What Is a Grid Connection Feasibility Study?

Every failed renewable project has the same origin story: someone got excited about a site and committed money to design, planning or land agreements before finding out whether the scheme could actually connect to the grid, or whether the numbers held up when you took a serious look at them. By the time reality catches up, six months of consultancy fees, planning costs and internal time have been spent chasing something that was never going to work.

A grid connection feasibility study is the cheapest insurance policy you can buy on a renewable project. This guide covers what a feasibility study actually includes, how much one costs in the UK, how long they take, and when to commission a lightweight budget estimate versus a full study.

What is a grid connection feasibility study?

A grid connection feasibility study is a structured desktop assessment carried out before a renewable energy project moves into design, planning or grid application. It answers three questions at once: is the site technically suitable, can it connect to the grid, and does the commercial case stack up? Everything else, planning, land, EPC contracts, DNO application, should sit downstream of that answer.

It's not a marketing document, and it's not a sales pitch. A proper feasibility study is written by engineers and analysts who spend most of their time submitting DNO applications and modelling revenue stacks, and it's designed to be read by investment committees, boards and landowners who need to make a real decision with real money.

Feasibility studies apply across every technology we cover: solar PV (rooftop, ground-mount and utility-scale), battery energy storage (BESS), hybrid solar + BESS schemes, EV charging hubs and heat pumps. The commercial variables differ (revenue stack for BESS vs self-consumption for rooftop solar vs utilisation for EV) but the structure of the study stays the same.

What's included in a feasibility study?

Every study follows a standard structure so outputs are comparable across sites and technologies. The core sections are:

• Site suitability. Roof orientation and shading for rooftop schemes; land use, topography, access and grid proximity for ground-mount and BESS; supply capacity for EV and heat pump.
• Technology sizing. Two or three sizing options benchmarked against yield, CAPEX and payback, so you're not stuck with a single number that may not be the right answer.
• Yield or throughput modelling. Solar PV output modelled against real irradiance data; BESS throughput modelled against target trading strategy; EV utilisation modelled against expected traffic.
• Grid-connection strategy. DNO region, likely constraints, network area headroom, and a recommended connection route (G99, ENA, or utility-scale pre-application). This is the section most feasibility studies get wrong.
• Ranged CAPEX. Itemised CAPEX with clearly stated assumptions and ranged sensitivities on the main cost drivers (equipment, install, DNO fees).
• Revenue or savings model. For BESS: revenue-stack modelling across the wholesale markets, ancillary services, and capacity market. For solar: self-consumption vs export SEG modelling. For EV: utilisation-based revenue.
• IRR, payback and sensitivities. The commercial output stated three ways: base case, downside, upside, so a board can see the range, not just the headline number.
• Recommendation. A clear go / no-go / conditional recommendation, and the specific next steps to unlock it.

How much does a grid connection feasibility study cost in the UK?

Feasibility study pricing in the UK sits in fairly predictable bands. Here's what fixed-price studies typically cost:

Two things to watch. First, "free" feasibility work from equipment suppliers is almost always a sales pitch, the numbers will be tilted toward whatever the supplier wants to sell you. Second, watch how grid analysis is treated: a feasibility study that skips the DNO capacity check isn't a feasibility study, it's a spreadsheet. Every genuine study should include a live grid-connection readiness check.

For a full breakdown by tier, see our feasibility studies pricing page.

Budget estimate vs full feasibility study

A budget estimate and a full feasibility study solve different problems. Understanding which one you need first saves time and money.

Choose a budget estimate when you need a defensible CAPEX figure fast, for a board paper, an investment memo, a landowner conversation, or a quick internal go/no-go. It won't tell you whether the scheme is truly viable, but it will tell you roughly what it will cost and whether the grid is likely to say yes.

Choose a full feasibility study when you're serious about committing capital. You need proper yield modelling, a real grid strategy including likely DNO constraints, a revenue-stack or savings model that survives investment-committee scrutiny, and a clear recommendation on how to structure the scheme.

The most common pattern for utility-scale projects is to run both in sequence: budget estimate first to confirm the scheme is worth pursuing, then a full feasibility study once the developer has decided to progress.

Why grid connection is the section that matters most

Historically, feasibility studies were about sunlight and roof space. Now they're about grid capacity. Across most of the UK, network headroom is the binding constraint on whether a renewable scheme happens at all, and a feasibility study that doesn't take the grid seriously is only telling you half the story.

A proper grid-connection section covers the DNO region, the likely constraints on that specific network, the connection routes available (G99, ENA, Section 15), the informal view we can get from the DNO's design team where a formal pre-application isn't warranted yet, and a clear recommendation on whether to proceed straight to a full DNO application or stage a pre-application first.

We write feasibility studies by a team that submits G99 DNO applications every day, so the grid strategy section reflects what's actually happening on the ground, not what a boilerplate template says it should be. If you're not sure whether a project needs a G99 or a G98 application, we've also written a G99 vs G98 guide that unpacks the difference.

Who commissions feasibility studies?

Feasibility studies are useful in more scenarios than most developers realise:

• Developers commission feasibility studies before land options, planning applications and equity raises, so the CAPEX and grid position are locked before any of those costs are committed.
• Landowners use feasibility studies to understand what a piece of land is worth to a developer before they sign an option agreement or lease.
• C&I businesses commission feasibility for on-site solar, BESS or EV charging so procurement, finance and operations are all working from the same numbers.
• Investors and lenders use independent feasibility studies to sense-check developer numbers before committing capital.
• EPCs and consultants commission feasibility work as an independent second opinion on their own designs, particularly on hybrid or grid-constrained schemes.

How to commission a feasibility study

A good feasibility study starts with a clear brief. Before commissioning one, gather:

• Site address and postcode, plus any land plans or roof plans you already have
• Target technology and rough capacity (a range is fine, sizing options are part of what a study will refine)
• Whether you already have an MPAN, half-hourly consumption data, or an existing G99 acceptance letter
• Your target use case: self-consumption, wholesale trading, capacity market, EV utilisation, or a combination
• Your decision deadline, the study should be delivered before the decision has to be made, not after

Send that to us via the feasibility studies page and we'll come back with a fixed-price scope and turnaround, usually within one working day. We're independent of equipment suppliers, so the numbers in your study aren't tilted toward anyone's line card.

The bottom line

The cost of a feasibility study is small. The cost of not doing one, realised six months into a project when the DNO comes back saying the network is full, or the yield modelling was wrong, or the revenue stack doesn't hold, is not small.

If you're at the front end of a solar, BESS, hybrid or EV project, a fixed-price feasibility study is the highest-return step in the whole development process. It makes the CAPEX defensible, the grid strategy realistic, the commercial case robust, and the investment decision one you can actually make with confidence.

You can see full pricing and how to commission a study on our feasibility studies page. Already past feasibility and ready to submit? G99 applications for sub-1 MW projects and utility-scale DNO applications for 1 MW+ are the natural next steps.