Continual power system

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A continual power system is a system for reliably supplying uninterrupted power. Examples of a continual power system include uninterruptible power supplies and emergency power systems. The need for continual power systems has risen because more and more essential services depend on consistent power, such as lighting, computing, and communications. [1]

Contents

Continual power systems are used because energy provider's roles and responsibilities are not rigorously defined.

The key to reliable power systems is to avoid power disturbances, such as deviation of voltage or current in an ideal single-frequency sine wave with constant amplitude and frequency. [2]

In a study conducted in 2011 with Flemish households, researchers found that a relatively small share were willing to accept lower reliability in return for a small bill discount. [3]

Flywheel

An example of a continual power system is the flywheel, which is common on colocation sites. These consist of an electric motor, a flywheel, a generator, and a diesel engine. In normal operation, the electric motor, supplied from the grid, turns the flywheel which in turn, turns the generator. In the event of generator failure, the flywheel keeps the generator turning while the diesel engine restarts. The flywheel is an effective way of governing the Flywheel Energy Storage System (FESS) for wind power smoothing. It stores in the range of 89-93% of the mean state of charge which means that as the blades on the flywheel turn, between 89-93% of the energy is stored. [4]

Turbines

A turbine is a set of blades that are forced to turn by an external energy source. When the blades start turning, the shaft to which they are connected starts to spin, and the generator then creates electricity. Examples of external forces that can power turbines include wind, water, steam, and gas. Turbines can be used in creating a continual power system because as long as the blades turn, power is created. [5]

Microbial fuel cells

Microbial fuel cells create energy when bacteria break down organic material. This produces a charge that is transferred to the cell's anode. Human saliva, which has much organic material, can be used to power a tiny microbial fuel cell. This can produce sufficient energy to run on-chip applications. This application can be used in things such as biomedical devices and cell phones. [6]

A study evaluated microbial fuel cells to create electricity and treat wastewater. During a five-month time period, a sucrose-based solution continuously generated electricity of 170mW/m2. Power density grew with increasing chemical oxygen demand up to 2.0g COD/day with no increase in power density after that. This shows that while this system can continuously provide electricity, it has its limitations. [7]

Related Research Articles

<span class="mw-page-title-main">Electricity generation</span> Process of generating electrical power

Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery to end users or its storage.

<span class="mw-page-title-main">Auxiliary power</span>

Auxiliary power is electric power that is provided by an alternate source and that serves as backup for the primary power source at the station main bus or prescribed sub-bus.

<span class="mw-page-title-main">Uninterruptible power supply</span> Electrical device that uses batteries to prevent any interruption of power flow

An uninterruptible power supply (UPS) or uninterruptible power source is a type of continual power system that provides automated backup electric power to a load when the input power source or mains power fails. A UPS differs from a traditional auxiliary/emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions by switching to energy stored in battery packs, supercapacitors or flywheels. The on-battery run-times of most UPSs are relatively short but sufficient to "buy time" for initiating a standby power source or properly shutting down the protected equipment. Almost all UPSs also contain integrated surge protection to shield the output appliances from voltage spikes.

<span class="mw-page-title-main">Electric generator</span> Device that converts other energy to electrical energy

In electricity generation, a generator is a device that converts motion-based power or fuel-based power into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all the power for electrical grids.

<span class="mw-page-title-main">Starter (engine)</span> Device used to start an internal combustion engine

A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.

<span class="mw-page-title-main">Power station</span> Facility generating electric power

A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.

Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).

<span class="mw-page-title-main">Cogeneration</span> Simultaneous generation of electricity and useful heat

Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time.

<span class="mw-page-title-main">Fossil fuel power station</span> Facility that burns fossil fuels to produce electricity

A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.

<span class="mw-page-title-main">Grid energy storage</span> Large scale electricity supply management

Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.

<span class="mw-page-title-main">Peaking power plant</span> Reserved for high demand times

Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the power supplied commands a much higher price per kilowatt hour than base load power. Peak load power plants are dispatched in combination with base load power plants, which supply a dependable and consistent amount of electricity, to meet the minimum demand.

<span class="mw-page-title-main">Thermal power station</span> Power plant that generates electricity from heat energy

A thermal power station is a type of power station in which heat energy is converted to electrical energy. In a steam-generating cycle heat is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a steam turbine connected to an electrical generator. The low-pressure exhaust from the turbine enters a steam condenser where it is cooled to produce hot condensate which is recycled to the heating process to generate more high pressure steam. This is known as a Rankine cycle.

<span class="mw-page-title-main">Emergency power system</span>

An emergency power system is an independent source of electrical power that supports important electrical systems on loss of normal power supply. A standby power system may include a standby generator, batteries and other apparatus. Emergency power systems are installed to protect life and property from the consequences of loss of primary electric power supply. It is a type of continual power system.

<span class="mw-page-title-main">Off-the-grid</span> Not being connected to public utilities

Off-the-grid or off-grid is a characteristic of buildings and a lifestyle designed in an independent manner without reliance on one or more public utilities. The term "off-the-grid" traditionally refers to not being connected to the electrical grid, but can also include other utilities like water, gas, and sewer systems, and can scale from residential homes to small communities. Off-the-grid living allows for buildings and people to be self-sufficient, which is advantageous in isolated locations where normal utilities cannot reach and is attractive to those who want to reduce environmental impact and cost of living. Generally, an off-grid building must be able to supply energy and potable water for itself, as well as manage food, waste and wastewater.

<span class="mw-page-title-main">Hybrid power</span> Combinations between different technologies to generate electric power

Hybrid power are combinations between different technologies to produce power.

<span class="mw-page-title-main">History of wind power</span> Aspect of history

Wind power has been used as long as humans have put sails into the wind. King Hammurabi's Codex already mentioned windmills for generating mechanical energy. Wind-powered machines used to grind grain and pump water — the windmill and wind pump — were developed in what is now Iran, Afghanistan, and Pakistan by the 9th century. Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American midwest or the Australian outback, wind pumps provided water for livestock and steam engines.

Most forms of uninterruptible power supply (UPS) can be either powered by battery or flywheel energy. These are ready for immediate use at the instant that the mains electricity fails, but the relatively small and finite amount of stored energy they contain makes them suitable for short periods of use, typically in the order of a few dozen minutes to a couple of hours depending on the actual load. To get uninterruptible and continuous power supply, a diesel-generator back-up system is needed along with a fuel supply plan that includes on-demand replacement.

<span class="mw-page-title-main">Wind turbine</span> Machine that converts wind energy into electrical energy

A wind turbine is a device that converts the kinetic energy of wind into electrical energy. As of 2020, hundreds of thousands of large turbines, in installations known as wind farms, were generating over 650 gigawatts of power, with 60 GW added each year. Wind turbines are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, as of 2009, wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas energy sources.

<span class="mw-page-title-main">Power plant engineering</span>

Power Plant Engineering or Power Plant Engineering abbreviated as TPTL is a branch of the field of Energy engineering, and is defined as the engineering and technology required for the production of an electric power station. Technique is focused on power generation for industry and community, not just for household electricity production. This field is a discipline field using the theoretical basis of mechanical engineering and electrical. The engineering aspects of power generation have developed with technology and are becoming more and more complicated. The introduction of nuclear technology and other existing technology advances have made it possible for power to be created in more ways and on a larger scale than was previously possible. Assignment of different types of engineers for the design, construction, and operation of new power plants depending on the type of system being built, such as whether it is power generation fueled fossil, NPP, hydropower plant, and solar power plant.

References

  1. A. Ganjehkaviri, M.N. Mohd Jaafar (2015, January) "Optimization and the effect of steam turbine outlet quality on the output power of a combined cycle power plant." "Energy Conversion and Management" 89(1), 231–243
  2. Moreno-Munoz, A., Juan José González De La Rosa, Flores-Arias, J., Bellido-Outerino, F., & Gil-De-Castro, A. (2011, April) “Energy efficiency criteria in uninterruptible power supply." Applied Energy 88(4), 1312-1321
  3. Pepermans, G. (2011, December) "The value of continuous power supply for Flemish households. Energy Policy". "Energy Policy" 39(12), 7853-7864
  4. Díaz-González, Francisco, Andreas Sumper, Oriol Gomis-Bellmunt, and Fernando D. Bianch (October, 2013) "Energy management of flywheel-based energy storage device for wind power smoothing". "Applied Energy" 110, 207-219
  5. Energy.gov. (n.d.) “How Do Wind Turbines Work?” “Office of Energy Efficiency & Renewable Energy”
  6. Messer, A'ndrea (2014, April) "Tiny power generator runs on spit." "Penn State"
  7. He, Zhen, et.Al. (2005, June) "Electricity Generation from Artificial Wastewater Using an Upflow Microbial Fuel Cell"