Download Energy Conservation – the Fifth Fuel?

Climate Change – The Greatest Threat to Mankind?
The fifth fuel – Energy Conservation?
Park Lane Methodist Church 28th May 2006
Keith Tovey
CRed
Keith Tovey (杜伟贤) M.A., PhD, CEng, MICE, CEnv
Energy Science Director: Low Carbon Innovation Centre
School of Environmental Sciences, UEA
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Climate Change – The Greatest Threat to Mankind?
The fifth fuel – Energy Conservation?
• Last Week
• We have hard choices to make
• Promote all renewables
• Energy conservation – each of us to reduce
consumption by 1.5% each and every year – i.e. by
20+% by 2020
• Even then we would see gas consumption rise by
over 60% and up to 70+% will have to be imported
from countries like Russia and Middle East
• We delayed making a decision about nuclear in 1997
• Now it will be very difficult to avoid a small nuclear
new build
2
Electricity Consumption (TWh)
Historic and Future Demand for Electricity
500
450
400
350
300
250
200
150
100
50
0
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
Number of households will rise by 17.5% by 2025 and consumption per household
must fall by this amount just to remain static
3
Electricity Options for the Future
Low Growth Scenario
Carbon Dioxide Emissions
300
Capped at 420 TWh
250
• Means everyone must reduce consumption by
1.5% each year.
MTonnes CO2
200
• Assume Renewable targets are met but we are
currently falling well short
150
Actual
100
Gas
• 33% CO2 reduction cf 1990
No Renewable Increase
50
• 68 % increase in gas consumption cf 2002
0
1990
1995
2000
2005
2010
2015
2020
2025
•CAN WE JUSTIFY THIS INCREASE IN GAS?
Renewable assumption we achieve target
Carbon Dioxide Emissions
250
10 times as many wind turbines as present
Nuclear option – 62% reduction in CO2
Mix option retains nuclear proportion at ~ 20%
~ 5 new nuclear to replace 13 existing ones
MTonnes CO2
200
150
100
50
0
1990
Actual
Gas
Nuclear
Coal
40:20:40 Mix
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1995
2000
2005
2010
2015
2020
2025
Implications of some of the Scenarios
In addition we would need 11000 MW
of installed capacity of biomass – or
30000 sq km devoted to biomass
cultivation or we would need many
more wind turbines.
Number of New Nuclear Stations
Nuclear Station Requirements
10
9
8
7
6
5
4
3
2
1
0
Mix Low Growth
Mix High Growth
But we are exploiting resources of
developing countries such as
Malaysia – should we continue to do
so and increase this exploitation?
2010
2015
2020
2025
Numbers of Wind Turbines
Percentage Renewable Generation
25
14000
Meeting Targets
20
Meeting Targets
12000
Realistic ?
10000
%
No
15
Realistic ?
8000
6000
10
4000
5
2000
0
0
1990 1993 1995 1997 1999 2002 2005 2010 2015 2020 2025
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1990 1993 1995 1997 1999 2002 2005 2010 2015 2020 2025
Climate Change – The Greatest Threat to Mankind?
The fifth fuel – Energy Conservation?
• By 2050 we could readily have a renewable an low carbon
future.
• However we cannot now have a non-nuclear scenario in the
period 2015 – 2030,
• Unless
– we wish to be dependent on Russia and the middle east for are
heating and electricity generation for almost all our electricity and
heating.
• Or
– we wish to see a return to coal and global warming exacerbated. By
2030 significant possibilities will exist for carbon sequestration,
• Or
– we make more drastic cuts in energy use – a 20% cut will only see us
stand still
• But conservation measures often do not achieve the
theoretical savings predicted because of “comfort taking”
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Climate Change and our insatiable appetite for energy
So where does it all go?
Per Capita Consumption in Watts
~ 5 kW
1970
816
623
1379
411
1980
882
786
1069
414
1990
902
1076
855
425
2002
1060
1207
769
442
Conversion and
Transmission
1712
1565
1745
1844
Total
Non-Energy
4942
240
4716
165
5004
249
5321
241
Domestic
Transport
Industry
Other
• Transport Energy use has risen 10.5% in last decade
• Domestic use has risen by over 10%
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Climate Change – The Greatest Threat to Mankind?
The fifth fuel – Energy Conservation?
• Opportunities for Conservation
– Reduce transmission losses
• Local generation of electricity (8.5% in case of
electricity)
– Make more effective use of energy during
conversion.
– Reduce demand
• Technical means
• Promoting Awareness
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Local Provision of Energy
Solar Pump
Normal hot water circuit
Solar Circuit
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Local Provision of Energy
It is all very well for South East, but what about the North?
House in Lerwick, Shetland Isles
- less than 15,000 people live north of this in UK!
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Saving Energy – A Practical Guide
Ways to Reduce Your Carbon Footprint
Micro CHP
Heat Pumps
Micro Wind
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Involve the local Community
• Many residents on island of Burray (Orkney)
compaigned for a wind turbine.
• On average they are fully self-sufficient in electricity
needs and indeed are a net exporter of electricity
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8. Generation of Electricity - Conventional
Largest loss in
Power Station
Overall efficiency ~ 35%
Diagram illustrates situation with coal, oil, or nuclear
Gas Generation is more efficient - overall ~ 45%
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8. Generation of Electricity - Conventional.
Superheated Steam
563oC
160 bar
Multi-stage
Turbine
Generator
Boiler
Why do we condense the steam to water only
to heat it up again?.
Does this not waste energy?
Pump
NO!!
Thermodynamics? Condenser
Steam at ~
0.03 bar
Simplified Diagram of a “generating set”
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includes boiler, turbine, generator, and condenser
8. Generation of Electricity - Conventional
Chemical
Energy
Coal / Oil /
Gas 100 units
Power Station
Heat Energy 90 units
Boiler
90%
Turbine
Generator 95%
Electrical
Energy
48%
41 units
Mechanical Energy
Electricity used in Station
3 units
38 units
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8. Generation of Electricity - Conventional.
 Why not use the heat from power station? - it is
typically at 30oC?
 Too cold for space heating as radiators must be
operated ~ 60+oC
 What about fish farming - tomato growing?
- Yes, but this only represent about 0.005% of heat
output.
 Problem is that if we increase the output temperature
of the heat from the power station we get less
electricity.
 Does this matter if overall energy supply is increased?
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8. Generation of Electricity - CHP
Overall Efficiency - 73%
•Heat is rejected at ~ 90oC for supply to heat buildings.
•City Wide schemes are common in Eastern Europe
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8. Generation of Electricity - Conventional.
 1947 Electricity Act blinked our approach for
35 years into attempting to get as much
electricity from fuel rather than as much
energy.
 Since Privatisation, opportunities for CHP
have increased
 on an individual complex basis (e.g. UEA),
unlike Russia
 A problem: need to always reject heat.
 What happens in summer when heating is not
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required?
9. Applications of Thermodynamics.
Combined Heat and Power
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Engine
Generator
Generation of Electricity with a Gas Engine
61% Flue
Losses
3% Radiation
Losses
36%
efficient
GAS
Engine
Generator
36% Electricity
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Combined Heat and Power at UEA
3% Radiation
Losses
11% Flue
Losses
81%
efficient
Exhaust
Heat
Exchanger
GAS
Reduces
conversion losses
significantly
Engine
Engine heat Exchanger
45% Heat
Localised
generation can
make use of
waste heat.
Generator
36% Electricity
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Performance of CHP units
Before installation
1997/98
electricity
gas
oil
19895
35148
33
MWh
Total
Emission factor
kg/kWh
0.46
0.186
0.277
Carbon dioxide
Tonnes
9152
6538
9
15699
After installation
1999/
2000
Electricity
Heat
Total
CHP export import boilers CHP
site generation
MWh 20437
Emission kg/kWh
factor
Carbon Tonnes
dioxide
15630
oil
total
977
5783
14510 28263 923
-0.46
0.46
0.186
0.186 0.277
-449
2660
2699
5257 256 10422
This represents a 33% saving in carbon dioxide
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Load Factor of CHP Plant at UEA
Demand for Heat is low in summer: plant cannot be used
effectively
More electricity could be generated in summer
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Before and during the break
• Use the computers to model the carbon
emissions at home and to identify the
issues which are of greatest importance.
• The model is approximate and will not
necessarily indicate total consumption,
but it will identify the issues you should
think about
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The Heat Pump
A Heat Pump or refrigerator
High Pressure
Warm Temperature
Heat to
building
High Pressure
High Temperature
Condenser
Work In
Throttle
Valve
Compressor
Evaporator
Low Pressure
Cold Temperature
Heat from
outside
Low Pressure
Cool Temperature
• 3 to 4 times as much energy out as energy in!!
• Works with thermodynamics – NOT against it
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Normal
Air-conditioning
Adsorption
Air-Conditioning
Heat from external
source
Heat rejected
High Temperature
High Pressure
Desorber
Heat
Compressor
Exchanger
Condenser
Throttle
Valve
W~0
Evaporator
Absorber
Heat extracted
for cooling
•
•
•
•
Low Temperature
Low Pressure
Adsorption Heat pump uses Waste Heat from CHP
Will provide most of chilling requirements in summer
Will reduce electricity demand in summer
Will increase electricity generated locally
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The Norwich Heat Pump
Original Paper by
John Sumner
Proc. Institution of Mechanical
Engineers (1947): Vol 156 p 338
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The History of the Site
• The building was unique - the very first heat pump in the
UK.
• Installed during in early 1940s during the War.
• Built from individual components which were not ideal.
• Compressor was second hand built in early 1920’s ! for Ice
making.
• The evaporator and condenser had to be built specifically
on site.
• Refrigerant choice was limited during War - only sulphur
dioxide was possible.
• A COP of 3.45 was obtained - as measured over 2 years.
• Even in 1940s, the heat pump was shown to perform as
well as, if not better than older coal fired boiler.
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The History of the Site
Evaporator
Compressor
Condenser
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• The Norwich Heat Pump - note the shape of the columns
The Norwich Heat Pump
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The Duke Street Project
Domestic Units –
Rebuild/Refurbishment
of existing façade on
Duke Street
Location of former
Heat Pump – the first
in the UK
Domestic Units –
Refurbishment of
former Electricity
Board Offices
Commercial /Hotel Development
Model of the Redevelopment Site showing relationship between
Domestic and Commercial parts of Site.
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A concluding thought
650 m
Our Wasteful Society
We behave as though we call in the
RAF
The Heat Pump is the analogy with the
crane
In memory of John Sumner
21 m
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273 m
Climate Change and the Environment
The greatest threat to mankind?
•
•
•
•
Our insatiable appetite for Energy
Potential of Energy Resources
Hard Choices Ahead
The fifth fuel – Energy Conservation?
• Next Week
Crunch Time!
– What can you do in your homes or as a
community?
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To discuss next week
• 1. When cooking vegetables on a stove. How much energy (as a
percentage) is saved by putting a lid on the saucepan.?
• 2. What are the major sources of heat loss from a house? List the
conservation measures which should be adopted in order of effectiveness,
and also cost? What measures would you take to improve the energy
efficiency of your home?
• 3. By time switching the heating in a house so that it is off from 11pm until
7am the next morning, a saving of one third in energy will be possible. Is
this correct? What disadvantages are there from time switching ?
• 4. It is often argued that with a well insulated hot water tank it does not
matter if the heating source is left on. In what circumstances is this statement
correct, and in what circumstances is it not?
• 5. Fluorescent lights use as much energy when switched on as they do in
running for 15 minutes [some people say 30 minutes] or is this a myth?.
What evidence can you use to confirm this or otherwise.
Remember to bring your data you have been collecting with you
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