Project Amazonia: Solutions - Energy Resources

Problem:

Brazil needs more efficient energy sources to combat its shortage of power.

Hypothesis:

Fluidized bed coal combustion and combustion turbines are the most effective energy resources.

Background and Suggestions:

Brazil uses the largest amount of energy in South America, consuming 9.1 quadrillion British thermal units (Btu) of commercial energy in 2000.¹  Fifty-eight of the 64 gigawatts of power produced in Brazil come from hydroelectricity.  Brazil is the largest emitter of carbon dioxide in the region.  In 2000, nine hundred fifty-one million metric tons of carbon were released into the atmosphere.  The interest in building new energy supplies provides an opportunity to implement cleaner and more efficient power plants in Brazil.  The comparisons of the alternatives to hydropower are given below.

In 2001, Brazil’s demand for energy exceeded its supply.  The country experienced severe droughts which resulted in an energy crisis.  New initiatives have been taken to diversify the power sources in order to prevent such a disaster from occurring again.  For example, Brazil established hydrocarbon power plants and began to construct a third nuclear power plant, Angora-3.

Power sources include:

·        Oil/Petroleum

Brazil has the second largest number of oil reserves in South America, containing around 8.4 billion barrels of petroleum.  In 2001, production was at 1.6 million barrels per day while oil consumption was approximately 2.2 million barrels per day.  Consequently, oil supplies were imported from Venezuela and Argentina.  Oil is a non-renewable energy source and its combustion creates many toxins, such as sulfur and nitrogen impurities.  This pollution continues to increase the greenhouse effect.¹ 

·        Natural Gas

Production and consumption of natural gas in Brazil has risen since the 1990's.  Brazil has the fifth largest number of natural gas reserves in South America at 7.8 trillion cubic feet.  Gas is more efficient in power production than some coal and nuclear plants; however, this method still generates harmful waste.  According to the International Energy Annual, “20% of total CO₂ emissions from fossil fuels in 1996 came from consuming and flaring natural gas.  Emissions increased 26.9% from 1987 to 1996” due to the burning of natural gas.”¹

·        Coal

Brazil consumed about 23.5 million tons of coal in 2000.¹ This energy source also has the most damaging effects on the environment.  Coal contains carbon in high concentrations and its combustion produces toxins including carbon dioxide and sulfur dioxide.

·        Nuclear

Brazil currently has two operational nuclear power plants, Agnra-1 and Angra-2.  The construction of Angra-3 has been delayed because of decreases in military funding.  Nuclear power creates energy through fission.  This fission generates a greater quantity of energy than fossil fuels; however, there is a great deal of controversy surrounding the production of nuclear energy.  In addition, nuclear power is a non-renewable energy source, and the nuclear fission creates a radioactive substance.  Problems with the malfunction of nuclear plants can also have disastrous effects on the environment.  The older plant, Angra-1, is known for routine shutdowns and has had several spills of radioactive water.  Based on their histories, these power plants demonstrate poor management and such complicated technology is too sensitive to human error for valuable benefits.¹

·        Solar Power

Solar power is an excellent power source.  This fusion energy can be easily renewed, but continues to be a pricey practice.  Although it is becoming less expensive, the comparative cost to other energy sources is great.  Solar energy remains a very efficient solution and attempts to incorporate this source of energy have been made.  For example, Siemens has plans to build a new solar power plant in Manaus, Amazona, which is projected to supply about 30% of the Brazilian energy market in the future.²

·        Wind Power

Wind power transfers energy from wind into usable electricity.  It can operate at low costs and is a renewable power source.  Brazil currently has a total capacity of only 20 megawatts.  In the north-eastern state, Ceara, estimates predict that solar production will total 50 megawatts per year through 2010 and 2000 megawatts by 2015.² Compared with the 58 gigawatts produced by hydropower, solar power is considerably less efficient.  The cost of wind power, although relatively low, is nearly 70% higher than the price of hydroelectric production.²

·        Biomass

Biomass is the process of converting stored solar energy to electricity or fuel.  The sugar cane industry of Brazil currently generates more than 4000 gigawatts annually to run its own refineries and distilleries.  Between 3.4 and 3.7 billion gallons of ethanol are produced for automobiles each year; however, the burning of biomass still contributes to global warming, and does not produce a substantial amount of energy.³

·        Fluidized Bed Coal Combustion

During combustion, the fluidized beds support solid fuels on air jets.  This results in a powerful mixing of gas and solids which causes the fuel gases to contact a sulfur-absorbing chemical, such as limestone or dolomite.  More than 95 percent of the sulfur pollutants in the coal can be captured inside the boiler by the absorbent.  “Fluidized bed boilers can burn almost any combustible material, from coal to municipal waste, and are capable of meeting sulfur dioxide and nitrogen oxide emission standards without the need for expensive add-on controls.”⁴ This makes fluidized bed coal combustion a very practical and efficient energy source.

·        Integrated Coal Gasification Combined Cycle (IGCC)

“Rather than burning coal directly, coal gasification reacts coal with steam and controlled amounts of air or oxygen under high temperatures and pressures to produce a gaseous mixture, typically hydrogen and carbon monoxide.”⁵  In the same manner as natural gas, a gas turbine is powered by these gases.  The heat produced is then used in a heat recovery steam generator (HRSG).  A conventional steam turbine then uses the steam from the HRSG to produce a second source of power.  “Gasification is used today in refineries and chemical plants, but the technology is still in the demonstration phase for electric power generation.”⁵

·        Combustion Turbine (Gas Turbine)

By combusting the fuel, a high-temperature, high-pressure fluid is produced.  This gas is funneled through the gas turbine which triggers the shaft to rotate.  The expanding gas drives a series of specially designed blades which powers an electric generator and compressor for the air used by the gas turbine.  With the addition of a heat exchanger, extra heat will accelerate the combustor's mixing of air and fuel and further drive the electric generator.  “Gas turbines are compact, lightweight, easy to operate, and come in sizes ranging from seven hundred kilowatts to hundreds of megawatts.”⁵

Conclusion:

After comparing these potential energy sources, the integrated systems such as fluidized bed coal combustion and combustion turbines appear to be the most clean, efficient, and viable technologies.  Although they are non-renewable, these power supplies seem more environmentally friendly than the other non-renewable supplies, such as traditional fossil fuel systems, and more feasibly utilized than the renewable sources, including solar, wind and biomass.  Further investigation in renewable power supplies should be made because they are continually becoming more proficient and economically practical than non-renewable energy sources. 

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