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Knowledge Base

Everything you need to understand the UK OFTO regime.
OFTO RegimeTender ProcessCost AssessmentTransmission AssetsREGULATORY FRAMEWORKCOMMERCIAL

OFTO Regime • Lifecycle & Key Stages

OFTO Regime

Generator Build

Generator Build

The UK OFTO regime is Ofgem's competitive process for transferring eligible transmission assets from an offshore wind developer to an independently licensed Offshore Transmission Owner (OFTO). 

Generator Build

Generator Build

Generator Build

The developer designs and builds the offshore and onshore transmission assets before transferring ownership to the successful OFTO following construction and Ofgem's cost assessment. 

OFTO Build

Generator Build

Tender Process

Under OFTO Build, the OFTO is responsible for delivering some or all of the transmission assets, rather than purchasing them after construction.  This alternative delivery model is being developed for future offshore wind projects.  

Tender Process

Preferred Bidder

Tender Process

Ofgem's competitive process for selecting an OFTO, taking a project from qualification through competitive bidding to licence grant and asset transfer. 

Preferred Bidder

Preferred Bidder

Preferred Bidder

The OFTO bidder selected by Ofgem as the preferred owner of the transmission assets, subject to satisfying the remaining legal, financial and regulatory requirements before licence grant. 

Licence Grant

Preferred Bidder

Preferred Bidder

The point at which Ofgem grants the transmission licence, allowing the Successful Bidder to become the OFTO and  own, operate and maintain the transmission assets  for a licence term of up to 25 years. 

Tender Process • Competition & Bid Process

Tender Round

EPQ (Enhanced Pre-Qualification)

EPQ (Enhanced Pre-Qualification)

The overall competitive process run by Ofgem to appoint an OFTO for one or more qualifying transmission projects. Each Tender Round follows a series of defined stages from qualification through to licence grant. 

EPQ (Enhanced Pre-Qualification)

EPQ (Enhanced Pre-Qualification)

EPQ (Enhanced Pre-Qualification)

The first assessment stage where prospective bidders demonstrate they have the financial strength, technical capability, organisational experience and resources required to participate in the tender. 

ITT (Invitation to Tender)

EPQ (Enhanced Pre-Qualification)

ITT (Invitation to Tender)

The stage where shortlisted bidders submit their full tender response, including commercial, financial and technical information, for evaluation against Ofgem's tender requirements. 

Bidders

SB (Successful Bidder)

ITT (Invitation to Tender)

Companies or consortiums competing to become the OFTO. Bidders are assessed by Ofgem throughout the tender process against published evaluation criteria. 

PB (Preferred Bidder)

SB (Successful Bidder)

SB (Successful Bidder)

The bidder selected by Ofgem as the preferred owner of the transmission assets, subject to  satisfying the remaining legal, commercial and regulatory requirements before licence grant. 

SB (Successful Bidder)

SB (Successful Bidder)

SB (Successful Bidder)

The Preferred Bidder that satisfies all remaining legal, commercial and regulatory requirements before being granted the OFTO licence and assuming ownership and operation of the transmission assets. 

Cost Assessment • How Ofgem Assesses Costs

InTV (Initial Transfer Value)

ITV (Indicative Transfer Value)

ITV (Indicative Transfer Value)

The first of three cost submissions to Ofgem. The developer provides an initial estimate of the cost of designing and constructing the transmission assets, forming the starting point for Ofgem's cost assessment. 

ITV (Indicative Transfer Value)

ITV (Indicative Transfer Value)

ITV (Indicative Transfer Value)

The second of three cost submissions to Ofgem. A detailed cost submission reviewed by Ofgem to determine the estimated economic and efficient costs of the transmission assets. The ITV is used by bidders during the Invitation to Tender stage.  

FTV (Final Transfer Value)

ITV (Indicative Transfer Value)

IDC (Interest During Construction)

The third and final cost submission to Ofgem.  Following completion of the project and a detailed review of the actual costs, Ofgem determines the Final Transfer Value, which forms the amount paid by the OFTO for the transmission assets.  

IDC (Interest During Construction)

IDC (Interest During Construction)

IDC (Interest During Construction)

A financing allowance calculated by applying Ofgem's IDC methodology to eligible DEVEX and CAPEX from the date payments are made to suppliers and contractors until first power. It is not a recovery of the developer's actual borrowing costs, interest or bank charges. 

Disallowed Costs

IDC (Interest During Construction)

Disallowed Costs

Costs that Ofgem determines are  not considered economic, efficient or otherwise eligible for inclusion, or are not eligible for inclusion within the transfer value. These costs are excluded from the final assessment.  

Shared Costs

IDC (Interest During Construction)

Disallowed Costs

Costs that relate to both generation and transmission assets. Developers must use a transparent and justified allocation methodology to ensure only transmission-related costs are included. 

Transmission Assets • Infrastructure Transferred to the OFTO

HVAC (High Voltage Alternating Current)

HVAC (High Voltage Alternating Current)

HVAC (High Voltage Alternating Current)

HVAC uses alternating current (AC) and has been the preferred transmission technology for the majority of UK OFTO projects because it is well suited to shorter transmission distances. 

HVDC (High Voltage Direct Current)

HVAC (High Voltage Alternating Current)

HVAC (High Voltage Alternating Current)

A transmission technology increasingly being adopted for larger and more distant UK offshore wind projects.  HVDC uses direct current (DC) and is increasingly being adopted as the transmission technology for larger and more distant UK offshore wind projects. 

ONSS (Onshore Substation)

HVAC (High Voltage Alternating Current)

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

One of the four principal transmission asset categories transferred to the OFTO. The Onshore Substation receives electricity from the ONCA, transforms the voltage where required and connects the transmission system to the National Electricity Transmission System (NETS). 

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

One of the four principal transmission asset categories transferred to the OFTO. The Offshore Substation collects electricity from the wind turbines,  transforms the voltage for transmission and connects to the OFCA. 

OFCA (Offshore Export Cable)

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

OFCA (Offshore Export Cable)

One of the four principal transmission asset categories transferred to the OFTO. The Offshore Export Cable  transports electricity from the OFSS/OSP to the onshore landfall, where it connects to the ONCA. 

ONCA (Onshore Cable)

OFSS/OSP (Offshore Substation / Offshore Substation Platform)

OFCA (Offshore Export Cable)

One of the four principal transmission asset categories transferred to the OFTO. The Onshore Cable connects the onshore landfall point to the ONSS.

Regulatory Framework • Legislation & Codes

Ofgem

The National Energy System Operator (NESO)

The National Energy System Operator (NESO)

The independent energy regulator responsible for the UK OFTO regime. Ofgem runs the competitive tender process, grants OFTO licences and assesses the costs developers can recover for eligible transmission assets. 

The National Energy System Operator (NESO)

The National Energy System Operator (NESO)

The National Energy System Operator (NESO)

NESO is responsible for planning and operating Great Britain's electricity transmission system. Within the OFTO regime, NESO manages generator connections, administers Tender Revenue Stream (TRS)  revenue  payments to OFTOs and calculates Transmission Network Use of System (TNUoS) charges payable by offshore wind generators. 

Electricity Act 1989

The National Energy System Operator (NESO)

CUSC (Connection and Use of System Code)

The primary legislation governing the electricity industry in Great Britain. The Electricity Act 1989 provides the legal framework for electricity transmission, licensing and the establishment of the OFTO regime. 

CUSC (Connection and Use of System Code)

TNUoS (Transmission Network Use of System Charges)

CUSC (Connection and Use of System Code)

The industry code governing how users connect to and use the National Electricity Transmission System (NETS). CUSC sets out the commercial and operational arrangements that apply to transmission network users, including offshore wind projects. 

TNUoS (Transmission Network Use of System Charges)

TNUoS (Transmission Network Use of System Charges)

TNUoS (Transmission Network Use of System Charges)

TNUoS charges are payable by transmission network users for using the NETS.  Offshore wind generators become liable for TNUoS charges once electricity is exported onto the NETS. 

The Generator Commissioning Clause (GCC)

TNUoS (Transmission Network Use of System Charges)

TNUoS (Transmission Network Use of System Charges)

GCC provides a 27-month period from the completion notice during which the developer can operate the transmission assets without an OFTO licence,  allowing time to complete commissioning before the transmission licence is granted and the assets transfer to the OFTO. 

Commercial • Revenue, Incentives & Finance

TRS (Tender Revenue Stream)

MRA (Market Rate Adjustment)

MRA (Market Rate Adjustment)

The annual regulated revenue an OFTO is entitled to receive following licence grant. The TRS is paid by NESO for the duration of the licence (typically 20–25 years) and is indexed annually in accordance with the licence. 

MRA (Market Rate Adjustment)

MRA (Market Rate Adjustment)

MRA (Market Rate Adjustment)

A mechanism that adjusts the OFTO's TRS between the winning bid and licence grant to reflect defined changes in market conditions, helping ensure the OFTO is not financially disadvantaged before the licence starts. 

Availability Incentive

MRA (Market Rate Adjustment)

CPI (Consumer Prices Index)

A financial incentive that rewards OFTOs for achieving annual transmission asset availability above 98%.  Availability above the 98% target can earn a bonus of up to 5% of the annual TRS, while poor performance can reduce revenue. 

CPI (Consumer Prices Index)

CPI (Consumer Prices Index)

CPI (Consumer Prices Index)

CPI is the inflation measure used to index the OFTO's TRS and by NESO when calculating TNUoS charges payable by offshore wind generators. 

Pass Through Costs (PTt)

CPI (Consumer Prices Index)

Pass Through Costs (PTt)

Specified costs that are recovered separately from the TRS because they sit outside the OFTO's control. Examples include licence fees, business rates, Crown Estate lease costs, tender fees and other specified adjustments defined in the OFTO licence. 

Socialisation

CPI (Consumer Prices Index)

Pass Through Costs (PTt)

The mechanism under which a proportion of an OFTO's TRS is recovered through transmission network charges and ultimately recovered from electricity consumers through transmission network charges rather than directly from the offshore wind generator. 


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