Renewable energy is energy derived from natural sources that are replenished at a higher rate than they are consumed. Sunlight and wind, for example, are such sources that are constantly being replenished. Renewable energy sources are plentiful and all around us.
Fossil fuels - coal, oil and gas - on the other hand, are non-renewable resources that take hundreds of millions of years to form. Fossil fuels, when burned to produce energy, cause harmful greenhouse gas emissions, such as carbon dioxide.
Generating renewable energy creates far lower emissions than burning fossil fuels. Transitioning from fossil fuels, which currently account for the lion’s share of emissions, to renewable energy is key to addressing the climate crisis.
Renewables are now cheaper in most countries, and generate three times more jobs than fossil fuels.
Here are a few common sources of renewable energy:
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SOLAR ENERGY
Solar energy is the most abundant of all energy resources and can even be harnessed in cloudy weather. The rate at which solar energy is intercepted by the Earth is about 10,000 times greater than the rate at which humankind consumes energy.
Solar technologies can deliver heat, cooling, natural lighting, electricity, and fuels for a host of applications. Solar technologies convert sunlight into electrical energy either through photovoltaic panels or through mirrors that concentrate solar radiation.
Although not all countries are equally endowed with solar energy, a significant contribution to the energy mix from direct solar energy is possible for every country.
The cost of manufacturing solar panels has plummeted dramatically in the last decade, making them not only affordable but often the cheapest form of electricity. Solar panels have a lifespan of roughly 30 years, and come in variety of shades depending on the type of material used in manufacturing.
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WIND ENERGY
Wind energy harnesses the kinetic energy of moving air by using large wind turbines located on land (onshore) or in sea- or freshwater (offshore). Wind energy has been used for millennia, but onshore and offshore wind energy technologies have evolved over the last few years to maximize the electricity produced - with taller turbines and larger rotor diameters.
Though average wind speeds vary considerably by location, the world’s technical potential for wind energy exceeds global electricity production, and ample potential exists in most regions of the world to enable significant wind energy deployment.
Many parts of the world have strong wind speeds, but the best locations for generating wind power are sometimes remote ones. Offshore wind power offers tremendous potential.
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GEOTHERMAL ENERGY
Geothermal energy utilizes the accessible thermal energy from the Earth’s interior. Heat is extracted from geothermal reservoirs using wells or other means.
Reservoirs that are naturally sufficiently hot and permeable are called hydrothermal reservoirs, whereas reservoirs that are sufficiently
2. PASSIVE SOLAR HEATING
Passive solar heating – captures sunlight directly with a structure
and converts it to low-temperature heat for space heating.
Advantages Disadvantages
1. save money 1. expensive for initial costs
2. create 2-5 more jobs/unit of electricity 2. aesthetically not pleasing
3. eliminate/reduce fossil fuels 3. latitude
4. less pollution
5. less environmental damage
4. ACTIVE SOLAR HEATING
Active solar heating – specially designed collectors absorb solar energy and
fan/pump distributes energy to parts of a building to meet space/water heating
needs.
Advantages Disadvantages
1. save money 1. expensive for initial costs
2. create 2-5 more jobs/unit of electricity 2. aesthetically not pleasing
3. eliminate/reduce fossil fuels 3. latitude
4. less pollution
5. less environmental damage
6. SOLAR POWER TOWER
Solar Power Tower –huge arrays of computer controlled mirrors that
track the sun and focus sunlight on a central heat collection tower.
(Mojave desert in California)
Advantages Disadvantages
Cost will drop as Costs 8X more to
Technology improves build
8. SOLAR THERMAL PLANT
1Solar Thermal Plant – sunlight is collected and focused on oil-filled pipes
that run through the middle of curved solar collectors.
Advantages Disadvantages
1. Can generate temperatures high 1. central receivers are
enough for industrial processes expensive to operate.
2. can supply back-up electricity
3. cheaper than nuclear
10. SOLAR COOKER
1Solar Cooker – focuses and concentrates sunlight in a box typically covered in
glass to trap infrared radiation waves to cook food in rural villages in developing
countries.
Advantages Disadvantages
Does not reduce deforestation 2-4 hours to cook average meal.
12. SOLAR HYDROGEN
Solar-Hydrogen – Water can be split into gaseous hydrogen and oxygen.
It is in its infancy. So far… we can create fuel cells where hydrogen and oxygen
combine to produce an electrical current, but it is difficult to store enough hydrogen
gas in a fuel tank for very long.
Politics and economics are “holding up” this technology.
R&D from government needed.
must convince energy companies and investors to $ into this type of power and
phase out fossil fuels.
must convince public to change over.
…Not Yet!
14. HYDROPOWER
1. Hydroelectric power plants – A dam is built across a large river to create a
reservoir. The higher the head, the greater the amount of power that can be
generated. Water is stored in a reservoir during low electricity production. Water
is released and flows are controlled as electricity demands peak. Water spins the
turbines in the “powerhouse”. Electricity is distributed to end user.
Examples – Aswan High Dam (Egypt) and Colorado River Basin (USA/Mexico)
Advantages Disadvantages
1. Moderate to high energy yield 1. create floods
2. low operating/maintenance costs 2. destroys habitats
3. low air pollution 3. uproots people
4. 2-10 times longer life than othe 4. 2-10 x longer lifespan than other
4. pesticides/algicides used
5. Power sources 5. Decreases fish harvests
17. TIDAL POWER
1Tidal Power- power created from tidal energy
Advantages Disadvantages
1. tidal energy spins turbines 1. few suitable sites
2. Construction costs high
19. BIOMASS
Biomass – organic matter in plants produced through photosynthesis and can be burned
directly as a solid fuel or converted into a gas or liquid fuel.
1. Burning wood
2. Agricultural Waste
a. Bagasse (sugar cane residue)
b. Straw
3. Urban Waste (WTE)
a. burning garbage
4. Biofuels
a. Biogas – a mixture of 60% methane and 40% carbon dioxide.
b. Liquid ethanol- (grain alcohol) – sugar + grain; mix gasoline + ethanol = gasohol
which can burned in conventional gasoline engines (super-unleaded)
21. BIOMASS
Advantages Disadvantages
1. potentially renewable resource 1. removal of trees depletes
soil nutrients
2. less air pollutants released 2. soil erosion (turbidity)
3. decrease in use of fossil fuels 3. flooding
4. moderate-high net energy yield 4. loss of wildlife habitats
5. large land areas needed
6. heavy pesticide/fertilizer use
7. reduces biodiversity
8. reduces ecological integrity
22. GEOTHERMAL
Geothermal Energy - Heat contained in underground rocks and fluid
that can be tapped for energy.
Extract dry steam, wet steam or hot water and can be used to heat
space or water.
“Potentially renewable resource”
22 countries currently use geothermal, it supplies 1% of world
energy. In the USA (44% geothermal energy produced worldwide)
geothermal electricity is produced mostly in Hawaii, California,
Nevada, and Utah.
23. GEOTHERMAL
Advantages Disadvantages
1. Reliable 1. Scarcity of reservoirs
2. Renewable 2. Deforestation to
3. Moderate Net Energy Yield build plants
4. 96% less CO2 emitted 3. Land subsidence
5. Competitive Cost 4. Noise, odor
25. SOLUTIONS FOR
SUSTAINABLE ENERGY
Improve energy efficiency
Increase local availability of renewable energy resources
Find transitional resources (natural gas, nuclear)
Government must promote R&D for alternative renewable energy resources.
Educate the public
All energy resources should compete in an open, free-market with NO government
control!
Government needs to implement constructive subsidies not destructive subsidies to
promote change, this will lead to conservation of resources and less over-
consumption.
