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Light for the Future PUBLIC ACCESS

Forecasts See a Brighter Age in Which Electric Power Reaches Farther and does more. Exactly how that Will Happen Remains an Open Research Question.

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Mechanical Engineering 123(10), 60-65 (Oct 01, 2001) (6 pages) doi:10.1115/1.2001-OCT-3

Electric Power Research Institute (EPRI), a nonprofit organization for energy and environmental research, has predicted that worldwide power demand will see a fourfold increase by 2050. Meeting the demand will require an effort equivalent to opening a 1-gigawatt power plant every two days for the next 50 years. The study projects the future of known technologies, including many in development. It takes into account variables, including the estimated learning curve for adoption and how far an idea is from commercialization. APERC and other energy research groups recommend the use of renewables instead. Systems bankrolled by grants, often from governments, can run on local resources. Engineering is working toward an unprecedented era in which the very poor—the quarter, or perhaps third, of the world without the juice to run a pump—within a generation or so may be able to offer their children a bedtime drink of clear water and light to drink it by.

In the developed world, they say we don’t think about electricity until the lights go out. It’s an annoyance, or maybe a novelty, scrambling in the dark for candles and the flashlight, and service is usually back up in hours. If the outage runs longer, things can start to get real: spoiled food in the fridge, no flush toilets, no showers, not even the basic of potable water at a tap.

Here we are. The last time a decade had so many zeros in it, Leif was colonizing America, Avicenna the mathematician was turning 20, and nobody had electricity or a safe water supply.

Plenty has changed in 10 centuries. More people live at one time on this globe than ever before, yet even with all that crowding, on the whole we still live better than those distant ancestors did. Only one in three or four people has no electricity. But in a generation or two, even they may see light at the end of their poverty.

The U.S. Energy Information Administration this year published a forecast of a 73 percent increase in world power consumption between 1999 and 2020 to 22 trillion kilowatt-hours.

The Electric Power Research Institute, or EPRI, a nonprofit organization for energy and environmental research, has predicted that worldwide power demand will see a fourfold increase by 2050. Meeting the demand, EPRI said, will require an effort equivalent to opening a 1-gigawatt power plant every two days for the next 50 years.

The industrialized world will draw ever more power, but the big growth is expected in the developing economies and in parts of the world with no juice at all. How the job gets done will likely depend in equal measure on politics, economics, and technology.

Among those trying to get a jump on the future is Robert Schock, a senior fellow in the Center for Global Security Research at Lawrence Livermore National Laboratory in California. He chairs a study group for the London-based World Energy Council, or WEC, that is trying to identify the energy technologies that will play key roles in electricity markets over the next century.

Tampa Electric Co.’s Polk power station uses syngas to drive a combined-cycle plant. Gasification is one of several DOE-backed clean coal technologies.

Grahic Jump LocationTampa Electric Co.’s Polk power station uses syngas to drive a combined-cycle plant. Gasification is one of several DOE-backed clean coal technologies.

The study projects the future of known technologies, including many in development. It takes into account variables, including the estimated learning curve for adoption and how far an idea is from commercialization.

“We are trying to identify the robust technologies expected to have significant impact on economies,” Schock said.

The group’s projections, involving 36 different scenarios, use an integrated modeling system developed at the International Institute for Applied Systems Analysis near Vienna. The institute is conducting the modeling work for the WEC.

Now one year into the three-year study, Schock said some patterns are emerging. For instance, nuclear power could grow as an electricity source by the middle of the century. Advanced coal, hydrocarbon fuel cells, and photovoltaics may also be bets for 2050.

There is a wide range from scenario to scenario in the estimates of electric energy generated by each source. For instance, projections for gas in 2050 range from 20 to 160 exajoules, with a median of 56 exajoules, Schock said. Estimates for advanced light-water nuclear reactors have a median of 65 exajoules.

An exajoule, 1018 joules, equals about 1.055 quadrillion Btu.

Another prediction emerging is that conventional steam-cycle plants may be phased out by 2020, as cleaner technologies become more competitive.

Gasification and other clean coal technologies stand to accelerate their gains in the marketplace if there are social or legislative pressures to reduce C02, Schock said.

Schock will report on the findings in a program titled “Energy Technologies for the 21st Century,” at the World Energy Congress this month.

The consensus among forecasters is that fossil fuels will continue to provide the majority of electric power through much of the century in the industrialized world and in developing economies such as China and India.

The fossil fuel infrastructure is well established, and the leading rival is the nuclear reactor, which is getting more respect these days in the U.S. Congress and the White House.

EPRI, based in Palo Alto, Calif., observed a revival of nuclear power in a 1999 document called Energy Technology Roadmap. But EPRI also called the nuclear plant “an exceptionally brittle technology.” The authors of the Roadmap warned that a single event involving plant safety anywhere in the world could turn public opinion.

According to EPRI, “It is therefore essential to the future of nuclear power that all operators worldwide maintain and strengthen their active collaboration on best practices and technology.”

Predictions for nuclear power vary. The Energy Information Administration, or EIA, for instance, sees nuclear sources accounting for 12 percent of the world’s fuel for electricity in 2020, down from a share of 18 percent in 1999. Schock said his numbers show nuclear power coming in considerably higher.

The pressure vessel as it was outfitted for a demonstration at American Electric Power's Tidd plant; the vessel held a fluidized bed combustor.

Grahic Jump LocationThe pressure vessel as it was outfitted for a demonstration at American Electric Power's Tidd plant; the vessel held a fluidized bed combustor.

The J-shaped boiler of a LEBS plant, which will be demonstrated by Corn Belt Energy in Illinois, contains a number of N0X reducers.

Grahic Jump LocationThe J-shaped boiler of a LEBS plant, which will be demonstrated by Corn Belt Energy in Illinois, contains a number of N0X reducers.

The EIA’s report, International Energy Outlook 2001, calls gas “the fuel of choice for new electricity generation investment around the globe.”

A visit to the competition section of the Electric Power Supply Associations Web site, epsa.org, will turn up a list of “Announced Merchant Plants,” a roster of almost 500 projects scheduled to come on line in the United States, some this year, most later, with a total capacity of more than 330 GW. Almost all of them are gas-fueled in simple or combined cycle.

In its Survey of Energy Resources, published in 1998, the World Energy Council reported: “In terms of growth rates, most experts now view natural gas as the most dynamic primary energy source for the coming decades. Its annual growth rate could lie between 2.5 percent and 3 percent between now and 2010.”

The WEC’s forecast for gas may have changed in three years. The organization is due to publish an update of the survey later this month at its congress in Buenos Aires, but the contents of the 2001 edition were not available for review at press time.

Although coal is the planet’s most abundant fossil fuel for generating electricity, gas is the most efficient.

Engineers generally estimate the efficiency of U.S. coal-fired plants at 35 percent. The efficiency of a simple-cycle gas turbine plant can exceed 40 percent, and combined cycle, in which turbine exhaust is recovered to produce steam, can deliver almost 60 percent efficiency. The makers of gas turbines are continuing to push for higher yields.

Gas burns cleaner than coal, and so a gas turbine plant doesn’t require as much investment in cleanup technology as a coal plant does. There is no particulate matter to remove. Sulfur is stripped out of natural gas before it is piped to the plant.

The carbon content, in relation to hydrogen, is lower in natural gas than in coal, so gas turbine exhaust contains less CO2. Throughout most of the industrialized world, even in the United States, which is not bound by the targets of the Kyoto Protocol, carbon is a big deal, and any technology that promises to give off less of it is welcome.

A plant built around a gas turbine is quicker to build and starts sooner to generate power and revenue than one that uses coal.

According to Lee Langston, a professor of mechanical engineering at the University of Connecticut in Storrs and a past ASME vice president of the International Gas Turbine Institute, a gas turbine plant with a capacity of perhaps 300 megawatts can be on line in a year and a half to two years after construction starts. A steam power plant of comparable size can take three to five years to build.

Langston also estimated approximate costs of about $400 per kilowatt to build a simple-cycle gas turbine power station and $600 per kilowatt for combined cycle. He compares those costs with an estimated range of $1,200 to $1,600 per kilowatt for steam fueled by a hydrocarbon, which is often coal or oil, and $2,000 or more for a nuclear plant. He pointed out that the estimates are approximate, with the nuclear estimate the roughest of all because no one has applied to build one in the United States since the 1970s.

The Energy Information Administration, a unit of the U.S. Department of Energy, predicts that consumption of natural gas to generate electricity will more than double between the base year of 1999 and 2020, rising from 28 quadrillion Btu to 60 quadrillion. That comes to 26.5 percent of the energy consumed to generate electricity in 2020 versus 19 percent in 1999.

For all the virtues of gas, coal provides more energy to produce electricity than any other fuel today, and is expected to do so 20 years from now, as well. The EIA estimates that coal accounted for just over 50 quadrillion Btu, or 34 percent of the fuel for electric power generation, in 1999. Consumption will double and share will dip to 31 percent by 2020, making coal still the leading fuel for power generation.

With so much coal lying in the ground, few planners expect the world to stop using it. Out of the 500 merchant plants listed by the Energy Power Supply Association, 23 are to burn coal. EPRI and the U.S. Department of Energy are among the institutions backing the development of technologies to make the stuff cleaner and more efficient to burn.

Nelson Rekos, product manager for combustion technologies at the DOE’s National Energy Technology Laboratory in Morgantown, W.Va., has a number of ideas about cleaner-burning and more efficient coal systems.

In this part of the DOE, at least, coal is seen as much maligned. As one of Rekos’s associates, Don Bonk, a project manager in the coal power projects at NETL, put it, “It’s not a question of ‘if it can be made clean.’ It can.”

For instance, a concept in the making is a hybrid plant that would combine partial gasification with coal firing and conventional downstream cleanup.

According to Rekos, the system has yet to be built, but “we have run the numbers.” He predicted the system could be nearly 50 percent efficient, or 10 to 15 percentage points more efficient than current U.S. coal-fired plants.

In the hybrid plant, a low-temperature gasifier, similar to a fluidized bed, would convert much of the energy from coal into char and synthetic gas. The syngas would fuel a gas turbine. The remaining char containing the majority of the sulfur, alkali, trace elements, and other pollutants would be piped to an advanced coal-fired boiler and burned with state-of-the-art cleanup technologies to achieve emissions well below New Source Performance Standards.

Rekos said that among the advantages to the design, besides the higher efficiency of diverting energy to the gas turbine’s more efficient Brayton cycle, is that the method of partial gasification would require less cleanup of the syngas before combustion. It could also be used to repower an existing coal-fired plant.

Rekos said that Corn Belt Energy Corp., a co-op based in Bloomington, Ill., plans to test another refined coal system. It will build a plant at a mine mouth near Elkhart in the center of Illinois, the state’s first new coal-burning power plant in 14 years.

The 91-MW plant’s purpose is proof of concept for a low-emission boiler system.

According to Tony Campbell, vice president at Corn Belt Energy, construction hasn’t begun yet. The company has been testing the site for such surprises as mine subsidence. “We’re in the fatal-flaw stage,” Campbell said.

He characterized the low-emission boiler system, or LEBS, as “taking a lot of proven technologies and putting them together.”

The boiler will come from Babcock Borsig Power Inc. of Worcester, Mass. Jerry Gilda, Babcock Borsig’s project engineer for LEBS, said the system has three keys to reducing nitrogen oxide emissions. One is the introduction of the company’s low-NOx burners in the slagging boiler. Another is air staging, which will bring in combustion air gradually. The third NOx reducer is an optional second burn in the U-shaped combustor.

According to Bill Howarth, project manager for LEBS, the system is designed to work with or without the second burn and still will deliver reductions in nitrogen oxides.

Tests with a 100-million-Btu scale boiler measured NOx at 0.2 pound for every million Btu.

An early design feature had been the use of a copper sorbent to remove sulfur. According to Ed Smith, manager for business development at Babcock Borsig, that intention proved too expensive to carry out, so conventional controls will be applied to keep SOx within federal targets.

The boiler will also turn out a slag about two-thirds the volume of ash. The glassy slag can be sold for blasting grit or roofing granules.

The plant will cost $137 million. The state of Illinois, the Illinois Clean Coal Board, and the DOE together have chipped in more than $50 million.

Another DOE clean coal project supports an idea that has been put into limited use in Japan and Europe and has been demonstrated but not commercially exploited in the United States.

In a demonstration of pressurized fluidized bed combustion, American Electric Power Corp. of Columbus, Ohio, ran a 70-MW plant in a coal-fired combined cycle.

Babcock Borsig tested its coal-fired low-emission boiler system in this 100-million-Btu model, and measured 0.2 lb. of N0X for every million Btu.

Grahic Jump LocationBabcock Borsig tested its coal-fired low-emission boiler system in this 100-million-Btu model, and measured 0.2 lb. of N0X for every million Btu.

AEP repowered its Tidd coal plant in Brilliant, Ohio, where it installed a bubbling fluidized bed inside a pressure vessel. The imminent launch of the Tidd plant was reported in an article in the September 1990 issue of Mechanical Engineering.

According to Mike Mudd, an ASME member who was AEP’s project manager for the Tidd demonstration, the pressurized combustion system, known as PFBC, registered a number of gains over conventional coal burning and over atmospheric fluidized bed technology.

Combustion took place in the aerated bubbling bed under a pressure of about 12 atmospheres. Flue gases were cleaned by high-efficiency cyclones to remove 98 percent of ash and all particulates down to five microns. The cleaned gases were used directly to drive gas turbines.

Turbine exhaust was recovered to begin heating process steam. Pipes passed under the bed, too, before steam reached its own set of turbines. The second cycle generated about three-quarters of the plant’s output.

The bed burns at 1,580°F, a relatively low temperature that curbs NOx production. The pressure yields more power from smaller volume.

A 350-MW commercial scale plant had been planned, but was never built, largely because coal’s bad-boy image made the project look like a difficult prospect at the time. The Tidd demonstration closed in 1995.

Mudd is now AEP’s manager for business development in Latin America, where his job includes developing combined-cycle gas turbine plants.

According to Rekos of the NETL, a circulating fluid bed could be pressurized with the expectation of further gains in efficiency.

Don Bonk at NETL said one of the advantages is that limestone captures sulfur more efficiently in the circulating bed than in the bubbling bed.

Arizona Public Service Co. in Phoenix did a feasibility study of repowering one of its plants with advanced pressurized fluidized bed combustors, which use the circulating rather than bubbling bed. The plant sits at a coal mine site near Fruitland, N.M., not far from the Four Corners, where New Mexico, Arizona, Utah, and Colorado meet. It contains three units with a total output of 574 MW.

Softer technologies are making encouraging advances in some of the poorest parts of the world.

A paper delivered at ASME’s International Conference on Fluidized Bed Combustion last May described some of the predictions of the study. The new technology, APFBC, could raise plant efficiency from the current 35 percent to 38 percent, and total output to 904 MW, a 57 percent increase.

It also predicted that, combined with selective catalytic reduction, the repowered plant would turn out 94 percent less particulate matter, 86 percent less NOx, and 82 percent less S02. Its operations would also use less water, an important consideration in the arid southwestern United States.

The estimated cost came to $1,100 per kilowatt. One of the authors of the paper, Bruce Salisbury, a senior mechanical engineer for Arizona Public Service, said in an interview that “project management could bring that number down.”

The authors of the paper decided that the technology is still too new for commitment. “To reduce risk, success in long-term operations of full-scale APFBC demonstrators is needed first,” they wrote. They added that when the technology had been tested, their research showed the promise of significant benefits from such a project.

EPRI has launched a program it calls the Global Coal Initiative, with many of the same areas of interest as the DOE’s research. Among them are “ultrasupercritical plant designs,” aiming to develop combined-cycle coal plants with efficiencies in the neighborhood of 60 percent. Gasification, advances in fluidized beds, and cogeneration of chemicals and hydrogen from coal are also under study.

The country likely to be the fastest-growing consumer of electricity for the next 20 years is China, which is No. 3 in terms of coal reserves. According to the WEC’s Survey, China holds 12 percent of the world’s coal. Only the United States, with 25 percent, and the Russian Federation, with 16 percent, have more.

The U.S. Department of Energy predicts that China will consume more than 3 trillion kilowatt-hours of electricity in 2020, about three times the consumption in 1999. Its average annual growth in power consumption is 5.5 percent, double the 2.7 percent rate for the entire world. China is already regarded as the country with the second-largest electrical generating infrastructure.

According to the Chinese government, the country had an installed capacity of 319 GW in 2000. The United States has a capacity of 870 GW, according to the Utility Data Institute in Washington.

At the conclusion of the current five-year plan, in 2005, China aims to have an installed capacity of 390 GW

Some 73 percent of the generating capacity will run on fossil fuels in 2005. Huang Wei, an energy specialist for the Science and Technology Office at the Chinese Embassy in Washington, said he was unable to specify how much of that would come from gas, coal, or oil.

The EIA’s International Energy Outlook estimated that coal represents 65 percent of China’s electricity fuels, and that its share is likely to decline slightly through 2020.

China’s major hydroelectric project, the Three Gorges Dam, is scheduled to be fully on line in 2009 or 2010 with a capacity of about 18 GW

The government also plans to increase the contribution of nuclear power from its current 2 GW, or 0.7 percent of the country’s capacity, to almost 9 GW, or 2 percent.

India, another emerging giant, is expected by the EIA to more than double its electric consumption over the 20 years, from 424 GWh to about 950 GWh. India has the Earth’s sixth-largest coal reserves, about 8 percent of the world’s total, according to the World Energy Council.

Beside the big-plant developments, softer technologies are making encouraging advances in some of the poorest parts of the world. But it will take a long time and concerted effort to bring all the rural villages of Africa and Southeast Asia into the circle of electric light.

“Getting technology to the people who need it is the problem,” said Jan Murray, deputy secretary general of the WEC. “People have to understand and maintain the technology.”

That is, the technology must be sustainable by the people who use it. Sustainability would be required even in a place where the per capita income is less than a dollar a day.

In a report, Energy for Tomorrow’s World—Acting Now!, the WEC had this to say:

“In 1993 there were nearly 1.8 billion people in the world without access to commercial energy. Despite efforts to connect roughly 300 million people to electricity grids or to provide them with modern biomass and other commercial energy over the last eight years, there are still an estimated 1.6 billion people in such a situation. Four to five hundred million people out of the 1.4 billion to be born between now and 2020 will join them. Most of these people are in rural areas and shanty towns in developing countries.”

A bitter irony is that the population of the unelectrified world is growing faster than that of developed areas. The advent of electricity not only means clean water to drink and all-around better health, but it also implies education, economic advancement, and broader horizons. Often, development lets families see ways of life that include more options than procreation to secure a future.

According to Murray, the largest concentration of people without electricity is in Southeast Asia. As a percentage of population, the least electrified region is Africa.

The relative prospects for economic growth on the two continents suggest that Asia will be faster to spread electric power to its people.

According to Nebojsa Nakicenovic, a specialist in technology forecasting at the Austrian Institute who is working on the scenarios for Schock's project, it is likely to be the middle of this century before electricity reaches most of Africa.

Although progress may be quicker, it won’t come overnight in Asia.

In Indonesia, the fifth most-peopled nation in the world, an estimated 45 percent of the population, some 97 million, have no electricity, according to the Asia Pacific Energy Research Centre in Tokyo.

The Philippines has about a quarter of its population, or 20 million people, with no electricity, and has set an ambitious schedule to electrify 90 percent of the country’s rural administrative areas, or barangays, by 2004, and 100 percent by 2006.

China’s Three Gorges Dam, due to come on line at the end of the current decade, will generate 18 GW.

Grahic Jump LocationChina’s Three Gorges Dam, due to come on line at the end of the current decade, will generate 18 GW.

According to the Philippine Department of Energy Web site, 81.6 percent of the barangays were electrified as of July this year. The Philippine program extends the country’s national electrical grid to rural users.

A study issued this year by the Asia Pacific Energy Research Centre, or APERC, recommends distributed generation as a more efficient way to deliver electricity to remote villages. Not only can distributed systems be up and running in less time than it takes to string power lines, but there are no power lines to pay for. What’s more, a local system avoids the waste represented by transmission losses.

An appropriately chosen system of distributed generation, coupled with conservative use of power, can be sustained with little or no subsidy. And yet there are agrarian villages where fueling a diesel generator may be beyond the means of the community.

APERC and other energy research groups recommend the use of renewables instead. Systems bankrolled by grants, often from governments, can run on local resources.

Solar power, for instance, is costly to set up, but the fuel is cheap enough. (For more on photovoltaics in distributed generation and rural electrification, see “Solar Gains,” on page 66.)

The APERC report, Sustainable Electricity Supply Options, touches on rural electrification efforts from small-scale hydroelectric power in Nepal to experiments with palm oil waste in Malaysia.

Stu Dalton, director of fossil generation and emission control at EPRI, sees the eventual possibility of a village operating a microturbine and an anaerobic digester to provide methane. That would be sustainable, but the sophistication of the technology makes it an option for the future.

As Murray explained it, change has to come in steps.

Biomass, for instance, is far and away the most-used fuel in Central Africa. She said that wood may account for as much as 96 percent of the energy consumed in Chad and Burkina Faso, and 98 percent in Cameroon. The first step toward improving quality of life, she said, may be to use that biomass more efficiently.

In the developed world, it’s a truism that we don’t notice electricity till the lights go out. Actually most of us do, but usually in terms of TV, computers, or The Next New Thing. Only in the dark do we see how much we depend on reliable power supplies to keep us informed, productive, and, above all, healthy.

Engineering is working toward an unprecedented era in which the very poor—the quarter, or perhaps third, of the world without the juice to run a pump—within a generation or so may be able to offer their children a bedtime drink of clear water and light to drink it by.

Copyright © 2001 by ASME
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