The VSRT-E hybrid steam boiler from Fulton represents a significant advancement in industrial steam generation, addressing the pressing demands of decarbonisation and energy flexibility, whilst maintaining the flexibility and resilience dual fuel operation offers to critical operations such as medical support facilities.
Developed in response to global net-zero initiatives and evolving regulatory landscapes, this innovative steam boiler combines gas-fired efficiency with electric operation to offer a future-proof solution for facilities striving to balance operational costs, emissions reduction, and infrastructure constraints.
Development Rationale and Industry Need
The VSRT-E emerged from the urgent requirement to reduce Scope 1 emissions while maintaining operational reliability. With the UK’s Net Zero by 2030 targets and tightening emissions standards – such as the Medium Combustion Plant Directive (MCPD) limiting NOX to 100mg/Nm³ at 3% O2 reference – some more traditional steam boilers and steam generators faced obsolescence, with facilities requiring systems capable of transitioning between energy sources without costly infrastructure overhauls.
Rather than trying to match improved combustion technologies to existing boiler designs, Fulton designed a completely new product over 10 years ago, looking at what constituted the ideal steam boiler, i.e.
- Competitive initial capital cost
- Low cost of ownership – efficient and low maintenance
- Small footprint – less plant room space needed
- Quick startup from cold – saves time and fuel
- Durable pressure vessel – Rugged, Robust, Reliable (Fulton’s values)
- Relatively high mass water volume – ability to react to load swings
- Integrated ultra-low emission NOx burner as standard
- As fully automated as possible – compliance with all relevant guidance and ACOPs.
- High steam quality – as near to dry saturated steam as possible
This led to the introduction of the VSRT range of gas fired boilers, with outputs from 160kg/hr to 2,000kg/hr, expanding to 10,000kg/hr when supplied as a modular system.
Available to run on natural gas, LPG or natural gas/hydrogen blend with no fundamental changes to the burner or associated equipment, the VSRT met those initial ideals, particularly extremely high steam quality, which has also provided documented results where typical fuel savings of between 20-30% have resulted as a direct result of efficiency improvements from the steam system.
Whilst these fuel savings provided financial and environmental sustainability (the fuel savings also resulted in directly proportional reductions in Carbon emissions as well as monetary) the next logical solution in an ever-changing market was to address zero emissions and dual fuel requirements, and so the VSRT-E concept was born.
Fulton’s solution leverages its proven VSRT fuel-fired steam boiler and integrates electric heating elements to create a dual-fuel (gas-fired and electrically powered) system. This hybrid approach allows operators to utilise existing gas infrastructure while preparing for electrification, particularly valuable in regions with constrained electrical grids or phased decarbonisation plans. The boiler’s ability to switch fuels based on time-of-day pricing or grid demand events addresses both economic and environmental priorities, a critical consideration as energy cost volatility persists.
Technical Innovations & Key Features
The VSRT-E distinguishes itself through several engineering advancements:
Dual-Fuel Flexibility
The system operates at 82.5% thermal efficiency on natural gas (20-30% lower associated Carbon emissions than conventional boilers) and 99% efficiency in electric mode, achieving zero Scope 1 emissions during electrical operation. This dual capability enables facilities to meet immediate emissions targets while retaining gas backup for energy security.
Automated Fuel Management
An intelligent control system permits scheduled fuel switching, allowing operators to capitalise on off-peak electricity tariffs or respond to demand response events. For example, a hospital could programme overnight electric operation to avoid daytime peak rates while maintaining daytime gas use for steam-intensive procedures.
Ultra-Low Emissions Profile
When operating on natural gas or hydrogen blends (tested up to 23% hydrogen), with its high-pressure pre-mix head design, the VSRT-E maintains NOx emissions below 40mg/Nm³, well under the 42mg/Nm³ threshold for low-emission zones. Electric mode eliminates NOx entirely, making it suitable for urban installations with strict air quality regulations. Even on LPG, the boiler has a proven record of producing NOx emissions less than half of the associated MCPD threshold, making it suitable for utilisation on “off-grid” sites
Maintenance-Optimised Design
The vertical spiral rib tubeless construction features heat exchanger walls up to 350% thicker than traditional tubed boilers, with the tubeless design eliminating retubing requirements and the requirement for five-yearly non-destructive testing (NDT) associated with conventional boiler designs (SAFeD Guidance SBG01). This robust fully-wetted design, combined with over 90% vertical heating surfaces, reduces the likelihood of oxygen pitting and extends service life beyond conventional systems.
Operational Applications
The VSRT-E’s four primary use cases demonstrate its adaptability:
Gradual Electrification
Facilities awaiting electrical upgrades can install the VSRT-E initially as a gas-fired boiler, activating electric elements incrementally as infrastructure permits. This phased approach aligns with long-term decarbonisation strategies without requiring premature capital expenditure.
Demand Response Participation
Organisations can automatically switch to gas during grid stress events, reducing electrical load by up to 600kW per boiler, a valuable capability for energy-intensive users managing capacity market obligations.
Cost-Emission Balancing
The system’s scheduling functionality lets operators optimise fuel use against variable energy prices. A food processing plant might prioritise electric operation during renewable energy surplus periods while reserving gas for production peaks.
Oil Replacement
For dual fuel sites reliant on liquid fuels, the VSRT-E offers immediate CO₂ reductions of 40-50% when switching to gas-electric operation, alongside eliminating fuel storage risks and maintenance.
Particular attention should be given to sites, including off-grid facilities, where the option of self-generating electricity influences both financial sustainability and environmental impact. Self-generation schemes can now offer competitive electricity costs, especially when considering the additional 17% increase in boiler efficiency achieved when operating on electricity.
Future Development
Fulton plans to expand the VSRT-E range with 100HP (1,000kW) and 125HP (1,200kW) models, responding to industrial users requiring higher steam outputs. These additions will complement the existing 60HP (600kW) model available in the UK, creating a comprehensive portfolio for commercial and light industrial applications.
The company is also exploring advanced control integrations, including AI-driven load prediction algorithms and blockchain-enabled energy trading compatibility, developments aiming to position the VSRT-E as a grid-interactive asset capable of autonomously optimising fuel selection based on real-time carbon intensity data and energy market signals.
Strategic Importance
For gas engineers and facility managers, the VSRT-E redefines boiler specification criteria. Its ability to future-proof installations against evolving energy policies makes it a strategic investment rather than a compliance exercise. The boiler’s compliance with EN12953 and PED standards ensures suitability for high-risk environments, while BacNet/Modbus compatibility simplifies integration with existing building management systems.
Summarising, UK Sales & Export Manager Dave Dolan says: “Hybrid systems like the VSRT-E will be indispensable in achieving net-zero targets without compromising operational resilience. They represent not just technological innovation, but a fundamental shift in how industrial energy systems are conceived and optimised.”
The Fulton VSRT-E hybrid steam boiler exemplifies the practical application of sustainable engineering principles. By addressing immediate decarbonisation needs while accommodating future energy transitions, it establishes a new benchmark for intelligent, adaptable steam generation in an era of rapid environmental and regulatory change.