Project Background
Client: Unidisclosed
Industry: Offshore Oil & Gas
Location: North Sea
Date: 2025
Project Overview
EPS was commissioned to conduct a comprehensive electrification feasibility study for a North Sea-based Floating Production, Storage and Offloading (FPSO) facility. The FPSO is located east of the Shetland Isles. The vessel is currently powered by onboard diesel generation, which incurs high operating costs, increased greenhouse gas emissions, and logistical complexities.
In alignment with the North Sea Transition Authority’s 2030 emissions reduction targets, we aimed to identify viable electrification pathways to reduce emissions and operational expenditure.
Electrification Feasibility Study Objectives
The study was structured into two main phases:
Phase 1:
Power Import Concept Screening
A broad conceptual evaluation of 53 potential power import configurations culminated in four refined options for further assessment.
Phase 2:
FPSO Modifications and Feasibility Assessment
A pre-FEED level engineering analysis focused on the FPSO’s technical modifications, layout, CAPEX estimation, risk review, and implementation constraints.
FPSO Electrification Concepts Assessed
EPS electrical engineers developed four key electrification scenarios at the pre-FEED levels:
Option 1A: HVAC Import with Onshore Static Frequency Conversion (SFC)
Approach: Convert 500Hz power to 60Hz onshore and transmit it as 132kV AC to the FPSO
- Advantages: Lowest FPSO carbon footprint and cost ($23.9m); minimised onboard equipment and weight (654Te).
- Drawbacks: Higher transmission losses over long subsea AC distances increase OPEX.
Option 1B: HVAC Import with Offshore Static Frequency Conversion (SFC)
Approach: Transmit 132kV AC at 50 Hz to the FPSO and convert to 60 Hz onboard.
- Advantages: Reduces onshore infrastructure requirements.
- Drawbacks: Higher complexity and weight (935Te); higher FPSO CAPEX ($44.8m).
Option 2A: HVDC Import with Onboard Inverter
Approach: Convert AC to DC onshore, transmit as 110 kV DC, invert back to 60 Hz AC on the FPSO.
- Advantages: Highly efficient transmission; estimated £4.7m annual OPEX savings.
- Drawbacks: High FPSO CAPEX ($142.9m); heavy inverter (1,280 Te) complicates offshore installation and space allocation.
Option 2B: HVDC Import via Floating Hub (NUI Bouy)
Approach: Use a nearby unmanned floating substation to convert 110 kV DC to 66 kV AC, then step down onboard.
- Advantages: Use a nearby unmanned floating substation to convert 110 kV DC to 66 kV AC, then step down onboard.
- Drawbacks: Highest combined CAPEX ($212.3m for buoy + $23.7m for FPSO); complex offshore floating infrastructure.
Key Outcomes & Insights
Technical Insights
We found all four options to be technically viable for integration with the FPSO. The use of the M80 module space for new electrical equipment proved sufficient across all configurations. Also, our detailed load flow and short circuit analyses confirmed that the FPSO’s electrical infrastructure would be able to accommodate the proposed modifications, with varying degrees of redundancy and complexity.
Economic & Operational Trade-offs
| Option | Outcome |
|---|---|
| 1A | Offers the most cost-effective and lightweight solution for the FPSO but incurs higher long-term OPEX due to AC transmission losses. |
| 1B | Assessing the electrical measurements between key earthing points, i.e. switchgear, a moderate compromise between CAPEX and onboard complexity. |
| 2A | Presents significant space and installation challenges, potentially requiring large marine lifting equipment. |
| 2B | Despite high CAPEX, it may become more attractive when full project economics and offshore labour costs are considered. |
Conclusion & EPS Recommendations
This feasibility study highlights the multifaceted nature of FPSO electrification. Each of the four options we evaluated provides a distinct balance of CAPEX, technical complexity, space utilisation, and long-term operational efficiency. Options 1A and 1B offer proven HVAC-based solutions, while on the other hand, options 2A and 2B both present future-ready HVDC alternatives that could yield more efficiency and long-term savings (provided technology and installation risks are carefully managed).
Further studies encompassing the complete electrification scope, including subsea cables, grid interconnection, offshore wind synergies, economic analysis, and emissions evaluation, are essential to inform final investment decisions and ensure regulatory alignment.
Explore Pathways to Offshore Electrification with EPS
If you’re considering electrification for your FPSO, platform, or other offshore infrastructure, EPS can help. Our expert team delivers tailored feasibility studies, concept development, and engineering design to support investment-grade decision-making.
Explore our full range of offshore oil and gas capabilities here.
