RENEWABLE ENERGY

HMMMM.... If nonrenewable resources are resources that cannot be replaced in a short period of time, what are renewable resources?

Renewable Energy  Renewable energy is energy from sources that are constantly being formed.  Types of renewable energy include: solar energy wind energy the power of moving water Earth’s heat  All sources of energy, including renewable sources, have some effect on the environment.

Alternative Energy  To achieve a future where energy use is sustainable, we must make the most of the energy sources we already have and develop new sources of energy.  Alternative energy describes energy that does not come from fossil fuels and that is still in development.  source must be cost effective  environmental effects of using must be acceptable

Solar Energy-Power from the Sun  Nearly all renewable energy comes directly or indirectly from the sun.  Passive solar energy is used every day, when the sun shines on a window and heats the room.  Solar energy can also be used indirectly to generate electricity in solar panels.

Active Solar Heating  runs on nonpolluting power from the sun  expensive investment – can take 3-5 years to pay off  extended periods of sunshine required to produce electricity  energy is stored in batteries, which supplies electricity when the sun is not shining

Solar Cells  very small current – a small city would require hundreds of acres of solar panels  solar roadways?  Currently, solar cells provide energy for more than 1 million households in developing countries, where energy consumption is minimal and electricity distribution networks are limited. Solar Roadways

Passive Solar Heating  the use of sunlight to heat buildings directly  Northern Hemisphere - south facing windows receive the most solar energy - passive solar buildings have large windows that face south  avg. household could reduce its energy bills by using any of the passive solar features shown.

Wind Power  converts the movement of wind into electric energy  the fastest growing energy source in the world  wind farms supply electricity to thousands of homes  take up little space - some farmers add wind turbines to their land and still use the land for other purposes  cost of wind power has been steadily falling as wind turbines have become more efficient

Jersey Atlantic Wind Farm 1 st wind farm to be built in NJ and 1 st coastal wind farm in US 5, 380-foot turbines produces approx. 19 million kWh emission-free electricity per year – enough to power 2,500 homes In the future, electricity generated from wind farms may be used to produce hydrogen from water.

Biomass-Power from Living Things  plants, wood, manure, or any other organic matter that is used as an energy source  fossil fuels are nonrenewable biomass energy sources  renewable biomass fuels, such as wood and manure, are major sources of energy in developing countries  more than half of all wood cut in the world is used as fuel for heating and cooking

Biomass-Power from Living Things  harmful air pollution may result from burning wood, manure and other matter  trees being cut down faster than they grow will result in habitat loss, deforestation and soil erosion  50% of wood cut in the world is used for heating and cooking

Biodiesel renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant grease for use in diesel vehicles

Methane Gas  made when bacteria decompose (breakdown) organic waste  can be burned to generate heat or electricity  In China, more than 6 million households use biogas digesters to ferment manure and produce gas for heating and cooking.  Some landfills in the US generate electricity by using the methane from the decomposition (breakdown) of trash.

Alcohol  Liquid fuels can be made from biomass  ethanol, an alcohol, can be made from corn  Gasohol - blend of gasoline and ethanol - produces less air pollution than burning fossil fuels  Some states require the use of gasohol in vehicles as a way to reduce air pollution.  our gas is E10 – 10% ethanol and 90% gasoline

Hydroelectricity-Power from Moving Water  dam built across a river to hold back a reservoir of water  Provides 20% of the world’s electricity.  water released from reservoir to turn a turbine, which generates electricity

The Benefits of Hydroelectric Energy  expensive to build, but inexpensive to operate  no air pollution  last much longer than fossil fuel-powered plants  dams also provide flood control and water for drinking, agriculture, industry, and recreation

Disadvantages of Hydroelectric Energy  a dam changes a river’s flow  a reservoir floods large areas of habitat above the dam and water flow below the dam is reduced  disrupts ecosystems downstream  example - salmon fisheries of the northwestern US have been destroyed by dams that prevent salmon from swimming upriver to spawn

Disadvantages of Hydroelectric Energy  When the land behind a dam is flooded, people are often displaced.  If a dam bursts, people living in areas below the dam can be killed.  River sediments build up behind the dam instead of enriching land farther down the river, making farmland below the dam less productive.  Recent research has also shown that the decay of plant matter trapped in reservoirs can release large amounts of greenhouse gases-sometimes more than a fossil-fuel powered plant.

Modern Trend  in the US, large dam construction is probably over  modern trend is micro-hydropower - electricity produced in a small stream without having to build a big dam  turbine may float in water – doesn’t block river  cheaper than large hydroelectric dams  permits energy to be generated from small streams in remote areas

Geothermal Energy-Power from the Earth  Geothermal energy is the energy produced by heat within the Earth.  US - the world’s largest producer of geothermal energy  although it is considered a renewable resource, the water that is used must be managed carefully so that it is not depleted

Geothermal Energy-Power from the Earth 1)Steam rises through a well 2)Steam drives turbines, which generate electricity 3)Leftover liquid is pumped back into the hot rock 4)Leftover liquid, water, is returned to Earth’s crust because it can be reheated by geothermal energy and used again.

Geothermal Heat Pumps: Energy for Homes More than 600,000 homes in the US are heated and cooled using geothermal heat pumps (a loop of piping that circulates a fluid underground). 1) In the summer, the ground is cooler than air and the fluid cools the home. 2) In the winter, the ground is warmer than air, and the fluid warms the home.

Tidal Power  works much like a hydroelectric dam  2 types – turbine or dam  at low tide, a gate opens and the water comes in and spins a turbine that generates electricity  cost of building and maintaining tidal power plants is high, and there are few suitable locations

Tidal Power

Hydrogen-A Future Fuel Source?  Hydrogen, the most abundant element in the universe, can be burned as a fuel.  does not contain carbon, so it does not create air pollution  a fuel cell combines hydrogen with oxygen from the air to produce electricity  water is the only byproduct

Hydrogen-A Future Fuel Source?  can be produced by using electricity to split molecules of water (H 2 O) – not a good choice if fossil fuels used to generate electricity  can be made from any material that contains a lot of hydrogen  may be able to grow plants to produce hydrogen someday

Energy Efficiency  preventing the wasteful use of energy  more than 40% of all commercial energy used in the US is wasted  increasing efficiency may involve sacrifices and/or investments in new technology  There are two main ways to reduce energy use: lifestyle changes increases in energy efficiency

Energy Efficiency internal combustion engines that power most vehicles are inefficient and produce air pollution hybrid cars are examples of energy-efficient vehicles - use small, efficient gasoline engines most of the time

Hybrid Cars convert some energy of braking into electricity - store this energy in the battery gasoline engine is sometimes shut off to save fuel - when the car is stopped at a red light aerodynamic in design – needs less energy to accelerate

Energy Conservation  Energy conservation - saving energy by reducing energy use and waste  using energy-efficient devices and wasting less energy  1975 – conservation made more energy available in the US than all alternative energy sources combined

Cities and Towns Saving Energy  Osage, Iowa - 3,600 people.  saved more than $1 million/year in energy by conservation  economy improved  businesses relocated to the area to take advantage of low energy costs  unemployment rates declined Running on renewable energy, Burlington, Vermont powers green movement forward

Conservation Around the Home  average household in the U.S. spends more than $1,200 on energy bills/year  much of the energy from homes is lost through poorly insulated windows, doors, walls, and the roof  simple lifestyle changes can help save energy  using less of any resource saves energy

Conservation Around the Home