Green Ride

Transportation sector moves to solar to reduce power costs

Most countries have lower commercial and industrial (C&I) power tariffs and higher residential tariffs. However, in India, most states have significantly higher tariffs for C&I consumers than for residential and public sector consumers. Thus savings in electricity bills have become the primary driver for C&I consumers to migrate to solar projects. For this reason, the Indian rooftop solar market has seen higher growth in the C&I space than in the residential space. C&I consumers account for about 70 per cent share of the total installed rooftop capacity in India. This is in sharp contrast to many other rooftop solar-rich countries that have seen much higher capacity addition in the residential rooftop segment.

Renewable Watch takes a look at the various initiatives taken by three large power consumers in the transportation sector – Railway Energy Management Company Limited (REMCL), Delhi Metro Rail Corporation (DMRC) and National Highways Authority of India (NHAI) – in the distributed solar segment.


Indian Railways (IR) is the single largest consumer of electricity in the country. In 2017-18, it consumed 18.98 BU of power, of which 16.63 BU was used for traction load and 2.35 BU for non-traction applications. REMCL, a joint venture of IR and the Rail India Technical and Economic Service, looks after power planning and power procurement for IR. This includes renewable energy as well as energy efficiency.

IR’s current power requirement is 2,000 MW, which is expected to increase to 2,500 MW over the next five years. This entire requirement can be met through solar power, and IR plans to achieve about 1 GW of solar power capacity addition by 2020-21. IR has about 50,000 hectares of vacant land at its disposal, which can be used for solar power deployment. Of this, about 42,500 hectares or 85 per cent of the vacant land is along railway tracks. IR’s vision is to deploy solar panels along these tracks. The estimated total solar power capacity that can be deployed on vacant railway land along the tracks is 20 GW. This can be used partly to meet IR’s power needs and the remaining can be sold to discoms.

Solar panel deployment along tracks offers multiple benefits to IR such as significant savings in power bills, revenue from the sale of power to discoms, natural fencing, and prevention of encroachments. IR is also planning to install 500 MW of rooftop solar plants, of which 60 MW has been completed, power purchase agreements (PPAs) have been signed for 114 MW and tenders have been floated by REMCL for another 100 MW. Similarly, 500 MW of solar power procurement is planned from land-based solar projects.


The operations of Delhi Metro’s vast network and high frequency of service require a huge amount of power. In fact, about 38 per cent of DMRC’s total input cost is on account of its large power consumption. With rising grid tariffs, this operating cost will keep increasing year on year and affect the financial viability of the project. Hence, DMRC is developing solar projects on a massive scale in order to leverage the declining cost of solar power. Due to land constraints, DMRC decided to install solar plants on the existing rooftops of metro stations and train depot sheds. These plants are helping DMRC meet its daytime auxiliary power needs.

All of DMRC’s rooftop solar plants have been set up in the renewable energy service company (RESCO) mode, with zero capital investment from itself. The developer, who is selected through an open e-tender to ensure transparency, is also responsible for the plant’s operations and maintenance for 25 years. The target rooftop solar capacity is being tendered in stages to benefit from the continuously decreasing solar tariffs. For each tender, the quantum of work is split amongst the three lowest bidders at the tariff quoted by the lowest bidder. DMRC is able to achieve savings of Rs 1.36 per kWh as it pays a solar tariff of Rs 5.80 per kWh against the grid tariff of Rs 7.16 per kWh. The company expects to achieve total savings of Rs 75 million per MWp in its electricity bill, considering a PPA term of 25 years.

DMRC had initially set a target of 20 MWp of rooftop solar plants by 2017, which was achieved within the set period. This target was then revised to 50 MWp by 2022. Of this, 25 MWp has been commissioned till date and PPAs for 35 MWp have been signed. In fact, all the metro stations and depots on the Magenta Line of Delhi Metro have rooftop solar projects. In Kochi Metro, another project executed by DMRC, all metro stations and depots have rooftop solar plants. In March 2017, DMRC’s rooftop solar initiative was registered with the United Nations Framework Convention on Climate Change under the Clean Development Mechanism, the first for any metro or railway system in the world.


NHAI has taken steps to deploy solar panels along highways, largely for powering its streetlights and supplying power to the grid. NHAI aims to save significant operating costs from the flat solar tariff, which is 30 per cent lower per unit than grid power and 70 per cent lower than expensive diesel genset-based power. Other major advantages of using solar power for NHAI are ease of installation, durability of the solar system, tax benefits, a one-time investment with a fixed energy cost and good returns on investment. Also, the lightning arrestors of the solar plants protect the surrounding area.

One of the first highway projects to benefit from this initiative is the Delhi-Meerut Expressway. A solar project is being set up along a 1.5 km stretch between Nizamuddin Bridge and the Commonwealth Games Village flyover on the capex model. The 1 MW solar project uses about 3,200 modules of 325 Wp each and is being extended on both sides of the road up to a distance of 400 metres. The electricity generated will be used for powering streetlights and the surplus power will be supplied to the grid under a net metering arrangement. The project successfully highlights the potential for installing solar power plants on highways as a viable and replicable option.


With the increasing cost of grid power, the migration of C&I consumers to solar power is likely to continue, including in the transportation sector. The solarisation of railway stations, metro buildings and highways is just the beginning of this trend. IR has already taken its first steps in deploying solar plants on railway coaches and plans to replicate this on a massive scale. Going forward, solar power is expected to become a key driver for all modes of land transport.

Based on presentations by Alok Mathur, General Manager, REMCL; Manuj Singhal, Chief, Electrical Engineering Planning, DMRC; and R.P. Singh, Project Director, NHAI at Renewable Watch’s conference on “Distributed Solar in India”


Enter your email address