Renewable energy sources

Nowadays and predictions for the future

In the last 10 years, the Earth warmed up by 1C

Why can’t we notice the change?The answer, according to a new paper

in Geophysical Research Letters, is that a lot of it is being stored in the deep ocean, more than a half-mile down. “We normally think about global warming as what we experience on the Earth's surface,” said co-author Kevin Trenberth, in an interview. If extra heat is temporarily stored elsewhere thanks to natural climate variations, we won't necessarily notice it. 

Consumption of energy till 2020

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Quadrillion Btu

History Projections

Solar, wind and waterWe don’t know how to store

electrical energy on a massive scale.

Michael Levi: Three Reasons Solar Will Succeed

• Solar can take advantage of improvements in materials, computing and nanotechnology in ways other technologies can't do nearly as effectively. Solar also has a host of initial niches it can grow in, from rooftop generation in places like California, to off-grid and micro-grid energy in often-sunny developing countries that lack good infrastructure. Solar is also a much better match for our energy demand than wind is. Solar power peaks when it's hot—exactly when people want to crank up their air conditioners. Wind power peaks in the middle of the night when people are using a lot less power.

How solar works

Powering devices with solar energy

Examples of gathering water energy• A hydroelectric dam captures energy from the movement of

a river. Dam operators control the flow of water and the amount of electricity produced. Dams create reservoirs (large bodies of calm water) behind them, which can be used for recreation, wildlife sanctuaries, and sources of drinking water.

• Wave power captures energy from waves on the surface of the ocean using a special buoy or other floating device.

• Tidal power captures the energy of flowing waters with the help of turbines as tides rush in and out of coastal areas.

Dam and generator collect water energy

Wind energy• Stand-alone wind turbines are typically used

for water pumping or communications. However, homeowners, farmers, and ranchers in windy areas can also use wind turbines as a way to cut their electric bills.

Is a wind turbine loud?

Heat from the Earth.• Geothermal energy is the heat from the Earth.

It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.

Heating a home with geothermal energy.

Geothermal in detail

Solar  Advantages:Energy is free although there is a cost of building

collectors, does not cause pollution, can be used in remote areas, can power low energy consuming devices, it is infinite

Disadvantages:

Can be gathered only during sunny days, collectors are expensive, relies on climate, it is hard to store solar energy, batteries are heavy.

WaterPros

• Provides water for 30-30% of the world’s irrigated land • Provides 19% of electricity

• Expands irrigation • Provides drinking water

• Supplies hydroelectric energy (falling water used to run turbines) • Easier for third world countries to generate power (if water source is

available) • It is cheaper

Cons • Destabilizes marine ecosystems

• Water wars (up river and down river; e.g., the water war between Georgia, Alabama, and Florida is ongoing)

• Dam building is very costly • People have to relocate

• Some dams have to be torn down (Some older ones are not stable.) • Restricted to areas with flowing water

• Pollution affects water power • Flooding of available land that could be used for agriculture

WindAdvantages

• Continuous sources of energy • Clean source of energy

• No emissions into the atmosphere • Does not add to thermal burden of the earth

• Produces no health-damaging air pollution or acid rain • Land can be sued to produce energy and grow crops simultaneously

• Economical • Benefits local communities (jobs, revenue)

Disadvantages • For most locations, wind power density is low

• Wind velocity must be greater than 7 mph to be usable in most areas • Problem exists in variation of power density and duration (not reliable)

• Need better ways to store energy • Land consumption

Geothermal• Advantages

• Significant Cost Saving • Reduce reliance on fossil fuels

• No pollution• Direct use

• Job creation/ economic benefits• Disadvantages• Not widespread• High costs

• Can run out of steam• Suited to particular region• May release harmful gases

• transportation

Potential Sources of Energy when Fossil Fuels Run Out

NUCLEAR FUSION Magnetic Plasma Confinement,

Inertial FusionNUCLEAR FISSION

Waste &Nuclear Proliferation