Decentralized Generation and Power Transmission
A news story broke in early September that a wind farm in Upstate New
York had to suspend operations due to a shortage of transmission capacity
going into New York City. An announcement followed in regard to plans to
build additional transmission capacity. Despite claims that the North
American grid is rugged and robust, many sections of that grid are old and
need to be replaced. That upgrading coincides with a steadily increasing
demand for electricity.
During the summer of 2003, most of the North American transmission grid shut
down at around 4:15 p.m. Eastern Standard Time. During the winter of 1998
the American Northeast and parts of Eastern Canada were battered by a severe
ice storm that incapacitated much of the transmission grid in that region
for up to two weeks. Power outages still occur during severe storms that
inflict damage on local distribution networks and to sections of the
transmission system.
Since the late 19th century when large generation facilities first appeared,
the economy of scale has favored large-scale power generation at centralized
installations. By the early 20th century it became cheaper to generate
electric power at Niagara Falls and transmit electric power to New York City
along transmission lines than to build multiple small thermal power stations
in the city. By the mid-20th century many small hydroelectric power dams
ceased operation as economics favored the mega hydroelectric dams at remote
locations from major population centers. At the dawning of the 21st century
there is still a powerful economic case for generating power at remote
locations and transmitting it over extended distances using ultra-high
voltage transmission lines.
Historically, hydroelectric was the only cost-competitive form of renewable
power generation. The cost per kilowatt of many other renewable technologies
is gradually declining and over the long term they are projected to become
cost-competitive with fossil-fuelled power generation. The promising
technologies include airborne wind turbines that can access powerful air
currents that flow at higher elevations and free flow kinetic turbines that
can be placed in ocean currents, ocean tidal currents and in fast flowing
rivers. There have been recent research breakthroughs in solar thermal power
conversion technology and into concentrating solar power onto advanced PV
cell technology.
There have also been ongoing and recent research breakthroughs into various
forms of on-site and small-site power generation. Micro gas turbine engines
of around 30-kW output evolved from automotive turbocharger technology and
can burn a variety of fuels in very remote locations where no transmission
lines exist. Micro turbine engines that burn natural gas and/or biogas from
gasified biomass can generate up to 150-kW output in the basements of
several large office towers in large cities like New York. Such technology
can provide essential back-up power, base line power and/or additional power
during peak demand periods.
A project recently got underway in France where ultra-deep geothermal wells
are being drilled to access high-grade heat that is in excess of the boiling
point of water. Such temperature can be found at the bottom of salt domes
that have been flushed of salt and that the natural gas industry uses to
store compressed natural gas. It is theoretically possible to build an
office tower located next to a river or ocean coast and generate electric
power from geothermal heat. A closed-cycle engine that circulates a
refrigerant such as ammonia or R-134a can operate from the difference in
temperature found between the lower depths of the geothermal well and water
in the nearby river or ocean coast.
The cost per kilowatt is expected to decline for both thin-film solar PV
technology that can be installed as siding on buildings and for solar PV
windows. Both technologies would likely be included in the construction and
refurbishing of high-rise commercial buildings located in regions that
receive generous solar energy throughout the year. Over time and as the cost
per kilowatt decreases over time for decentralized power generation, the
percentage of such power generation may be expected to increase over time.
Some building owners may choose to go off-grid altogether and transfer
on-site renewable power generation for solar and wind sources into on-site
storage technology such as flow batteries.
Other owners of buildings with on-site power generation may maintain the
grid connection and sell excess renewable power to the grid during weekends,
during the AM period that precedes the onset of the business day and during
the PM period after the close of the business day. In this way decentralized
power generation that is connected to the grid could benefit a larger
population. There are several micro nuclear technologies that could be used
where mass decentralized power generation feeds into the grid.
Toshiba has developed a micro nuclear reactor that uses lithium-6 for fuel
and can produce several hundred kilowatts of power for several years.
Another competing group proposes to develop atomic batteries use the
isotopes from spent nuclear fuel rods. Each atomic battery is estimated to
be able to continually generate electric power without using nuclear
reactors for up to 28 years. The spent atomic batteries would contain a
radiation-free form of strontium. Hyperion Technologies has developed a
sealed nuclear battery that uses uranium hydride fuel. Each generating unit
can be buried underground from where it may generate up to 25MW for up to
five years when the unit would be returned to Hyperion and recharged.
Conclusion
Buildings with off-grid decentralized power generation and energy storage
capability may be independent of any outside power line while serving the
needs of building owners and their tenants. Decentralized power generation
that is connected either to privately owned power lines that connect to
other buildings or to the power transmission grid can serve the needs of a
larger community. There is future role for both types of decentralized power
generation where they may co-exist with various forms of renewable and
non-renewable forms of centralized mega-power generation installations.
Copyright © 2002-2006,
CyberTech, Inc. - All rights reserved.
|