By M Durairaj
I remember that, on a pitch-dark midnight in Oct 1973, we were working on the second circuit of 110KV Dandeli-Ponda line at Anmod. We were extremely worried and praying that nothing adverse should happen to the healthy first 110KV circuit because in the event of any unfortunate breakdown, entire Goa would have plunged
We were able to restore both the circuits and returned to our homes in Ponda and sleep comfortably in the knowledge that now there was enough redundancy in the system.
Then Goa was being supplied by a 110 KV double circuit (DC) line from Sharavathi Hydro Power Plant in Karnataka which was commissioned in 1964. It had an approved and installed capacity of 1035 MW. The tariff was Rs 0.0575 per unit.
The comfort of cheap hydro power and a redundant line could not last long. In June 1974, due to monsoon failure and increase in power demand by the state, Karnataka imposed power cuts and this ushered in the culture of energy quota.
The earlier ten years’ agreement entered into with Karnataka for supply of 50 MW of power at 110 KV expired on March 31 1978, and Karnataka agreed to continue power supply to Goa with the increased contract demand from 50 MW to 65 MW over the next three years (1978-81). This agreement also expired
by March 1981.
220KV inter-state lines
In the meanwhile, the following two schemes were sanctioned by the Planning Commission as centrally sponsored schemes:
►Erection of 220 KV Kolhapur-Ponda line was sanctioned on 23-9-1974 and
►Erection of 220 KV Nagjhari-Ponda line was sanctioned
Initially the 220 KV Kolhapur-Ponda line was executed as a single circuit line on double circuit towers from Kolhapur to Ponda. The section between Gadhinglaj to Ponda was initially energized temporarily at 110 KV to meet the immediate power requirement of Goa. It was energized at 220 KV on 26-2-1981.
The 220KV Nagjhari-Xeldem-Ponda interstate line was commissioned on 15th March 1992.
Power allocation from central generating stations- NTPC
The center as a long term arrangement for power supply to Goa, had allocated in 1981 (a) 110 MW power from Korba Super Thermal Power Station in western region and (b) 100 MW power from Ramgundam Super Thermal Power Station in the southern region with a phased availability of 12 MW initially from 1982-83 onwards.
Though the power to Goa was from central generating stations, delivered through lines constructed as part of centrally sponsored schemes, in the perception of the people of the state it was Maharashtra and Karnataka power. Even today people talk in those terms and suggest alternate solutions considering the same.
It was in the year 1995, that the power demand of Goa reached 300 MW, and the voltage of 220 KV line sagged to 180 KV. There was a shortage of 50 to 80 MW and the government invited proposals to set up liquid fuel based power plants within Goa. Reliance Salgaocar was the successful bidder who then set up a 48MW power plant at Sancoale.
Simultaneously the state pursued and a power grid 400/200 KV 2×315 MVA substation at Colvale, Mapusa was set up and commissioned on November 1 2002. Through the tariff order dated February 17 2003, the tariff for 400 KV transmission line was determined as Rs 1129.82 lakhs and Rs 528.90 lakhs per annum for the 1st and 2nd Ckt respectively. Goa thus became a part of the national grid and for the first time had to pay for transmission projects in addition to generation tariff.
Electricity Act 2003
The Electricity Act was enacted to consolidate the laws relating to generation, transmission, distribution, trading and use of electricity and generally for taking measures conducive to development of the electricity industry. The said act was published on May 26 2003.
Under the Electricity Act 2003, energy exchanges were established to enable merchant power plants to trade in energy. Indian Energy Exchange and Power Exchange of India were established. They provide a platform to trade in power.
JERC Order May 2020
The tariff order of JERC dated May 19 2020, gives the present power demand, power allocations from different sources, transmission system and their cost. The state purchases power from 16 central power generating stations, nuclear power from Tarapore, two new thermal stations and one hydro power station, from open market through power exchanges and three power generating stations within Goa.
In addition, Renewable Power Purchase obligations are fulfilled by purchasing from six non-solar power plants and five solar power plants. Presently, power purchase by the electricity department (ED-Goa) is not limited to a few major sources but a fairly complex activity.
The ED-Goa has set up a modern state load dispatch centre at Margao, to monitor on line 24×7 this power purchase activity. ED-Goa pays transmission charges to power grid. During 2020-2021, Goa was expected to purchase 4874 MU at a cost of Rs 1661.83 cr. The average power purchase cost works out to be Rs 3.40/ unit
Redundancy in transmission lines and sourcing power from multiple sources has been the strategy of the state to ensure low tariff and availability. The government in association with CRISIL developed a document for 24×7 power supply to consumers in 2014. It had proposed a 400 KV line for connecting from Jharkhand through South India to Xeldem, Quepem. It also proposed interconnecting with 400 KV sub stations at Colvale of the western grid. This will bring in robustness in power availability to Goa. Thus, the proposal for the Tamnar transmission is on the table since 2014.
The need and importance became much more evident when on September 18 2016 there was a power failure in the 400 KV Kolhapur-Mapusa line. The Reliance power plant generation had also closed on expiry of the 15- year contract in 2014.The state had submitted this proposal as part of the business plan to JERC in 2015-16.
The Raigarh power pool in Chattisgarh had been facing high-fault levels and this project aims at creating an alternative path of evacuation. The project will help address the quality of power transfer from generating stations connected to the Raigarh pool to Goa. Hence, the transmission system includes construction of 765 KV double circuit line of 70 Km in Chhattisgarh.
This project is spread across Goa- Karnataka- Chhattisgarh and passes through the heavy dense forest of the Western Ghats in Goa and Karnataka.
Generation within Goa
Some persons are suggesting development of liquid/gas based generation as a solution. The major risk here is the price volatility of fuel. We must remember that one of the objectives of the state has been also to insulate its consumers from the price volatility and provide
Experience of eco sensitive states
The border of Kerala with Tamil Nadu and Karnataka is highly eco sensitive. It has wild life sanctuary and dense forest. Mysore -Kozhikode 400 kV D/C Line and 400kV Edamon (Tamil Nadu)- Kochi 400 KV D/C line, are the examples of transmission line through highly eco-sensitive route. Both these lines were commissioned after 12 years and 15 years of initiating the proposal. Public opposing the transmission lines is not a new phenomenon in India. The Kerala Government claims completion of power highway as ‘making impossible as possible.’
The ground reality is that 400 KV DC line connectivity with the southern region is required for the energy security of Goa.
Winning the energy security strategy
Goa has one of the lowest tariffs in the country and is free from any energy cut. As seen historically, it is because of sourcing cheap power from anywhere in India including from power exchanges. This strength comes from having robust connectivity at 400 kv with the national grid.
The present unrestricted, post- COVID power demand of nearly 700 MW is being met by 220kv line from Nagjhari .. 100 M to 250 MW by Kolhapur – Ponda 220 kV line and 350 MW by 400 kV line.
Goa is talking about a 400 kV transmission line providing second connectivity to national grid, after nearly two decades. Any connection to a 220 kV sub-station like Ambewadi does not form part of 400 kV national grid and hence has limited
Some recommend upgrading of existing 220kv line. When additional power needs to be transmitted, the conductors have to be bigger in size and the voltage also needs to be at higher level. This simply means the existing towers are to be replaced with new ones. Then the question of continuing power supply during up-gradation period has to be considered. In India, we have to provide for contigencies of project being suspended midway due to change in government priorities, funds, vested interests etc.
The next transmission line may be thought of after another two decades. So the proposed transmission line should have capacity to serve till then. The proposal of Quad 400kv line from Narendra (near Dharwad), a national grid substation, is the best available choice.
The route to Goa is inevitably through forest. A biodiversity impact detailed study report BIA and BMP report by ERM had considered three alternatives and selected the proposed one which causes least impact and maximises the use of defunct 110 lv line corridor.
The writer is a member of the State Advisory Committee, JERC and on the Basic Infrastructure Committee of GCCI. He was formerly the CEO of Reliance Salgaocar Power Company.