Energy sources Flashcards
(15 cards)
Define renewable energy and non-renewable energy
Renewable: Energy that comes from a renewable source which is replaced by natural processes at about the same rate at which it is being used. It comes from a resource that can be replenished naturally over time. It won’t run out.
Non-renewable: Energy that comes from a non-renewable source that takes a very long time to be replaced. It is from a source that we use faster than it’s naturally made or replenished. It will run out and will not be replenished in our lifetimes.
List examples of renewable energy sources
- Solar energy: Solar panels
- Wind energy: Wind turbines
- Geothermal energy: Heat extracted from underground.
- Hydropower: A dam that produces energy.
List examples of non-renewable energy sources
Oil, natural gas, coal, nuclear energy
How do solar panels convert sunlight into electricity?
Solar energy is produced into usable energy when the sun shines onto a solar panel, and the energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that are moving in response to an internal electrical field within the cell, which causes electricity to flow.
What form of energy is sunlight, and what form does it become after conversion in a solar panel?
Sunlight is both a form of heat and light energy, but also electromagnetic energy.
After conversion in a solar panel, sunlight is converted into electrical energy.
How is electricity generated from fossil fuels like coal, oil, or natural gas?
Fossil fuel power plants burn coal or oil to create heat which is in then used to generate steam to drive turbines, generating electricity.
What is the role of combustion in fossil fuel power plants?
(The main role of combustion is to burn the fossil fuels to produce heat energy)
In fossil fuel power plants, combustion’s primary role is to release the chemical energy stored within the fuel (coal, oil, or gas) and convert it into heat. The heat is used to produce steam, which drives turbines connected to generators to produce electricity.
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The combustion system, typically made up of a ring of fuel injectors that inject a steady stream of fuel into combustion chambers where it mixes with the air.
The combustion produces a high temperature, high pressure gas stream that enters and expands through the turbine section.
What do turbines and generators do in a fossil fuel power plant?
The heat from combustion is used to produce steam.
Turbines convert the energy from hot gases (like steam) into mechanical energy (rotation), and generators then convert this mechanical energy into electrical energy
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The hot steam is sent through controlling valves to a turbine. As the steam expands and cools, its energy is transferred to the turbine blades which turn a generator. The spent steam has very low pressure and energy content; this water vapor is fed through a condenser, which removes heat from the steam.
What is the main difference between renewable and non-renewable energy sources?
Renweable energy sources come from natural resources that can be replenished again and again, while non renewable energy sources come from resources that are limited, cannot be replished and will run out eventually.
What are some environmental drawbacks (disadvantages) of using fossil fuels to generate electricity?
Fossil feuls pollute the environment:
- Climate Change
Burning fossil fuels releases large amounts of carbon dioxide (CO2), a greenhouse gas, into the atmosphere. This traps heat and contributes to global warming.
- Air Pollution
Fossil fuel combustion also releases other harmful pollutants, such as sulfur dioxide and nitrogen oxides.
Why can renewable energy sources like solar and wind be less reliable?
Solar energy is not always 100% reliable because their output depends on how much sunlight there is. Sometimes their reliablity is impacted by the amount of sunlight a solar panel is receiving. Cloudy conditions and storms can affect the amount of sunlight input in the solar panel, generating less electricity.
Wind energy’s reliability is affected by how windy the conditions are, meaning it’s not consistently available when needed. Wind turbines do not generate electricity when it’s not windy. They also don’t generate electricity when the wind speed drops below a certain level. They rely on the movement of air, or wind, to turn their blades. Without wind, the blades won’t spin and won’t generate electricity.
What is one advantage of fossil fuels in terms of energy output and reliability?
Fossil feuls are much more reliable than renewable energy sources because like solar and wind energy, they don’t rely on weather patterns to work. Whether day or night, fossil fuel can provide a stable and continuous energy supply. Their output is always 100% guaranteed no matter when.
How can renewable energy sources help reduce greenhouse gas emissions?
Because renewable energy sources substitute fossil fuels, and emit little to no greenhouse gases or pollutants into the air. They do not rely on burning fuel, so they don’t release CO₂ during operation. By using renewable energy sources, we reduce the amount of carbon dioxide and other greenhouse gases entering the atmosphere.
Which energy sources tend to be more cost-effective in the short term, and why?
In the short term, wind and solar energy are considered more cost-effective because running costs are much lower compared to fossil fuels, and also don’t use fuel which needs to be purchased.
What is an example of a non-renewable energy source that is still widely used? Why is it still chosen despite its environmental impact?
Coal: Provides affordable, reliable and constant power that is available on demand to meet energy consumption needs.
Oil: Still used because of its High Energy Density, cheap costs and reliability, and ease of transport. Oil is incredibly energy-dense, meaning a small amount of oil can produce a large amount of energy.
