Energy Generation

• How many forms of energy generation can you think of?

• What fuel do you think generates the most power in the country?

• What fuels do you think are high carbon?

High Carbon

• The term High carbon relates to energy generated using fossil fuels.

• Fossil fuels are burned generating heat, the heat is used to super heat water.

• The steam is used to turn a turbine that is connected to a generator.

• The steam is condensed back into water and returned into the system for re-boiling the hot water reduces the amount of energy required to boil the water the subsequent times.

• Why are energy companies trying to reduce their dependency of fossil fuels?

• The energy industry is trying to reduce its dependency of fossil fuels because:– They are limited; fossil fuels are finite, once

they are gone they are gone. – Cost; as the fuels start to run out the cost

rises, fossil fuels will only get more expensive.– Pollution; all fossil fuels release CO2 and

other greenhouse gasses when burned these are environmentally damaging and have been linked to global warming.

High Carbon

• The reason fossil fuels are so polluting is they are releasing carbon that has been stored in the planet for millions of years in the form of coal, oil & gas.

• Burning these fuels releases the carbon into the atmosphere.

High Carbon

Coal

Coal

• Coal used to account for the majority of energy production, both in this country and the world.

• It is the ‘dirtiest’ form of energy releasing the most amount of CO2 per kw of energy generated.

• Coal powered stations are being phased out in Europe due to concerns over emissions, but are on the rise in developing countries who have an increased demand for power and an abundant supply of coal and labour to mine it!

Coal

Oil

Oil

• Oil has become a minor contributor to power generation because of its use in other types of industry are more important; fuel for vehicles, use in plastic industry, use in pharmaceutical industry, etc.

• With the cost of oil going up all of the time its use to generate electricity can not be justified.

Gas

Gas

• Gas fired power stations are the ‘cleanest’ of the fossil fuels releasing less than half the CO2 per Kw than coal.

• Gas is transported via pipe lines across countries / continents or liquefied and shipped across the oceans in bulk transporters.

• Gas makes up the majority of energy generation in the UK but as the cost of gas goes up so does the price of electricity.

Gas Transport

• What fuels do you think are medium carbon?

Low Carbon

• Low carbon energy is a subjective term; it usually relates to energy generated either by a fuel that releases less carbon or by a process that is more efficient, e.g. utilizing what would have traditionally been waste heat to heat water as in the CHiP (combined heat and power) system.

• Other systems whilst on the face of it are carbon intensive e.g. biomass the CO2 emissions are offset by burning quick growing plant mass creating a mini carbon cycle so you are not adding any additional carbon to the system.

Biomass

• Biomass is considered to be carbon neutral; this is because the carbon in the fuel being burned has been captured in the bio-material from the atmosphere. When you consider transport and processing the process in not quite carbon neutral.

• There are two main types of biomass boilers;– Direct burn– Gasifier

CO² is released into the

atmosphere by burning

CO² is absorbed by the leaves by the process of photosynthesis

The CO² is broken down by the leaves

into carbon and oxygen, the carbon is used by the tree

to grow and the oxygen is released

back into the atmosphere

Waste wood from the

manufacturing industry is

processed into pellets

A small amount of CO² is

released during the processing and transport of the wood waste

Stored energy is released by

burning the pellets

Biomass Direct burning

• With the direct burn as the name suggests the biomass fuel is burned in a power plant like any other fuel.

• The biomass is processed in to pellets and dried. When it is in this form it can easily be stored, transported and used.

• Can you think of fuels that can be used in a biomass power plant?

Biomass

Rubbish

Bio-mass Pellets for ease of

transport and supply to the

boiler Animal Waste

Rice Husks

Sugar Cane Waste

Elephant Grass

Wood Waste

Biomass Gasifier

• In the biomass Gasifier the biomass is heated / partially burned to release gas, the gas is burned in a traditional gas powered power station or any other gas appliance.

Biomass Gasifier

Hydrogen Fuel Cell

• Hydrogen fuel cells combine oxygen and hydrogen together with the help of catalyst to form water; this reaction gives of electricity.

• The process is the reverse of electrolysis where an electrical current is passed through water, splitting it into its component parts hydrogen & oxygen.

Hydrogen Fuel Cell

CHiP

CCH&P

• http://www.youtube.com/watch?v=uXLUoqzlT2k&feature=youtu.be

Heat Pumps

• A heat pump uses the principal of tacking a small amount of heat in a large body of water or air and converting it a large amount of heat in a small amount of water or air.

Heat Pumps

Compressor

• The compressor moves & compresses the refrigerant through the system. As the refrigerant is compressed (changed from a gas to a liquid) it changes from a gas to a liquid. This process is an exothermic reaction

Evaporator

• The evaporator uses the small amount of energy collected from the underground coil to evaporate the refrigerant (the refrigerant absorbs energy making the molecules more energetic this allows them to break free from each other and change from a liquid to a gas). The evaporation process is an endothermic reaction.

Condenser

• The condenser cools the gas until it turns back into liquid; as it turns back into liquid form it gives up energy in the form of heat, this heat is exchanged to the water of the heating system and is used to augment the heating system of the house.

Expansion Valve

• The expansion valve is used to reduce the pressure of the liquid refrigerant. This allows the liquid to boil / evaporate more easily when it enters the evaporator.

Pump

• The pump circulates the water through the underground coil / heat sink and the evaporator.

Underground Coil

• The underground coil absorbs latent heat from the ground and transports it via the liquid to the evaporator.

Heating circuit in the house

• The house hold heating circuit is augmented by the heat pump, it is typically used in conjunction with another more traditional system.

Solar Thermal

Solar collector

Hot water to taps

Cold water feed

Hot water tank

Boiler

Controller&

pump

Cold water feed

Hot water tank

Controller&

pump

Boiler

Solar collector

• What do you think are low carbon methods of energy generation?

Low Carbon

Solar Photo-voltaic

Solar Photo-voltaic

Photo-Voltaic panels convert the energy of the sun (light) into a DC

voltage

DC Isolator is a switch that allows

the power from the solar panels to flow

to the DC/AC inverter

DC/AC Inverter converts the low

DC voltage to high AC voltage

(230V)

The AC isolator isolates the AC

power generated by the solar panels

from the rest of the dwelling

The PV Generation Meter measures how much electricity has been generated by the solar panels

Fuse Board or to give it its proper name consumer unit,

this holds the circuit protection devices and

distributes the electricity around the various circuits in

the house

Import / export meter this is a special meter that

measures the amount of electricity the dwelling

uses from the distributor and how much electricity

the dwelling has ‘sold’ back to the supplier.

Wind

Wind

Blades

Rotor

Generator

Gear Box

Low Speed Shaft

Brake

Pitch Control

High Speed Shaft

Nacelle

Wind Vane

AnemometerController

Tower

Yaw Motor

Yaw Drive

Hydroelectric

Hydroelectric

• http://www.youtube.com/watch?v=S4B2gODY3Mk

Tidal

Tidal

• http://www.youtube.com/watch?v=F0mzrbfzUpM

Nuclear

Nuclear

Glossary

• Augmented– To make bigger, larger, to add to.

• Latent– Potential but not obvious.

• Endothermic – A chemical or mechanical process that absorbs

heat.

• Exothermic – A chemical or mechanical process that gives off

heat.