6.02 - Renewable Energy I

(pg. 3) Advantages of Wind Energy

-Can be constructed quickly -Generates no greenhouse gases -Can be placed on land or in large bodies of water -Land below turbine can be used for agriculture -Can be done at small scale or large scale -Most cost competitive of renewable energy sources (least expensive)

(pg. 2) Disadvantages of Solar Energy

-Construction of large-scale power plants disrupts ecosystems. -Weather affects the quality of how solar cells work. -Water is often necessary to clean solar panels, which may strain aquifers in water-scare regions.

(pg. 4) Disadvantages of Water Energy

-Damns can change path or temperature of river -Can affect recreation with restricted shoreline access -Can change tidal levels and increase turbidity in coastal ecosystems -Expensive to build compared to other energy plants -Not available to every geographic location -Building a dam and reservoir can flood habitat

(pg. 4) Advantages of Water Energy

-Hydropower from wave energy does not produce greenhouse gases -Water movement is predictable, making it easier to use for energy -Low cost maintenance compared to other energy plants

(pg. 3) Disadvantages of Wind Energy

-Relies on consistent wind above a certain speed -May produce noise -Qualifies as visual pollution (depending on observer) -May be dangerous for bird populations and species living in the region

(pg. 2) Advantages of Solar Energy

-Solar power plants produce no air, water, or soil pollution. -Solar cells can be used in isolated locations. -Solar power plants produce little noise pollution.

(pg. 4) List what is used to harness the energy from tides or currents:

-barrages: a dam constructed near the mouth of a tidal body; the tide rises and falls, moving water through tunnels in the damn -tidal fences: vertical posts in a fence with turbines powered by water -tidal turbines: similar to wind turbines in structure, but made for the water

(pg. 2) Solar Homes: Active solar homes

Active solar homes absorb and collect energy from the sun with panels placed directly on the roof. These panels store and circulate the energy using a flat-plate solar panel. The system also has insulation that keeps the heat in and prevents freezing in the winter. Transportation tubes of water within the system remove heat from the absorber, which can be used for baths or showers, to heat a whole building, or even a swimming pool.

(pg. 3) How do wind turbines capture wind energy?

As wind passes around both sides of the blade, the difference in air pressure causes the blades to spin around the center of the turbine. Turbines turn a shaft that spins gears. These gears rotate fast enough to generate electricity.

(pg. 4) hydroelectric power: Which of the following is the best explanation for why hydropower is considered renewable?

Because water can be recycled over and over.

(pg. 4) hydroelectric power: What new innovations are protecting migrating fish?

Fish ladders and fish friendly turbines

(pg. 5) discouraging factors on the shift to clean energy: No funds for structure

If a country is struggling economically, or its residents have already invested in a fossil fuel infrastructure, it will be very difficult to raise funds or get support for additional monies to build new clean energy infrastructure.

(pg. 2) Photovoltaic Cells: What are the advantages of using PV panels for energy?

It is clean energy with no greenhouse gas emissions and no moving parts.

(pg. 3) Where can wind turbines be placed to capture wind?

Offshore in oceans or large lakes, hillsides, deserts, or across prairies

(pg. 2) Solar Homes: Passive solar homes

Passive solar homes use the angle of the sun and the position of a building to absorb heat. The building usually needs to be south facing for the best sunlight. The floors and walls of the building absorb solar heat, which radiates outward to heat the rest of the building. Good insulation within the building prevents heat loss in the winter, and insulated shades and overhangs can block out the summer sun.

(pg. 2) Photovoltaic Cells: How is sunlight converted to electricity using PV panels?

Photons free electrons within the semiconductor of a PV panel.

(pg. 5) discouraging factors on the shift to clean energy: Small-scale versus large-scale options

Small-scale wind and hydropower systems can be too expensive for the typical consumer. This limits wind and hydropower's ability to be used directly. While solar panels can be put directly on roofs, single home versions of wind or water energy are more difficult to implement. For some countries, large utility grids that cover all regions of their country are too expensive. These regions are looking for direct energy options for local communities to meet energy needs.

(pg. 5) encouraging factors on the shift to clean energy: Ease of use in developing countries

Solar energy is particularly helpful in developing countries. Solar energy allows families to control their own individual power source. Using a photovoltaic panel the size of two pizza boxes, a family can generate enough energy to pump water and power lights. Solar cookers can also be helpful devices in developing countries. They rely entirely on the energy of the sun and cost nothing other than the initial investment in the cooker. Rather than chopping firewood, which contributes to deforestation, desertification, and indoor air pollution, solar cookers use the energy of the sun to heat food.

(pg. 2) Explain what electricity costs depend on.

Some energy companies are giving residents the option of selecting where their energy is sourced from—fossil fuels or clean energy, or a combination of both. Their electricity costs depend on the choices and percentages they select from each energy type. This is referred to as green power purchasing.

(pg. 2) Concentrating Solar Power Plants: True or False? In parabolic troughs, sunlight reflects off mirrors heating a liquid in a receiver tube; the heated liquid turns water to steam, which runs a turbine that spins an electricity generator.

TRUE

(pg. 4) hydroelectric power: True or false? Flowing water moves turbines and uses generators to produce electricity, which is similar to how wind produces energy.

TRUE

(pg. 5) encouraging factors on the shift to clean energy: Decreasing costs of clean energy

The cost of renewable energy has declined rapidly in the last decade. This has brought the prices of clean energy down to the more affordable prices of fossil fuels. -6 cents per kilowatt-hour for utility-scale photovoltaic (PV) solar power -9 cents per kilowatt-hour for onshore utility-scale wind energy -0.85 cents per kilowatt-hour for hydroelectric or hydrokinetic power -Between 3 and 17 cents per kilowatt-hour for fossil fuel-powered energy

(pg. 6) Describe two potential approaches to harvesting tidal energy.

The first potential solution is a floating platform to which two rotors are mounted. The rotor's turbine produces electricity, which moves into the machine, where it's transformed and stacked up to bring back and transfer to the energy grid. The second potential solution is a device called the penguin with a large pendulum inside a ship. And as the ship moves, so this pendulum turns horizontally, generating electricity.

(pg. 5) encouraging factors on the shift to clean energy: Increased clean energy legislation

There are many countries making new commitments to clean energy and net zero-emissions, including the United States. This includes new legislation that repairs and invests in new infrastructure to increase clean energy options. Germany has implemented renewable energy goals to cut its greenhouse gas emissions to 1990 levels.

(pg. 6) How do these tidal system innovations prevent harm to coastal ecosystems?

They do not change the volume of water, or the patterns of waves or tides that move into coastal ecosystems.

(pg. 6) Explain two positive advantages of using the tidal energy systems in the video.

Tidal energy is a clean energy source and does not release carbon emissions. Since it floats on the water's surface and uses natural tidal and wave action, it has minimal effects on marine ecosystems.

(pg. 2) Concentrating Solar Power Plants: What are the advantages of using concentrating solar plants for energy?

Water in the system is recycled, and the heated fluid can be stored for night time use.

(pg. 5) discouraging factors on the shift to clean energy: Past constraints are not forgotten

a constraint of using solar energy was the inability to use solar energy at night. However, better energy storage during the day has taken care of that consideration. Another source of resistance to solar energy was the cost of installation. The mass production of the panels was expensive. The cadmium and other metals used to make PV panels was costly as well. Increased demand, innovation, competition, and supply have lowered these costs. More clean energy incentives have lowered the cost of solar installation further. More often, the money saved in long-term energy costs outweighs the money spent for solar energy set-up.

passive solar home

a home designed and constructed to maximize south-facing exposure without moving parts

active solar home

a home that includes special technologies to collect and store sunlight energy using moving parts

(pg. 3) Watch the video on wind turbines and explain how much energy they can create.

a small wind farm can generate enough electricity to power more than 9,000 homes, and larger farms can provide much more clean energy for our homes and businesses.

photovoltaic (PV) cells

an electronic component that generates electricity when exposed to particles of light

clean energy

energy derived from renewable, zero-emissions sources

(pg. 4) Watch the video on hydrokinetic energy and explain how it works.

extracting power from moving water. Currents and tides can also spin a turbine in various directions as water moves through an ocean power device, generating electricity.

utility-scale

power plants of at least one megawatt (1,000 kilowatts) of total electricity generating capacity

green power purchasing

represents a sale of electricity generated from renewable energy resources by a local utility or power service provider

(pg. 2) __________ energy converts sunlight into electricity.

solar

(pg. 5) discouraging factors on the shift to clean energy: Location

some places in the world are better than others for accessing an energy source. Constantly moving wind or water can provide a large amount of energy, but only certain locations and conditions make it feasible to construct and maintain a wind or hydropower energy plant. For example, there must be a large range of tide and strong tidal flow with a large volume of water for tidal energy. Environmental impacts must be evaluated, too, because some tidal power plants use a dam or tidal wall, which affect local estuaries. Not all geographic locations can support solar power either.

concentrating solar power

technologies that use mirrors to focus the sun's light energy to create steam to drive a turbine or engine that generates electricity

solar energy

the energy harnessed from radiant light and heat from the sun

wind energy

the energy that is generated from the movement of air particles

hydropower

the use of falling or quickly moving water to generate electricity