Energy used for human applications can be broken down into two broad categories: non-renewable energy sources (fossil fuels and nuclear) and renewable energy sources (biomass, hydrologic, solar, wind, and geothermal). Fossil fuels preserve solar energy that was stored in organic compounds millions of years ago. Coal, oil and natural gas are today the dominant forms of fossil fuels used around the world accounting for 80% of all energy used globally (Figure 2). Coal accounts for ~24% of the energy used around the world, which is harvested from rock layers that originate from ancient swamps. Oil (~34%) and natural gas (~21%) account for more than half of all energy used around the world, and is trapped in rocks that form natural containment vessels. Because fossil fuels were formed tens to hundred of millions of years ago, they and cannot be replenished, so these energy resources are finite.
Coal-fired power plant exhaust
Nuclear fuel accounts for ~7% of global energy use and is also considered a non-renewable form of energy because the uranium needed to create nuclear fuel is a finite, mined resource. Nuclear fuel goes through many steps before it can be used in a nuclear power plant to generate electricity, but is involves more efficient energy transformations than other fossil fuels. Whereas no significant greenhouse gases are emitted, radioactive waste products greatly complicate the use of nuclear power as an energy source.
Primary energy supply by fuel type
In 2003, renewable energy resources accounted for ~13% of the total global energy supply. Of that, combustible renewables or biomass burning accounted for the greatest proportion of energy. Combustible renewables are distinct from fossil fuels because they are a renewable resource. Combustible renewables and renewable waste are organic material and waste from plants, trees and crops that are traditionally used as firewood for cooking and heating in many developing countries. However, modern uses include combustion to produce energy in the form of electricity, steam and biofuels. Hydroelectric energy accounts for the second largest proportion of renewable energy with ~2% of global energy use. Hydroelectric power plants use the kinetic energy of falling water to generate electricity. A turbine and a generator convert this energy into mechanical and then electrical energy.
Modern renewable forms of energy account for less than 1% of global energy used today. However, their use is on the increase as the impact of fossil fuels burning is become clearer and this resource is becoming scarcer or politically more difficult to secure. Modern renewables are generated from solar, wind, water and geothermal energy, and are produced on local scales; therefore, their use would result in renewable energy development, changes in infrastructure, and job creation in many regions of the world.
Solar panels use photovoltaic cells that convert light energy into electricity at the atomic level. Photovoltaic systems can be constructed to any size based on individual energy requirements, and are low-maintenance. They are ideal for supplying power to homes far from utility power lines in remote areas, especially when their efficiency is further improved. Electricity generating wind turbines are used to harness the kinetic energy from wind created by the uneven heating of Earth lower atmosphere (or troposphere). Renewable energy can also be generated from wave and tidal movement at coastal areas or it can be captured from Earth's internal heat. Typically, geothermal energy is used where access to hot rocks and water is available.
Energy is a key component of modern human society. It is used to power our daily lives and the world’s growing population demands considerable increases as non-western economies grow. The goal of this lab is to explore the differences between conventional and renewable energy resources. We will investigate the costs and benefits associated with the fossil fuel economy and determine whether there are better energy choices available. We will also discuss the pros and cons of alternative forms of energy and the political and social barriers that impede switching to a more sustainable renewable energy infrastructure.
To achieve this, we will discuss three articles relating to energy. In the week prior to this discourse, students should be broken up into three groups to facilitate using the jigsaw puzzle technique. The jigsaw method allows a class to cover a large amount of material, in depth, in a short amount of time. Each group will be assigned one of the following three readings from the WorldWatch Institute.
Windmills generate electricity
Nuclear power plant
In Class - The Jigsaw Puzzle Technique
The jigsaw puzzle method will then be used in class to explore issues related to Energy. Students should come to class having read the article assigned to their group. For the first part of the class, students that read the same article should get together and distill the most important themes, concepts and problems in their paper. Once this has been accomplished, mixed groups should be assembled. Make sure that each mixed group has at least one reader from each of the assigned papers.
The mixed groups should then discuss the most important concepts covered in each paper and come to general conclusions about energy based on information provided in the articles. During the mixed group discussion, using a poster board, PowerPoint slide, or a transparency for the overhead projector, half of the mixed groups should answer Question 2 by creating a chart of the pros and cons of each energy type. These groups should also determine what the most feasible and effective combination of energy types would be for the state or region. The other half of the mixed groups should each develop a plan to encourage and implement change in energy policy for civil society, businesses, and government.
In the third part of the class, each group should present their energy plan to the class. Then in the last part of the section, the whole class should discuss the energy plans together. The following questions may be of use to guide the discussion:
By the year 2020, energy consumption is expected to rise by more than 60% and the largest share of that growth will occur in the developing world. Assuming that fossil fuel resources fill this deficit, what types of pressure will this put on the natural environment, public health and international stability?
What are some of the pros and cons of current fossil fuel and nuclear energy resources? What are the pros and cons of other renewable energy resources?
What are the biggest obstacles to implementing biofuels, solar, and wind energy on a global scale?
What lessons can we learn from
What policies should be implemented to encourage the use of renewable energy resources? What are some of the potential roadblocks to implementing these policies?
Should there be governmental subsidies for renewable energy development? What types of problems are associated with giving tax credits for development and implementation of renewable energy technology?
What role does information dissemination play in implementing renewable energy technology and infrastructure? How can this be improved?
How do implementing public participation and industry standards avoid problems associated with renewable technology?
In the 1990's, the World Bank put 100 times more money into fossil fuels than into renewable technologies. How do we divert this trend of investment in unsustainable conventional energy toward more sustainable renewable technologies?
What information do we have to support the notion that renewable energies can meet all of our current and future energy needs? How can we overcome the barriers that impede progress toward a more sustainable renewable energy economy?
Windmills under a rainbow
Solar panel at sunset