1 CRed Keith Tovey ( ) M.A., PhD, CEng, MICE, CEnv Energy
Science Director: Low Carbon Innovation Centre School of
Environmental Sciences, UEA Keith Tovey Park Lane Methodist Church
28th May 2006 Climate Change The Greatest Threat to Mankind? The
fifth fuel Energy Conservation?
Slide 2
2 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 Climate Change The
Greatest Threat to Mankind? The fifth fuel Energy
Conservation?
Slide 3
3 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
Slide 4
4 Electricity Options for the Future Low Growth Scenario Capped
at 420 TWh Means everyone must reduce consumption by 1.5% each
year. Assume Renewable targets are met but we are currently falling
well short 33% CO 2 reduction cf 1990 68 % increase in gas
consumption cf 2002 CAN WE JUSTIFY THIS INCREASE IN GAS? Nuclear
option 62% reduction in CO 2 Mix option retains nuclear proportion
at ~ 20% ~ 5 new nuclear to replace 13 existing ones Renewable
assumption we achieve target 10 times as many wind turbines as
present
Slide 5
5 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. But we are exploiting resources of developing countries
such as Malaysia should we continue to do so and increase this
exploitation?
Slide 6
6 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 Climate Change The Greatest
Threat to Mankind? The fifth fuel Energy Conservation?
Slide 7
7 So where does it all go? Climate Change and our insatiable
appetite for energy Per Capita Consumption in Watts ~ 5 kW
Transport Energy use has risen 10.5% in last decade Domestic use
has risen by over 10%
Slide 8
8 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 Climate Change The Greatest
Threat to Mankind? The fifth fuel Energy Conservation?
Slide 9
9 Local Provision of Energy Normal hot water circuit Solar
Circuit Solar Pump
Slide 10
10 House in Lerwick, Shetland Isles - less than 15,000 people
live north of this in UK! It is all very well for South East, but
what about the North? Local Provision of Energy
Slide 11
11 Saving Energy A Practical Guide Ways to Reduce Your Carbon
Footprint Micro Wind Micro CHP Heat Pumps
Slide 12
12 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
Involve the local Community
Slide 13
13 8. Generation of Electricity - Conventional Diagram
illustrates situation with coal, oil, or nuclear Gas Generation is
more efficient - overall ~ 45% Overall efficiency ~ 35% Largest
loss in Power Station
Slide 14
14 8. Generation of Electricity - Conventional. Pump
Multi-stage Turbine Generator Boiler Condenser Simplified Diagram
of a generating set includes boiler, turbine, generator, and
condenser Superheated Steam 563 o C 160 bar Steam at ~ 0.03 bar Why
do we condense the steam to water only to heat it up again?. Does
this not waste energy? NO!! Thermodynamics?
Slide 15
15 8. Generation of Electricity - Conventional Chemical Energy
Coal / Oil / Gas Electrical Energy Heat Energy Boiler Turbine
Generator Mechanical Energy Electricity used in Station Power
Station 100 units 38 units 90 units 3 units 90% 95% 48% 41
units
Slide 16
16 Why not use the heat from power station? - it is typically
at 30 o C? Too cold for space heating as radiators must be operated
~ 60+ o C 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? 8. Generation of Electricity - Conventional.
Slide 17
17 8. Generation of Electricity - CHP Overall Efficiency - 73%
Heat is rejected at ~ 90 o C for supply to heat buildings. City
Wide schemes are common in Eastern Europe
Slide 18
18 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 required? 8. Generation of Electricity - Conventional.
Slide 19
19 9. Applications of Thermodynamics. Combined Heat and Power
Engine Generator
Slide 20
20 Engine Generator 36% Electricity GAS 61% Flue Losses 3%
Radiation Losses 36% efficient Generation of Electricity with a Gas
Engine
Slide 21
21 Engine Generator 36% Electricity 45% Heat GAS Engine heat
Exchanger Exhaust Heat Exchanger 11% Flue Losses 3% Radiation
Losses 81% efficient Combined Heat and Power at UEA Localised
generation can make use of waste heat. Reduces conversion losses
significantly
Slide 22
22 1997/98electricitygasoilTotal MWh198953514833 Emission
factorkg/kWh0.460.1860.277 Carbon dioxideTonnes91526538915699
ElectricityHeat 1999/ 2000 Total site CHP generation
exportimportboilersCHPoiltotal MWh204371563097757831451028263923
Emission factor kg/kWh -0.460.460.186 0.277 Carbon dioxide Tonnes
-44926602699525725610422 Performance of CHP units Before
installation After installation This represents a 33% saving in
carbon dioxide
Slide 23
23 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
Slide 24
24 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
Slide 25
25 The Heat Pump High Pressure High Temperature Low Pressure
Cool Temperature Low Pressure Cold Temperature High Pressure Warm
Temperature Evaporator Throttle Valve Compressor Condenser Heat to
building Heat from outside Work In A Heat Pump or refrigerator 3 to
4 times as much energy out as energy in!! Works with thermodynamics
NOT against it
Slide 26
26 Condenser Evaporator Throttle Valve Heat rejected Heat
extracted for cooling High Temperature High Pressure Low
Temperature Low Pressure Heat from external source Absorber
Desorber Heat Exchanger W ~ 0 Normal Air-conditioning 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 Compressor Adsorption
Air-Conditioning
Slide 27
27 The Norwich Heat Pump Original Paper by John Sumner Proc.
Institution of Mechanical Engineers (1947): Vol 156 p 338
Slide 28
28 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 1920s ! 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.
Slide 29
29 The History of the Site The Norwich Heat Pump - note the
shape of the columns Evaporator Compressor Condenser
Slide 30
30 The Norwich Heat Pump
Slide 31
31 Commercial /Hotel Development Domestic Units Refurbishment
of former Electricity Board Offices Domestic Units
Rebuild/Refurbishment of existing faade on Duke Street Model of the
Redevelopment Site showing relationship between Domestic and
Commercial parts of Site. Location of former Heat Pump the first in
the UK The Duke Street Project
Slide 32
32 A concluding thought Our Wasteful Society 650 m 21 m 273 m
We behave as though we call in the RAF The Heat Pump is the analogy
with the crane In memory of John Sumner
Slide 33
33 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?
Slide 34
34 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. To
discuss next week Remember to bring your data you have been
collecting with you