Environmental Science: Energy Efficiency

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Questions and Answers

What is the primary focus of energy efficiency?

Total energy output compared to useful energy produced

Minimizing total energy consumption

Useful energy produced compared to total energy output (correct)

Maximizing heat production

Which of the following methods can improve energy efficiency in industry?

Implementing lower efficiency motors

Increasing insulation in buildings

Using cogeneration systems (correct)

Reducing the number of energy-efficient fixtures

Which fuel type is highlighted as the most significant source of electricity in Canada?

Coal

Wind

Hydropower (correct)

Natural gas

What is a benefit of hybrid-electric vehicles in terms of energy efficiency?

They improve fuel economy. Signup and view all the answers

Which of the following is NOT considered a sustainable energy source?

Nuclear energy Signup and view all the answers

What defines sustainable energy in terms of generation and consumption rates?

Generation rate is equal to or greater than consumption rate Signup and view all the answers

Which statement best describes large-scale hydropower?

It uses high dams to create reservoirs but has ecological impacts. Signup and view all the answers

What percentage of Canada's electrical generation comes from hydropower?

60% Signup and view all the answers

What is one of the major drawbacks of large-scale hydropower?

It can cause flooding and displaces people. Signup and view all the answers

Which of the following describes small-scale (run-of-river) hydropower?

Has lower environmental impact but is less reliable. Signup and view all the answers

What was the installed capacity of wind power in Canada by 2020?

13,588 MW Signup and view all the answers

What change occurred in the cost of wind energy from 2009 to 2020?

Declined by 67% Signup and view all the answers

How does wind energy operate in relation to turbine blades?

Wind flows over the blades, influencing their movement. Signup and view all the answers

What is the primary source of energy for wind turbines?

Kinetic energy of wind Signup and view all the answers

Which of the following statements about wind energy is true?

Wind energy has a lifespan of more than 25 years. Signup and view all the answers

Which of these is NOT considered a disadvantage of wind energy?

High initial investment cost Signup and view all the answers

What are the two major types of solar energy technologies?

Thermal and Photovoltaic Signup and view all the answers

How many Solar PV farms in Canada have a capacity greater than 1 MW?

138 farms Signup and view all the answers

What is a disadvantage of active solar energy systems?

They require maintenance and repair. Signup and view all the answers

Which of the following is a source of geothermal energy?

Heat stored in the ocean Signup and view all the answers

Which factor is critical for the efficiency of passive solar energy systems?

Access to sunlight 60% of the time Signup and view all the answers

What is a common environmental concern associated with the production of solar photocells?

Release of toxic chemicals Signup and view all the answers

What characterizes biomass as a source of bioenergy?

It is derived from recently living organisms. Signup and view all the answers

Which of these statements is NOT a common limitation of solar energy?

It cannot be installed in urban areas. Signup and view all the answers

Which statement correctly describes biofuels?

They include solid, liquid, and gaseous forms. Signup and view all the answers

What is a key advantage of using solar energy?

It can be stored long-term and released on demand. Signup and view all the answers

What is biodiesel primarily derived from?

Vegetable oils or animal fats Signup and view all the answers

Which province in Canada is noted for having significant forestry activities related to bioenergy?

British Columbia Signup and view all the answers

Which of the following categories of biofuels is specifically used in spark ignition engines?

Bioethanol Signup and view all the answers

What was Canada's ethanol production in liters for the year 2020?

1.6 billion liters Signup and view all the answers

Which is a significant environmental concern related to biomass energy?

Soil degradation Signup and view all the answers

Which type of biomass does the pulp and paper industry primarily consume?

Industrial wood waste Signup and view all the answers

What kind of feedstock can be used to produce biodiesel?

Animal fats and non-edible waste greases Signup and view all the answers

What is one potential consequence of increased bioenergy production?

Indirectly increase GHG emissions due to land use changes Signup and view all the answers

Study Notes

Course Information

Course Title: Environmental Science
Course Code: CENV 1119
Instructor: Dr. Ali Al Jibouri, P.Eng.
Office: SW01-1580
Email: [email protected]

Energy Efficiency

Energy Efficiency = Useful energy produced by a device compared to total energy output (including heat).
To improve net energy efficiency:
- Minimize the number of conversion steps.
- Maximize the efficiency of each step.
Examples:
- Fuel cell: 45-65%
- Steam turbine: 45%
- Human body: 20-25%
- Fluorescent light: 22%
- Internal combustion engine (gasoline): 20-25%
- Incandescent light: 5%

Net Energy Efficiency

Electricity from a nuclear power plant:
- Uranium (100%) → Uranium mining (95%) → Uranium processing and transportation (57%) → Electricity (31%) → Waste heat (17%, 14%, 14%)
- Window transmission (85%) → Waste heat (90%) → Waste heat (100%)
- Sunlight (100%) → Window transmission (90%) → Waste heat

Improving Energy Efficiency

Industry:
- Cogeneration
- Replace inefficient electric motors
- Higher efficiency lighting
Transportation:
- Increased fuel economy
- Hybrid-electric vehicles
- Fuel-cell vehicles
Building Design:
- Insulation
- Energy-efficiency standards for fixtures

Fuel Cells

A fuel cell stack combines hydrogen and oxygen chemically to produce electricity.
A fuel tank stores hydrogen gas or liquid, or solid metal hydride, which can be made from gasoline or methanol.
A turbo compressor pressurizes air to the fuel cell.
The traction inverter converts DC electricity from the fuel cell to AC for the electric motor.
An electric motor and transaxle turn the wheels.

Canada's Energy

Hydropower is the leading electrical energy source in Canada.
In 2019, 60% of Canada's total electricity generation came from Hydropower.

Sustainable Energy

General:
- Sustainable: Rate of generation is equal to or greater than the rate of consumption.
- Energy types:
  - Hydropower
  - Wind
  - Solar
  - Geothermal
  - Bioenergy
Hydropower:
- Large-scale hydropower creates a reservoir with high dams across major rivers, but this can lead to issues like flooding and ecological impacts on fish.
- Small-scale run-of-river hydropower employs a lower dam on small streams, reducing environmental impact but lowering reliability.
- Water flowing across dams creates kinetic energy; controlled flow spins turbines generating electricity.
Wind:
- The wind does not directly push the blades but passes by, and the air pressure differential across the blades creates thrust.
- 1998: 60 wind turbines = ~27 MW installed capacity
- 2020: 6,590+ wind turbines = ~13,588 MW installed capacity
- Canada ranks 8th in the world in wind use; 5% electricity in 2019; 67% decline in costs since 2009.
Solar:
- Solar energy includes heat and light radiation.
- Two major types: thermal and photovoltaic.
- Scalability of solar systems is easy (large or small). In 2019, 3,273 MW of solar capacity was installed.
Geothermal:
- Geothermal energy uses heat stored beneath the earth's surface or heat/energy absorbed from atmosphere and oceans.
- Natural underground steam can be used to generate electricity.
- Heating and cooling can be achieved using the temperature differential between outside air and the ground (or groundwater)
Bioenergy:
- Bioenergy utilizes biomass (organic matter from plants) and biofuels, which are fuels produced from recently living organisms or their by-products (e.g., manure).
- Biomass feedstock includes carbohydrates (e.g., sugar), lignocellulose (e.g., crops), and other sources.
- Processing techniques include combustion, biochemical processing, pyrolysis, hydrolysis/fermentation, and gasification.
- Biofuels include biodiesel (from vegetable/animal fats) for compression engines.
- Biofuel include ethanol (produced from fermentable sugars like sucrose/glucose) for spark-ignition engines.
- Huge variety of source materials.
- Industrial wood waste is a significant biomass source.

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Description

This quiz explores the concept of energy efficiency within environmental science. It covers examples of energy-producing devices and their efficiency rates, as well as strategies for improving net energy efficiency. Test your understanding of these crucial topics in energy management.