Chapter 4 Quiz

disruption of the water flow - slowing down of certain parts of the rivers' reaches sedimentation behind the dam - this puts pressure on the structure changes in water temperatures resulting from changes in water depth and speed obstacles that migratory fish have to pass around on their way to spawning grounds disruption of aquatic habitats disruption of wildlife corridors as reservoirs are constructed and lands are flooded

Concerns over dams and reservoirs include

cost being a past factor, and more recently electricity produced by solar and wind

Currently, renewable energy resources account for around 8% of the world's energy usage (5% for the US) - there are a number of reasons for these statistics what are they?

8% of the world's energy usage and 5% for the US

Currently, renewable energy resources account for around what percent?

Solar energy, wind power, hydroelectricity, geothermal energy, tidal power/wave energy, nuclear power

Examples of alternative ("carbon neutral") energy resources that are being explored by different countries, town/city managers, and individuals include what?

electricity grid, especially in developed countries with large markets - in the grid-connected PV systems, use of energy storage is optional

Many residential systems are connected to what?

direct current (DC) power

Modern solar cells produce what?

nuclear power stations provided about 5.7% of the world's energy and 13% of the world's electricity in 2012

Most nuclear power stations utilize the nuclear fission of uranium (and other elements in the actinide series) -

having excess capacity storage that can include pumped-storage hydroelectricity, exporting and importing power to neighboring areas, or reducing demand when wind production is low- can be used to migrate problems

Power management techniques are

alternative ("carbon neutral") energy resources

many countries are exploring ways to phase out fossil fuels and switch to what?

to change our energy policies with regard to fossil fuel usage (on both a large-scale and on an individual-scale)

scientists and others have suggested that one way to stop and possibly even reverse anthropogenic climate change is what?

Charles Fritts in the 1880's

the first solar cell was constructed by who?

1%

the prototype selenium cells converted less than what percent?

a device that converts light into electrical current using the photovoltaic effect

what is a solar cell, or photovoltaic cell (PV)?

can produce a cheap source of power downstream flooding is reduced provides a year-round source of water for irrigation of cropland reservoir is useful for recreation and fishing

Advantages of large dams and reservoirs are

solar energy

Arguably the most abundant and sustainable energy resource is what?

Run of the river systems - here the natural flow of the water is harnessed - there is no impoundment of the water in a reservoir - power generation is variable with spring melt generating the highest power levels Reservoir systems - in this type of system, the water is held behind the dam and released when needed - power generation can, and is controlled for times of peak demand - this type of system is used for more consistent power demands

Dams on rivers and streams come in two major forms

83

Denmark is generating more than a quarter of its electricity from wind power and how many countries around the world are using wind power as a supplement to their electricity grid?

from the sun or indirectly harnessed from wind, flowing water, and/or biomass

How can solar energy be harnessed?

dams on rivers (both large and small) and streams

Hydroelectricity/hydropower is associated with the construction of what?

silver selenide instead of copper oxide

In 1931, the German engineer Bruno Lange developed a photo cell using what?

2.5%

In 2010 wind energy production was over what percent of of the total worldwide electricity usage?

satellites, lighthouses, or in developing countries, batteries or additional power generators

In certain applications, what is used as backup?

these processes can includes nuclear fission, nuclear (radioactive) decay, and nuclear fusion

Nuclear power or nuclear energy, involves the harnessing of exothermic nuclear processes, to generate electricity

this type of wind farm takes advantage of winds that are typically steadier and stronger than their land counterparts

Offshore wind power describes the construction of wind farms in bodies of water which are used to generate electricity

noise and visibility (on hilltops and mountains)

Opposition to wind power has mainly come in the form of concerns over the wind turbines because why?

It is an abundant and renewable energy resource It has a medium to high net energy yield (depending on technology and application) It produces little to no direct greenhouse gas emissions and other air pollutants PV cells and solar arrays are relatively easy to install and expand upon The cost of these systems (especially the newer ones) have become more competitive

Some of the advantages of solar power are...

These systems need constant sun/solar access Some designs have a low net energy yield - some only convert 20% of incoming solar energy Some designs need electricity storage and backup systems Fossil fuels are used to manufacture and transport solar panels and arrays Some solar cells contain toxic and hazardous materials that must be recovered before they are discarded/disposed of

Some of the disadvantages of solar power are...

describes the difference between the energy needed to make the resource available and the energy it provides by its application

What does and energy yield do?

net energy yield

What is an important measure of an energy resource?

solar and wind energy

What kinds of energy have a high energy yield?

The 1930's and 1940's

What was the era of large dam construction in the US

atmospheric pressure gradients which results from unequal heating of the Earth's surface and the generation of areas of high and low atmospheric pressure

Wind is generated in response to what?

wind energy into a useful form of energy (typically electricity)

Wind power is the conversion of what?

Windmills for mechanical power, wind-pumps for water pumping or drainage, or sails to propel ships

Wind power is the conversion of wind energy into a useful form of energy (typically electricity) - this can be done in a number of ways which are...

plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, and uses little land

Wind power, as an alternative to fossil fuels, is what?

large solar thermal plant opened in the Mojave Desert The Desert Sunlight Solar Farm in Riverside County, California The Topaz Solar Farm in San Luis Obispo County, California The Blythe Solar Power Project in Riverside County, California

Within the US there are several recent solar plants that are supplying solar power to the electricity grid which are...

which fluctuates with the intensity of incident sunlight

direct current (DC) power fluctuates what?