CO2 EMISSIONS FROM RAILWAYS – USE OF EMISSION FACTORS

Sudhir Gota

Quantifying emissions from Railways (including LRT/MRT) is really tricky. Some of the variables which often trouble analysts are – use of construction, technology and occupancy factors which can make or break an analysis. Last year, Mikhail Chester brought forward a very interesting analysis on complete carbon footprint of transport modes and this study was critically accepted. The study provided a comprehensive environmental life-cycle assessment of not only vehicle and fuel components but also infrastructure components for automobiles, buses, commuter rail systems and aircraft. Many processes were included for vehicles (manufacturing, active operation, inactive operation, maintenance, insurance), infrastructure (construction, operation, maintenance, parking, insurance), and fuels (production, distribution). The vehicles inventoried in the study were sedans, pickups, SUVs, urban diesel buses, light rail, heavy rail and aircraft.

The important argument made by Chester was that one needs to closely look at the occupancy of Rails and its built infrastructure which often tip the scales. But, more often researchers think that one can always borrow the emission factors from different sources and this would provide some estimates of reasonable accuracy. This is a myth.

In order to demolish the argument of usage of common emission factor, we summarize many of the emission factors [1]available online. The data collation was further helped by inputs from ADB-TA - Reducing Carbon Emissions from Transport Projects.

It is to be noted that emission factors have been quantified using different methodologies with different boundaries. What sets them apart is the huge variation. The variation is between 16 to 1200 g/pkm. The Asian MRT’s which have very high occupancy ratios have values between 20 to 110 g/pkm. Segregating heavy rails, MRT and LRT may help in refining this further. However, it is to be noted that emission factors cannot be constant but dynamic with time in order to reflect changes in design, occupancy and other factors.

Thus, one cannot borrow the emission factor straight away. What one should do is to measure the fuel/electricity consumption to derive emissions. There is no easy way out.

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[1] Please send us a request in case you would like to access the sources.

Transport Infrastructure Efficiency

Which kind of transport investments are the most efficient?

Sudhir Gota

This question bothers many policy makers. Answering this question is rather difficult as different projects require different scale of investments which carry variable load and satisfies diverse set of consumers. Also it would be wrong to assume that we can always build different alternatives physically having same bunch of people using it.

Knowing the above limitations, we can still assess efficiency of infrastructure requiring different set of investments – from High Cost such as Metro, to median ranged projects such as BRTS, Roads to low cost projects such as bikelanes and footpaths.

Let’s consider the following projects – Metro, BRTS, Expressway of 4 lane, two lane urban in high income zone, two lane urban in Low income zone, Bikeways and Footpaths and thus using the law of averages to evaluate the construction cost efficiency.

In order to compare efficiency – one needs average capacity and average cost. Let’s make an assumption as detailed in below table.

	Capacity (average person/hour)	Cost (million USD)
1 km of Footpath of 2m wide	2400	0.1
1 km of Bikeways of 3m wide	3000	0.15
1km of two lane urban (Low income)	4500	1
1km of two lane urban (high income)	2600	1
1 km of Expressway of 4 lane	8500	3.5
1 km of BRTS	16000	2
1 km of Metro	60000	35

1. The Metro represented here is a replica of Bangalore Metro being constructed now. Its estimated to cost 35 million USD/Km.

2. BRTS – The BRTS taken above satisfies 8000 pphpd and costs 2 million USD/Km. this represents an average BRTS which is being constructed in many Asian cities.

3. Roads are tricky as they can carry a highly variable set of volume. So let’s assume LOS “B” and and 7% as peak hour volume. Lets also assume that a freight vehicle is equivalent to a vehicle carrying 15 passengers. ( this thumb rule matches with Value of time concept)

a. consider 35000 PCU/Day for Expressway – 4 lane

b. consider 15000 PCU/day for 2 lane urban road

c. Occupancy of 1,2,1.5 and 25 for two, three wheeler, car and Bus

d. Assume 50% mode share of freight in expressway and 9% in urban roads ( data Indian Roads)

e. Assume 55% two wheelers in low income and 55% Cars in high income areas

f. The other mode share epitomizes typical Asian roads ( 6% of vehicles as Bus)

4. Use Passenger Car Units to convert PCU’s into vehicles and then using occupancies break down the vehicles into passengers

5. Consider Bikelanes to carry 3000 cyclists/hour suggesting a dense network as seen in Delhi BRTS costing 0.15 million USD/km

6. Consider footpaths to carry 2400 persons/hour at a speed of 1.2 m/sec indicating LOS B. It may cost approx ) 1million USD/km.

Using the same money as required for constructing 1 km metro, one can on an average construct

1. 18 km of BRTS
2. 10 km of four lane Expressway
3. 35 km of two lane urban road
4. 235 km of Bikeways
5. 350 km of footpaths

Thus normalizing different projects into same investment of say 1 km of metro and thus using the capacities and length, we can calculate efficiencies.

The below graph gives the efficiencies

The low cost projects such as bikeways and footpaths in fact provide best efficiency!!

They are 12 to 14 times more efficient than a system like metro. The above calculations can be made more useful by including operation costs and emissions. But the footpaths and bikelanes would be the winners but they often receive least attention and funding.

HIDDEN EMISSIONS FROM TRANSPORT

Sudhir Gota

Latest news from Mumbai got many people excited about Monorails and its impact on emissions. The news report claimed that on an average the mono rail would save 3500 tons/year/km. This kick started a debate on emissions savings from metro rail projects and its hidden component – construction emissions. The debate pitchforked the main issue of infrastructure construction as a significant component of transport emissions. Experts believe that we do a great disservice to entire emissions argument from transport by not considering such hidden aspects and we need to consider whole emissions argument from transport with a pinch of salt. Researchers like Mikhail Chester have proved that Construction is significant component of total life cycle and should not be neglected.

Gigantic infrastructure projects take ages to plan, get approved, and finally to get implemented in a developing country. Bangalore metro substantiates the above statement. Mass rapid system in Bangalore have been studied from past late 1980’s and it was only until in early 2000’s that some actual planning was initiated. Main construction for approx 40 km of metro was initiated in 2006 and the people would only get a chance to experience the system in the year 2012. By the time metro starts chugging along the Bangalore streets, things would have changed. This argument is in fact more worrisome for elevated roads and isolated flyovers which take two years as an approximate to complete in a city like Bangalore. While the traffic suffers, emission gets multiplied and finally it opens to jam-packed traffic created by land use manipulations by builders anticipating zero congestion.

Massive projects require huge quantities of material, machinery and workers which create many leakages in emission profile. Research coming out from Japan reinforces this argument that expensive metro can in fact accumulate high intensity of emissions during construction. Researchers from Nagoya university have estimated that a station of the Superconducting MAGLEV generates emissions of magnitude 2,430[t-C/station] during construction only. Many researchers in order to to simply the calculations argue that only the emissions generated during material production be considered as a basis. But then, research also suggests that material movement, use, disposal can accrue 42% of production emissions.

The above argument looks minute in nature if we consider emissions quantified from Cairo Subway which shows that construction emissions are equivalent to 28 years of operation emissions !!

This above arguments raises an important related question –

would High speed rails really save emissions?

There has been tremendous push for such massive projects in developing countries in the name of climate change. Do we really need such expensive solutions to “reduce” emissions? Literature suggests that high speed rails emit approx 73 grams/passengerkm during operations. Indian railways preliminary estimates suggest that a High-Speed Rail consumes 0.933 litres of fuel per 100 km travelled, in comparison to the 4.04 litres consumed by an airplane and 5.69 litres consumed by an economy car. But, what remains hidden in the entire argument is fact about construction emission. Experts have suggested that high-speed rail can produce some 10 million metric tons of CO2 per year during construction.

Back of the envelope calculations suggest that a kilometer of high speed rail would cost anything from 10-20 million $/km in developing countries when neglecting land costs. Even if we blindly assume that emissions are being saved by such corridors, can developing countries really afford it?

We need more debate and need to see more numbers as massive construction can really change the game!!