Section 3: Energy Use bySector & Energy Conservationby Fuel Switching
Dr. Congxiao Shang
Room No.: 01 37P
ENV-2D02 (2006):Energy Conservation –power point versions of lectures
Main Objective of the Lecture
The display of energy consumption: per capita consumption in Watts (i.e. arate of energy consumption) – Table 4.1 , or as the total annual consumption –Table 4.2.
4.1 Summary of Consumption in UK
The consumption in the domestic andpublic administration sectors hasremained approximately constant
The improved insulation standardsin new houses and upgrade inolder property are just keepingpace with increase in demand.
Industry is continuing to becomemore efficient in energy terms, buttransport is continuing to show anever increasing demand.
4.2 Electricity use in the UK
1.8% increaseper annum
4.2 Electricity use in the UK
Growing consumption;
The growth is partly linked to an small increase inpopulation, but more importantly to the decline inhousehold size leading to more dwellings.
Though there has been a substantial increase in thedeployment of renewables in the last decade, thisincrease is NOT keeping pace with the growth indemand.
However, we have to develop renewableenergy technology.
Is hydrogen safe?
ENERGY CONSUMPTION IN UK -DOMESTIC SECTOR (PJ)
1950
1866
Note: Figures are for Delivered Energy
Table 4.4 Distribution of Energy use inDomestic Sector (PJ) in year 2000
Note: Figures are for Delivered Energy
4.3 Primary Energy Ratios (PER)
Gas - 1.06 (historic) , but improved to around 1.05 in last few years
Oil - 1.08
Coal - 1.02, currently it is around 1.015
Electricity - varies with efficiency of generation
Year
PrimaryEnergy ratio
Year
PrimaryEnergy ratio
1930
6.54
1991
3.06
1950
5.13
1994
2.94
1960
4.07
1998
2.89
1970
3.80
2000
1980
3.33
2002
1987
3.19
Table 4.5 Variation of Primary Energy Ratio for Electricity Generation
with time.
Total Primary Energy Requirement forDomestic Sector in 2000 was :
electricity gas oil coal
403*2.89 + 1332*1.05 + 136*1.08 + 80*1.02 = 2796 PJ
compared to 1951PJ, which is the actual demand for delivered energy
- an overall - PER of 1.43
==========
This figure of 1.43 has remained constant since 1994
4.4 Useful Energy (Domestic Sectorusing 2000 data –Table 4.4)
NOTE: Electricity use for Appliances/ Lighting/ Refrigeration istreated as 100% efficient in this exercise
Useful Energy (PJ)
off-peak electricity
0.9 * 76
68
remaining electricity
1.0 * 327
327
Gas Cooking (50% efficient)
0.5 * 80
40
Gas Water and Space Heating
0.75 * 1252
939
Oil
0.65 * 136
88
Coal
0.40 * 80
32
TOTAL
1495
This represents an increase of around 150 PJ since 1991
2796 -------------> 1951 ----------> 1495Primary Delivered Useful
Overall only just over 50% of energy extracted isactually useful
4.5 Energy Conservation by Fuel Switching
Current HeatingMethod
ExistingDeliveredEnergy
UsefulEnergy
Energy Requiredwith GasCondensing Boiler
Electricity Full Rate)
32+50
82
91
Electricity (Off Peak)
76
68
76
Gas
1252
939
1043
Oil
136
88
98
Coal
80
32
36
TOTAL
1626 PJ
1344PJ
Consider the replacement of all heating by most efficient means available (i.e.condensing Gas Boilers). We shall exclude appliances. [Data taken from Table4.4].
So saving by fuel switching in terms of current
Delivered Energy is 1626 - 1344 = 282PJ or17.3%
====
New Primary Energy requirement would be
1344*1.05 + 80*1.05 + 245 *2.90 = 2207 PJ
The 245 comes from the residual electricity demand forappliances/refrigeration/cooking.
so saving in Primary Energy Terms is 589 PJ or 21%,compared with 2796 PJ
5. Energy Balance Tables
Thank you