Governance
Six industry codes control how the system operates. Six reform programmes are trying to change it. Both move at their own pace, and neither moves quickly.
The GB energy system is governed by six major industry codes. Each code covers a different domain, is administered by a different body, and follows a modification process that typically takes one to three years from proposal to implementation.
Technical rules for connection to and operation of the transmission system. Covers frequency response, voltage control, fault ride-through, and data exchange requirements for generators, interconnectors, and demand facilities.
Rules for balancing the electricity system and settling imbalance charges. Governs how generators and suppliers are measured, how imbalance prices are calculated, and how settlement runs produce financial positions.
Rules for connecting to and using the transmission system. Covers charging methodologies, connection agreements, and use of system charges. The main commercial framework for transmission-connected parties.
Rules for connection to and use of distribution networks. Governs the relationship between DNOs, suppliers, and distributed generators. Covers metering, data flows, and charging arrangements at distribution level.
Rules for retail trading, supplier switching, and consumer data management. Created to consolidate the previous Master Registration Agreement and Supply Point Administration Agreement. Governs the consumer-facing side of the market.
Rules for gas transmission and distribution. Covers gas transportation, metering, balancing, and capacity allocation. Administered jointly by the gas transmission and distribution network operators through the Joint Office of Gas Transporters.
Each code emerged from a different part of the system at a different point in its history. The BSC came from electricity privatisation and the creation of the balancing mechanism. The Grid Code grew out of the technical standards needed to connect generators to the transmission system. The UNC covers gas, which was always regulated separately. The REC was created more recently to consolidate retail switching rules. Consolidation has been proposed multiple times, but the stakeholder groups for each code are different, the technical domains are different, and the political cost of merging governance structures has always outweighed the efficiency gains. The result is six parallel processes that sometimes need to coordinate on cross-cutting changes, and that coordination is where the system slows down most.
Market-wide Half-Hourly Settlement (MHHS) will move all electricity consumers to half-hourly metering for settlement purposes. Currently, most domestic consumers are settled using profiles that estimate when they use electricity. MHHS replaces those profiles with actual half-hourly data from smart meters. This matters because it creates the pricing signals that make time-of-use tariffs, demand response, and home battery arbitrage economically rational. Without half-hourly settlement, suppliers have limited incentive to offer tariffs that reward shifting consumption away from peak periods. The programme goes live on 22 September 2025, with supplier migration running from October 2025.
Six reform programmes are running in parallel, each targeting a different part of the energy system. Some are near completion. Others are still in consultation. Together they represent the most significant structural change since privatisation.
Six reform programmes compared across target dates, current status, key metrics, and dependencies. Data sourced from Ofgem, DESNZ, and NESO publications as of March 2026.
Now that you understand the governance tools and reform programmes, these pages provide the context needed to see how decisions are made, who makes them, and what happens when changes reach the physical network.
How major decisions are made within the code governance framework. Covers Ofgem determinations, code modification outcomes, and the appeal process. Essential for understanding why some changes take years.
Who sits on which panel, who has voting rights, and how the relationship between Ofgem, DESNZ, NESO, and code administrators actually works in practice.
How a project connects to the grid, from application through to energisation. The connections queue is where governance reform meets physical reality. TMO4+ and queue reordering are reshaping this process.
How electricity is traded, priced, and settled. REMA and MHHS are fundamentally changing market structure. Understanding the market requires understanding the codes that govern it.
The code framework still operates through multiple rulebooks, panels, and modification processes. That structure reflects how the sector evolved, but it also means cross-code reforms can require parallel processes, different timetables, and coordination across several governance bodies. Current code governance reform work is intended to reduce that friction where possible.
MHHS is one of the most consequential consumer-facing reforms because it creates the settlement basis for time-of-use tariffs, demand response, and more granular flexibility participation. In practice, that means smart meter data can be used more consistently to reflect when energy is consumed and when system costs arise.
Last reviewed: 17 March 2026
Code governance structures, modification timescales, and administrator roles are drawn from published procedures. Reform programme status is drawn from government and regulator consultation documents and implementation plans.
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