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Hindustan Zinc Limited (HZL) is India’s largest and world’s second largest integrated zinc producer. Hindustan Zinc’s operations comprise lead-zinc mines, hydrometallurgical zinc smelters, lead smelters, pyro metallurgical lead-zinc smelter as well as sulphuric acid and captive power plants in northwest India.
HZL operates the Dariba Zinc Smelter which has a load of 200 MW which is mostly flat through out the year. Currently the load is served by 2×90 MW Captive Thermal Plants. Further, HZL has an State Tranmission Unit (STU) connection from local the Distribution company for ~90 mVA. Before venturing into renewables, the company primarily meets its energy requirements through a thermal captive power plant (CPP). With an internal voluntary target of achieving netzero emissions by 2050, Hindustan Zinc aims to integrate renewables as much as possible while remaining commercially viable.
Serentica helped decarbonize HZL’s electricity consumption, by designing a solution with three key characteristics:
High-assurance Hybrid renewables under the Captive scheme :
The client’s existing CPP used imported coal blended with domestic and given its high cost Serentica was able to displace a large quantum of it with a high-assurance (70% annual CUF) renewable solution. This represents a capacity overbuild which is greater than the PPA contracted capacity but was able to provide power round-the-clock and throughout the year. Such an overbuild reduces the amount of renewable intermittency experienced by the customer the remaining intermittency can be balanced by ramping the Thermal Units up and down to provide a smooth flow of power or procuring power from the national energy market. Setting up a Project under the captive generator rules eliminated the cross-subsidy surcharge and additional surcharge on HZL thus making the cost of renewables further attractive in comparison to their existing cost.
CTU connected Generation :
The Ministry of Power has incentivized the development of large scale renewables by waiving ISTS charges for using the central transmission system for projects commissioned up to Jun’25. Serentica capitalized on this incentive which further reduced the cost of renewable energy.
CTU connected Load :
Given the Serentica team’s experience with developing transmission lines (our sister company Sterlite Power is one of the largest private developer of transmission lines in the country with over 15000 ckm developed or under construction). We offered to build a direct transmission line to connect the HZL Dariba plant directly to the CTU. This led to the natural improvement in reliability that comes from being connected at a 220kV+ level. It also helps save on STU charges and losses. Finally, it also eases HZL’s ability to participate in the national energy market.
The line has been built in such a way that in years to come HZL shall be able to consume entire power through this line, preferabaly the green power and shutting down its thermal units.
We, at Serentica, believe that energy transition is the defining opportunity of our time. Globally, utilities, investors, corporations, and governments at every level are realising the sense of urgency required to aid decarbonisation and address climate change in the most efficient and effective way possible.
With ~1800 MW of Power Delivery Agreements (PDAs) signed till date, Serentica is the decarbonisation partner of choice for leading industries in India like Aluminium, Steel, Chemical, Oil & Gas, Mining, etc.
As a sustainable energy platform, we’ve charted out a roadmap to accelerate the energy transition for hard-to-abate industries, captured in our brand’s vision and mission statements.
