Environmental Science

Environmental Science

Law of Conservation of Energy

This law states that energy can neither be created and nor be destroyed, however it can be transformed from one from to another form and transferred from one body to another. The total energy in a closed system always remains same (Schobert, 2002).

In a system energy might be transformed in order that it exists in different state. Energy in several states might be utilized to do a number of physical works. Energy might be used in machines or natural processes or else to offer a number of services to the society.

Alternative Energy: Pros and Cons

Coal

Pros

Cons

Lignite may be detached easily thanks to its location and low

Coal burns more environmentally friendly than brown coal, as it contains less moisture

Non-renewable fossil fuel

Low electrical efficiency of coal plants (between 30 and 46%)

Handling and transport difficult and problematic

Accidents during the extraction

Difficult removal of ash

Release of harmful substances (such as mercury, dioxin, particulate matter and sulfur dioxide) during combustion

Current mode of production rejecting the more carbon dioxide

Table 1: Pros and Cons of Coal (Kruger, 2006)

Oil

Pros

Cons

High calorific

Dense distribution network and efficient

Non-renewable fossil fuel

Environmental risks in the extraction and transportation

Transport and storage problems

Emissions of air pollutants (carbon monoxide, volatile organic compounds (VOCs), particulate matter (PM10), sulfur dioxide, nitrogen oxides, etc.).

High emissions of CO 2

Table 2 (Schobert, 2002)

Natural Gas

Pros

Cons

Few releases toxic or carcinogenic combustion such as benzene and fine particulate

Hydrocarbons (HC) unburned rejected are mainly composed of methane, a greenhouse gas, but not toxic to humans

25% of CO 2 emissions in less than heating oil for the same calorific value

Transport by boat (in compressed form) and gas

Fossil fuel

Non-renewable fuel, supply cannot be replaced for millennia

Emits carbon dioxide when burned

Table 3 (Dresselhaus, 2001)

Nuclear Energy

Pros

Cons

high amounts of energy generated

Use of hazardous substances

Incidence of radioactive waste

Table 4 (Schobert, 2002)

Solar Energy

Pros

Cons

By module structure easily upgraded

The generated energy can be stored in batteries and fuel cells

Even off of energy supply systems used (e.g. Rent, developing countries)

The solar panels are very durable (20 years and over)

Low efficiency (approximately 10% to 15%)

Storing the energy in batteries and fuel cells are very expensive

Overnight no electricity!

Power output can vary a greatly depending on lighting conditions, i.e., conventional power plants must be in standby run along to you in case of need (e.g., Cloud, Thunderstorm, ...) go up quickly

Table 5 (Dresselhaus, 2001)

Wind Power

Pros

Cons

Little space

Large amounts of energy generated

Also be placed in the sea, so-called offshore operation

Very irregular, varying with the wind ...