During the Industrial Revolution, the power of steam provided the means to rotate turbines connected by an axle to generator coils placed within an induced magnetic field to generate electricity. The bulk of electricity generation is still produced using this principle.
A generator converts rotational energy (kinetic energy) into electrical energy. Using Faraday’s Law of Induction, a conductive loop is moved through a magnetic field, and an electrical potential is induced in the loop. Various sources can supply the rotational energy to generate the power.
The means of transforming kinetic energy (movement energy) to potential energy (electrical voltage difference) has been done according to the original steam-generated method to modern wind turbines. The modes of energy generation are:
- Hydro-electrical power
- Nuclear heated steam power
- Coal-fired steam power
- Wind turbines
- Wave turbines
- Internal combustion engine-powered generators
As the means to generate electricity depends on the available resources to provide the kinetic energy in a specific area, the type of generator used will be selected. Let’s look at how electrical generators work and what powers them.
When Was The Electrical Generator Invented?
Rapid advancements in the field of electrical conductivity and the generation of electricity were made from the late seventeen hundreds and into the eighteen hundreds.
The contributions from now-famous names have left their mark on the field of electricity. Benjamin Franklin’s famous conductivity experiment flying a kite in the middle of a thunderstorm is evidence of the fascination caused by electricity.
The invention of the battery by Alexandro Volta helped Michael Faraday and Joseph Henry to discover the relationship between electricity and magnetism. Their research that led to the discovery of the first electric motor led to establishing a power generating station in lower Manhattan.
The First Power Generator
Sir Charles Parsons built the first coal-fired steam-powered alternating current generator in 1884. By early 1900 many coal-fired steam generators and hydro-powered generators were operational.
The efficiency with which the first steam generators converted thermal energy into electrical energy was initially quite poor.
The first coal-fired steam generator only had a conversion efficiency of 1,6%, but advancements in the generator efficiencies rapidly led to conversion efficiencies of 15%. Improvements in how coal was crushed before burning and steam engine designs led to more efficient power generation.
General Electric
General Electric developed and patented the gas turbine generator and became the most efficient form of power generation in the 1950s. Companies like Westinghouse and General Electric became household names as the demand for electricity in homes and factories grew.
After the development of the atomic bomb during the final years of World War II, atomic power stations became the most sensible application of the power of the atom. The post-WW2 global economic boom was powered by coal, gas, hydro, and atomic-fueled power stations.
These modes of power generation have resulted in significant progress for the human species and have also resulted in significant damage to the environment. Even the most environmentally friendly hydropower generators have caused some unintended consequences.
Wind and wave-powered electrical generators are more recent to the mechanical power generation model. Solar power generation uses photovoltaic cells to generate electricity to power the energy grid.
What Are Generators Used For?
Generators can range from small domestic fuel-powered generators that produce enough power to provide electrical supply to a limited number of domestic appliances. They can power the lights and some essential appliances during electrical power outages. These generators are typically AC-type generators producing about 2500 W of power output.
Wind generators are often used in conjunction with solar panels to charge the battery bank of homes, yachts, RVs, and other off-grid locations. By deploying wind and solar power generators in tandem, the charging of the battery bank can happen during all times of day and night as long as there is some wind or sun available.
Remote Work
More powerful gas or diesel-powered generators are used on construction sites or remote work locations where power is needed to drive tools and lighting. These generators can provide a single or three-phase power and must be sized to provide power to all the applications that need to run simultaneously.
Large diesel generators are deployed to provide emergency backup power to hospitals and business premises. These generators will provide power to run the critical life support systems or security and lighting systems during power outages.
Industrial-sized gas turbine power generators provide power to run factories or drive large electrical systems such as the headgear of mines. These are often deployed where the grid power supply is unavailable or to keep critical processes powered up in case of grid power outages.
Coal Power Stations
Large coal-fired steam-driven power stations or nuclear power stations provide the baseload power to national and regional power grids. The baseload power supply has to be available at all times for the power grid to be operational. Large power generators are great at providing a large steady output of power continually.
The baseload power can be augmented by hydroelectric, wind, solar, and other types of generators that can be engaged as required. The maximum power demand in metro areas is between 4 pm and 8 pm when families cook supper, take baths and showers, use the lights, and do domestic chores.
Off-Peak Power
In off-peak times, the power supply is managed by the large baseload power generation plants and is normally available at lower rates than during peak demand times. Utility companies have to manage the power demand cycle and switch on power supply from auxiliary generators as the demand increases.
Let’s consider how many appliances and tools at home and work are powered by electricity and how helpless we become in the event of a power outage. We can appreciate that all the power needed to enable our way of life is has to be generated.
Since the invention of the steam engine and electricity in the eighteen hundreds, humanity has fast become addicted to the luxury of having power on demand in our homes. The generators used to supply this power are powered by mountains of coal or fossil fuels.
Industrial Revolution
Since the advent of the Industrial Revolution, power generation has resulted in so much burning of fossil fuels that the CO2 level in the earth’s atmosphere has increased above the critical level of 400 parts per million. As CO2 is a greenhouse gas that traps the sun’s energy in the atmosphere, it has led to global warming of more than 1.5 degrees Fahrenheit.
Sources of power generation that do not generate CO2 have been the focal point for engineers during the past thirty years to lessen the catastrophic effects of climate change. Nuclear energy is a good candidate, but it has some real challenges due to the disposal of nuclear waste and reactor meltdowns.
The nuclear disasters at Three Mile Island, Chernobyl, and Fukushima have caused many governments to phase out nuclear energy and introduce renewable energy sources. Large wind farms have been erected on land and shallow coastal waters to generate grid power in conjunction with massive solar arrays.
Tax Incentives
Governments have also created incentives for homeowners to install wind and solar-powered generators to supply domestic needs and feed surplus power into the grid. Net-metering arrangements with power utility companies allow homeowners to supply power from their home solar and wind generators to the grid and buy some back during peak demand hours.
The net-metering system determines whether the homeowner has a net positive income from power generation versus consumption.
The future of domestic solar power generation is very good as the production costs of solar panels have been significantly reduced as the manufacturing efficiency improved.
How Does A Mechanical Generator Work?
The mechanism used to generate electricity is to convert mechanical movement to electrical power is simple. The following methods can drive the rotation of a turbine:
- Hydraulic pressure of water at dam walls or waterfalls;
- Stream pressure generated by coal heating up water in a confined vessel
- Stream pressure generated by atomic radiation heating up water in a confined vessel
- A hydrocarbon-based combustion process generates gas pressure
- Air pressure on a wind turbine blade
- Water pressure on a wave generator
The mechanical rotation of the turbine will rotate the coiled conductor wire, which is surrounded by a magnetic field. The magnetic field is created by installing permanent magnets or electrically induced magnets.
The armature is the neatly wound-up wire coils around a metallic shaft that rotate the wire coils through the magnetic flux field. The movement of the coils through the magnetic field induces an electric potential difference between the ends of the coil wire.
Turbines
The turbine that supplies the rotational movement of the coil through the magnetic field is also called the prime mover. The movement of the prime mover can be due to high-pressure water, steam, or air flowing over the turbine’s blades and causing it to rotate.
The electrical potential generated by the magnetic field excitation in the conductive wire can be drawn as alternative current (AC) or direct current (DC) depending upon the arrangement of the connector brushes. The domestic power grid is 110 Volt at 50 Hertz, and it is most common to find that power generators produce AC power.
Direct Current (DC) power generators are useful in certain applications, such as powering the headgear of lifts in buildings and mines. DC power is also used to power the electric motors on trains or large lighting plants.
Are Photovoltaic (Solar) Power Generators The Answer?
The amount of solar energy that reaches the earth’s surface is ten thousand times more than our total energy needs. More solar power reaches the surface of the earth in one hour than what all of humanity needs in a year. It is estimated that a land surface the size of Spain would be sufficient to power the earth’s total needs by 2030.
The global energy demand is set to increase threefold in the next thirty years. The aging infrastructure of existing power generation and the critical need to arrest CO2 emissions pose the greatest challenge for humanity.
Scenarios to slow down and reverse the effects of global warming are essential for the viability of life on earth. Unfortunately, a single array of solar panels equivalent to the size of Spain placed in the middle of the Sahara Desert will not work. The sun only shines with sufficient intensity for about six hours per day at any one location.
If we were to spread out the solar panels to the rooftops of every home and provide sufficient energy to power all households with solar energy, we are almost there.
The challenge is not generating enough solar power but storing the energy when the sun no longer shines. Battery technology is advancing in leaps and bounds as the transition from internal combustion-powered vehicles to electric vehicles is happening rapidly.
Energy Storage
Energy storage systems are also being developed and deployed to capture solar energy during nighttime. Hydroelectric dams as simple batteries. Solar power generated during the day pumps water from a low-lying dam to a dam at a higher elevation.
When the energy is required at nighttime, the water from the upper dam is released to drive turbines that generate power.
Solar Energy
The solar heat is concentrated on a single point where the temperature is used to melt salt solutions. The salts are solid at room temperature, but it turns into a liquid that retains the heat for a very long time when superheated.
The superheated salt solution is used to boil water and generate steam pressure. The steam pressure is then used to drive turbines and generate electricity.
Solar energy alone is not yet able to provide the baseload power. Still, the development of Advanced Small Modular Nuclear (SMR) reactors is making progress and maybe the answer to providing a baseload power supply.
The SMR does not pose the same risk as to the aging nuclear reactors and is more stable and easier to control.
There are currently more than seventy projects to install SMR technology. The decommissioning and replacement of the conventional nuclear power stations with SMR and renewable energy such as solar and wind generators are essential if humanity succeeds in stabilizing and reversing the effects of global warming.
References:
- https://www.rigb.org/our-history/iconic-objects/iconic-objects-list/faraday-generator
- https://www.powermag.com/history-of-power-the-evolution-of-the-electric-generation-industry/
- https://www.energy.gov/articles/top-6-things-you-didnt-know-about-solar-energy
- https://www.businessinsider.com/map-shows-solar-panels-to-power-the-earth-2015-9?IR=T
- https://www.energy.gov/ne/advanced-small-modular-reactors-smrs
