25-41 Renewable resources

APES 2024

Potentially renewable

Potentially renewable

an energy source that can be regenerated indefinitely as long as it is not overharvested

Nondepletable

an energy source that cannot be used up

Renewable

in energy management, an energy source that is
either potentially renewable or nondepletable

Renewable energy resources provide about

14% of energy worldwide

Roughly 10% of the energy used in the US comes from

renewable energy resources

The Sun is the

ultimate source of almost all types of energy

Wood, charcoal, and manure are used to

heat homes throughout the world

In the developing world, people often cannot

afford fossil fuels or do not have access to them

Net removal

The process of removing more than is replaced by growth, typically used when referring to carbon

Biofuel

Corn and sugar cane are fermented into ethanol which is mixed with gasoline

Biofuel examples

• E85

• Flex fuel

• Algae

Algae

produce oils that can be used as biofuels (more sustainable than corn)

Active solar energy systems use solar energy to

heat a liquid through mechanical and electric equipment to collect and store energy captured from the sun

Passive solar energy

absorb heat directly from the sun without the use of mechanical and electric equipment (energy cannot be collected and stored)

Technologies that employ active solar energy include

• Solar water heating systems

• Photovoltaic systems PV system

• Photovoltaic solar cell

• Large-scale concentrating solar thermal systems for electricity generation (CST)

Photovoltaic solar cell

a system of capturing energy from
sunlight and converting it directly into electricity

Heliostats (mirrors)

reflect sun’s rays onto a central tower in order
to heat water to produce steam to turn a turbine to produce electricity (can cause habitat destruction and light may fry birds)

Hydroelectricity

Electricity generated by the kinetic energy of moving water

Run-of-the-river

hydroelectricity generation in which water is
retained behind a low dam or no dam

Water impoundment

the storage of water in a reservoir behind a dam

Tidal energy

energy that comes from the movement of water
driven by the gravitational pull of the moon

Geothermal energy

heat energy that comes from the natural radioactive
decay of elements deep within Earth. Heat is used to heat up water, which is brought back to the surface as steam which then is used to drive an electric generator

Geothermal energy can be used directly as

a source of heat

Many countries obtain clean, renewable energy from

geothermal resources

have substantial geothermal resources, are the largest geothermal energy producers

US, China, Iceland

Hydrogen Fuel Cells

use hydrogen as fuel, combine hydrogen and oxygen from the air to form water

Hyfrogen fuel cell emissions

• Releases energy (electricity) in the process

• Water is the only product (emission)

In a fuel cell vehicle, hydrogen is the fuel that reacts with

oxygen to provide electricity to run the motor

Hydrogen gas enters the cell from an external source, protons from the hydrogen molecules pass through a membrane, while

electrons flow around it, producing an electric current, water is the only waste product of the reaction

Wind turbine

a turbine that converts wind energy into electricity, the blades of the wind turbine transfer energy to the gear box that transfers energy to the generator

Wind turbines on land are typically installed in

rural locations, away from buildings and population centers (typically grouped into wind farms or wind parks)

Wind energy is the

fastest growing major source of electricity in the world

Household ways to conserve energy

• Adjust thermostat higher in summer and lower in winter

• Conserve water

• Use energy efficient appliances

• Conservation landscaping – do not water grass

• Unplug “vampire” devices

Vampire devices

things like phone chargers, computers etc. that are plugged in but not being used

Passive solar design

uses solar radiation to maintain indoor temperature, roof overhangs make use of seasonal changes in the Sun’s position to reduce energy
demand for heating and cooling. In winter,
when the Sun is low in the sky, it shines
directly into the window and heats the
house. In summer, when the Sun is higher
in the sky, the overhang blocks incoming
sunlight and the room stays cool

High-efficiency windows and building materials with

high thermal inertia are also components of passive solar design