Engineering Issues
Modern commercial size wind
turbines are an amazing marvel of engineering. Along with hydroelectricity,
they are a commercially viable way of tapping the energy produced by a nuclear
fusion reactor - the sun - and they have the potential to produce hundreds of
times the power currently tapped in hydroelectric schemes. Unlike the
dams and reservoirs often required in such projects, which can be
environmentally altering and in many cases "mixed blessings", modern
wind turbines have negligible detrimental side effects. However, unlike many
electric power production techniques, large-scale wind power production is
difficult to conceal. It will mean that the source of this electricity will be
very apparent over a considerable area, unless it is very foggy or dark. To
some, these are a graceful way of making pollution-free electricity, while
others may view these as being similar to cell phone, radio, TV and microwave
towers - an alteration the landscape.
A modern turbine may seem to
be simple enough to design, build and operate, but the reality of the design is
far more complicated. These are highly automated, computer controlled
systems that tap a variable source of energy - the wind - and can change its
form into electricity that can be connected into the electrical grid, which is
also varying in load over the course of a day, as well as by the season. Very
advanced understanding of mathematics, meteorology, aerodynamics, mechanics,
electrical engineering, materials science, foundation engineering, acoustics
and industrial automation, combined with an understanding of how these systems
interact with the environment and society, are needed to manufacture, install
and operate a useful turbine. The success of those involved can be viewed in
their reliability (> 98 % "uptime"), and by observing wind
turbines in operation. They are very quiet, and very dependable - to the point
that they are easy to ignore, or they simply become another object of the
landscape to look upon. Here are some photographic
examples from one of the world's larger manufacturers, NEG-Micon
(obviously using their turbines).
The windy state of Buffalo
is well known to those who live in the area, and especially those who frequent
areas near Lake Erie. However, before anyone invests large amounts of money in
wind turbines, the average wind speed and the availability of land where
turbines could be located must be defined. Then other issues, such as the
stability of the power grid, the cost of energy produced by the wind turbines,
and the amount that could be produced can be estimated. These engineering
issues will need to be integrated with many other topics, such as environmental
concerns, the public perception and the public acceptability of this
technology.
To start off the process, a
discussion of what constitutes ideal sites and conditions for wind turbines in
the Buffalo area has been initiated. This will provide a basis to compare
proposed sites with an "ideal case" for both large arrays of
commercial scale turbines and possible locations for demonstration unit(s).
There are differing criteria for these two types of wind turbine installations.
Obviously, the most economical way to allow the community to judge this
technology would be to install a demonstration unit in an area of high
visibility and some accessibility to the general public. Otherwise, a lot of
tour buss rides will need to be undertaken to the nearest wind farms.
While the amount on
information about the wind speeds in the Buffalo area is far from optimum (and
which obviously should have been done several years ago, as is the case of many
other locations throughout the world), some of this does exist. This has been
utilized to provide some estimates of the potential for wind energy in this
part of this country's North Coast. The upcoming waterfront survey funded by
Erie County and NYSERDA is a welcome addition to the existing wind data. The existing
wind data from NOAA, the Buffalo Coast Guard Station and NYSERDA (including the
New York Wind Map) indicates that
commercially viable wind speeds exist in this area, especially along the Lake
Erie shoreline, where most of the data has been obtained. Most (over 80
%) of the "power winds" in this area are from a southwest to west
direction (see the "wind
rose" for the Buffalo Coast Guard Station location and a "Detail
Sheet").
Modern wind turbines can
produce electricity for less than 3.5 cents per kw-hr if the average wind
speed at the hub height is greater than 7 meters per second, or 15.7 miles per
hour. Wind speeds in Buffalo, like most places in the world, increase in
velocity as the height above the ground or lake surface increases. Knowledge of
how this relationship works is key to predicting the wind speeds at hub heights
from data obtained at lower heights, and often at the "standard"
height of 10 meters (about 33 feet). Modern sophisticated computer programs can
also accurately predict local wind speed patterns as a function of height and
location (this takes into account the terrain and "ground obstacles"
such as buildings, trees and elevated roadways). However, these simulation
programs (such as WAsP, WindFarm, WindPro, WindSim, WindFarmer) still need a
starting point of known wind speeds at a known height and location, and the
more information that they use for their initial conditions, the more accurate
they become.
As the average wind speeds
increase, the power production costs decrease in a significant manner. Turbines
to be used in this area need to be designed for moderate wind speeds, as
opposed to the generally impressive winds experienced in Northern Scotland,
which is one of the windiest locations in the inhabited parts of the planet.
Fortunately, there are several models of turbines that fit the bill for the
Buffalo area. Perhaps Buffalo will soon follow in the footsteps of Toronto,
Tokyo and many cities in Europe, such as Hamburg and London, and allow the
public to experience and judge this technology up close and personal. If the
community decides that this power generation route is acceptable, then perhaps
the simulation, data gathering, planning, engineering, and design work can be
done in a more robust manner. Then we may be able to tap some of the
region's huge wind energy potential for something other than a topic of
conversation.
Dave Bradley
Chair, WAG Engineering Committee
4-05-03