Governance

Who decides what in GB energy, and why the 2024 NESO launch changed the map.

No single body runs the GB energy system. Policy lives with DESNZ. Regulation with Ofgem. Operation with NESO. Settlement with Elexon. Technical rules with seven industry codes owned by the parties they bind. Knowing which actor owns which decision is the foundation for reading any GB energy debate.

07 Route 7 of 12 · Governance
18 min read 5 sections 2 diagrams 1 decision tool Last verified

After this route you will be able to

  • Name the role and limits of DESNZ, Ofgem, NESO, Elexon, the DNOs, and the TOs.
  • List the seven main industry codes and the parties each binds.
  • Trace a proposed change from government policy to implemented operational rule.
  • Explain what the 2024 NESO launch changed and what it did not.
  • Make a reasoned call on who should own a given decision.
Aerial view of an electricity control room with screens showing the GB grid

1 October 2024NESO launches · first new GB energy institution in a generation

The Energy Act 2023 carved out the system operator from National Grid and made it a public corporation.

For 31 years, the company that balanced the GB electricity system also owned the transmission lines it balanced. National Grid plc was both the system operator and the majority transmission owner. That worked when growth was slow and the operator's job was largely technical. It stopped working when the operator's decisions started determining which connection offers got made, which balancing providers got paid, and which reinforcement got prioritised.

The Energy Act 2023 legislated a separation. On 1 October 2024, the National Energy System Operator became a new public corporation, owned by HM Treasury and accountable to the Secretary of State for Energy Security and Net Zero. It took the people, the systems, and the operational licences. National Grid kept the transmission assets, now run as NGET.

The change is not cosmetic. NESO's remit now explicitly includes gas system operation, strategic planning, and whole-system analysis. Ofgem's oversight of NESO is structured differently from its oversight of a private firm. The Energy Ombudsman and the competition regulators have new touchpoints. The practical effect will take years to play out, but the governance map of GB energy changed on that Tuesday morning.

Separating the operator from the asset owner is a textbook regulatory move. Why did it take until 2024, and what did the transition actually deliver?

The answer starts with the six actors. Each owns a slice of the decision space. Most of the governance debates in GB energy turn on which slice a particular question belongs in.

Section 01 · The six actors

Policy, regulation, operation, settlement, delivery, consumer voice.

The clean separation is a useful fiction: the actors overlap and contest each other, and that contest is often the point. But every decision eventually resolves to one of the six.

Policy

DESNZ

Department for Energy Security and Net Zero. Sets strategic direction, writes White Papers, introduces primary legislation. Owns Clean Power 2030 and the Warm Homes Plan. Funds through HM Treasury.

Regulation

Ofgem

Office of Gas and Electricity Markets. Non-ministerial department, independent. Issues licences, approves price controls (RIIO), enforces consumer protection, authorises code modifications.

Operation

NESO

National Energy System Operator. Public corporation since October 2024. Balances electricity every second, runs the Balancing Mechanism, coordinates gas system operations, produces the Future Energy Scenarios.

Settlement

Elexon

Balancing and Settlement Code Company. Runs half-hourly settlement for GB electricity, publishes BMRS, administers the BSC. Owned collectively by BSC parties.

Delivery

TOs, DNOs, Suppliers

Private companies that own and operate assets. Three transmission owners. Six DNO groups across 14 licence areas, transitioning to DSO. About 50 licensed electricity suppliers, declining.

Consumer voice

Citizens Advice, Energy Ombudsman

Citizens Advice is the statutory consumer advocate for energy under the Consumers, Estate Agents and Redress Act 2007. The Energy Ombudsman resolves supplier disputes. Both feed into Ofgem's decisions.

Section 02 · The seven industry codes

Seven codes bind the system. All seven are changed by the same process.

Below the legislation and above the daily operational decisions sit seven multi-party technical codes. They define everything from how you metered your electricity last night to whether your substation can connect a new battery.

BSC

Balancing and Settlement Code. How GB electricity is metered and settled every half hour. Administered by Elexon. Being overhauled by Market-wide Half-Hourly Settlement (MHHS).

Grid Code

Grid Code. Technical standards for connecting to and operating on the transmission system. Covers frequency, voltage, fault ride-through, telemetry. Administered by NESO.

CUSC

Connection and Use of System Code. The commercial contract between NESO and transmission-connected parties. Home of the connection-queue reform CMP434 (TM04+).

DCUSA

Distribution Connection and Use of System Agreement. The distribution equivalent of CUSC. Binds DNOs and their customers.

STC

System Operator Transmission Owner Code. Defines how NESO and the three TOs coordinate operation and investment.

UNC

Uniform Network Code. The gas equivalent of the BSC. Administered by Xoserve. Governs gas balancing, shipping, and transportation.

SEC

Smart Energy Code. Governs smart metering infrastructure (DCC), data privacy, and supplier access. Overseen by the Smart Energy Code Administrator (SECAS).

A change to any of these codes starts with a modification proposal, goes through a workgroup of code parties, is consulted, recommended by the code panel, and approved (or rejected) by Ofgem. Typical timeline: 9 to 18 months for a substantive change. Complex reforms like MHHS or TM04+ run for years.

The Authority may direct that a code modification be made where it is satisfied that the modification better facilitates the achievement of the relevant objectives. The Authority may require changes to the proposed modification before it approves the change.

Electricity Act 1989, Section 11A

Section 03 · From policy to rule

A proposed change crosses six gates.

This is the practical path from White Paper idea to operational fact. Most debates about GB energy governance sit at one or another of these gates.

Diagram 01 · The six gates from policy to operational rule
  1. Gate 1

    Policy proposal. DESNZ White Paper, Statement of Intent, or manifesto commitment. Sets direction but binds no-one operationally.

  2. Gate 2

    Primary legislation. Act of Parliament. Gives Secretary of State or Ofgem the powers needed. Energy Act 2023 is the current example, introducing NESO and the Future Homes Standard.

  3. Gate 3

    Secondary legislation. Statutory Instruments made under Act powers. Faster to amend than primary law. Most licence condition changes land here.

  4. Gate 4

    Licence modification. Ofgem changes the terms of a licence (e.g., supply licence, NESO licence). Appealable to the Competition and Markets Authority.

  5. Gate 5

    Code modification. The industry code change process. Proposal → workgroup → consultation → panel recommendation → Ofgem decision. Where most operational detail actually sits.

  6. Gate 6

    Operational implementation. NESO, Elexon, DNOs, suppliers change their IT systems, retrain staff, go live. TSO-class systems take 12 to 36 months to change.

Most people working in GB energy spend their careers at Gates 4, 5 and 6. The earlier gates move on political calendars; the later gates move on engineering calendars.

Section 04 · What NESO changed

The separation resolved three things and left three open.

NESO is a young institution. Some of what it was set up to do is already visible. Some will not be clear until it has had a full winter of independent operation and an election cycle.

What changed:

First, conflict of interest. NESO's connection decisions no longer favour its own (as National Grid) transmission owner. The Clean Power 2030 Action Plan and the TM04+ queue reform both depend on this neutrality. Second, whole-system remit. NESO covers gas system operation as well as electricity, and has strategic spatial planning duties. Third, public accountability. The Secretary of State sets strategic priorities annually; Ofgem regulates, but the ultimate accountability runs to parliament.

What did not change:

First, the code structure. The seven industry codes still run through Ofgem-approved modification processes. Second, the DNO landscape. Privatised, regulated, moving to DSO, but structurally unchanged by NESO. Third, consumer-side markets. The supply-retail relationship, the price cap, the supplier-of-last-resort process are all untouched by the NESO reform.

Common misconception

NESO replaced National Grid.

National Grid plc still exists as a listed transmission asset owner. NGET (National Grid Electricity Transmission) is its regulated subsidiary for the England and Wales 400 kV and 275 kV network. What changed is that the system operator function moved out of National Grid, became public (HM Treasury owns NESO), and is now independent of any transmission owner.

Section 05 · Ownership test

Given a policy question, which actor should decide?

Most GB energy disputes are not really about the substance. They are about which actor gets to decide the substance. This decision tree applies the separation-of-powers test.

The question is which actor has the authority to introduce such a requirement. The substance of whether it is a good idea is separate. Ofgem DESNZ NESO Primary legislation in Parliament This is the distinction between implementation authority and direction-setting authority. Ofgem is usually the former. Start over DESNZ leads on mandatory behavioural requirements because they touch on fuel poverty, consumer protection and cross-departmental policy (Treasury, DfT, DHSC). Start over This is the most common mistake people make: conflating operational capability with policy authority. Start over Parliament grants the powers; government exercises them. Going back to Parliament for each policy adjustment would be unworkable. Start over

Check your understanding

Three questions on what you have just read.

DESNZ NESO The code panel Ofgem The transmission network System operator responsibilities for electricity and gas Regulatory authority over the sector Settlement functions BSC CUSC DCUSA SEC

Key takeaways

  • Six actors. DESNZ sets policy, Ofgem regulates, NESO operates, Elexon settles, TOs and DNOs deliver, Citizens Advice speaks for consumers.
  • Seven industry codes. BSC, Grid Code, CUSC, DCUSA, STC, UNC, SEC. All changed through modification processes approved by Ofgem.
  • Six gates from policy to rule. White Paper → Act → Statutory Instrument → Licence mod → Code mod → Operational implementation.
  • NESO launched 1 October 2024. It separated the operator from the transmission asset owner, which was the largest structural reform in GB energy since privatisation.
  • Most governance disputes are about which actor owns the decision, not about the substance. The ownership test is often more useful than the substance test.

References

  1. Energy Act 2023

    Primary legislation creating NESO, Ofgem powers on Future Homes Standard, offshore co-ordination.

    Statutory authority for the 2024 governance reform.

  2. Ofgem

    Licences, code modifications, RIIO price controls, consumer protection decisions.

    Primary regulatory source.

  3. NESO

    Operational information, Future Energy Scenarios, strategic planning outputs.

    System operator authoritative reference.

  4. Elexon and the BSC

    Balancing and Settlement Code, BMRS data, MHHS programme.

    Settlement authority and real-time data.

  5. DESNZ

    Policy direction, Clean Power 2030 Action Plan, Warm Homes Plan, Statements of Intent.

    Policy and strategic authority.

  6. Citizens Advice energy policy

    Statutory consumer advocate for GB energy under CEARA 2007.

    Consumer voice in governance.

The next route opens the data layer. How information flows through this governance structure, and where the bottlenecks are.