T he battle between conventional and renewable sources of power is as old as the technologies to mine these resources. While the domination of coal in power generation over the last century or so may be waning, in favour of renewables, State governments seem to be still betting heavily on thermal power. They do believe, quite sincerely, that any sort of renewable source cannot replace coal-generated electricity to meet the rising demands.
While it is a known fact that establishing thermal plants would have a longer gestation period and leave a dark mark on the environment, not to mention a hole in the ozone layer, the need to generate enough power for handling the demand, and faith in thermal source to do so, has been overwhelming.
The Tamil Nadu Generation and Distribution Corporation (Tangedco) has the best balanced electricity generation of 50% polluting energy and 50% non-polluting power, comprising wind, solar, gas, and hydro. But the fine balance remains only on paper, rue renewable energy activists. The activists point out that whether it is the backing down of wind energy or the lack of provision of grid support to solar power, renewable energy has remained the victim.
The victimisation of renewable energy has been highlighted in various reports. The latest report from the Climate Risk Horizons (CRH) paints a dark picture of Tangedco’s plan to go ahead with the construction of the Udangudi power project which could burn a hole in the pocket of the power utility and add to the State’s fiscal deficit. The study, ‘White elephants-New coal investments threaten Tamil Nadu’s financial recovery’, bats for the freezing of the construction of coal plants in the State and for a mix of renewable energy, with coal only to manage the peak demand.
The report says the construction would put the power utility in a financial mess of ₹29,000 crore from 2024-2030 and an annual fixed cost of ₹5,000 crore. Also the cost of power generated from the plants would be as high as ₹8.20 per unit, with the lowest cost worked out at ₹6.70 per unit if the plant load factor is at 75%. The report said, “Renewable energy is available at ₹3 per unit, and combined with storage cost, it would amount to ₹4.97 per unit. It could further drop to ₹3.40 per unit by 2030 when the thermal project would be commissioned.”
Regardless of the ‘sunk cost’ of ₹6,155 crore spent on the Uppur project (which the National Green Tribunal has cancelled) and the Udangudi project, the study says the State can salvage ₹15,000 crore to ₹20,000 crore by freezing the Udangudi project and going for a mix of renewable and thermal energy.
A senior official of Tangedco said that though renewable energy, especially solar energy, was being projected as a cheap option, in actual terms it is costlier than conventional power if round-the-clock supply is required. Comparing the cost of setting up a solar plant with that of a coal plant, the official said the storage cost for battery is anywhere in the range of ₹12-₹15 per unit. The storage would last only six to eight hours. But what is required is storage for a minimum of 14 hours; in that case, the cost would be ₹25 to ₹30 per unit. There is the option of hydro pump storage with the cost being ₹8 and ₹12. But the potential is limited, and it would require a forest area for mining, leading to forest destruction.
The power utility has planned to construct two mega plants under the Udangudi power project with a capacity of 1,320 MW and 1,600 MW. Both plants would cost nearly ₹27,000 crore, and this would put a heavy debt burden on the power utility, claims the report. The 1,600-MW plant has been planned as a replacement for the Uppur thermal plant, which was cancelled by the National Green Tribunal.
A senior official of Tangedco, who went through the report, claimed that some of the facts cited in the study were incorrect. Officials said they were aware of the financial risks involved in the construction of the Udangudi power project, but they had no option since battery storage for solar power is in a nascent stage and the cost is prohibitive. Establishing a thermal plant is cheaper. However, the official said that going ahead with the Udangudi project would not mean that the State, a leader in the wind power generation, had closed the door on renewable energy; there are plans for increasing the renewable energy generation through solar plants with battery storage and hydro plants to 20,000 MW by the end of 2030.
The power managers said a road map for increasing the share of renewable energy in the total mix from 50% to 60% was being readied by resolving the challenges, including the difficulties in the integration with the power grid. Wind, solar and hydro, which remain the mainstay of renewable energy for the power utility, are set to see an expansion. Solar power will be expanded to a capacity of 8,500 MW and hydro power generated through pumped storage to 11,500 MW. The solar plants are to be set up in the next five years and the pumped storage projects over a period of 10 years.
Tangedco’s Non Conventional Energy Sources (NCES) Department has started the groundwork for generation of 6,000 MW of solar power in the first phase and 2,500 MW in the second phase. A senior official of the Department said that as part of the 6,000-MW project, solar parks with a total capacity of 4,000 MW would be established in all districts and a capacity of 2,000 MW in battery storage would be created. The Department has started readying the detailed project report for the 11,500 MW of hydro power through pumped storage.
T.R.B. Rajaa, legislator and member of the Tamil Nadu State Planning Commission, said Chief Minister M.K. Stalin was keen on promoting renewable energy and environmentally sustainable projects. Tamil Nadu is a leader in renewable energy with a capacity of more than 15,500 MW. The Chief Minister has set a target of adding 18,000 MW in renewable energies in the next 10 years.
He said Tamil Nadu would switch to no-coal policy after it reached surplus capacity in wind, solar and other renewable sources of energy. The Minister for Electricity had said the State was developing land banks for building solar parks and Guidance Tamil Nadu had a list of land banks for wind and solar projects. He said one of the issues with renewable energy was that it would be available only at a particular period of time and so the main challenge would be storage. The Planning Commission is working towards finding the right solutions.
Mr. Rajaa said that with Tamil Nadu accounting for 13% of India’s coastline, the State is looking at tapping into offshore wind potential. Some companies have shown interest. According to a preliminary assessment carried out by the National Institute of Wind Energy, 31 gigawatt of offshore wind power potential exists off the coast of Tamil Nadu. However, Mr. Rajaa said, offshore wind energy should be developed carefully as there are eco-sensitive zones and fishermen have expressed concerns.
One of the challenges in the push towards green energy is the weak financial position of Tangedco, which has been posting huge losses. The tenders issued by Tangedco for procuring solar energy have received a tepid response. A few years ago, Tangedco handed over the task of procuring wind and solar energy to Solar Energy Corporation of India, a Central government agency. As per official data, Tangedco owes over ₹2,000 crore to renewable energy generators.
There has been an issue of curtailment of renewable energy generation, which has become a never-ending dispute between Tangedco and the generators. In August 2021, the Appellate Tribunal for Electricity directed Tangedco and the Tamil Nadu State Load Despatch Centre to jointly pay compensation to solar energy developers for curtailment of generation from March 1 to June 30, 2017.
Based on the report from Power System Operation Corporation Ltd., the Appellate Tribunal for Electricity concluded that the curtailment instructions were issued for reasons other than grid security and fixed the compensation at 75% of the tariff per unit as per the power purchase agreements. The Tamil Nadu Electricity Regulatory Commission, too, had directed the State Load Despatch Centre to evolve a protocol of reasons for curtailment such as transmission constraints and grid safety and security. Curtailment shall be done after communicating the reasons to generators in writing, or through the State Load Despatch Centre website.
