Coal to maintain leading role in electricity production

To feed our tremendous hunger for electricity, we will need to tap deeper into all of our world's primary energy sources. Most projections show that coal will maintain its leading role in producing the world's electricity.

By Robert Giglio and Justin Wehrenberg

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Looking back over the last 150 years or so, it is not hard to see that electricity has been a primary force in shaping human development. It has been a basic ingredient in our industrial revolutions that simultaneously improved the productivity, working and living conditions within our farms, factories, hospitals, offices and homes.

Today, it has become an essential part of our daily life and our future. Our economies need it to grow, our scientists need it to discover, our doctors need it for our health care and our nations need it for our security and defense. The amazing thing is that we keep finding new ways to use electricity to make our lives more safe, comfortable and productive. It is a great success story of human ingenuity, achievement and development.

Our hunger for electricity

The convenience and value of electricity has not gone unnoticed by consumers. According to the Department of Energy1 (DOE), electricity is the fastest-growing form of energy in the world, and during the next 20 years, the world will likely consume twice as much of it as it does today.

In 2008, we consumed almost 20,000 terawatt hours of electricity globally1. That’s enough electricity to light-up over two million baseball stadiums or power over 11 billion computers continuously for an entire year. No matter how you look at it, we consume an incredible amount of electricity.

The United States has the dubious distinction of being the largest consumer of electricity in the world with enough power to provide each American with over three kilowatts of electricity — that is about twice the power currently available to Europeans, eight times the power available to the Chinese and over 25 times the power available to the citizens of India2.

Yet the US represents less than 5% of the world’s population. Further, an astounding 1.6 billon people (almost 25% of the world’s population), doesn’t have access to electricity at all1.

The rest of the world has a long way to go to catch up with the US and if they ever do, we would need over five times more power plants than we currently have in the world today. 

Electricity and the environment

Electricity is not an energy source by itself; rather it is produced from primary energy sources like fossil fuels, nuclear and renewable energy. Today most of our electricity, about 67%, is produced from fossil fuels (coal, natural gas and oil), with coal being the largest single contributor producing about 43% of the total electricity in the world1.

Figure 1 -  World Electricity Generation (Terrawat-Hours)
(Click to enlarge image) Figure 1 —  World electricity generation (terrawat-hours)

Looking out to the future, to feed our tremendous hunger for electricity, we will need to tap deeper into all of our world’s primary energy sources. Most projections show that coal will maintain its leading role in producing the world’s electricity.

There are good reasons for coal playing such a large role in our power generation. It is the most abundant primary energy source in the world, capable of supporting our energy needs for over 300 years at our current usage rate, as compared to oil or natural gas which is projected to be exhausted in about 30-50 years3. It is located in or near our largest population centers and our largest industrialized countries like the US, UK, Germany, China and India. It can also be easily transported and produces among the most reliable and affordable electricity today.

However, coal also carries a significant environmental cost with its use. When coal is burned to produce electricity, it emits air pollutants in the form of oxides of sulfur, nitrogen and carbon into the atmosphere. The oxides of sulfur and nitrogen can contribute to acid rain and smog. And the oxide of carbon in the form of carbon dioxide (CO2) is a green house gas that can contribute to global warming.

Steam generator technology – the critical component

At the heart of every coal plant is the steam generator, which converts the energy stored in coal into high quality steam needed to drive a steam turbine generator for efficient production of electricity.

The steam generator is the most critical component in our energy future since it allows us to unlock the energy value of coal, but also determines the environmental impact or cost we pay for this value. Improving its environmental performance is the most important thing we can do for ourselves and the environment.

CFB technology 

At Foster Wheeler, we have developed a different steam generator technology called Circulating Fluidized Bed (CFB). Unlike conventional steam generators which burn the coal in a massive high temperature flame, CFB technology doesn’t have burners or a flame within its furnace. It utilizes fluidization technology to mix and circulate the fuel particles with limestone as they burn in a low temperature combustion process.

The limestone captures the sulfur oxide pollutants as they are formed during the burning process, while the low burning temperature minimizes the formation of the nitrogen oxide pollutants.

The fuel and limestone particles are recycled over and over back to the process which results in high efficiency for burning the fuel, capturing pollutants and for transferring the fuel’s heat energy into high quality steam used to produce power.

Due to the vigorous mixing, long burning time and low temperature of its combustion process, CFBs can cleanly burn virtually any combustible material; greatly surpassing the fuel limitation of conventional combustion processes. Unlike conventional steam generators, CFBs capture and control harmful pollutants during the burning process and don’t need to rely on add-on pollution control equipment.

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