Hume 114 Module 2: Lecture 2 (Energy and Energy Flow)

Sun

primary source of energy for ecosystems

Law of conservation of energy:

• energy is neither created nor destroyed

• energy just transforms; changes from one point to another.

ecosystems

• ________ are dependent upon solar energy flow and finite pool of nutrients.

Heat

All energy content of organic matter

e.g. plants give food & oxygen thru photosynthesis.

EARTH'S energy is derived from:

1. solar radiation.

2. Tides

3. own heat (galing sa core)

Solar Radiation

Energy used in photosynthesis

1/50 of 1%

________ of the solar energy that reaches the earth supports life.

Tidal Energy

• the mechanical energy stored in the Earth-moon system

• through intermediary of gravitational force

Geothermal energy source

• provide very little energy compared to that provided by the sun.

• by hot springs, volcanoes (from earth's interior to its surface)

• From tectonic activities and earthquakes.

• e.g. Makban Geothermal plant, Laguna

beginning of life

Energy was needed to catalyze the ________; energy is also needed to sustain it.

Food, sun

For most of life, animals and plants, energy means ____ and most life turns to the __ as the ultimate source.

Pre-historic times

- food like raw meats/plants (initial)

- fire

• keeping them warm

• digestible food

4000-5000 BC

first jump in energy use

• Man domesticated several animals.

• Triple the amount of energy available to man.

1st century BC

• invention of water wheel

• mainly used for grinding grain, then irrigation

• most important source of energy (thru hydropower energy) for a long time.

12th century AD

• invention of the windmill

• mainly used in grinding grain, pumping water, and later support mechanical tasks

18th - 19th century (modern era of industry)

• development of steam engine during industrial revolution

• First widely used in coal mines, then in factories, railways, and ships

1850s

• wood as dominant fuel

• mainly used for heating, cooking, and small industries

1900s

• coal as the primary energy source.

• congressmen = shareholders of coal

1975

• use of natural gas and oil as fossil fuels

• shift was due to:

  1. high energy density

  2. ease of use

  3. versatility

exponential

nergy consumption isn't linear, it is _____ in nature.

linear

vast increase in energy use in the industrialized countries, in contrast w/ comparatively modest (____) increases in population

industrialized, Developing

• ______ countries: resulted from increases in per capita consumption

• _____ countries: increase in population

at 2040

• Developing world will account for 65% of the world's energy consumption

Energy as a resource

• energy can be found in nature or society which can potentially be used to satisfy human needs.

• energy makes things happen.

• Energy is a fundamental input that powers human activities: From basic needs (cooking, heating, lighting) to large-scale economic production (industry, transport, etc.)

Energy as a commodity

• energy can be measured, bought and sold.

• Depends on supply, demand, and market prices, making it an economic good

• price variations: (1) spot prices vs contract (2) geographic differences (3) supply and demand

• Energy becomes a commodity when it is commercialized and exchanged in markets

Energy conversion

• Except for solar energy, other energy sources are of little use to us in their primary form.

• They must be converted to intermediate forms and often converted again to the end uses

energy pathway

chemical energy -> thermal/heat energy -> mechanical energy -> electrical energy.

electrical energy

• _______ is the major intermediate form (most usable) of energy

intermediate form

• ____________: most usable form

Reason for Rapid Increase in Demand for Electrical Energy

The most convenient of the forms of energy

➔ can be transported by wire to the point of consumption

➔ turned into mechanical work, heat and other uses.

• BUT!! It cannot be very effectively stored thus increase its usage

• Promotion on off-peak usage (lower cost of electricity)

Law of conservation of Energy

"Energy can neither be created nor destroyed. It can only change form."

Potential sources of Energy crisis

• Extraction and supply chain issues: political conflicts, natural disasters, or economic factors that disrupt extraction and transportation.

• Affected supply chain

• Energy conversion Inefficiencies: converting raw energy sources into usable forms can be inefficient (e.g., losses in combustion, and electricity generation and transmission)

• Dependence on Limited & Finite Resources

• Outdated Infrastructure (e.g., Blackouts, brownouts)

• Environmental and Regulatory challenges.

ways to improve energy pathways

• improving technology

• Diversifying energy sources

• upgrading infrastructure

• Support from the government and exploration of public priv. partnership

Global Energy consumption

• nuclear energy: 6%

• oil = 36%

• coal = 28%

• Hydro electric: 6%

• natural gas = 24%

Philippine Energy consumption

• transport

• Households

• Industry

• services

• Agriculture

• Non energy use

Air pollution

• electricity generation, transport related, industrial, dwelling-related, accidental

• Air pollutants: carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen oxide, hydrocarbon pollutant, particulate matter (smoke, dust)

• some costs of pollution

  1. Effect on human health (e.g. respiratory diseases)

  2. damage to crops, trees, and other plants.

  3. Acid rain

  4. reduced food productivity (both animals & humans - kasi nasisira habitat nila)

Radioactive waste

switch to nuclear energy for electricity generation -> growing problem of the disposal of radioactive waste

Heat pollutant

• Energy conversion is largely a one-way street: all work eventually produces heat

• e.g., steam power plant

• increased electricity demand = increased heat discharge.

• urban heat island

Lifespan of Resources

1. based on estimation of resources

2. based on the rate at which resources are being used.

1. estimation of resources

• based on geological conditions.

• distribution and extent of resource in the area

• e.g., coal: Always found where it's predicted to be

• oil and natural gas: erratic distribution w/in favorable areas -> found only by exploration

2. rate at which resources are being used.

• rate of energy use = pure life

• fossil fuels are a finite resource

Energy for the future

• renewable - solar energy, biomass, tidal, geothermal, wind

• nuclear fission or fusion

What can we do?

1. plan and project further into the future.

2. Reduce our energy expenditure

3. increase R&D