Renewable Energy Systems in the Future: Part 1

Despite the recent negative publicity surrounding fossil fuels, crude oil, and natural gas have been beneficial for the growth of the modern world. It has allowed us to have life after dark, transport goods all over the world, and enabled technology to advance. However, the use of fossil fuels has also resulted in many negative consequences: it has created severe pollution, political conflict, economic control and dependence of countries on others who have this natural resource.

The supply of fossil fuels is limited and is only located in certain areas of the world. The demand for fossil fuels creates conflict which threatens peace. Countries that have adequate fossil fuel supplies could potentially threaten the security and economy of countries that are dependent on these countries. Also, there have been many estimates regarding the quantity of fossil fuel left in the world. These estimates are dependent upon the population growth, and the actual fossil fuel consumption. These estimates predict there is enough for approximately another 30 years of oil, 35 years of natural gas, and 100 years of coal. In addition to the negative environmental consequences associated with these fuels, there is a finite supply of fossil fuels that will force the use of an alternate form of energy. The limited supply and large demand will inevitably cause price increases.

The use of fossil fuels to fulfill the world's energy needs has harmful side-effects for people, plants, and animals. Waste products from these fuels heat the earth's atmosphere and pollute the earth's air, water, and ground. This results in decreased living conditions for all species. In addition to being hazardous to our ecosystem, the pollution is also changing our atmosphere. This trend is called global warming and will continue to worsen due to the increase in fossil fuel consumption due to the growing world population. In the process of burning the gasoline, several by-products are released: carbon monoxide, nitrogen oxides, and unburned hydrocarbons. In automobiles, the catalytic converters reduce a large portion of the pollution, but they are not perfect. Many cities around the world have dangerous levels of ozone in the air. Therefore, we need power sources that have low pollutant emissions, good energy-efficiency, and an unlimited supply of fuel for a growing world population.

Many alternative energy technologies have been researched and developed. These include solar, wind, fuel cells, bioenergy, geothermal energy as well as many others. Solar cells use the sun to generate electricity, wind power is obtained from the kinetic energy of the wind, fuel cells use hydrogen, bioenergy is extracted from plants and geothermal energy is from the earth. Each of these alternative energy sources has its advantages and disadvantages, and all are in varying stages of development.

For most countries around the world, if the supply of fossil fuels were cut off, the entire economy would come to a halt. People could not drive to work or use electricity in their homes or workplaces. The global population consumes petroleum products at a rate of 100,000 times greater than the rate that they are formed. The United States currently imports 70% of the oil, and about 80% of the total energy in the world is provided by fossil energy sources. The International Energy Agency estimates that the primary world demand for energy is expected to grow by about 45% by 2030, and this equates to a cost of $20 trillion U. S. dollars. Since a lot of money needs to be spent on the investment in energy infrastructure in the upcoming years, this creates an opportunity for replacing (at least a portion) of the fossil fuel infrastructure with a renewable energy infrastructure. U.S. coal and fossil fuel plants are already fairly old because at least half of the plants were built before 1970. If the oldest plants are retired first, it may be an easy to transfer the energy production to alternative energy without retiring the plants prematurely.

Although the demand for oil is increasing, the world's oil production peaked in 2005. Countries that have a significant percentage of their power from renewable energy are Canada (16%), followed by France (6%), Italy (6.5%), Germany (5.6%), United States (4.8%), and the United Kingdom (1.7%). The global community needs to balance future energy demands with future economic and environmental needs. We have a real opportunity to transform the way that our economy utilizes energy, prevents further pollution, and helps to ensure a safer and more secure future.

About Climate Change

The definition of global warming is a significant increase in the Earth's temperature over a short period due to human activities. An increase in temperature of 0.4° Celsius is significant over a century, and an increase of 1° Celsius is considered global warming. Although 1° or 2° Celsius may not seem like a lot -- small temperature changes have significant effects. When you hear the term "ice age," you probably think of the world covered in snow and ice. Ice ages occur every 50,000 to 100,000 years, and the average global temperature was only 5 °C cooler than they currently are.

The Intergovernmental Panel on Climate Change (IPCC) is a group of over 2,500 scientists from countries around the world that meet to advance climate research. One of the conclusions is that 14 of the 15 hottest years on record have occurred since the year 2000. Some of the observations are that glaciers and snow have decreased in the northern and southern hemispheres, and average arctic temperatures have increased by twice the global average during the last 100 years. Rain has increased in the Americas, northern Europe and parts of Asia, and South Africa and the Mediterranean have been experiencing drying trends. Overall, hot days globally have become more frequent, and cold days have become less frequent and severe.

Natural changes in climate such as heating due to volcanic activity, radiation from the sun, and changes in the chemistry of the atmosphere usually take thousands of years to change only 1 °C. The current carbon dioxide concentration (CO2) determined from the ice cores (180 to 300 ppm) is far greater than the natural range found over the last 650,000 years. If the CO2 concentration rises to 400 - 440 ppm and stays there, the eventual rise in temperature will be around 2.4 - 2.8 °C.

To stabilize the CO2 level, it needs to peak and then decline. The more quickly that this occurs, the lower the peak stabilization level. According to the IPCC, to stabilize the CO2-equivalent concentrations around 445 to 490 ppm, CO2 emissions would need to peak now, and then fall to between 50 - 85% below the year 2000 levels by 2050. A later peak and higher concentrations will ultimately lead to larger increases in temperature.

Our Future Using Alternative Energy

There is no single “right” answer for our future energy system. The future energy economy will most likely consist of many renewable energy technologies used in combination, such as wind, solar, geothermal and fuel cell energy. The technology to accomplish this is either available or being developed. Some of the tasks that we need to accomplish include:

• Build an industry based upon alternative energy technologies
• Reduce energy costs
• Reduce climate change
• Increase energy security
• Create conditions for long-term prosperity for all nations

To accomplish these tasks, we will have to:

• Use a combination of wind power (both on and off-shore)
• Use both concentrating and standard PV power systems
• Use geothermal systems
• Use fuel cell systems that generate hydrogen using electrolysis
• Use biomass and municipal waste

Figure 1: Rate of Change in U.S. Energy Consumption

To successfully use renewable energy, good energy storage is required because renewable energy (solar and wind) can be intermittent. These renewable energy sources can fluctuate with levels of sunshine, shading, and wind intensity. When these sources are not available - electricity cannot be generated. When a large amount of energy is produced, hydrogen can be created from water and then stored for later use.

Hydrogen is one of the most powerful fuels, but it does not exist in its pure form on earth. Therefore, it has to be extracted from fuel or water. The process that is used most frequently for extracting hydrogen is the steam reforming of natural gas. It can also be extracted from coal, nuclear power, biofuels or even waste products. Hydrogen can also be produced using water through the process of electrolysis. Electrolysis splits water into hydrogen and oxygen using electricity. Renewable forms of energy such as photovoltaic cells, wind, hydro and geothermal are increasingly being used to produce electricity, and excess electricity can be used for the electrolysis process. The hydrogen can be used or stored to generate electricity at a later time.

Dr. Colleen Spiegel Posted by Dr. Colleen Spiegel

Dr. Colleen Spiegel is a mathematical modeling and technical writing consultant (President of SEMSCIO) and Professor holding a Ph.D. and an MSc degree in Engineering. She has seventeen years of experience in engineering, statistics, data science, research & technical writing work for many companies as a consultant, employee, and independent business owner. She is the author of ‘Designing and Building Fuel Cells’ (McGraw-Hill, 2007) and ‘PEM Fuel Cell Modeling and Simulation Using MATLAB’ (Elsevier Science, 2008). She previously owned Clean Fuel Cell Energy, LLC, which was a fuel cell organization that served scientists, engineers, and professors world-wide.

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