Dams and Electricity – How does it Work?
There
are many dams around the world that create electricity to power cities and
villages all over the country, providing an essential service to people living
in rural areas who often don’t have access to other sources of electricity or
fuel. However, how exactly does electricity generated from dams work? And how do
dams produce electricity in the first place? This guide explains everything you
need to know about the relationship between dams and electricity.
Introduction
Dams are
used for many things. Some dams are made to provide water for people to drink, while others hold back large amounts of water, creating reservoirs that can be used
for recreation, irrigation, or hydroelectricity. When a dam is used for
hydroelectricity, it produces electric energy by using turbines that are
powered by flowing water.
Here’s
how electricity is generated in dams. The amount of water flowing into a dam
has to match exactly the amount going out. If more water flows into one
end than goes out at another, there will be flooding downstream (in other
words, if you don’t have enough space at your end to put all that extra water).
Similarly, if more water is coming out than what goes in (perhaps because you
need less), there will be drought upstream. That makes sure that not too much
pressure builds up behind a dam—but it also means you can't use too much power
from your dam!
Hydroelectricity
This is
how dams generate most of their power. It's generated when water flows over
turbines that turn a generator. This means that a dam can be powered only by
water (or ice, in some cases). The rate at which electricity is generated
depends on many factors: wind velocity, river flow, size of the generator, the slope of the riverbed, etc. For example, Hoover Dam has a maximum generating capacity of
2,074 megawatts. This is because its 765-foot tall concrete arch-gravity design
lets water rush through quickly.
To
understand how dams generate hydroelectricity, we must take a look at how water
pressure changes in relation to depth. Since water is denser than air, a column
of water exerts more pressure as you go deeper into it. Think about a long tube
(like a pipe) filled with both air and water: The higher you go in that tube,
the greater the force on your feet from all of that weight pressing down on top
of you. If you want to know what those forces are exactly, check out Newton's
law of gravity. If water flows through turbines attached to an electrical
generator when there’s high pressure beneath it, electricity will be generated
once they spin around fast enough.
To
determine how much electricity a dam can generate, engineers multiply water
flow in cubic meters per second by its head or elevation change. A river's head
is its difference in elevation between two points. For example, if a river has
a height difference of 10 feet between the source and end point, that means there
are 100 feet of drop over a distance of 1000 miles (elevation = √(length x
width)). For hydroelectricity to be produced efficiently, dams must have large
generators as well as high head ratings. Large generators also mean that you
need more water pressure in order to generate more electricity at higher flow
rates.
Types of Hydropower Plants
The most common types of hydroelectric power plants
are run-of-the-river, reservoir, and pumped storage. In a run-of-the-river
plant, water goes directly from a river to electricity turbines with little or
no temporary storage. A reservoir plant has a dam that provides holding
capacity for excess generation in order to meet peak demands. A pumped storage
plant uses off-peak energy to pump water from one location up into a reservoir.
Then when demand is highest, electricity generators use water stored at a high
elevation to turn turbines that produce electricity.
Each type of hydropower plant uses different methods
to extract energy from moving water. To produce electricity, a power station
usually has multiple turbines that spin around and create kinetic energy. The
force of moving water pushes them, which spins a shaft in a generator that
produces an electrical current. A run-of-the-river plant captures only water
flowing past, while reservoir plants use either an offshoot of river flow or
pumped water to fill up reservoirs at different levels behind dams. A pumped
storage plant creates both types by using off-peak electricity to pump water
from one location into another reservoir at a higher elevation.
Advantages of Generating Electricity Through Hydropower
Creating electricity through hydropower is
cost-efficient, especially when considering its ability to generate large
amounts of power from a relatively small amount of water. A typical
hydroelectric dam can produce anywhere from 20 to 60 megawatts (MW) of energy
depending on how much water passes through it. In addition, once constructed,
there are virtually no running costs associated with hydropower beyond paying
for an annual inspection by a safety inspector. That means that once you’ve
paid to build your dam, it will continue to generate electricity without using
any additional resources or requiring any more money spent on upkeep. If you
add up all those benefits, you’ll see why many people are interested in
learning more about hydroelectric power generation!
Building a new dam isn’t always possible or
feasible, however. For instance, many existing dams have either been
decommissioned because they have gone obsolete or are not generating enough
electricity to be profitable any longer. These dams could represent another
great opportunity to learn about building new infrastructure while reaping all
of their existing benefits at the same time! For instance, even if a dam only
generated 1 MW before being decommissioned, installing solar panels alongside these
old turbines could help offset some initial costs and increase profitability
over time.
Disadvantages of Generating Electricity through Hydropower
Although hydroelectricity provides an eco-friendly
source of energy, it is not without its drawbacks. Hydroelectric dams can be
expensive to build and take years to construct. Additionally, generating
electricity through hydropower takes a lot of water (to create large quantities
of electricity), which can lead to problems downstream or cause flooding in some
areas (as a result of decreasing water levels). This means that creating
hydroelectric power can sometimes lead to negative environmental impacts.
However, some environmentalists argue that although these issues exist, they
are often offset by other advantages associated with hydropower such as
reducing carbon emissions or providing stable energy supplies. Furthermore, new
technology has allowed researchers to improve efficiency in generators and
minimize environmental impacts caused by hydro projects.
Despite these concerns, hydroelectricity is still
considered to be an environmentally friendly source of energy. For instance, it
does not emit any greenhouse gases into Earth’s atmosphere like fossil fuels do
(which contributes to climate change). Additionally, unlike nonrenewable forms
of energy, hydroelectric power does not run out over time. Hydroelectric dams
are designed to be dispatchable in that they can store electricity until
needed. If a drought strikes and water levels drop, operators can simply release
water from storage into a reservoir where it can later be used when needed.
This means that hydropower provides a steady source of electricity over time
regardless of weather fluctuations or seasonal changes in demand.
Conclusion
Dams
have a lot of benefits. They supply electricity, create employment
opportunities, and play a key role in flood control. However, they also result
in flooding for people who live downstream. While there are plenty of benefits
to damming rivers, there are also drawbacks that should be considered carefully
when deciding whether or not to build one in an area that has been historically
flooded. Flooding is an important consideration because dams help control
floods by impounding water behind their walls when water levels get too high.
This water can then be released back into the river at a more controlled pace
later on downstream which prevents flooding from occurring further downstream
as well. On top of protecting communities against flooding upstream dams also
protect them from being damaged by flooding even further downstream.