How to make Electricity?

Different Ways to Make Electricity

Electric power generation is typically a two-step process in which heat boils water; the energy from the steam turns a turbine, which in turn spins a generator, creating electricity. The motion of steam produces kinetic energy, the energy of moving objects. You also get this energy from falling water. It is directly proportional to the speed of the moving body – the faster it moves, the greater the energy. Electricity is produced when kinetic energy turns copper coils (or wire) within the turbine.

Dynamos and Generators

A key part of most electric power plants is the generator, a device that turns rotary motion into electricity. Inside the generator, coils of copper wire spin inside a strong magnetic field. As the coils move, the magnetic field creates the flow of alternating current (AC) electricity inside the wire. The source of the rotary motion, whether a windmill, a turbine, or a diesel motor, doesn't matter; it just has to be strong enough to turn the generator. The dynamo, a "cousin" of the generator, works in much the same way; however, it produces direct current (DC).

Electricity from Steam

A steam power plant (or generator) produces electricity by burning fuels, including biomass, coal, or petroleum. Steam generated from the process is fed into a turbine. The copper armature (wire) in the generator turns with the rotation of the turbine, producing an electric current. An example of a steam power plant is the Big Bend Power Station located in Tampa, Florida.

Hydroelectric Power: Falling Water

The electricity that is generated from water is called hydroelectricity. Falling water rotates the blades of a hydroelectric turbine, which in turn moves the copper armature inside the electric generator to produce electricity. An example of a hydroelectric power plant is the Great Hoover Dam (located near Las Vegas, U.S.). It has a total of 19 turbines that produce enough electricity to serve more than 1.3 million people annually.

Windmills: Energy from Wind

A wind power plant rotates the blades of a turbine, which move the copper armature (that lies within the generator) to generate electricity. Windmills have been utilized in the past to rotate the wheels of the attached mills. Modern windmills turn mechanical energy (generated from movement) into electrical energy. An example of a wind-powered electricity plant is the 107 Mega Watt (MW) wind farm located near Lake Benton, Minnesota.

Solar Power: Energy from Sunshine

Photovoltaic cells utilize the energy of the sunlight to produce electricity. Direct current (DC) is generated from stationary solar panels (which are made up of photovoltaic cells) and is commonly used for local applications, including running small-scale irrigation pumps or to charge battery-powered devices. Commercial-scale solar power plants are steadily gaining popularity with the increase in the price of fossil fuels. They function by trapping solar energy through large reflectors. The trapped energy is then directed onto receivers that use various technologies to generate electricity by powering gas or steam turbines. The Nellis Power Plant is the largest solar power plant in North America. It is located in the Nellis Air Force Base in Clark County, Nevada, near Las Vegas. The plant is made up of more than 70,000 photovoltaic solar panels and its maximum electrical capacity is estimated at 13 megawatts of alternating current (13 MW AC).

How Is Hydropower Gathered or Created?

Hydropower is the energy that derives from the movement of water. This movement is part of the Earth’s water cycle, which is the continuous circulation of water through the ground, oceans, and atmosphere. The amount of energy that moving water provides depends on the volume in motion, and its speed. Water is one of the oldest sources of energy. Ancient civilizations used hydropower for irrigation, and as a grinding mechanism for grain. In the modern period, hydropower provides 20 percent of the world’s renewable energy.

Water Wheel

Water wheels were the most common form of hydropower, from over 4,000 years ago through the 19th century. They converted the energy of flowing water into a rotary motion. This motion then powered the movement of stones and levers to grind grain, mineral ore, and cut lumber. The wheel lay horizontally or vertically in flowing water, such as a river or stream. Water flow forced the wheel to move when it hit paddles attached to the wheel’s external frame. Water power increased as it flowed through narrow channels or nozzles.

Turbines

Water turbines are a development from the water wheel and precursors of modern electricity generation. Rather than hitting a fixed paddle on a wheel, the water flow activates a spinning rotor that can have hundreds of blades. A shaft attached the rotor links to a turbogenerator, which is a giant magnet with a coiled wire inside of it. An electric current is generated in the turbine as the shaft turns.

Dams

Dams impound large volumes of water that flow from rivers and create a reservoir behind a retaining wall. A penstock is a pipe, or a sluice gate, from the bottom of the reservoir, passing through the dam, to a water turbine. Water from the reservoir flows at high pressure from the reservoir to the turbine and generates electricity. The Three Gorges Dam on the Yangtze River in China is the world’s largest hydroelectric installation where water flows powers 32 turbines.

Pumped Storage

Hydropower plant operators can store energy during periods of low customer electricity demand, and release it during periods of peak demand, using pump storage methods. During periods of low demand, water that has already flowed through turbines is pumped back to a separate storage reservoir above the turbines. This water flows back through the turbines during periods of peak demand. The system provides a quick start-up for extra power generation.

How Does a Waterfall Generate Power?

History

Humans have long been harnessing the power of naturally flowing water in order to make life more convenient. Before the invention of electricity, river waterfalls were used to move turbines, which powered mills that could grind wheat into flour far faster than any human hand. Not only were these machines so effective that they are still used today, but they became the mechanical basis for generators which could create electricity from the motion of falling water or hydroelectricity.

Turbines

The creation of hydroelectric power begins with a water turbine. This device consists of angled blades wrapped around a wheel. Its operation is analogous to that of a pinwheel with the turbine spinning as it comes into contact with moving water. When the turbine is placed in the path of falling water, the turbine moves a shaft which, in turn, powers an electrical generator.

Magnetic Generators

The type of electrical generator that is generally used to power water turbines is a standard electromagnetic generator. This machine works to convert mechanical energy (the energy of moving objects) into electrical energy. This is done through an apparatus which moves magnets around a conductor, generating an electromagnetic field that is then collected as electricity.

Damming

While hydroelectricity can be generated from naturally existing waterfalls, most hydroelectric plants generate water from human-made waterfalls. These waterfalls are made by building dams, which restrict the natural flow of a river into channels where the water will power turbines. This process maximizes the efficiency of energy collection because the control of the water flow creates higher pressure in a smaller area.

How to Calculate the Efficiency of an Electrical Generator

When an electrical generator incurs losses, its efficiency drops from 100 percent. The efficiency of a generator is determined by the power of the load circuit and the total watts produced by the generator. It is expressed as a percentage since you are dividing units of power by units of power. For most commercial electrical generators, this ratio can be upwards of 95 percent. The losses that are incurred typically arise from the transformer, the copper windings, magnetizing losses in the core, and the rotational friction of the generator.

Determine the amount of fuel consumed in an hour by the generator. You can use a diesel fuel consumption chart to calculate how much fuel is used in an hour by generators of various sizes.

Determine the total electrical power load consumed during an hour. This can be done by connecting a kilowatt-hour meter to the output of the generator, or by referencing the electrical output label on the generator.

Convert the amount of fuel used to British Thermal Units, or BTUs. The Oak Ridge National Laboratory has a chart that has the number of BTUs in various types of fossil fuels.

Convert the fuel's BTU value to kilowatt-hours by using the conversion factor of 1 kWh = 3413 BTU.

Divide the output of the generator in kWh by the input value of the fuel used in kWh. Multiply this figure by 100 to express it as a percent.

What Is the Electrical Power Source in Hawaii?





The group of islands that constitute the state of Hawaii sits atop some of the highest volcanic mountains in the world, and particularly in the case of the big island of Hawaii, the landmasses are still being formed by volcanic activity.

The islands are too young to have coal or oil deposits, and since it became a state in 1959 – and even before – Hawaii has depended on imported coal and petroleum to fuel electric plants.

With the adoption of the Hawaii Clean Energy Initiative (HCEI) in 2008, in partnership with the U.S. Department of Energy, the state began shifting its energy dependence toward renewable resources.

The state legislature made a bold move in 2015 by committing to generate 100 percent of its electricity from renewable resources by 2045. Since that decision, the percentage of Hawaii's electricity generated by fossil fuels has been declining.

Petroleum and Coal

In 2018, Hawaii had two crude oil refineries located in the Honolulu port area of the island of Oahu, but the U.S. Energy Information Administration (EIA) reported in 2017 that one was about to cease operations and sell its equipment to the other refinery.

According to the EIA, the crude came from Russia and other Pacific Rim suppliers, as well as from Africa and the Middle East. For the two decades prior to 2014, petroleum supplied three-quarters of Hawaii's electricity, but by 2017, that fraction had fallen to two-thirds.

Hawaii has only one coal-fired electric plant, located on the island of Oahu, and it produces about 180 megawatts a year, which represented about one-seventh of Hawaii's electrical consumption in 2017. Hawaiian Electric Company (HECO) supplies power to each of the main islands except Kauai, which has an electric cooperative. Each island has its own power grid and must generate its own electricity.

The Waves of the Future

Hawaii doesn't have any coal or oil of its own, but it does have significant natural resources, including some that aren't available elsewhere. It's one of only seven states with a utility-grade geothermal plant, which is located on Kilauea Volcano on the Big Island. It supplied almost one-quarter of the island's electricity, but it had to be shut down in 2018 when the volcano erupted and is expected to re-open in 2020.

Studies have also shown that wave energy in the ocean that surrounds the islands has the potential to generate a significant amount of energy. In addition, thermal currents in the ocean water can also be harnessed for electricity. Deep, cooler currents can also be drawn to the surface to provide cooling for nearby communities, thus reducing the need for air conditioning.

Visible Light Uses, Wind and Water

Hawaii's largest solar farm went online in 2017, generating 28 megawatts and effectively doubling the amount of solar electricity available on the islands. In addition, about half the households in the state (220,000 households), had solar panels installed in 2018, and state building codes require all new homes to have solar water heaters.

Solar panels convert visible light energy from the sun, as well as ultraviolet light, into electricity by virtue of the photovoltaic effect. In addition, Hawaii has over 120 wind turbines that convert its abundant onshore and offshore wind resources into 200 megawatts of electricity. In rural parts of the state, biomass such as sugarcane is converted into electricity.

Owing to its relatively small waterways, Hawaii doesn't generate much hydroelectric power, but a new hydroelectric plant came online on Kauai in 2019 to supply 6 megawatts annually. The Kauai Island Utility Cooperative is planning to integrate hydroelectric and solar generating stations to supply supplemental nighttime peak energy demands in the near future.

How Are Magnets Used to Generate Electricity?




When a conductor is placed in a changing magnetic field, the electrons in the conductor move, generating an electric current. Magnets produce such magnetic fields and can be used in various configurations to generate electricity. Depending on the kind of magnet used, a rotating electric generator can have magnets placed in different locations and can generate electricity in different ways. Most of the electricity in use comes from generators that use magnetic fields to produce that electricity.

Using Magnetism to Create Electricity

While an increasing amount of electricity is produced by solar panels and a small amount is obtained from batteries, most electricity comes from generators that use magnetic fields to create electricity. These generators are made up of coils of wire that are either rotated through magnetic fields or are stationary around a shaft with rotating magnets. In either case, the coils of wire are exposed to changing magnetic fields created by the magnets.

The magnets can be permanent or electric magnets. Permanent magnets are mainly used in small generators, and they have the advantage that they don't need a power supply. Electric magnets are iron or steel wound with wire. When electricity passes through the wire, the metal becomes magnetic and creates a magnetic field.

The coils of wire of the generators are conductors, and when the electrons in the wires are exposed to changing magnetic fields, they move, creating an electric current in the wires. The wires are connected together, and the electricity eventually leaves the power station and goes on to power homes and factories.

Trying to Build a Perpetual Magnetic Generator

When permanent magnets are used in a generator, you just have to turn the generator shaft to produce electricity. After these generators were first developed, people thought they could get the generator to power a motor that would then turn the generator. They thought if the motor and generator were matched exactly, they could build a magnetic power source that would run forever as a perpetual motion machine.

Unfortunately, it didn't work. Although such generators and motors are very efficient, they still have electric losses in the resistance of the wires, and there is friction in the shaft bearings. Even when the people doing the experiments got the generator-motor unit to run for a while, eventually it would stop because of the losses and the friction.

How a Typical Power Plant Generator Works

Large power plants have big, room-sized generators that produce electricity using magnetic fields from electric magnets. Usually the electric magnets are mounted on a shaft and are connected to the electric power supply. When the electricity is switched on, the electric magnets create powerful magnetic fields. Coils of wire are mounted around the shaft. As the shaft with the magnets rotates, the coils of wire are exposed to changing magnetic fields, and an electric current is generated in the wires.

Many different methods can be used to make the shafts of the generators rotate and produce electricity. In wind turbines, the propeller rotates the shaft. In coal and nuclear power plants, the heat from burning coal or from the nuclear reaction creates steam to run a turbine that drives the generator. In natural gas-powered plants, a gas turbine does the same job. Power plants need a source of energy that can make the generator shaft rotate, and then the magnets can produce the magnetic fields that generate electricity.

How to Convert Mechanical Energy Into Electric Energy

A battery converts chemical energy into electricity, and a solar cell produces electricity from the sun's energy, but if you want to produce electricity from mechanical energy, you need an induction generator. These generators can be small enough to power a crank-style flashlight or large enough to energize entire cities, but all work on the principle of electromagnetic induction, discovered by Michael Faraday, the 19th-century English physicist, and inventor. Today, induction generators running on a variety of fuels supply electricity for most of the world's population.

How Induction Works

Faraday's induction experiment is probably one of the most important in physics, and it was a relatively simple one. He coiled a length of conductive wire around a circular core and connected the wire to a meter. He found that moving a magnet through the center of the circle caused current to flow in the wire. The current stopped when he stopped moving the magnet, and it flowed in the opposite direction when he reversed the direction of the magnet. He later formulated the law of electromagnetic induction, now known as Faraday's Law, which related the strength of the current to the magnitude of the change of the magnetic field, also known as magnetic flux. The strength of the magnet, the number of coils around the core, and the characteristics of the conducting wire all influence calculations for real-world generators.

How Generators Use Induction

Whether located inside a household utility generator, your car, or a nuclear power plant, generators generally incorporate the same features. They include a rotor with a hollow core that rotates around a stator. The stator is typically a powerful magnet, while the coils that carry electricity are wound around the rotor. In some generators, the coils are wound around the stator and the rotor is magnetized. It doesn't matter. Either way, electricity will flow.

The rotor has to spin for electricity to flow, and that's where the input of mechanical energy comes in. Large-scale generators tap a variety of fuels and natural processes for this energy. With each rotation of the rotor, the current flow stops, reverses, stops again and returns to the forward direction. This type of electricity is called alternating current, and the number of times it changes direction in a second is an important characteristic.

Types of Fuel

The rotor in most generators is connected to a turbine, and in many generating plants, the turbine is steam-driven. Energy is needed to heat water to produce this steam, and that energy can be supplied by fossil fuels, such as coal and natural gas, biomass or nuclear fission. The fuel can also come from natural sources, such as geothermal energy – natural heat emanating from deep in the ground. Hydroelectric generators are powered by the energy of a waterfall. The world's first hydroelectric generator, designed by Nikola Tesla and built by George Westinghouse, is located at Niagara Falls. It generates about 4.9 million kilowatts of power, enough for 3.8 million homes.

Making Your Own Generator

It's very easy to construct a generator. Many designs are possible, but one of the easiest consists of a stationary coil and a rotating magnet. The wires are wound around a nail coated with insulating tape, and the magnet can be a simple horseshoe-shaped one. When you drill a hole through the base of the magnet, insert a tight-fitting shaft and attach the shaft to a drill, you can generate enough electricity to light a bulb just by operating the drill to make the magnet rotate around the coil.

How Does Nuclear Energy Get From the Plant to the Customer?

Nuclear power plants have many features in common with traditional electrical power facilities; the main difference is that they produce energy with radioactive materials instead of conventional fuels. The same commercial power grid carries electricity from nuclear and fossil-fuel plants as well as renewable sources. A series of power distribution lines carry the electricity from the sources to the end-users, including homes, commercial customers, government, and industry.

Nuclear Reaction and Heat

A nuclear reactor produces large amounts of heat from the controlled radioactive decay of elements such as uranium and plutonium. The nuclei of these heavy elements are unstable; they emit radiation in the form of neutrons, alpha and beta particles and gamma rays, becoming more stable in the process. As they produce radiation, they also become very hot. In a nuclear reactor, the heat is used as a substitute for the burning of coal or natural gas. Both fossil fuel and nuclear power plants use heat to boil water and make steam.

Steam and Generator

Pipes carry high-pressure steam from the nuclear reactor to a steam-powered turbine. The steam propels the turbine’s blades, causing the turbine shaft to spin rapidly, turning a generator that produces electricity. The steam condenses into water, which is recycled back to the reactor to become steam again. A typical nuclear power plant has several turbines and generators working in tandem.

Step-Up Transformer and High-Voltage Lines

A device called a transformer uses principles of electromagnetic induction to connect two alternating-current (AC) circuits together. In addition, a transformer can increase or decrease the voltage of the AC at its input; utilities use high-voltage lines to carry electricity long distances efficiently, so they employ step-up transformers near the power plant to increase a generator’s output. The transformer’s output voltage is set to match the capacity of local high-tension power lines, which may range from 230,000 to 765,000 volts.

Step-Down Transformers and Distribution

Power companies transmit electricity at high voltage to reduce energy losses, but the high voltage is not useful or safe for most customers. The high-voltage lines are connected to substations having step-down transformers that reduce the voltage for commercial and industrial users. Once the power lines reach the level of neighborhoods, the voltages are reduced further for home use. In the U.S., utilities provide 120-, 208- and 240-volt service for homes and small businesses.