ENV-2D02 Energy Conservation

2005 - 06

Keith Tovey

HSBC Director of Low carbon Innovation

Energy Science Director CRed Project

10. Electricity Conservation

10.1 Introduction

• Growth in Population• greater in last 10 years than previously

• Reduction in Household size• has fallen from 2.9 to 2.3 in 30 years

A saving of 17.5% per household by 2020 will not reduce demand – Will just keep pace with increase in demand

• growth in use of appliances and refrigeration

• the issue of “STANDBY”

• technical improvements leading to more efficient use of electricity

• controlling demand for electricity

• fuel switching to electricity

Several aspects to consider

• Demand for electricity was almost static 1972 – 1982• Has risen at 1.8% per annum since• Consumption is 17% higher than 1997

• 1970 – 1980– Increase in demand for appliances and decorative lighting– Compensated by reduction of electric heating– Much more efficient televisions (solid state vs valves)

• 1980 onwards– Little further opportunity for reduction in electric heating– Increased use of heavy energy users – tumble dryers etc.– Further move to more decorative lighting – Use of cheap halogen bulbs in recent years– Limited reduction from use of low energy– Increase from Digital Televisions

10.2 Growth in Demand for Electricity

• Appliances do not always switch off even with the button!!!

10.3 The Standby Problem

transformer

Main functional circuits

Switch control by STANDBY

Plug for appliance

transformer

Main functional circuits

Switch control by STANDBY

Plug for appliance

This appliance switches of by pressing button

But this one does not!

transformer

Main functional circuits

Switch control by STANDBY

Plug for appliance

Setting control

Rechargeable battery

10.3 The Standby Problem

transformer

Main functional circuits

Switch control by STANDBY

Plug for appliance

Setting control

This appliance has to be on otherwise settings are lost.

This appliance can be switched off as settings are retained by battery which is recharged on next use.

See IEA Website: Things that go blip in the night

• Electrical appliances ~ nearly 100% efficient in converting energy

motive power, sound, light, heat

?? Form of energy required

• Tungsten filament light is 100% efficient - – but mostly heat

• Fluorescent tubes – much more efficient

• CFL consume ~ 20% of energy

• T8 tubes are more efficient than older T12

• Electronic control even better

• LED 25% or less of CFL – the light of the future

– Halogen spot lights consume as much as some tungsten filament and if multiple use then room can consume significantly more

• Microwave/radio frequency heating uses less energy as can infra red in some circumstances.

• Improvements in insulation in hot/cold appliances

• Mixed fuel appliances e.g. – White Knight BG437 Standard Gas Dry Tumble Dryer

10.4 Technical improvements to reduce electricity consumption

• Tungsten filament lights have little reactive load.

• Machinery (fluorescent lights) waste energy – reactive load

20-30% of energy is lost

• Alternative current Line voltage is +/- 340 : 50 Hz.

• Root Mean Square (RMS) volts is 240

DC Power = volts x amps

For a power of 1 kW Current = 1000/240 = 4.17 amps. AC situations Current and volts often out of phase power = volts x amps cos is the phase angle, cos is the power factor.

10.4.1 Power Factor Correction

• Typical values of 30 – 50o

• cos ~ 0.8

~ 20% loss

• Resistive loads have current in phase with voltage

• Inductive loads have current lagging behind phase of voltage

• Capacitive loads have current leading phase of voltage.

• Can compensate for power factor by including a device of the opposite type to compensate

• Must be carefully matched.

10.4.1 Power Factor Correction

• 10.5.2 Meeting the demand for electricity

10.5 Controlling the demand for electricity

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• 10.5.2 Meeting the demand for electricity

10.5 Controlling the demand for electricity

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• 10.5.2 Meeting the demand for electricity• Dinorwig Power Station 25th May 2005

10.5 Controlling the demand for electricity

• Pumped Storage ~ 10 seconds• Hydro 10 – 90 seconds• Open Circuit Gas Turbine - 2 to 3 mins• Interconnector to France• New interconnector to Norway• Balancing Mechanism operation

Running under low load pick up / run down at rate of 8 MW per minute per set

Consequence of NETA / BETTA

• Meeting the short term fluctuations

10.5 Controlling the demand for electricity

.1. the day time peak• Fossil fuel power station take up to 24 hours to come on

line

• Run these continuously where possible

might have to be brought up for load and then not used.

• Encourage people to switch from peak to night time use.

• Use pump storage schemes to pump water up at times of low demand – increasing utility of fossil fuel power stations.

• May not save if electric storage heaters are used.

2) the short term transient peak

• arising primarily from TV scheduling.

• Use pump storage

• 10.5.3 Shifting Demand

10.5 Controlling the demand for electricity

• Economy 7 (10) Tariffs• Lower night time rates but higher day time rates. • Need to use at least 15% overnight ot make it worthwhile

• 10.5.4 Financial Incentives to Switch Demand

10.5 Controlling the demand for electricity

10.5.5 Financial incentives to deter use of electricity at peak periods

1) Maximum Demand Tariffs2) Seasonal Tariffs3) Time of Day Tariffs4) Tariffs which vary according to other factors.

Maximum Demand Tariffs – tariff as of 19991) A standing charge for each month £92.92 charge for use of the system2) An availability charge £ 1.03 per kVA of potential demand

There is also a charge for units consumed in the 30 minute period of maximum demand during the month. This varies according to month

March - October NIL November and February £2.17 December and January £6.92A unit charge (midnight to 7 am) 2.45pUnits at other times of day 5.32pA REACTIVE POWER charge for each kiloVAR 0.18pin excess of half the number of units supplied

1) A standing charge for each month £92.92 charge for use of the system2) An availability charge £ 1.03 per kVA of potential demand

A charge for units consumed in the 30 minute period of maximum demand during the month. This varies according to month

March - October NIL November and February £2.17 December and January £6.92

A unit charge (midnight to 7 am) 2.45pUnits at other times of day 5.32p

A REACTIVE POWER charge for each kiloVAR 0.18pin excess of half the number of units supplied if power factor falls below

0.895

Maximum Demand Tariffs – tariff as of 1999

Note: Maximum Demand Tariff is ~130 times normal rate >>> in December and January 25 – 30% of electricity bill could come from a single 30 minutes period

• Seasonal Tariffs

– e.g. Arizona Public Service ~ 400 kWh / month

• Time of Day Tariff

– An extension of the Economy 7 tariff

– Salt River Project

– Up to 5 different tariffs during the day

– Radio/Computer technology could be used to display varying tariffs in the kitchen

• Tariffs according to other factors

– South Carolina uses mean temperature as the key to tariffs.

– Charges are higher when temperature exceeds 26oC

10.5 Controlling the demand for electricity

• Large Consumers - usually much larger than UEA• Electricity Supply industry to directly control demand• Supplier requests that a consumer shed a given amount of load

– Typically the load management time is for no more than 2 hours on any one day – with a maximum of say 100 hours in a year.

• Consumer gets a significant discount, but discount depends on length of warning• best tariffs for consumers prepared to have only 15 minutes warning of a load

management shedding. • Scheme is attractive to the Electricity Supply Industry • Directly tackles the problem of the peak demand, • 1GW or more of load have been shed in this way. • Small/Domestic Consumers• Little done in UK• 1980 Florida Power experimented with radio control of:

1.Central heating

2.Air-conditioning

3.Swimming pool filtration plants

10.5.6 Load Management Schemes

Other possible ideas for Load Management.• microprocessor switching devices controlled to selectively

shed load at peak times in a consumer’s premises,

• As above but restrict load to a given amount at peak times say 1000W.

• microprocessor devices to alter the tariff structure during the day

– reflecting the marginal cost of generating electricity at that time of day.

• multiple rate tariff at any time during day

– Possibilities in Dongtan

10.5.6 Load Management Schemes

• Rescheduling TV adverts etc

• More direct relationship between use and payment for energy– 3 month readings in arrears– Direct debit– Are disincentives to promoting energy

conservation

• Smart Cards

• Reverse Tariffs – e.g. IrkutskEnergo

10. Other methods to reduce demand

A Paradox: Effective Energy Conservation will lead to an increase in Electricity Consumption

• Industrial Processes• Drying (a heat pump is much more efficient)• Air-knife• Dehumidifying• Case Hardening• Inductive heating

• Space heating with heat pumps

Other reasons for increase in electricity consumption

• Move to electric vehicles

• Move to hydrogen economy

• Increase in population

• Decrease in household size.

Our Choices: They are difficult

If our answer is NO

Do we want to return to using coal? • then carbon dioxide emissions will rise significantly• unless we can develop carbon sequestration within 10 years which is unlikely

If our answer to coal is NO

Do we want to leave things are they are and see continued exploitation of gas for both heating and electricity generation? >>>>>>

Do we want to exploit available renewables i.e onshore/offshore wind and biomass. Photovoltaics, tidal, wave are not options for next 20 years.

If our answer is NO

Do we want to see a renewal of nuclear power

• Are we happy on this and the other attendant risks?

Our Choices: They are difficult

If our answer is YES

By 2020

• we will be dependent on around 70% of our heating and electricity from GAS

• imported from countries like Russia, Iran, Iraq, Libya, AlgeriaAre we happy with this prospect? >>>>>>

If not:

We need even more substantial cuts in energy use.

Or are we prepared to sacrifice our future to effects of Global Warming? - the North Norfolk Coal Field?

Do we wish to reconsider our stance on renewables?

Inaction or delays in decision making will lead us down the GAS option route

and all the attendant Security issues that raises.

Our Choices: They are difficult

A diverse renewable supply will be local, and will be less prone to cascade power cuts such as those recently in US, London, Italy, Denmark.

Conventional generation is based on large units: 500 – 660 MW enough to supply over 1 million homes. These do fail from time to time, and require much greater backup than required for the failure of a few wind turbines. A reactor trip at Sizewell B has an even larger effect ~1188 MW.

Renewable generation is less prone to major interruption

We must not get drawn into a single issue debate

– a rational debate covering all the alternatives is needed.

Available Renewables: Nuclear: Conservation

Local Small Scale generation saves 8.5% from losses in transmission

An important advantage over conventional generation or far Offshore Wind

Historic and Future Demand for Electricity

Number of households will rise by 17.5% by 2025 and consumption per household must fall by this amount just to remain static

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The Gas Scenario

Assumes all new non-renewable generation is from gas.

Replacements for ageing plant

Additions to deal with demand changes

Assumes 10.4% renewables by 2010

20% renewables by 2020

• High Growth – Business as Usual

• Low Growth capped at 420 TWH by 2010

• Rise in emissions 2005 – 2010

• loss of nuclear generating capacity

• Fall in 2010 – 2020

• loss of nuclear and coal capacity

• Little new generating capacity available before 2010 except Wind

Electricity Options for the Future

Electricity Options for the FutureLow Growth Scenario

Capped at 420 TWh• 33% CO2 reduction (Gas) cf 1990

• 62% CO2 reduction (Nuclear) cf 1990

• 68 % increase in gas consumption

( Gas Scenario) cf 2002• Mix option: 6 new nuclear plant by 2025• Mix option: 11% increase in gas

consumption (cf 2002)

High Growth Scenario

Business as Usual• 0.3 % CO2 reduction (Gas) cf 1990

• 54% CO2 reduction (Nuclear) cf 1990

• 257% increase in gas consumption

( Gas Scenario) cf 2002

Carbon Dioxide Emissions

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25% Renewables by 2025

• 20000 MW Wind

• 16000 MW Other Renewables inc. Tidal, hydro, biomass etc.

Conclusions• Global Warming will affect us all - in next few decades

• Energy Security will become increasingly important. Inaction over making difficult decisions now will make Energy Security more likely in future.

• Move towards energy conservation and LOCAL generation of energy

It is as much about the individual’s response to use of energy as any technical measures the Government may take.

• Wind (and possibly biomass) are the only real alternatives for renewable generation in next 5 – 10 years.

• Otherwise Nuclear??? – but Uranium resources are limited

• We need to have a multi-pronged approach – we need all available renewables, much more conservation, and possibly some nuclear.

• Even if we are not convinced about Global Warming – Energy Security issues will shortly start to affect us.

Conclusions

Lao Tzu (604-531 BC) Chinese Artist and Taoist philosopher

"If you do not change direction, you may end up where you are heading."