Tables to Convert Energy (kWh) or CO2 (saved or used) to Familiar Equivalents
- Cars, Homes, or Power Plants (India Average Data)*
Satish Kumar (skumar@irgltd.com), ECO-III Project
Arthur H. Rosenfeld (arosenfe@Energy.State.CA.US), California Energy Commission
Ravi Kapoor (rkapoor@irgssa.com), ECO-III Project
Kailash Mahajan (kcmahajan@irgssa.com), ECO-III Project
Anurag Bajpai (anurag@irgssa.com), ECO-III Project
Neerav Verma (neerav.iitr@gmail.com), ECO-III Project
March 2009
Background
Energy consumption and savings are normally measured in several different units but can easily be converted
to kilowatt hours (KWh) the unit of electricity. The energy savings can be directly converted into avoided
millions of tons of Carbon (MtC) or of carbon dioxide (MtCO2). But most of us have little "feel" for these
strange units, so the news media tends to convert energy savings to avoided cars, homes, or power plants.
Tables 1 & 2 will show us how to do this, but first we must define a typical car, home, and power plant things we can visualize. We define:
•
•
•
A Typical Car with an average fuel economy of 12 KM/liter of petrol†, driven 6,000 KM/year with
petrol use of 500 liters/year‡. This suggests a passenger car, not a van or SUV or light truck.
A Typical Urban Home with an average annual electric use of 1,200§ kWh. This suggests a typical
middle-class urban home.
A Typical Thermal Power Plant with a 250** MW generation capacity, running for 6000 hours per
year††, and thus generating annually 1.5 billion kWh, (or 1.5 billion units)‡‡ of electricity. However,
considering the efficiency of a power plant as 31%, the equivalent energy consumption in the typical
power plant would be 5.34 billion kWh.
These typical uses are shown in Col. A of the two tables below.
Table 1 converts energy used in cars, homes, and plants to electrical energy. It compares the annual energy
consumption of a typical car, a typical home with the electricity generated by a typical thermal power plant.
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The preparation of the equivalent matrix is an attempt by the ECO-III team to convert energy units into real-world examples
that lay persons can understand and relate to. The other objective of the paper is to highlight the difference between source
(coal, gas, oil, etc.) and site (electricity) energy and the role it can play in devising sensible energy policies. The paper has been
adapted from Equivalent Matrix paper (Rosenfeld and Kumar, 2002) developed for the US. As can be seen, there are many
assumptions and estimates that have been used to derive the equivalence concepts with the hope that the feedback that ECOIII team will get will help us improve and refine this document even further."
†
Best guess estimate
‡
Best guess estimate
§
Best guess estimate based on Ministry of Power, Govt of India web-site
**
Best guess estimate
††
Based on plant load factor statistics from Ministry of Power, Govt. of India web-site
$$
"1 Electric unit = 1 kWh"
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Table 1: Energy use of a typical car, a typical home, and a typical power plant in India
A
B
Annual energy
Consumption
Conversion to
kWh§§
Home
Typical Urban Home
One lakh (0.1 million)
typical urban homes
One lakh typical cars
D
Equivalent
Annual
Energy***
Number of
equivalent
typical homes
(in lakhs)
Total Indian houses (Urban (70) + Rural (163)) : 233 million†††
1200 kWh‡‡‡
Not needed
1200 kWh
–
120 million
kWh
Not needed
120 million
kWh
1
Passenger Car
Typical Car
C
Indian Stock (Private and Commercial): 8.5 million§§§
500 liters****
50 million liters
Typical Power Plant (250
MW ! 6000 hours/year)
1 litre = 10
kWh††††
1 litre = 10 kWh
5000 kWh
500 million
kWh
–
4
Indian Power Generation: 845 billion kWh‡‡‡‡
Energy Generation
1.5 billion
kWh§§§§
Not needed
1.5 billion kWh
12.5
Energy Consumption
5.34 billion
kWh*****
Not needed
5.34 billion
kWh
43
How to Use Table 1 (Electrical Energy)
Suppose you learn that low-E windows are saving 5 billion units of energy consumption per year, which is
about 0.7% of the total Indian energy production. We can use Col. C of Table 1 to divide energy use by one
lakh homes to get an equivalent of 41 lakh (4.1 million) typical homes.
Similarly we can calculate 10 lakh (1 million) equivalent cars or 4 typical thermal power plants avoided.
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§§
***
See http://bioenergy.ornl.gov/papers/misc/energy_conv.html
For all units, the US multiplier has been used as shown in the table titled Metric Prefixes and US Multiplier
†††
‡‡‡
Census of India estimates, 1971 - 2001
Per National Sample Survey Organization (NSSO) estimates for Household Consumption for Goods and Services for the year 2004-
05
§§§
Projected data from Table: Growth of motorized transport vehicles in India, Integrated Energy Policy, Planning Commision of India,
August 2006.
****
Per best guess estimate
3
†††† Based on calorific value of petrol = 46 MJ/kg and density = 737 kg/m . (1 MJ = 0.278 kWh)
‡‡‡‡
st
Power Generation status of India as on 31 May, 2008 as per Ministry of Power, India (http://powermin.nic.in)
Per best guess estimate
*****
Estimated from International Energy Studies, 2004. A typical power plant consumes 3.56 kWh of source energy to generate and sell 1
kWh of energy.
§§§§
%"
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Similarly, suppose you learn by using an energy efficient refrigerator standard will save 15 billion kWh
annually. Table 1 reminds us that a typical power plant sells 1.5 billion kWh, so the standard has avoided 10
power plants. It reminds us that 1 lakh homes use 0.12 billion kWh, so it means that we can supply electricity
to additional 12.5 crore (125 million) homes without the need for adding new power generation capacity.
Table 2 below provides the Carbon Dioxide emission by typical home, car and thermal power plant.
Table 2: CO2 Released by Cars, Homes, and Power Plants (Units: metric tons of CO2)
A
B
Typical Energy
Consumption/
Generation
(Rounded)
Passenger Cars
(Energy Consumption)
D
Annual CO2
emission
Number of
equivalent
typical
cars/homes
(in lakhs)
Indian Stock (Private & Commercial): 8.5 million
500 liters
1 litre = 1.8 kg‡‡‡‡‡
0.9 t
50 million liter
''
0.09 Mt
Typical Car
One lakh typical cars
Conversion to
CO2†††††
C
Homes ( Urban)
Indian Stock: 70 million
(Energy consumption)
Typical Home ( Urban)
(Electricity)
1200 kWh
1 kWh = 0.80 kg§§§§§
0.96 t
One lakh typical homes
120 million kWh
''
0.096 Mt
Power Plants
Typical thermal plant
(Energy generation)
1
1
Indian Power Generation: 704 billion kWh
1.5 billion kWh
1 kWh = 0.80
kg******
1.2 Mt
13
How to Use Table 2 (CO2)
Finally, suppose that manufacturers want to get CO2 credit for the same refrigerator standards, so they use
Table 2 to convert the 10 power plants avoided into 12 MtCO2/year. As before, we can divide 12 Mt of CO2
by the 1 lakh cars row (0.09 MtCO2) to get 13 million equivalent cars.
Often the CO2 savings will be stated in Mt of carbon, rather than CO2, and we must know that 1 ton of CO2 is
equivalent to 12/44 = 0.27 tons of carbon.
Col. D of Tables 1 and 2 shows that the two tables differ slightly in their equivalence of cars and homes.
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†††††
1 tC corresponds to 3.67 tCO2.
CO2 emission factor for cars and SUVs, CSE estimate 2008 (One car produces an average of 150 g CO2 on travelling a distance of
1 km)
§§§§§
On the basis of CO2 emitted for equivalent power generation at source
******
CO2 Baseline Database for Indian Power Sector, December 2007 by the Central Electricity Authority, India.
‡‡‡‡‡
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Table 1 shows that 1 lakh cars use as much energy as 4 lakh homes, but Table 2 shows that the same 1 lakh
cars produce only as much CO2 as 1 lakh homes. This is because, per kWh, petrol produces 1/4 as much
CO2 as electricity. This concept is important to grasp so that the full benefits of fuel switching options in
the context of mitigating climate change can be understood and appropriate energy policies can be
developed.
Converting Power Plants (or Peak Saving) to “Homes”
In the above analysis, we have discussed energy (kWh) and not power (kW or MW).”
National newspapers and magazines of India can use “1 kW = 5 urban homes” conversion factor. An average
urban home uses approximately 1200 kWh whereas an average U.S. home uses 12,000 kWh. However, owing
to fluctuations in power demand or operation and maintenance requirements, a typical Indian power plant
runs for approximately 6,000 hours/year and not 8,760 hours/year.
Which Table to Use?
The conversion by energy (Table 1), and carbon or CO2 (Table 2) differ in their values, and the choice
depends on your "model".
Those of us most interested in saving money, energy, and electric trade-off will prefer Table 1; and CO2
traders will chose Table 2. To avoid confusion, we have presented both the tables. The Multiplier tables
shown below are the basis of all notations used in Tables 1-2.
Indian Multiplier
Unit Multiple
10
Indian Multiplier
3
Thousand
105
Lakh
10
Crore
7
Metric Prefixes and US Multiplier
Unit Multiple
Metric Prefix
Symbol
US Multiplier
kilo
k
thousand
106
mega
M
million
10
giga
G
billion
1012
tera
T
trillion
10
peta
P
quadrillion
10
3
9
15
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