renewables lecture - .ppt

7/28/2019 renewables lecture - .ppt

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Renewable Energy

Garth Ratcliffe

Department of Environmental andGeographical sciences

Manchester Metropolitan University


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Specific Questions

What are the current and projected UKenergy (fuel + electricity) demands?

How is the demand for electricity currentlybeing generated? In the future?

What contribution can renewable energymake to future fuel and electricity needs?


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UK Energy Demands 2000

Data fromDTI EnergyStatistics

2000


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How areenergyneeds

supplied?

Source DTIenergy Statistics


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Present Energy

Resources Fossil fuels - coal, oil, gas are all of limited

amounts. Cant be replaced.

Nuclear fuels -limited amounts of uranium fornuclear fission reactors but reprocessing offuel possible.

Difficult to estimate how long these fuels willlast - but is it sustainable economically orenvironmentally?


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How much energy is

needed? DTI Energy Statistics for 2000

308,332 GWh of electricity was distributed to 29.068 millionconsumers.

i.e. on average, each consumer used 10, 607 kwh ofelectricity.

In 2000, the total energy consumed in the domestic sectorof the UK was 46,833 thousands tons of oil equivalent.

Dividing this value by the number of consumers andconverting to kwh gives the average amount of energy usedper household as 18,737 kwh.


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Sustainable situation

Renewable energy resources are beingreplaced / generated at the same rate that

they are being utilised.

Hence they will last indefinitely.


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Renewable Energy

What is renewable energy?

What forms does it take?

Why is it needed? Targets exist for renewable energy to

generate 10% of electricity by 2010 and20% by 2020!

Can these be achieved? What forms of renewable energy will

deliver these targets?


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Electricity Generation

by Renewables

Source DTiEnergy

statistics 2000


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Generating Capacity of

Renewable Plants


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The DTI List of

Renewable ResourcesWind, Wave and Hydro Power

Photovoltaics Active Solar Heating

Municipal and General Wastes

Landfill Gas Geothermal

Agricultural and Forestry Wastes

Energy Crops Fuel Cells


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Other

Renewables

Nuclear

CombinedCycle Gas

Turbine

GasTurbine

Coal


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Forms of Renewable

Energy

All sources of energy ultimately come from the

sun.

This is particularly obvious in the case ofrenewable energies.


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Solar Radiation

solar heating panels/passive

solar power generation

solar cells / photovoltaic cells


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Solar cells

convert light into a small electrical output -milliwatts output.

need a bank/array of cells for useful output.

cost of cells is high but reducing.

efficiency of cells is up to 23%/ improving.


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Solar Panels

are situated on roof of building.

absorb heat in the form of radiation from sun.

basically system is like a domestic central heatingradiator painted black/insulated.

provides topping up of domestic hot water.


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Photovoltaics on Buildings

PV arrays, generating around54kW (peak) with a total areaof 430m2, form the slopingglazed roofs of the atrium

spaces in the four mainbuildings.

Ove Arup has designed thesystem to match the annualelectricity demand of the

supply and extractor fans,effectively providing zero-energy ventilation systems.


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Solar Roof tiles(Solar Grants now available)

Integrated solar tiles installed by Solar Centuryon a current development in Milton Keynes byEnglish partnership and Bloor homes

Roof mounted solarpanels (Solarcentury)

Innovative SunSlates installation by

Solar century for Liang Homes


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Solar Power Generation

located in desert/high intensity/long sunlighthours

parabolic mirrors reflect/focus suns rays ontometal water pipe located along focal axis ofmirrors.

High temperature produced - steam -

electrical power generated


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Wind Turbines


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Location of UKWind Clusters


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Windpower

Each windturbine can produce between 1/4and 2 MW of electrical power.

Windfarm needs to be located where there is arelatively high average wind speed.

Advantages?

Disadvantages?


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Calculation of number ofhouseholds supplied by a

windfarm

Assume 24 windturbines each generating0.25 MW for 70% of time.

In a year this amounts to 3.66 x 107kwhr.

If this figure is divided by average amountof electricity used by a consumer ie 10,607kwhr in a year,

Answer is 3600 consumers.

But 166 of these wind farms = 1000Mwpower station!


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Offshore Wind

Turbines


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Offshore Wind

Cluster Features Larger average wind speed than onshore

Easier planning consent

Technical expertise exists from oil rig experience

Suitable location


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Offshoresites


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Hydroelectric

Currently largest source of electricity fromrenewables.

Needs guaranteed supply of water.

Galloway-West of Scotland - series of lochsand rivers-cascade of flowing water.

Kinetic energy of water rotates turbines whichgenerate electricity.


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Tidal Power

Located at some coastal sites - usuallyestuaries and bays with large tidal range.

Shape of coastal site above and below sealevel determines range eg Bay of Funday,

Severn. At high tide reservoir of water is created

which is allowed to ebb through turbineslocated in dam.

Expensive construction.


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Wave Power

Land InstalledMarine PoweredEnergyTransformer on

Islay, West Coastof Scotland.

Wavegen Co.

LIMPET provides 500kW of electricityfor the National Grid Three floating wave power

stations at Lewis/1 MW each


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Biomass

cycle of sunlight - photosynthesis - plant growth -absorption of CO2 - emission of O2.

combustion of wood - heat

some plants - alcohol

decomposition - methane/landfill gas/fuel forheating.


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ARBRE is the first commercialwood-burning plant of itstype in Europe.

It produces enough electricity

for 33,000 people from cleanand sustainable wood fuelsources.

The plant has a 10MWelectricity generating capacityand 8MW is exported to thelocal grid.

The fuel for the plant is woodchips from forestry and short

rotation coppice.

WoodburningElectricity Generation


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Short rotation coppice harvesting for ARBRE wood-fuelled powerstation. As trees grow they store energy from the sun in theirbiomass. At ARBREs power plant the energy stored in thebiomass is converted to electricity.

Coppice harvesting

First RenewablesLtd


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Straw BurningPower Plant

Elean Power station near Ely,Cambridgeshiregenerates 36MW of electricity and is the worldslargest such facility. It supplies 80,000 homeswith electricity.

Lorry leavingplant afterdelivering straw


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Biomass Plant in Fife

Plant burns poultry litterand produces 10MW ofelectricity and fertiliser

Fluidised bed boilerensures efficient burningand low emissions


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Landfill Gas

Landfill gas, Dorset

1MW generator at

Buckden- BiogasAssociation


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SCENARIO STUDIES

Suggest that delivering 10% of electricity fromrenewables by 2010 at a cost of 3.5 p/kwh isfeasible

Requires 3-4 GW new plant

Dominant technologies

1) Waste (Municipal/industrial/agricultural)2) Remainder landfill gas + hydro (small scale)

3) Longer term - photovoltaics


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Conclusions

Major difficulties in attaining target of 10%of electricity generated by renewables by2010

Main contributors to this target will be :-

1) Offshore and Onshorewindfarms/clusters

2) Biomass/wood, straw, etc

3) PhotovoltaicBut policies like Climate Change Levy and

the Renewables Obligation will helpestablish renewables.


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Relevant Websites

www.dti.gov.uk/industries_energy (for energystatistics, indicators, new and renewable energy)

www.cabinet -office.gov.uk/innovation/2000/energy/energysco

pe.shtml

www.offshorewindfarms.co.uk

www.britishwindenergy.co.uk www.bwea.com

www.energy-efficiency.gov.uk

www.guardian.co.uk/renewables
http://www.dti.gov.uk/industries_energy(energyhttp://www.cabinet/http://www.offshorewindfarms.co.uk/http://www.britishwindenergy.co.uk/http://www.bwea.com/http://www.energy-efficiency.gov.uk/http://www.energy-efficiency.gov.uk/http://www.energy-efficiency.gov.uk/http://www.energy-efficiency.gov.uk/http://www.bwea.com/http://www.britishwindenergy.co.uk/http://www.offshorewindfarms.co.uk/http://www.cabinet/http://www.dti.gov.uk/industries_energy(energy

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