Which planning constraints actually stop a renewable scheme?

The most-cited consideration for ground-mounted solar, and the one where policy states a preference without ever quantifying its cost. Here it is quantified: Grade 1 82%, Grade 2 86%, against 89% on Grade 3 land.

Grade 3 is published without a 3a/3b split, and only 3a is best and most versatile, so that row mixes land that counts with land that does not. Treat this ladder as suggestive rather than established: the gaps between adjacent grades are small relative to the number of decisions behind them, so the ordering is more trustworthy than any individual difference.

Two other things move outcomes, and both come out of the same recorded decisions. Note the change of scope: the designation tables above are England only, because that is where the boundaries are published. Size and timing carry no such limit, so these two are UK-wide and use every recorded decision.

The first is scheme size — and for solar the interesting part is what it does not do.

Approval rates barely move across the size bands — 87% to 96%, a spread of 9 points. What changes is the clock: a median 3.4 months for under 1 MW against 15.9 months for 50 MW and above. Size buys you delay, not refusal.

Onshore wind behaves quite differently: approval drops sharply once a scheme leaves the very smallest band — 91% under 1 MW against 60% at 5-20 MW — then partially recovers at the top, where the largest projects leave the council system altogether and are decided nationally. Not a steady decline; a cliff and a rebound. Read this one with its composition in mind — Scotland supplies more of these decisions than England does, and Scottish policy on onshore wind has been markedly more permissive, so this table describes the UK as a whole rather than an English site.

The second is when you applied.

Solar consent got dramatically easier through the early 2020s and has tightened again since, while the median time to a decision has roughly doubled. Treat the most recent year with care: refusals that will be appealed and overturned have not resolved yet, so the newest years read harsher than they will once the appeals land.

A refused scheme can appeal to the Planning Inspectorate, and the record shows how often that works. Same scope as everything else on this page: England, ground-mounted for solar.

Two numbers, kept apart on purpose: how often a refusal is appealed, and how often an appeal that reaches a decision succeeds. Around half of refusals are never appealed; of those that are, a majority win.

One thing this does not mean: it does not sit on top of the rates above. The planning database records a scheme's current status, and a scheme that wins its appeal is recorded as consented — so appeal wins are already counted as approvals in every rate on this page. If anything the rates flatter the councils, because a refusal overturned by an inspector still reads as an approval here. What the appeal record tells you is something different and more useful: a refusal is a cost and a delay rather than a verdict.

The success rate is subject to obvious selection: developers appeal the cases they expect to win and drop the rest, so read it as the success rate of chosen appeals, never of all refusals. Withdrawn and still-pending appeals are excluded from the denominator — a withdrawn appeal is not a win.

These are associations, not causes. Sites are not randomly assigned to designations: a scheme inside a National Landscape usually differs from one outside it in size, siting and how much work went into the application before it was submitted. The planning database also gives one representative coordinate per scheme rather than a red-line boundary, so a site that straddles an edge can be recorded either side of it. The boundaries are published for England only, and for solar we count ground-mounted schemes alone — rooftop solar inside the Green Belt is approved at almost exactly the rate it is outside, which is precisely why pooling the two would destroy the finding.

What the numbers are good for is calibration: the size of the hill you are being asked to climb, and whether a designation is a genuine blocker or a routine hurdle. What they cannot do is predict your application. Landscape and cumulative impact — the two reasons most often given for refusal — are professional judgements that appear in no dataset.