Lecture 4 Review
Lecture
4's focus was wind power. An inherent advantage of wind power was
highlighted straight away in that it is direct in it's power
generation. The wind pushes the turbines round, which are directly
coupled to the generator, contrary to fossil fuel and nucleur (i.e. no
intermediate burning, steam generation and turnbine is needed). Another
interesting fact is that around
100 times more energy is converted to wind than is converted to biomass
by plants. These are some of the reasons why wind is among the fastest
growing sources of energy.
Historically
wind power was used in the form of windmills, which performed such
tasks as grinding crops. The basic idea has not changed, only now the
blades of the turbine drive a generator. Currently a wind turbine can
generate up to 5 MW of electricity, at a cost of about 5
cents/kiloWatt-hour. Denmark is the biggest wind power user, with over
20% of it's energy production coming from wind farms. This makes it a
clear leader in wind power usage, however many countries plan to expand
their renewable energy usage through wind power.
In
the United States, less than 1% of the electricity generated is from
wind, with the leading state being Texas, generating over 4 MW.
However with the decreasing costs involved, and and increase in the
power capacities of turbines, predictions for 2020 state that 6% of US
energy could be through wind power. There is a maximum efficiency of a
wind turbine of about 60%, due to Betz's Law, and it is impossible
to exceed this.
Wind
power technology has moved from drag type devices which had many
blades, to lift devices, which have only a few blades, which are
designed in a similar way to airplane wings. The turbine can
either have a horizontal axis or a vertical axis. With a vertical axis,
you do not need a yaw mechanism to turn the rotor into the wind.
However the turbine does need a motor to start moving. The Horizontal
axis is the more conventional design which is used in the majority of
cases. They typically have two or three blades, and do not require a
motor in the turbine. A downside is that they do generate more noise. The
different available technologies, along with the components that make
up a horizontal axis wind turbine, were covered in some details.
Some
cases brought against wind power are that it is noisy, kills birds and
requires too much land. These arguments can be seen to be weak, as the
noise is non mechanical, and it is possible to have a conversation
above it at they base of the turbine without difficulty. Wind turbines
are currently only responsible for 0.003% of bird deaths in the US, and
they land that they require can also be used for other things as they
take up very little space on it.
Historically
wind power was used in the form of windmills, which performed such
tasks as grinding crops. The basic idea has not changed, only now the
blades of the turbine drive a generator. Currently a wind turbine can
generate up to 5 MW of electricity, at a cost of about 5
cents/kiloWatt-hour. Denmark is the biggest wind power user, with over
20% of it's energy production coming from wind farms. This makes it a
clear leader in wind power usage, however many countries plan to expand
their renewable energy usage through wind power.In
the United States, less than 1% of the electricity generated is from
wind, with the leading state being Texas, generating over 4 MW.
However with the decreasing costs involved, and and increase in the
power capacities of turbines, predictions for 2020 state that 6% of US
energy could be through wind power. There is a maximum efficiency of a
wind turbine of about 60%, due to Betz's Law, and it is impossible
to exceed this.Wind
power technology has moved from drag type devices which had many
blades, to lift devices, which have only a few blades, which are
designed in a similar way to airplane wings. The turbine can
either have a horizontal axis or a vertical axis. With a vertical axis,
you do not need a yaw mechanism to turn the rotor into the wind.
However the turbine does need a motor to start moving. The Horizontal
axis is the more conventional design which is used in the majority of
cases. They typically have two or three blades, and do not require a
motor in the turbine. A downside is that they do generate more noise. The
different available technologies, along with the components that make
up a horizontal axis wind turbine, were covered in some details.Some
cases brought against wind power are that it is noisy, kills birds and
requires too much land. These arguments can be seen to be weak, as the
noise is non mechanical, and it is possible to have a conversation
above it at they base of the turbine without difficulty. Wind turbines
are currently only responsible for 0.003% of bird deaths in the US, and
they land that they require can also be used for other things as they
take up very little space on it.
