Scotland DNO Guide for Solar Inverter Replacement

Understanding SPEN, SSEN North, and SSEN South requirements for G98 and G99 applications

What is a DNO?#

DNO stands for Distribution Network Operator. They own and maintain the electricity network in your area. When you replace a solar inverter, you must notify or get approval from your DNO depending on the system size.

Scotland's Three DNO Areas#

SPEN

Scottish Power Energy Networks

Covers
  • Central Belt
  • Glasgow
  • Edinburgh (partial)
  • Falkirk
  • Ayrshire
  • Lanarkshire

SSEN North

SSE Networks North

Covers
  • Highlands
  • Islands
  • Inverness
  • Fort William
  • Aberdeen

SSEN South

SSE Networks South

Covers
  • Edinburgh (partial)
  • Fife
  • Perth
  • Dundee
  • Stirling

G98 vs G99 — Which Do You Need?#

RequirementG98G99
System size3.68kW or less per phaseOver 3.68kW per phase
When to applyPost-installation (within 28 days)Pre-installation (approval first)
Approval timeNot required (notification only)15-30 working days
We handle this?Yes — includedYes — included

What We Do For You#

As MCS certified installers, we handle all DNO paperwork:

  • Determine whether you need G98 or G99
  • Complete all application forms accurately
  • Submit to your DNO (SPEN, SSEN North, or SSEN South)
  • Track approval status for G99 applications
  • Provide you with all completion certificates

This is all included in your installation quote — no extra charge.

Common Questions#

Do I need DNO approval for like-for-like replacement?

Yes. Even if you replace a 4kW inverter with another 4kW inverter, you must notify the DNO to keep their records accurate.

Can I install before G99 approval?

No. For systems over 3.68kW, you must wait for DNO approval. Installing without approval can result in the DNO requiring removal.

What if the DNO rejects my application?

Rejections are rare for inverter replacements. If there are network capacity issues, we work with the DNO to find a solution (e.g., export limitation settings).

Need help understanding your DNO requirements? Call 0141 230 0198 and we will explain everything for your specific situation.