Grid Connection for Farm Solar Installations
A comprehensive guide to navigating the grid connection process for agricultural solar systems in the UK, from DNO applications and G99 assessments to rural grid constraints and export limitation strategies.
Why Grid Connection Matters for Farm Solar
Grid connection is one of the most important and often overlooked aspects of planning a farm solar installation. Your grid connection determines how much electricity you can export, whether you qualify for Smart Export Guarantee payments, and how your system interacts with the wider electricity network. Getting the grid connection right from the outset can save you thousands of pounds and months of delay.
For UK farmers, the grid connection process involves applying to your local Distribution Network Operator (DNO) for permission to connect a generating system to their network. This is a legal requirement for any solar system connected to the electricity grid, regardless of whether you intend to export electricity or consume it all on site. The process ensures that your solar installation does not adversely affect the local electricity network or the supply quality for neighbouring properties.
Understanding the grid connection process early in your project planning is essential because it can significantly influence the optimal system size, the project timeline, and the overall cost of your farm solar installation. Rural farms face particular challenges due to the nature of rural electricity infrastructure, but there are effective strategies to work within these constraints.
Three Key Reasons Grid Connection Matters
Export Excess Electricity
A proper grid connection allows you to export surplus electricity generated during peak solar hours. Without export capability, any generation above your instantaneous consumption is wasted. Most farm solar systems generate more electricity than the farm uses during summer midday periods, making export capacity valuable for maximising returns.
Smart Export Guarantee Payments
The Smart Export Guarantee (SEG) pays you for every kilowatt-hour of electricity you export to the grid, with current tariff rates ranging from 4p to 15p per kWh. To qualify for SEG payments, your system must be properly registered with a DNO-approved grid connection. For a 100kW farm system exporting 30,000 kWh per year, this represents £1,200 to £4,500 in annual income.
Future Battery Storage Compatibility
A well-planned grid connection provides the foundation for adding battery storage in the future. Battery systems that can charge from solar and discharge to the grid require adequate connection capacity. By securing appropriate grid connection terms now, you avoid the cost and delay of reapplying when you decide to add storage later.
DNO Regions: Who to Contact for Your Farm
The UK electricity distribution network is managed by six Distribution Network Operators (DNOs), each responsible for a specific geographic region. Your DNO is determined by the location of your farm, and all grid connection applications must be submitted to the correct operator. National Grid ESO oversees the transmission network at a national level.
UK Power Networks (UKPN)
Covers the South East, East of England, and London. This includes major farming regions in East Anglia, Kent, and the Home Counties. UKPN manages the largest number of connections in the UK and has an online portal for G99 applications.
Regions: South East, East of England, London
Western Power Distribution (WPD)
Covers the Midlands, South West England, and South Wales. This encompasses important agricultural areas including the Somerset Levels, Herefordshire, and the Welsh borders. WPD now operates under National Grid Electricity Distribution.
Regions: West Midlands, East Midlands, South West, South Wales
National Grid ESO
The Electricity System Operator manages the national transmission network and coordinates with DNOs on larger connections. For farm solar systems above 1MW, you may need to engage with National Grid ESO directly. They also publish grid capacity data that helps identify constrained areas.
Role: National transmission system oversight
SP Energy Networks
Covers Central and Southern Scotland, plus Merseyside, Cheshire, and North Wales. SP Energy Networks manages grid connections for farms across the Scottish Lowlands and North West England, including significant dairy and livestock farming areas.
Regions: Central Scotland, Southern Scotland, Merseyside, North Wales
SSE Networks
Covers Northern Scotland and the southern central region of England. SSE Networks operates under Scottish and Southern Electricity Networks and manages connections across remote Highland farms as well as large arable operations in central southern England.
Regions: North of Scotland, Central Southern England
Northern Powergrid & Electricity North West
Northern Powergrid covers the North East and Yorkshire, including the Yorkshire Dales and North York Moors farming areas. Electricity North West covers Lancashire, Cumbria, and Greater Manchester, encompassing the Lake District and Pennine upland farms.
Regions: North East, Yorkshire, North West England
How to Find Your DNO
If you are unsure which DNO covers your farm, you can check your electricity bill, which will state the name of your distribution operator. Alternatively, your MPAN (Meter Point Administration Number) begins with a two-digit code that identifies the DNO region. Your solar installer should identify your DNO as part of the initial site assessment and handle all communication with them on your behalf. Contact us and we will confirm your DNO and assess the local grid situation before you commit to a project.
G98 vs G99: Understanding Grid Connection Applications
All grid-connected solar installations in the UK must comply with either the G98 or G99 engineering standard. The applicable standard depends on the size of your system and determines the application process, timeline, and level of DNO scrutiny.
G98: Small-Scale Connections
For systems up to 16A per phase
G98 is designed for the simplest installations, typically domestic-scale systems. Your installer submits a notification to the DNO, and the system can be connected within 28 days unless the DNO raises an objection. Most farm solar installations exceed the G98 threshold because even a modest agricultural system will be larger than 11.04kW on three phase. However, G98 may apply to very small systems on farm cottages or ancillary buildings.
G99: Larger Installations
For most farm solar systems
G99 is the standard application route for the vast majority of farm solar installations. The process requires submitting detailed technical information about the proposed system, including inverter specifications, protection settings, and the proposed point of connection. The DNO then assesses the impact on their network and may require additional grid studies if the local network is constrained. Most farm systems between 50kW and 500kW follow the G99 process.
The Grid Connection Application Process: Step by Step
The G99 grid connection process follows a structured sequence of steps. Understanding each stage helps you plan your project timeline and budget effectively. Your installer should manage the entire process, but knowing what to expect puts you in control.
Budget Estimate Request
The first step is requesting a budget estimate from your DNO. This is a free, no-obligation enquiry that gives you an indicative cost for connecting your proposed solar system to the grid. The DNO typically responds within 1 to 2 weeks with a high-level assessment of whether the local network can accommodate your system and an approximate cost range for any required works. This information is invaluable for project planning and financial modelling before committing to a formal application.
Cost: Free
Timeline: 1-2 weeks
Output: Indicative connection cost and feasibility assessment
Formal Connection Application
Once you are satisfied with the budget estimate, the next step is submitting a formal G99 connection application. This requires detailed technical information including inverter datasheets, proposed system layout, single-line diagrams, and protection relay settings. Your installer prepares all technical documentation. The application fee is typically between £350 and £500, depending on the DNO and system size.
Cost: £350-£500 application fee
Requirements: Technical specifications, single-line diagram, site plan
Submitted by: Your installer on your behalf
DNO Assessment and Connection Offer
The DNO has 45 working days to assess your application and issue a connection offer. During this period, they evaluate the impact of your proposed system on the local network, including voltage rise, fault level contribution, and thermal capacity. If the local network is constrained, the DNO may commission additional grid studies, which can extend the assessment period. The connection offer details the exact works required, the cost, and the timeline for completion.
Timeline: 45 working days (may be longer if grid studies are needed)
Output: Formal connection offer with detailed costs and conditions
Validity: Offer typically valid for 90 days
Accept Offer and Pay Connection Costs
Once you receive the connection offer, you review the terms, costs, and conditions. If acceptable, you formally accept the offer and pay the connection costs. Some DNOs require full payment upfront, while others accept staged payments. If the connection costs are higher than expected, this is the point to discuss alternatives with your installer, such as reducing the export capacity, applying export limitation, or adjusting the system design. The offer is typically valid for 90 days, giving you time to finalise project financing.
Action: Review and accept the connection offer
Payment: Full or staged payment of connection costs
Decision period: Typically 90 days
Installation and Commissioning
With the connection agreement in place, your solar installation can proceed. The DNO carries out any required network upgrades, such as transformer replacements or cable upgrades, while your installer completes the solar panel installation in parallel. Once both the solar system and any DNO works are complete, the system is commissioned and connected to the grid. Your installer tests all protection settings and confirms compliance with G99 requirements.
DNO works: Transformer upgrades, cable installation (if required)
Installer works: Solar installation, wiring, inverter commissioning
Timeline: 4-12 weeks after acceptance
Final Commissioning Certificate (G99 Form A)
The final step is the submission of the G99 Form A commissioning certificate to the DNO. This document confirms that the system has been installed and commissioned in accordance with the approved connection agreement and the G99 engineering standard. It includes test results for protection settings, frequency and voltage relay checks, and confirmation of anti-islanding protection. Once the DNO accepts the Form A, your system is officially registered as a generating station and you can apply for Smart Export Guarantee payments.
Document: G99 Form A commissioning certificate
Submitted by: Your installer
Enables: SEG registration and official generating station status
Grid Connection Costs for Rural Farms
Grid connection costs vary enormously depending on the state of the local electricity infrastructure at your farm. A farm with a modern three-phase supply and a nearby transformer with spare capacity will face minimal costs, while a remote farm on a single-phase supply may need significant upgrades.
Simple Connection
£500 - £2,000
Suitable where the existing grid infrastructure has sufficient capacity for your proposed system. Covers metering changes, protection upgrades, and DNO inspection. This is the best-case scenario and applies to farms with relatively modern three-phase supplies and lightly loaded local transformers.
Transformer Upgrade
£5,000 - £15,000
Required when the local pole-mounted or ground-mounted transformer cannot handle the additional generation capacity. The DNO replaces the transformer with a larger unit. This is common for farm systems above 50kW connected to smaller rural transformers originally sized for domestic loads.
New Cable Run
£10,000 - £50,000+
Required when the existing cable from the transformer to the farm is too small or too long to handle the additional generation. Rural farms often have long overhead line runs, and replacing these with appropriately rated underground cable can be a significant cost, particularly over distances exceeding 500 metres.
Substation Upgrade
£50,000 - £150,000+
Required in rare cases for very large systems, typically above 250kW, where the local 11kV network or primary substation needs reinforcement. This level of upgrade is uncommon for typical farm rooftop installations but may apply to large estates with multiple buildings or combined solar and battery projects.
How to Minimise Grid Connection Costs
There are several strategies to reduce grid connection costs for your farm solar installation. Sizing your system to match the existing grid capacity avoids the need for expensive upgrades. Using export limitation devices can allow a larger system while staying within the grid's current export capacity. Choosing to connect at an alternative point on the network, such as a different transformer, may offer lower costs. We assess all these options as part of our free site survey to find the most cost-effective solution for your farm.
Rural Grid Constraints and Challenges
Rural farms face unique grid connection challenges that urban and suburban properties do not encounter. Understanding these constraints is essential for designing a system that works within the existing infrastructure or for budgeting for necessary upgrades.
Single-Phase Supplies
Many rural farms still operate on a single-phase electricity supply, which limits the maximum solar system size to approximately 3.68kW under G98 without a formal application. Even with a G99 application, single-phase connections restrict the practical system size and export capacity. For farms with single-phase supplies wanting larger solar systems, a three-phase upgrade is usually necessary, which involves the DNO running new cables from the transformer and installing a three-phase meter. This typically costs £3,000 to £10,000 depending on distance.
Long Cable Runs
Rural farms are often located at the end of long cable runs from the nearest transformer, sometimes stretching over a kilometre. Long cables increase electrical losses and can cause voltage rise when electricity is exported from a solar system. If the voltage at the point of connection rises above the statutory limit of 253V (single phase), the DNO may require cable upgrades or impose export limitations. The cost of replacing a long overhead line with underground cable can be substantial, particularly across agricultural land where trenching and reinstatement costs apply.
Weak Grid Areas
Some rural areas have weak grid infrastructure that was designed decades ago for modest domestic loads, not for distributed generation. In these areas, the local network may already be at or near capacity, particularly where other solar installations or wind turbines have been connected nearby. The DNO may require an export limitation device to cap the amount of electricity you can export, or they may require reinforcement works that add cost and delay. Checking the available grid capacity early in the project planning stage is critical.
Shared Transformers
In rural areas, it is common for multiple properties to share a single pole-mounted transformer. If a neighbouring property has already connected a solar system or other generation to the same transformer, the available capacity for your system may be reduced. The DNO considers the cumulative impact of all connected generation when assessing your application. In some cases, a new dedicated transformer may be the most practical solution, though this adds cost. Your installer should check the transformer situation as part of their initial assessment.
Export Limitation as an Alternative
When the cost of a full grid connection upgrade is prohibitive, export limitation provides a practical and cost-effective alternative. An export limitation device monitors the electricity flowing at the point of connection and automatically curtails the solar system output when the export level approaches the agreed limit. This allows you to install a larger system than the grid could otherwise support, maximising self-consumption while staying within your grid connection constraints.
Zero Export Limiter
A zero export limiter prevents any electricity from being exported to the grid. The solar system output is dynamically reduced to match the farm's instantaneous consumption. This is particularly useful for farms with consistently high daytime electricity loads, such as dairy operations with milking equipment, refrigeration, and ventilation running throughout the day. A zero export limiter eliminates the need for a grid connection upgrade entirely, though you will not receive any SEG export payments.
Partial Export Limiter
A partial export limiter caps the export at a specific level agreed with the DNO, such as 20kW or 50kW. This allows some excess electricity to be exported and earn SEG payments while avoiding the cost of upgrading the grid connection to handle the full system output. For example, a 100kW system with a 30kW export limit would export up to 30kW when generation exceeds on-site consumption, and curtail only the excess above this threshold. This is often the optimal balance between system size, grid connection cost, and export income.
Export Limitation and Battery Storage
Combining export limitation with battery storage is an increasingly popular strategy for farm solar installations in grid-constrained areas. Rather than curtailing excess generation, the battery stores it for use during the evening and overnight periods when solar production is zero. This maximises the value of every kilowatt-hour generated, reduces reliance on grid electricity during peak tariff periods, and provides backup power during grid outages, which is a valuable benefit for farms with livestock that depend on continuous power for ventilation, feeding systems, and refrigeration.
Three-Phase Supply Upgrade Options
Many rural farms considering solar installations discover that their existing single-phase supply is insufficient for a system that matches their energy needs. Upgrading to a three-phase supply opens up significantly greater capacity for both solar generation and general farm electrification, supporting future growth such as electric vehicle charging, heat pumps, and additional equipment.
A three-phase upgrade involves the DNO running three-phase cables from the nearest suitable transformer to your farm's meter position. The cost depends primarily on the distance from the transformer and the ground conditions along the cable route. For farms within 200 metres of an existing three-phase transformer, costs are typically £3,000 to £5,000. For longer distances or where a new transformer is required, costs can increase to £10,000 to £25,000.
We recommend considering a three-phase upgrade alongside your solar installation because the combined project benefits from shared trenching, shared DNO interactions, and a single project management process. A three-phase supply also enables larger solar systems, better balanced export across phases, and future-proofs the farm's electrical infrastructure for decades to come. See our roof suitability guide to understand how your building capacity aligns with available grid connection options.
Battery Storage to Reduce Grid Dependence
Battery storage systems allow farms to store excess solar electricity for use during evenings, overnight, and on cloudy days when solar output is low. This reduces the amount of electricity you need to export (lowering grid connection requirements) and the amount you need to import (increasing your savings). For farms in grid-constrained areas, battery storage can be the difference between a viable project and one that stalls due to connection costs.
Typical farm battery systems range from 50kWh to 500kWh depending on the solar system size and energy consumption patterns. A 100kWh battery paired with a 100kW solar system can increase self-consumption from 50-60% to 75-90%, substantially improving the financial return while reducing the export capacity required from the DNO. Battery costs have fallen significantly in recent years, and the economics are now attractive for many farm operations.
Battery storage also provides resilience against grid outages, which are more common in rural areas. For livestock farms where power interruptions can affect animal welfare and milk cooling, this added security is particularly valuable. Visit our services page to learn more about our integrated solar and battery storage solutions for farms.
Timeline Expectations: Application to Energisation
The total timeline from initial grid connection application to a fully energised and exporting solar system typically ranges from 3 to 6 months. Several factors can extend this period, and understanding the key milestones helps you plan your project schedule effectively.
Budget estimate request and response
Initial contact with DNO for indicative costs and feasibility
Formal G99 application submitted
Complete technical documentation and application fee submitted to DNO
DNO assessment period (45 working days)
Network impact assessment, possible grid studies, connection offer preparation
Connection offer review and acceptance
Review terms, confirm financing, accept offer and pay connection costs
Installation, DNO works, and commissioning
Solar installation, any DNO upgrades, system testing, and G99 Form A submission
System energised and exporting
Fully operational solar system, SEG registration, and monitoring activated
We strongly recommend starting the grid connection process at the earliest stage of project planning. Delays in grid connection are the most common cause of project timeline overruns, and early engagement with the DNO gives you the maximum flexibility to optimise system design and manage costs. Contact us to begin the process with a free initial consultation.
Smart Export Guarantee (SEG): Earning from Your Export
The Smart Export Guarantee is a UK government scheme that requires licensed electricity suppliers with 150,000 or more customers to offer a tariff for exported renewable electricity. Once your farm solar system is installed, commissioned, and registered with a DNO through the G99 process, you are eligible to sign up for a SEG tariff and start earning income from every kilowatt-hour you export to the grid.
How to Register for the SEG
Ensure your solar system is MCS certified and installed by an MCS-accredited installer. This is a mandatory requirement for SEG eligibility.
Obtain your G99 Form A commissioning certificate from your installer, confirming the system meets all grid connection requirements.
Have a smart meter or export meter installed. Most farms will need an export meter, which your DNO or energy supplier can arrange.
Apply to a SEG licensee of your choice. You do not need to export to your current electricity supplier, and you should compare rates to find the best tariff for your situation.
Typical SEG Tariff Rates
SEG tariff rates vary between suppliers and change regularly. As of 2025, typical rates range from 4p to 15p per kWh. Some key factors that affect the rate you receive include:
- Fixed vs variable tariffs: Fixed tariffs offer rate certainty for a set period (typically 1-2 years) at 4p to 8p/kWh. Variable or agile tariffs linked to wholesale prices can pay 6p to 15p/kWh but fluctuate with market conditions.
- Supplier comparison: Octopus Energy, EDF, British Gas, E.ON, and other major suppliers each offer different SEG rates. Smaller suppliers may offer competitive rates for larger export volumes.
- PPA alternatives: For larger farm systems exporting significant volumes, a Power Purchase Agreement may offer better rates than the SEG, particularly for systems above 100kW.
SEG Income Example for a Farm Solar System
A 100kW farm solar system generating 90,000 kWh per year with 35% export (31,500 kWh exported) would earn the following under different SEG scenarios:
These figures are in addition to the savings from self-consumption. We help all our customers identify and register for the most competitive SEG tariff available at the time of commissioning.
Grid Connection and Planning: Working in Parallel
It is important to understand that grid connection and planning permission are separate processes managed by different authorities. The DNO handles grid connection, while your local planning authority deals with planning permission. These processes can and should run in parallel to minimise overall project timescales.
Most farm solar installations on existing agricultural buildings fall under permitted development rights and do not require formal planning permission, which simplifies the overall process. However, farms in conservation areas, with listed buildings, or those proposing ground-mounted systems may require planning approval. Starting both the grid connection and planning processes simultaneously ensures neither becomes a bottleneck.
Our team manages both processes on your behalf, coordinating the grid connection application with any planning requirements to deliver the fastest possible project timeline. We have experience working with DNOs and local planning authorities across the UK and understand how to navigate both processes efficiently. Get in touch to discuss your specific situation and how we can help manage the entire process from initial enquiry through to a fully energised system.
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Frequently Asked Questions About Farm Grid Connections
Find answers to the most common questions about grid connections for agricultural solar installations in the UK.
Get Expert Help With Your Farm Grid Connection
Navigating the grid connection process can be complex, especially for rural farms with unique infrastructure challenges. Our team has extensive experience managing DNO applications for agricultural solar systems across all UK regions and can guide you through every step.
Our Grid Connection Service Includes:
- Full grid capacity assessment for your farm location
- Budget estimate and formal G99 application management
- Export limitation design where appropriate
- Three-phase upgrade coordination with DNO
- System commissioning and G99 Form A submission
- Smart Export Guarantee registration and tariff comparison