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Energy from Wind

Wind, which is caused by the uneven heating of the Earth’s surface by the sun, can be used to generate electricity. A wind turbine is used to collect the wind’s kinetic energy from its blades and converts the motion of the blades to electricity with an electric generator. 

The benefits of wind energy are:

• Sustainable
• Costs continue to decrease
• Often more available during seasons with higher electric demand
• Wind turbines do not release any emissions
• Wind turbines have a small physical footprint

The limitations of wind energy are:  

• Wind resources are difficult to map and predict
• The wind is not always constant
• Some people do not like the visual impact of wind turbines on the landscape or the sounds the blades make while spinning around
• Wind turbines are criticized for bird and bat deaths, although more deaths are caused by house cats and collisions with cars and buildings         

Energy from Biomass

Biomass is organic material from plants or animals. When considering the process of photosynthesis, biomass essentially contains stored energy from the sun. When burned, the chemical energy from the biomass is converted to heat and can be converted to electricity. 

Biomass is renewable because new crops can be grown in a relatively short period of time and they will always create waste. Examples of biomass fuels are wood, crops, manure, and garbage.

The benefits of biomass energy are:

• Widely available and abundant
• Generally low cost inputs
• Can be domestically produced for energy independence
• Low Carbon (carbon neutral) and generally cleaner than fossil fuels
• Can minimize negative environmental impacts of landfills and farms

The limitations of biomass energy are:

• Energy intensive and expensive to produce and sometimes to transport.
• Land utilization can be considerable and may lead to deforestation
• Requires water to grow crops
• Not 100% clean when burned
• Can compete with food production
• Some types are seasonal
• Not easily scalable    

Energy from the Earth

Geothermal energy is generated from the heat from within the earth. The heat can be moved to heat buildings or generate electricity. Heat from the earth is constantly replenished and thus renewable. The three main uses of geothermal energy are: direct use for heating systems, electricity generation power plants and geothermal heat pumps. 

The benefits of geothermal energy are:

• Emission free with no carbon emissions
• Can scrub out sulfur which would have been otherwise released
• Requires no fuel, mining or transportation
• Not subject to the same fluctuations as solar and wind
• A small land footprint
• Simple and reliable
• Can provide base load or peak power
• Cost competitive

The limitations of geothermal energy are:

• Very location-specific - prime sites for generation plants are located near plate borders and not necessarily near large populations
• Water usage
• High construction costs when considering drilling
• High level of planning and heat management

Energy from Water

Hydropower is energy produced from moving water. Since hydropower relies on the earth’s water cycle to replenish the water supply, hydropower is considered renewable.

Two main sources of hydropower are the natural run of rivers and storage systems such as a dam. Mechanical energy is harnessed from the moving water from these sources and can turn an electric generation turbine to produce electricity. Ocean tides and waves can also be a source of energy, however they are not as prevalent as the use of dams and rivers.  

The benefits of geothermal energy are:

• Electricity generation itself does not pollute environment
• Flexibility - adjusting the water flow and electric output is easy
• Compared to fossil fuels and nuclear energy, hydropower is much safer

The limitations of geothermal energy are:

• Unpredictable environmental and biological consequences from the damming of water, changing water flow and infrastructure construction
• Building power plants may be expensive
• A drought could affect electricity generation and energy prices
• Reservoirs that can be dammed are limited due to difficultly in siting