (Iceland, California)

Bath, England, with its natural hot springs, is the site of an elaborate Roman public bath built in the first century

People bathing in Blue Lagoon near Grindavik, Iceland

2) Renewable Energy Sources-Solar power-Wind power-Hydropower-Ocean currents/tidal-Biomass energy

Solar EnergyThe amount of incoming solar energyis immense. -in 10 weeks, the amount of incomingsolar energy would equal the energyof all known fossil fuel reserves.

-Distribution is variable, due to climate,location on Earth, etc…

Passive vs. Active Solar Energy-Passive solar energy collection mostoften involves the design of buildings,etc., to maximize the collection of Suns energy. No energy is spent.

-Orientation of building to face south-Glass walls to collect sunlight-“Thermal Mass” to hold warmth (brick/stone walls, beds of stone)

-Active solar collection requires energyto run pumps for circulation of water orair, or to move collectors orientation to follow the sun. -water/air filled solar panels, with pumpsto move heat to where it is needed. -The Luz Solar Electric generation systemuses heated oil to generate steam, whichthen generates electricity in a turbine. Located in the Mojave Desert, U.S.

The Luz Solar Electric Generation System

Photovoltaic Solar:Electricity is created directly from special solarpanels.

Hydrogen Power:

Hydrogen has the potential to be the largest energy source of all.

Clean Burning (only water as exhaust!)

Inexhaustible supply, which is recycled

No fancy new drilling technology needed!

Ways to create Hydrogen Gas

1)Electrolysis: breaking water into Hydrogen and Oxygen using electricity.

-uses lots of power to accomplish

-if harnessed to solar geothermal or wind power, the Hydrogen could be free.(Iceland is banking on it!)

2) Stripping Methane of Hydrogen: using steam to remove the 4 hydrogen atoms from CH4.

-still uses a fossil fuel, and releases Carbon Dioxide gas in the process.

Water Power: Hydro-power is a goodalternative energy source, becauseit is essentially unlimited.

-Direct hydro-power: using moving water to turn machinery, such as a mill.

-Hydro-electric power: using the powerof water to turn an electric generator,such as in a dam.

Hydroelectric Power Generation

Power is generated by harnessing the energy of falling water.

The greater the difference in waterlevel, the more energy

Outlook for Hydropower: The outlookis generally good for hydro-power,although there are a few drawbacks.

Dams prevent the migration of fish,and also prevent the natural flows ofrivers, causing sedimentation behindthe dam.

Water level

Original Level of Sediment

New level of Sediment

Dam

Water Flow

Tidal/Current Power: generation of electricity from movement of ocean tides or currents.

Rising tides are trapped behind a dam,then released to turn a generator.

Also some work on ocean buoys thatharness the movement of water to generate electricity.

Outlook: Generally good, but tidal energy can only be used in areas where tides are of sufficient heightto warrant an electrical station.High costs may be associated.

Offshore buoys would need electricaltransmission lines along the oceanfloor.

Wind Power: generation of electricityusing wind to turn turbines. Free energy, but needs to be in an area that has constant winds with enough velocity to warrant placingwindmills.

Best used in particular sites with a good steady supply of wind.

Outlook: Wind power will continue togrow, but in limited areas. Some disadvantages and concerns exist.

Windmills kill birds, and interfere withmigratory patterns.

Large windmill farms take up large areas of land.

Windmills also produce noise, which may be objectionable.

Biomass Energy: energy from organicmatter.

Probably the first source of energy for man, this energy is renewable and abundant.

Already in use in many places, such assugar plantations and saw mills.

Also includes the burning of urban waste, in “trash to steam” plants.

Outlook: Biomass fuel will continueto be a large part of the alternativeenergy picture. However:

Environmental degradation can and willoccur if the biomass is not harvested ina renewable manner.

Burning biomass causes pollution, especially air pollution, and leaves ashbehind. The ash can be very toxic.

Will the energy future include fossil fuels?

-There are a few “new” sources of fossil fuels which may play a role in the future.

-They are still NON-RENEWABLE.

-They still cause pollution (in varying amounts)

But there is a potential for LOTS of energy!

Oil Shale and Tar Sands

Deposits of sedimentary rock containingsignificant amounts of petroleum.

Oil Shale: yields as high as 14 galper ton of rock, 3 trillion barrels total(2/3 of which are in the U.S.)

Tar Sands: Known reserves in Canadaof 2 trillion barrels.

Problems with Oil Shale and Tar Sands

Both require extensive mining operations to be carried out. Some in protected areas.

Disposal of mine tailings/overburden (20-30%larger in volume than original rock.)

Possibility of acid mine drainage and runoff

Outlook: uncertain, at least until other possibilities are explored,and prices enable mining and proper reclamation of mined areas.

Methane Hydrates

White, ice-like compound consisting of Methane (CH4) and water.

A potential source of energy, as large as twice the known reserves of gas, oil, and coal COMBINED.

Found in very deep ocean sediments (over 1000 feet in depth)

Outlook:

Drilling technology has not caught up, and until it does, it is not possible to drill.

Methods to capture and transport the gas will be necessary.

Higher gas prices will be needed to supportthe large expense of exploration and drilling

The Future of Alternative EnergyAlternative energy sources will play larger roles in the future, but each needs to be utilized in a manner which damages the environment as little as possible.

Energy sources will need to be mixed,to use them to their maximum potential.