**Executive Summary**
This document is an official response from the Minister of State in the Ministry of Power to questions raised in Lok Sabha regarding the integration of coal-fired power plants with renewable energy. It details studies conducted on the impact of reduced technical minimum load, remedial measures considered, and policies for hybrid technologies, including co-firing bio-mass. A policy on co-firing bio-mass was issued on 07.11.2025.
**Key Points / Main Content**
* **Impact of Reduced Technical Minimum Load (TML)**
* The Central Electricity Authority (CEA) has conducted studies on the long-term impact of reduced TML on coal-fired Thermal Power Plants (TPPs).
* Studies indicate that operating at 40% Minimum Technical Load (MTL) results in:
* Accelerated wear of components (especially rotating components)
* Reduced lifespan and efficiency of key pressure parts
* Efficiency degradation
* Increase in creep-fatigue, accelerated corrosion, and erosion
* Higher risk of fatigue-related failures
* Increase in Equivalent Forced Outage Rate (EFOR) and Gross Heat Rate
* Higher auxiliary power consumption and reduced combustion efficiency at low loads
* **Remedial and Mitigation Measures**
* The CEA has prepared remedial measures to address potential impacts of reduced TML/flexible operation.
* These measures aim to ensure operational safety, maintain flame stability, combustion quality, and minimize stress on boiler and turbine systems.
* Key measures include retrofits in existing systems:
* Implementation of Automation
* Optimization of control systems
* Installation of scanner for proper flame detection
* Installation/ use of steam coil air-preheaters (APH)
* Improved condition monitoring of boiler and turbine
* Optimisation of Auxiliaries
* Generating Companies (GENCOs) are advised to adopt unit-specific retrofits.
* **Policy for Co-firing Biomass**
* The Ministry of Power issued a comprehensive policy on 07.11.2025 for co-firing of 5-7% blend of bio-mass pellets (including torrefied charcoal made from Municipal Solid Waste (MSW)) in Coal Based Power Plants along with coal.
* This policy is contingent upon assessment of technical feasibility.
**Impact Analysis**
**Generating Companies (GENCOs)**
* **Impact**: GENCOs are affected by the need to implement unit-specific retrofits in coal-fired plants to mitigate the impacts of reduced technical minimum load and co-firing biomass.
* **Action Required**: GENCOs need to adopt unit-specific retrofits, taking into account plant age, design parameters, coal quality, and vintage. They must also assess the technical feasibility of co-firing biomass.
**Central Electricity Authority (CEA)**
* **Impact**: The CEA is responsible for implementing the remedial measures to address the impact of reduced technical minimum load.
* **Action Required**: Continue conducting studies and monitoring the effectiveness of remedial measures, and refine approaches as necessary.
Key Entities Referenced
Ministry of Power: Indian government ministry responsible for electricity.
Central Electricity Authority (CEA): Statutory organization that advises the Indian government on policy matters and coordinates activities related to electricity.
Coal-fired Thermal Power Plants (TPPs): Power plants that use coal to generate electricity.
Integration of Coal-Fired Power Plants with Renewable Energy: Policy focused on incorporating renewable energy sources with existing coal power infrastructure to improve efficiency and supply.
Minimum Technical Load (MTL): The minimum power output level at which a power plant can operate efficiently and safely.
GOVERNMENT OF INDIA
MINISTRY OF POWER
LOK SABHA
UNSTARRED QUESTION NO.1975
ANSWERED ON 11.12.2025
INTEGRATION OF COAL-FIRED POWER PLANTS WITH RENEWABLE
ENERGY
1975. SHRI DUSHYANT SINGH:
Will the Minister of POWER
be pleased to state:
(a) whether any studies have been carried out on the long-term
impact of reduced technical minimum load requirements on the
lifespan and efficiency of the existing coal-fired power plants in light
of the commendable Government initiatives to enhance the share of
renewable energy in the India’s total energy generation, if so, the
details thereof;
(b) whether remedial measures are being considered by the
Government to address such potential impacts, if so, the details
thereof; and
(c) whether the Government has any plans to introduce or promote
hybrid technologies that can integrate the existing coal-fired power
plants with renewable energy sources to ensure optimum efficiency
and consistent power supply, if so, the details thereof?
A N S W E R
THE MINISTER OF STATE IN THE MINISTRY OF POWER
(SHRI SHRIPAD NAIK)
(a): The Central Electricity Authority (CEA) has carried out various
flexibility studies on the long-term impact of reduced technical
minimum load requirement of the existing coal-fired Thermal Power
Plants (TPPs), in association with Original Equipment Manufacturers(OEMs) / National & International partners. These studies indicate
that 40% Minimum Technical Load (MTL) operation result in
accelerate wear of components (particularly rotating components)
and also reduces life of key pressure-part along with their efficiency.
This impacts the lifespan and efficiency in long-term as:
Efficiency degradation;
Increase in creep–fatigue;
Accelerated corrosion and erosion;
Higher risk of fatigue-related failures;
Increase in Equivalent Forced Outage Rate (EFOR);
Increase in Gross Heat Rate;
Higher auxiliary power consumption;
Reduced combustion efficiency at low loads.
(b): The CEA has prepared several remedial & mitigation measures
to address such potential impacts on existing coal-fired plants from
reduced technical minimum load (TML) / flexible operation. These
measures aim to ensure operational safety, maintain flame stability
& combustion quality, and minimize stress on boiler and turbine
systems, thereby reducing equipment damage and efficiency losses
at low load. The key measures include retrofits in the existing system
as below:
Implementation of Automation
Optimization of control systems
Installation of scanner for proper flame detection
Installation/ use of steam coil air-preheaters (APH)
Improved condition monitoring of boiler, turbine etc.
Optimisation of Auxiliaries
Further, Generating Companies (GENCOs) have been advised to adopt
unit-specific retrofits rather than a ‘one-size-fits-all’, taking into
account plant age, design parameters, coal quality and vintage so as
to limit undue stress on plant equipment during flexible operation.
(c): Ministry of Power has issued a comprehensive policy on
07.11.2025 for co-firing of 5-7% blend of bio-mass pellets [including
torrefied charcoal made from Municipal Solid Waste (MSW)] in Coal
Based Power Plants along with coal, after assessing the technical
feasibility.