Energy — Hype or Real?
By Badrul H. Chowdhury
The latest adventure of fictional secret agent
Ethan Hunt in Mission: Impossible III has him flying in a helicopter
chase through a wind farm. Even though the movie portrays a
fictional wind farm, there is nothing fictional about wind power. The statue of liberty is now served by power generated by wind.
more than 10,000 MW of grid-connected wind power exists in the
United States today, second only to Germany in installed wind power
capacity. Although still a magnet for environmentalists' concerns
for bird mortality, today wind power enjoys a state of tremendous
appeal to power producers and consumers alike. The beginnings of
commercially available alternate energy, however, were very modest
by today's standards.
In 1982, the first central-station photovoltaic (PV)
power plant, rated at 1 megawatt (MW) went online in Hesperia,
Calif., and served Southern California Edison's (SCE) power grid.
1984 saw more utility interest in PV, with the most notable being
the 2 MW PV power plant at Rancho Seco, Calif., that was connected
to the Sacramento Municipal Utility District. In 1985, a third
grid-tied PV plant, rated at 6 MW, was completed in Carissa Plains,
Calif. This facility also supplied SCE's utility grid.
The 10-MW Solar One concentrating solar plant
constructed in 1982 near Barstow, Calif., is an example of the
so-called Power Tower technology, which utilizes a vast array of
mirrors, aptly named heliostats, to focus the sun's incident energy
to a central tower that has a receiver and a means to transfer the
energy to electricity.
The world's largest and perhaps the most successful
early solar power facility was built in the Mojave Desert near
Kramer Junction, Calif., in 1986 as a result of a collaboration
between the Department of Energy and private industry. This facility
consists of five solar thermal stations with a combined capacity of
150 MW. Solar energy is transferred as heat to a fluid in receiver
tubes which is pumped into a power generating block (with a steam
generator and a turbine) for conversion to electricity. The facility
covers more than 1,000 acres and has a collector surface area of
more than a million square meters. This facility continues to
operate today, providing clean renewable energy to SCE's customers,
but it is one of only a few remaining systems from that era.
Most of the others have either been dismantled or their permits have
run out. However, the lessons learned from these early ventures have
led to an expanding renewable energy industry which has benefited
from customer acceptance, which has, in turn, led to lower material
cost and further expansion in the utility market. A growing number
of impressive renewable and alternate energy installations are
cropping up around the world, and the economics continue to look
better and more in line with what is needed to make further inroads.
To gain a peek into the future of alternative energy, one must look at
the development of some of these technologies since the early
demonstrations of the 1980s.
Solar panels are now ubiquitous, found in
applications ranging from small highway signs to large
building-integrated systems on skyscrapers. Some notable examples
The Nevada Solar Dish-Engine project, rated at 1
MW, includes a parabolic dish and a Stirling engine for power
generation. Although not connected to the grid, the system has
demonstrated high efficiencies and holds promise for the future.
The building at 4 Times Square, Manhattan, New
York, built in the 1990s, includes building-integrated
photovoltaic (BIPV) panels on the 37th through the 43rd floors
on the south- and west-facing facades.
The world's largest solar electric plant is now
operating in Bavaria near Arnstein, Germany. Solarpark Gut Erlasse is a 12 MW PV plant constructed
in 2006 from about 28,000 Solon modules mounted on double-axis
trackers that continuously track the sun.
Because of a wide array of activities, international
standards bodies like the IEEE have developed new standards or
modified existing ones to standardize the application of alternate
energy sources. Many of these recommended codes deal with safety and
reliability issues, as well as interface procedures, allowable
voltages and currents, certification, testing and monitoring issues
In 2005, the lowest system prices in the off-grid PV
sector ranged from about $10 to $20 per watt. The average price of
grid-connected PV systems in 2005 was $6.6 per watt .
Concentrating solar power technologies, particularly parabolic
troughs, currently offer the lowest-cost solar electricity for
large-scale power generation (10 MW-electric and above). Current
technologies cost $2 - $3 per watt, resulting in a cost of solar
thermal power of 9 - 12 cents per kilowatt-hour. New innovative hybrid
systems that combine large concentrating solar power plants with
conventional natural gas combined cycle or coal plants can reduce
costs to $1.50 per watt and drive the cost of solar thermal power to
below 8 cents per kilowatt hour (kwh).
Once spurred only by tax incentives and attractive
utility buy-back rates, wind energy has come a long way from its
post-oil embargo status to enjoy unprecedented growth in recent
years. Under federal research funding in the 1970s and 1980s,
several "new generation" utility-scale wind turbines were built to
be tested for commercialization. Among these, the most notable were
the Mod 0A, Mod 1, Mod 2 and Mod 5B designs. These experiments were
largely unsuccessful — mainly because several design flaws were
eventually discovered. At about the same time in California,
private industry installed more than 17,000 machines in wind farms
between 1981 and 1990. These machines ranged in output from 20 to
350 kilowatts. Then in the 1990s, with a growing U.S. wind industry
buoyed by European success stories, several wind farms started
operating in wind-rich U.S. areas. The wind
industry has grown at a torrid pace since then (see Fig. 1),
currently boasting a total installed capacity of nearly 60,000 MW
worldwide. At the end of 2005, total wind power capacity stood at
59,260 MW, whereas total off-grid and grid-connected PV power stood
at about 3,700 MW (see fig. 2). The King Mountain Wind Ranch in west Texas, with more than 275 MW capacity boasts as the largest wind
farm in the world and rivals many conventional fossil-fired
generation plants in size.
With such huge amounts of intermittent generation,
operating large windfarms within an existing electric utility system
can bring about some uncertainties in both windfarm
behavior and network behavior. Studies have proven that, at
certain penetration levels, one may start to see problems with
interconnection. Some suggest this level to be 15 percent, while
others suggest 30 percent. Whatever the penetration level is,
it is clear that wind variability will most likely have an
impact on system operations, including voltage and frequency and, in
general, power quality. A second issue the industry has an eye
on is dealing with low-voltage, ride-through capability of wind
turbines. Presently, wind turbines are forced to trip out during
network disturbances. To counter some of these uncertainties, power
engineers are devising new
grid codes in many parts of the world,
particularly where wind power presence is beginning to be felt in
Advances in wind-turbine technology have cut the
average cost of wind energy to about 4 to 5 ¢/kwh in 2005, from more
than 80 ¢/kwh in 1980. With the tax credit, wind energy becomes
competitive with natural gas, and even with coal.
Fig. 1. Wind power generation is the fastest growing
source of energy worldwide. Source: REPP, Worldwatch 1999.
Fig. 2. A comparison of growth windpower and solar
(Source: PV data from  and Wind data from ).
Energy derived from biomass supplies almost 30 times
as much total energy (electric and non-electric power) in the United
States as wind and solar energy combined. Biomass is a renewable
resource because it is derived from plant materials, such as tree
and grass crops and animal and urban wastes. Production of
alternative fuels, such as ethanol, methanol and biodiesel are the
most common forms of biomass application. However, electric power
production using biogas derived from landfills, wastewater treatment
facilities, and livestock operations has reached a level comparable
to that derived from wind power. As a matter of fact, with about
9,730 MW of installed capacity in 2002, biomass power was the
leading alternative generating resource in the country. Since then,
of course, wind power has taken over as the leader.
In the year 2000, direct-fired biomass energy cost
7.5 ¢/kwh and gasification-based biomass energy cost 6.7 ¢/kwh. The
cost of biomass energy has stayed relatively steady since the 1980s.
Geothermal plants utilize the steam and hot water
trapped in underground wells and reservoirs to drive turbines for
power generation. Among the advantages are less environmental
pollution and very little land use for the amount of power
generated. However, the drawback lies in the fact that
well-developed geothermal sites are not frequently available. The
largest electricity producing geothermal plants in the world are
located in the Geysers area in Northern California. Total installed
capacity amounts to about 1,100 MW, having peaked at 1,967 MW in
1989. Total worldwide capacity is in excess of 8,000 MW.
The cost of geothermal electricity in the United
States ranges from 5 ¢/kwh to 8 ¢/kwh. These costs are steadily
declining due to technological improvements. The Geysers sells power
at 3 to 3.5 ¢/kwh. A geothermal power plant built today would
require about 5 ¢/kwh to be economic.
An electrochemical device, a fuel cell converts the
chemical energy in hydrogen into electrical energy. It functions
similar to a battery, except that the fuel has to be continuously fed
into the cell. The fuel cell consists of two electrodes, anode
(negative electrode) and cathode (positive electrode) separated by
an electrolyte. Hydrogen is fed into the anode where electrochemical
oxidation takes place and oxidant (Oxygen) is fed into the cathode
where electrochemical reduction takes place to produce electric
current that can be directed externally to power a load. Each
electrode is coated by a catalyst that speeds up the chemical
reactions. Water is the primary product of the cell reaction.
Fuel cells are classified in accordance to the type
of electrolyte used. Two popular types of electrolytes are the
Proton Exchange membrane, which may be used in low temperature
applications such as in vehicles, and the phosphoric acid
electrolyte, used in higher temperature applications, such as in
combined heat and power.
Hydrogen is attractive as a fuel source, because it
has the highest energy density by mass, thrice that of petroleum.
However, its energy density by volume is extremely low. Therefore,
to get any significant energy production, a very large hydrogen
storage volume is required. Hence, a primary concern is the fuel
supply. Without a hydrogen delivery infrastructure, one has to
depend on reforming natural gas to produce hydrogen.
Although the technology holds great promise, only a
handful of examples exist of commercial fuel cell application for
stationary power. The country's largest fuel cell power plant in
commercial operation is located in Garden City, Long Island, NY. The
phosphoric acid fuel cells, produced by UTC Power, are rated at 1.4
MW and provide power and heat for Verizon Communications, Inc.'s
office building and call-switching center.
Fuel cell cost is still an issue, as many fuel
cells require the use of expensive materials. Catalysts, such as
platinum, required to speed up the electrochemical reaction, are
often expensive. With only a small number of companies engaged in
commercial fuel cell production, this technology does not yet have
the advantage of cost efficiencies realized from mass production.
The most commonly known ocean power technologies
include: wave power, tidal power, ocean thermal
energy conversion, and Ocean currents. Although, these
technologies have been researched for several decades (mostly
outside the United states), not much progress has been made in
commercial applications. The technologies are still beset with high
initial costs, making them less attractive in comparison with
The Archimedes Wave Swing (AWS) is an example of
wave power technology that has great potential in the future. The
AWS consists of a cylindrical, air-filled chamber (Floater), which
moves vertically with respect to a fixed structure connected to the
seabed. A wave passing over the top of the device causes the Floater
to bob up and down and this relative motion can be used to turn a
turbine to produce electricity. Such a device — a 2 MW pilot plant —
is currently producing power off the coast of Portugal and feeding
the Portuguese grid.
The first and the largest tidal power station is the
Rance tidal power plant completed in 1966 at La Rance, France. It
has 240 MW installed capacity. Another, much smaller, facility
exists at the Annapolis Royal Generating Station, consisting of a dam
and 18-MW power house on the Annapolis River at Annapolis Royal,
Nova Scotia. The plant is located on an inlet to the Bay of Fundy on
the northeast end of the Gulf of Maine between the Canadian
provinces of New Brunswick and Nova Scotia. Like hydro power plants,
tidal power is subject to high cost of construction and
 IEEE 929-2000 Recommended Practice for Utility
Interface of PV Systems
 IEEE 1547-2003, Standard for Interconnecting Distributed
Resources with the Electric Power System.
 International Energy Agency, Photovoltaic Power Systems Program,
 Global Wind Energy council,
Badrul H. Chowdhury is a professor of electrical
engineering at the
University of Missouri-Rolla. Comments may be submitted