Glossary for Energy
Term
Aerogenerator
Aesthetic
Definition
Wind turbine
the issue of the appearance of things, e.g. the intrusion of power stations, wind
farms and pylons on the landscape.
Affluence
Increased income, generally
Air resistance
When a vehicle moves forward it must push the air apart. This uses energy that is
lost as frictional heat. The smoother its passage through the air is, the less energy
will be used and lost as friction. The amount of energy lost to air resistance
increases exponentially as the speed of the vehicle increases. Aerodynamics is the
attempt to design vehicle shapes that create as little air disturbance and
turbulence as possible, thereby reducing fuel consumption.
Available
The quantity of fossil fuels that exist is very large. Uranium is abundant but usually
energy resource at very low concentrations. Solar, wind, wave, tidal power vary in availability
Barrage
a dam built across an estuary with turbines for one-way or two-way generation
-see tidal barrage
Base load
Baseload (also base load, or baseload demand) is the minimum amount of power
that a utility or distribution company must make available to its customers, or the
amount of power required to meet minimum demands based on reasonable
expectations of customer requirements. Baseload values typically vary from hour to
hour in most commercial and industrial areas
Biofuels
are a wide range of fuels which are in some way derived from biomass. The term
covers solid biomass, liquid fuels and various biogases. This may be in its natural
form (e.g. wood, peat) or a commercially produced form (e.g. ethanol from
sugarcane residue, diesel fuel from waste vegetable oils).
Catchment area Where the water from a river is sourced
Carbon neutral The fuels only release the same amount of carbon dioxide as they absorbed during
growth.
Concentrating
(CSP) systems use lenses or mirrors and tracking systems to focus a large area of
Solar Power
sunlight into a small beam. The concentrated heat is then used as a heat source for
a conventional power plant. A wide range of concentrating technologies exists; the
most developed are the parabolic trough,
Condenser
Where water vapour has been used to turn turbines in power stations, the steam is
cooled in order to be recycled or placed in rivers or seas without thermal pollution.
Often cooling towers, but increasingly local heat power recycling.
Coppiced
Woodland where the trees are cut to ground level every 3 to 15 years. The
woodland
regrowing branches can be used as a biofuel.
Combined heat CHP The maximum efficiency of a modern thermal power station at converting the
and power
energy of a combustible or nuclear fuel into electricity using steam turbines is
about 40 per cent. The remaining 60 per cent is lost as waste heat energy, mainly
through the cooling water used to condense steam. This heat is discharged into the
environment through the cooling towers or into a river, lake or the sea. In a CHP
power station the heat energy is also used, as hot water for space heating of
homes, industrial buildings or for heating greenhouses or fish farms. In many CHP
control rod
Deep mining
Deplete
Drilling fluid
Dynamic tidal
power
Efficient
technologies
Electrolysis
Elephant grass
Energy density
stations the efficiency of electricity generation is deliberately kept below 40 per
cent. This increases the temperature of the hot water and increases its usefulness.
Is a rod made of chemical elements capable of absorbing many neutrons without
fissioning themselves. They are used in nuclear reactors to control the rate of
fission of uranium and plutonium. Designed for reactor safety e.g. gravity-drop
control rods that can shut down a reactor very quickly a strong containment
building should prevent releases if there was a reactor explosion
involves extracts less non-coal material than open-cast mining but it is relatively
labour intensive, cannot use the largest equipment and suffers from problems of
ventilation, overburden support, drainage and subsidence of the ground surface.
to reduce the amount of a resource that is available.
Often used while drilling oil and natural gas wells and on exploration drilling rigs,
providing hydrostatic pressure to prevent formation fluids from entering into the
well bore, keeping the drill bit cool and clean during drilling, carrying out drill
cuttings, and suspending the drill cuttings while drilling is paused and when the
drilling assembly is brought in and out of the hole. They can be:
 Air: Compressed air
 Air/water: with water added to increase viscosity, flush the hole, provide
more cooling, and/or to control dust.
 Air/polymer: A specially formulated chemicale.g. a foaming agent
 Water: by itself
 Water-based mud (WBM): A blend resembling something like chocolate milk
and a malt e.g. bentonite, aka"gel" to achieve various effects, including:
viscosity control, shale stability, enhance drilling rate of penetration, cooling
and lubricating of equipment.
 Oil-based mud (OBM): The use of oil-based muds has special considerations.
These include cost and environmental considerations.
 Synthetic-based fluid (SBM): Synthetic-based fluid is a mud where the base
fluid is a synthetic oil. This is most often used on offshore rigs because it has
the properties of an oil-based mud, but the toxicity of the fluid fumes are
much less than an oil-based fluid. This is important when men work with the
fluid in an enclosed space such as an offshore drilling rig.
DTP exploits an interaction between potential and kinetic energies in tidal flows. It
proposes that (for example: 30–50 km length) dams be built from coasts straight out
into the sea or ocean, without enclosing an area. Tidal phase differences are
introduced by the presence and dimensions of the dam, which is not negligible in
size compared to the local tidal wavelength. This leads to hydraulic head
differences across the dam. Turbines in the dam are used to convert power (6–15
GW per dam). In shallow coastal seas featuring strong coast-parallel oscillating tidal
currents such as found in the UK, China and Korea, a significant water level
differential (of at least 2–3 meters) would appear across the dam
Often in MEDCs may require less energy per unit of output than in LEDCs e.g. the
steel industry in the USA compared with India or China.
the splitting of molecules using electricity (lysis = splitting).
Miscanthus -Energy crops may be deliberately grown for their energy value
the amount of energy in a particular mass of fuel or that can be harnessed by a
particular mass of equipment. It is easy to quantify as Joules per kilogram of fuel,
such as uranium, coal, oil, wood or straw. Uranium and plutonium have very high
Energy security
Ethanol
Finite resource
Fissile fuel
fresnel
reflectors
Fuel cell
Fuel rods
Generator
Geothermal
power
Half-life
harnessing
head of water
heat exchanger
Heat recovery
energy densities so reactors do not need continual refuelling and they can be used
where the delivery of bulky fuels may be difficult. By comparison, renewable
energy resources have low energy densities.
Governments may have policies that will encourage or discourage the use of
particular resources e.g. France subsidised the nuclear power industry to protect
the country from unreliable oil imports
sugar from sugar cane and sugar beet can be fermented to produce alcohol as a
replacement for petrol
a resource where the amount is fixed. The processes that produce fossil fuels are
too slow to replace what has been used by humans. Uranium is not being formed.
Although none of these will be totally used up, exploitable deposits may be
depleted. Uranium is abundant but usually at very low concentrations.
Improvements in technology have continually increased the amounts that can be
found and extracted.
a fuel where the nuclei of the atoms can be split by neutron bombardment,
releasing large amounts of energy
Concentrating linear fresnel reflectors are CSP-plants which use many thin mirror
strips instead of parabolic mirrors to concentrate sunlight onto two tubes with
working fluid. This has the advantage that flat mirrors can be used which are much
cheaper than parabolic mirrors, and that more reflectors can be placed in the same
amount of space, allowing more of the available sunlight to be used.
an electrochemical device that produces electricity from the chemical reaction
between two substances, usually hydrogen or an alcohol, and oxygen. A fuel cell is
similar to a battery but it will not go flat as long as there is a continual fresh supply
of the chemicals that are involved in the chemical reactions. The simplest fuel cell
uses hydrogen and oxygen. The hydrogen gives up electrons that are accepted by
the oxygen. The hydrogen and oxygen ions produced combine to produce water.
metal rod in which uranium in the form of ceramic pellets are contained. cylinders
of enriched uranium (~3% uranium-235 and ~97% uranium-238); the uranium-235
nuclei are the main source of released energy in nuclear power.
Machine that converts kinetic energy into electricity by use of magnets
Harnessing the heat from hot rocks, especially in areas of recent volcanic activity.
The heat comes from the gravitational forces from the formation of the Earth and
the decay of naturally occurring radioisotopes in the mantle
the time it takes for half the original material to be lost.
Method of gaining energy
drop in height HEP where gravity creates kinetic energy for turbines to turn and
generate electricity
can be used to ventilate a house, but without losing the heatLiquid and gaseous discharges from industry are often hot. While the material itself
may be a waste, the heat energy may not be. Heat exchangers recover the heat
from hot effluents and transfer it to the incoming cold gas or liquid. Heat
exchangers involve a container through which both hot and cold fluids pass. They do
not mix as one is carried in pipes. The efficiency of heat exchange can be increased
by good design:
 long, narrow pipes are used to increase surface area for heat exchange
 pipes are made of a good thermal conductor, e.g. copper
 the two fluids flow in opposite directions (counter-current flow)
Heliostat
horizontal axis
wind turbines
‘hydrogen
economy’
Insulation
Intermittent
Isotope
Kinetic energy
Low energy
appliances
mechanization
National Grid
Non-renewable
resource
Nuclear power
Nuclear waste
Oilfield
 a slow flow rate gives more time for effective heat exchange.
a device that tracks the sun so the angle of incident sunlight stays the same. A solar
power tower uses an array of tracking reflectors (heliostats) to concentrate light on
a central receiver atop a tower. Power towers are more cost effective, offer higher
efficiency and better energy storage capability among CSP technologies e.g. The
Solar Two in Barstow, California
These are traditional wind turbines
is the name given to the proposal that hydrogen storage could be used to allow
society to be run on abundant, convenient energy from renewable sources.
The amount of heat energy input needed to keep anything warm is equal to the
amount of heat being lost. So, if the rate of heat loss can be reduced, then there
can be an identical reduction in heat inputs. E.g. Insulation around furnaces and
hot liquid holding tanks can save a lot of energy.
a process that is not constantly available, e.g. Tidal power is intermittent but very
predictable. Direct solar power has fluctuating supplies (Daily, seasonal, climatic )
Effect of clouds and suspended particles on scattering
A variety of an element where the number of neutrons is different.
the energy of movement e.g. wind turbine, HEP
The right choice of domestic appliance can help reduce energy use e.g. compact
fluorescent lights use less electricity than tungsten filament bulbs. E.g. thicker
insulation on ovens, refrigerators and freezers reduce electricity use lights can have
controls that turn them off automatically when natural light levels rise or when the
room is empty
The availability of energy has a significant impact on quality of life and the
development of societies. A shortage of energy inhibits many developments that
could benefit a communities e.g. mechanization of labour-intensive processes,
energy to process materials, transport, water pumping and purification
the distribution of electricity around the country from where it is generated to the
areas of demand. However, the resistance of the cables causes some energy to be
lost as heat. This energy loss is reduced if the electricity is transported at low
current, but this would cause the electrical power to be reduced. The power is
maintained by increasing the voltage of the electricity.
a resource that is renewed so slowly that the amount available for use is effectively
finite.
Large amounts of energy are released when small amounts of matter from the
nuclei of atoms are destroyed.
•Nuclear fission involves the splitting of the nuclei of fissile fuels that have large
atoms, such as the isotopes uranium 235 and plutonium 239.
•Nuclear fusion involves the joining of the nuclei of small atoms, such as the
isotopes hydrogen 2 and hydrogen 3.
Only nuclear fission is commercially viable at the moment; fusion being a research
project. In nuclear reactors, uranium is used to heat water to generate electricity.
Nuclear reactors are normally reloaded with new fuel every 12–24 months, during a
stop when maintenance also is done. Nuclear power is used as a base load power in
many energy systems.
Radioactive Wastes are easier to manage in solid form than if they are liquids or
gases
is a region with an abundance of oil wells extracting petroleum (crude oil) from
below ground. Because the oil reservoirs typically extend over a large area, possibly
several hundred kilometres across, full exploitation entails multiple wells scattered
across the area. In addition, there may be exploratory wells probing the edges,
pipelines to transport the oil elsewhere, and support facilities. E.g. Ghawar Field in
Saudi Arabia with more than 60 billion barrels (9.5×109 m3) estimated
oil recovery
Open-cast
mining
oscillating
water column
Parabolic
reflector
Passive solar
Peak shaving
Photothermal
Photovoltaic
Potential
gravitational
energy
Predictable
Primary fuel
Primary oil
recovery
can use large machinery but cannot access deeper coal. It also affects a larger area
of land and causes more problems of noise, dust and visual impact.
oscillating water column or Pelamis wave power schemes
a mirror system that reflects incoming light onto a single point. A parabolic trough
consists of a linear parabolic reflector that concentrates light onto a receiver
positioned along the reflector's focal line. The receiver is a tube positioned right
above the middle of the parabolic mirror and is filled with a working fluid. The
reflector is made to follow the Sun during the daylight hours by tracking along a
single axis. Parabolic trough systems provide the best land-use factor of any solar
technology e.g.The SEGS plants in California
is the heating of a building by absorbing sunlight without the use of additional
equipment. Building design/ architecture can increase passive solar gains by having
large windows or a conservatory facing in the direction from which most sunlight
will be absorbed – south-facing in the UK.
the process of storing surplus energy to satisfy later demand peaks. The supply of
energy and demand for it are not constant or perfectly matched. It may therefore
be necessary to store energy from when it is available until the time it is needed.
Storage may be needed to make intermittent supplies more useful, or to produce
energy at a constant rate so that they can be ‘peak shaved’: the surplus that is not
needed can be stored until supplies cannot meet demand.
a system that converts light into heat
a system that converts light into electricity.
The energy of raised position- see head of water
See reliable e.g. Solar, wind, wave power cannot be predicted reliably
An energy source that can be harnessed from the environment
involves the extraction of crude oil that is forced to the surface by the natural
pressure of water beneath the oil or natural gas above or dissolved in it. The
natural pressure of gas above the oil, or water beneath the oil, will force the oil to
the surface when a pipe is drilled down to the oil reservoir.
pumped storage Short-term surpluses of electricity may be stored as potential energy by using it to
hydroelectric
pump water from a lower reservoir up to a higher one. The stored potential energy
power
can be used later to generate electricity during times of high demand. These differ
from normal HEP stations by having two reservoirs. Because the water is reused
there is no need for a large catchment area to collect rainwater. Electricity can be
generated within 15 seconds of being switched from standby to generation. This is
much faster than conventional power stations e.g. Dinorwig wales
Radioactive
Any material that has, or could have been, contaminated with radioactive materials
waste
may be treated as radioactive waste, but the treatment method depends upon the
properties of the waste and the associated risks. In Nuclear Power Stations the
amount of radioactive waste produced is small compared with coal fired
Regenerative
braking:
Reliable
Renewable
energy
resources
Salter's Duck
Secondary fuel
Secondary oil
recovery
Sluice gates
Solar power
Space heating
Stirling solar
dish
storage
Suitability
temperature
gradient
When a vehicle has to slow down the kinetic energy of the vehicle’s momentum has
to be converted into another form of energy, which is usually heat by using friction
brakes. Some ‘hybrid’ cars are slowed down by using the motion of the car to drive
a generator. This slows the car while generating electricity that is stored in a
battery as chemical energy. This energy can be used later to propel the car. A car
that is mainly used for long distance journeys where braking is rare will recover
little energy but will use energy to carry the heavier batteries, so hybrid drive may
not be a good choice. But cars that are mainly used for stop–start urban driving may
save a lot of its primary fuel. Some electric trains, such as some Pendolino trains,
return electricity to the national grid and can recover over 15% of the energy
originally used.
an energy source where its availability can be predicted (although it does not have
to be available constantly). tidal power= intermittent but very reliable
are reformed by natural processes fast enough for new supplies to become available
within a human lifespan. Some are reformed instantly, such as sunlight, while
others, such as wood, take longer. Some of these renewable resources cannot be
depleted by using them. Using solar power, wind power or tidal power will not
make it less sunny, less windy or stop the tides from flowing. But other renewable
energy resources can be depleted if they are used unwisely. If trees are felled
faster than they are growing then supplies will be depleted.
energy from ocean waves, Professor Stephen Salter of the University of Edinburgh,
Scotland. His 1974 invention became known as Salter's Duck or Nodding Duck, the
Duck's curved cam-like body can stop 90% of wave motion and can convert 90% of
that to electricity giving 81% efficiency
An energy source that is produced by converting a primary fuel.
involves pumping water or natural gas down an injection well to increase the
pressure and maintain the flow of the oil
Mechanism to allow interruption in water supply
Energy from sunlight. Solar power is the conversion of sunlight into electricity,
either directly using photovoltaics (PV), or indirectly using concentrated solar
power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a
large area of sunlight into a small beam. Hydroelectric power and wind power can
be described as indirect solar power, as both are generated by heating from the
sun.
Domestic energy conservation- Space heating is the biggest domestic use of energy.
To achieve a constant internal temperature, the heat inputs must balance the
losses. If the losses can be reduced then the inputs can also be reduced
A stirling solar dish, or dish engine system, consists of a stand-alone parabolic
reflector that concentrates light onto a receiver positioned at the reflector's focal
point. The reflector tracks the Sun along two axes. E.g. 50 kW Big Dish in Canberra
Fossil fuels are readily stored. Most renewable energy forms cannot be stored –
solar, wind, wave power. Energy can be stored as potential energy of water in
reservoirs and chemical energy in biofuels
Many renewable resources produce large amounts of energy but it may be low
temperature heat or electricity that is not useful for powering most vehicles, which
are the biggest single use of energy e.g. the difficulties in using solar, wind, HEP to
drive road vehicles
the temperature difference between inside and out of a building
Tertiary oil
recovery
thermal
conductivity
thermal
resistance
Tidal barrages
Tidal power
Tidal stream
generators
Turbine
Vegetable oils
Vehicle design
Vehicle fuel
Vehicle weight
Vertical axis
wind turbine
involves a range of techniques to reduce the viscosity of the oil, including the use
of steam, detergents or solvents. Bacteria are used to partially digest heavy oil and
produce lighter oils that flow more easily. The bacteria also produce carbon dioxide
which helps to maintain the pressure and the flow of the oil.
of the materials that form the outside of the building- glass is a good conductor of
heat so there are losses of energy unless there is double glazing
These include polystyrene, mineral wool, shredded paper and wool- the materials
that form the outside of the building- air is a poor conductor of heat so the air in
double glazing preduces heat loss.
Make use of the potential energy in the difference in height (or head) between high
and low tides. Barrages are essentially dams across the full width of a tidal estuary,
and suffer from very high civil infrastructure costs, a worldwide shortage of viable
sites and environmental issues.
Aka tidal energy, is a form of hydropower that converts the energy of tides into
electricity or other useful forms of power. The first large-scale tidal power plant
(240 MW installed capacity) Rance, in France 1966. Tidal power is the only form of
energy which derives directly from the relative motions of the Earth–Moon system,
and to a lesser extent from the Earth–Sun system. Tidal power can be classified into
three generating methods:
1. Tidal stream generator
2. Tidal barrage
3. Dynamic tidal power
TSGs make use of the kinetic energy of moving water to power turbines, in a similar
way to wind turbines that use moving air. This method is gaining in popularity
because of the lower cost and lower ecological impact compared to tidal barrages
Mechanism for collecting kinetic energy e.g. wind or water power
such as sunflower oil, oilseed rape and palm oil can be used to make biodiesel. The
energy density of alcohol and biodiesel is nearly as high as that of fossil fuels.
Three design features reduce energy consumption
1. Air resistance
2. Regenerative braking
3. Vehicle weight
Usually in liquid form- petrol, diesel and aviation fuel. Current technology is very
reliant on fossil fuels, but biofuels such as ethanol and vegetable oils are suitable
replacements.
The lighter a vehicle is, the less energy it will need to propel it, although to
maintain safety, a compromise must be made between the structural strength of a
vehicle and lightness:
omany designers now use plastics instead of metals where strength is less
important, although some composite plastic materials, such as carbon fibres, have a
better strength:weight ratio than metals
ohigh strength steel is an alloy containing carbon, titanium and vanadium. It is
much stronger than ordinary mild steel so thinner, lighter sheets can be used
oaluminium engine blocks are lighter than cast iron ones
A VAWT tipped sideways, with the axis perpendicular to the wind streamlines,
functions similarly. A more general term that includes this option is "transverse axis
wind turbine". VAWTs offer a number of advantages over traditional horizontal axis
wind turbines (HAWTs). They can be packed closer together in wind farms, allowing
more in a given space. In counter-rotating configurations, turbines can extract
Viscosity
Viscous
vitrification
Watts
Wave power
Wind turbines
energy from the wakes of adjacent turbines. With HAWTs, this is not possible and
the turbines must be kept farther apart. VAWTs are rugged, quiet, omnidirectional, and they do not create as much stress on the support structure. They
do not require as much wind to generate power, thus allowing them to be closer to
the ground. By being closer to the ground they are easily maintained and can be
installed on chimneys and similar tall structures
a measure of the ease with which a fluid can flow.
a material that does not flow quickly.
Dried powdered solid high level nuclear waste (e.g. spent fuel rods) are mixed with
molten glass and allowed to solidify in stainless steel containers surrounded in
concrete to absorb the radiation. E.g. Sellafield, Cumbria, UK
Measure of electrical output- megawatts
energy by ocean surface waves— for example for electricity generation, water
desalination, or the pumping of water (into reservoirs). Wave power is distinct from
the diurnal flux of tidal power and the steady gyre of ocean currents. Wave power
generation is not currently a widely employed commercial technology although in
2008, the first commercial wave farm was opened in Portugal, at the Aguçadoura
Wave Park. Method types are
 point absorber or buoy;
 surfacing following or attenuator oriented parallel to the direction of wave
propagation;
 terminator, oriented perpendicular to the direction of wave propagation;
 oscillating water column;
 and overtopping.
Locations are shoreline, nearshore and offshore.
convert wind energy to electricity for distribution. Conventional horizontal axis
turbines can be divided into three components.
1. The rotor component, which is approximately 20% of the wind turbine cost,
includes the blades for converting wind energy to low speed rotational energy.
2. The generator component, which is approximately 34% of the wind turbine cost,
includes the electrical generator, the control electronics, and most likely a
gearbox component for converting the low speed incoming rotation to high
speed rotation suitable for generating electricity.
3. The structural support component, which is approximately 15% of the wind
turbine cost, includes the tower and rotor yaw mechanism.