Build Own Operate Solutions

Founded in 2009, Thermax Onsite Energy Solutions Limited (TOESL) is a wholly-owned subsidiary of Thermax Limited.

The company offers outsourced green utilities such as biomass-based steam, heat and cogeneration, water and wastewater solutions, bio-CNG and biomass gasification through the build-own-operate (BOO) business model. TOESL partners with its customers by providing green solutions and helping them achieve their ESG goals.

Customers shift from operating utilities to a contracted certainty model. The result is assured visibility of your lifecycle cost and guaranteed uptime backed by Thermax’s engineering depth.

110+

Green utility assets across 50+ sites

$50M+

Invested in assets across India, Sri Lanka and Southeast Asia

99.8%+

Portfolio uptime

1.6M+ tCO₂e

Abated through biomass based green solutions

How Thermax solves industry
challenges

01 Utility performance volatility

Utility performance is often inconsistent due to multiple partners, driven by fragmented ownership. This leads to operational uncertainty, inefficiencies, and difficulty in meeting production targets. TOESL addresses this by investing 100% capital and taking end-to-end responsibility for delivery and performance.

02 Biomass Supply Chain Reliability

Biomass-based operations face challenges due to unstructured sourcing, fragmented suppliers, and seasonal variability, affecting fuel availability and cost predictability. TOESL addresses this through structured sourcing and vendor management.

03 Fuel quality variability

Fuel quality tends to vary, affecting efficiency and stable operations. TOESL controls this through defined quality checks and standardised protocols under FuelGenome™ & FuelSure™.

04 Operational discipline & plant hygiene

Inconsistent operating practices and lack of standardised plant hygiene (6S) reduce efficiency, safety, and asset reliability, with limited digital monitoring affecting visibility. TOESL addresses this through standardised operations supported by monitoring and analytics.

Offerings

Assured Green Utility-as-a-Service

Steam-aaS (Process Steam Utility)
End-to-end steam utility on a BOO model - design, finance, build, own, operate, with guaranteed availability and performance. Delivers predictable steam without capex or operational risk.
Heat-aaS (Process Heat Utility)
BOO-based process heat solutions (hot water, thermic fluid, hot air), ensuring consistent temperature, high availability, and reduced downtime for critical operations.
Water-aaS (WTP/ETP/ZLD & Desalination)
Onsite water utilities on a BOO model - desalination, DM, ETP, ZLD, with assured quality, compliance, recycling, and minimal supply risk.
Multi-Utility-aaS (Integrated Utility Contract)
Integrated BOO model for steam, heat, and water/wastewater, with single-point accountability, unified governance, and performance aligned to uptime and cost stability.

Fuel Assurance System

BioWeave™ (Biomass Supply Chain System)
Structured biomass supply model ensuring continuity and spec control - includes vendor governance, sourcing strategy, risk buffers, and disciplined intake to prevent fuel-driven operational disruptions.
FuelGenome™ & FuelSure™ (Fuel Science & Quality Seal)
FuelGenome™ manages fuel variability, FuelSure™ certifies quality - together delivering retail-grade fuel assurance to test, approve, track, and protect uptime from variability.

Digital Operations

PulseOps™ (Operations OS)
A digital operating system for uptime - enabling monitoring and operating discipline that scales across sites, making utilities measurable, governable, and traceable.
PulseOps™ (Analytics & Performance Layer)
Advanced analytics and reporting layer - delivering exception handling, performance insights, and leadership-ready visibility for plant performance and safety.

Assured green utility model - An overview

We own the asset and ensure 24x7 operations with strong engineering discipline across maintenance, safety, compliance, spares, and fuel governance, supported by transparent performance reporting.

Customers benefit from auditable uptime and clear cost-of-utility visibility.

Built-in capabilities that make TOESL's delivery predictable at scale

Biomass supply continuity mechanisms and vendor partner governance

24x7 operations with certified site teams

Safety and compliance documentation discipline

Fuel management, sampling and spec-control

Spares strategy and critical equipment redundancy planning

Performance-linked KPIs and uptime governance (contractual)

Preventive plus predictive maintenance cadence

Remote monitoring and exception-based response

Featured capabilities

Build-Own-Operate

Build-Own-Operate Model

50+ utility islands connected under a common uptime contract, delivering ~99.8% uptime

BioWeave™

BioWeave™ secures 3,000+ TPD equivalent biomass through 250+ strategic vendors and farmer networks, covering 30+ biomass types

FuelGenome™ & FuelSure™

Optimised fuel mix and quality consistency via standardised protocols

PulseOps™

PulseOps™ enables real-time IIoT monitoring of green utility assets, turning operating data into actionable insights, trip prevention, efficiency gains, emission control, reliability flags, and leadership-ready reports