A comprehensive comparison of Vertical Bifacial Photovoltaics (VBPV) and Tilted Bifacial PV (TBPV) — the current UK industry standard, using bifacial panels on conventional south-facing tilted mounts. Supersedes Tilted Monofacial PV (TMPV), which remains the reference system in cited academic studies — across energy generation, agricultural productivity, grid infrastructure, and biodiversity, based on peer-reviewed research at UK latitudes.
Badran, G., & Dhimish, M. (2024). "Comprehensive study on the efficiency of vertical bifacial photovoltaic systems: a UK case study." Scientific Reports, 14, 18380. doi:10.1038/s41598-024-68018-1
Full-year empirical study at University of York, Feb–Dec 2023. Peer-reviewed, open access. Supported by EPSRC and Over Easy Solar AS / Norwegian Research Council.
The solar industry has upgraded its panels. It hasn't upgraded its thinking.
Tilted Bifacial PV (TBPV) is now the UK default — bifacial panels on conventional south-facing mounts. Better than monofacial. Still fundamentally wrong for Best and Most Versatile agricultural land.
VBPV uses identical bifacial panels — mounted vertically, oriented east-west. Same panels. Same land. Fundamentally different outcomes: generation peaks aligned with morning and evening demand rather than the grid's midday minimum; 10–15% higher revenue per kWh; significantly less battery storage required; and 80–90% of agricultural productivity retained on the same land.
University of York field data confirms the winter advantage reaches 24.52%. The grid argument, the food security argument, and the land use argument all hold — against TBPV as much as against its monofacial predecessor.
| Feature | Vertical Bifacial (VBPV) ✓ | Conventional Tilted (TBPV) |
|---|---|---|
| Panel Orientation | Vertical, bifacial — east/west facing | Tilted 30–45° facing south (bifacial panels on conventional racking) |
| Generation Pattern | Dual peaks: morning (07:00–10:00) and evening (15:00–18:00) | Single midday peak (11:00–14:00) — lowest demand period |
| Annual Energy Output | Seasonal advantage up to 24.52% over TBPV in winter; east-west profile delivers 10–15% higher revenue per kWh | Baseline — bifacial rear-side gain increases midday output but deepens duck curve |
| Winter Generation | +24.52% over TBPV — critical for UK seasonal balance | Low — severe shortfall October–March |
| Morning Peak Advantage | +26.91% higher daily energy capture during 07:00–10:00 | Minimal output during peak demand |
| Evening Peak Advantage | +22.88% higher daily energy capture during 15:00–18:00 | Rapidly declining output |
| Duck Curve Severity | 57% less severe — inherently better demand matching | Creates severe duck curve — key grid management problem |
| Demand Correlation | 18% better correlation with UK electricity demand | Baseline — misaligned with demand peaks |
| Land Use | 80–90% agricultural productivity maintained | 100% dedicated to solar — zero agriculture |
| Machinery Access | Full access — 10–12m row spacing | Impossible — panel racking blocks all access |
| Ground Coverage | ~8% per row (0.45m clearance each side + ~100mm post, on 12m spacing) | 40–50% blocked by racking |
| BESS Required (47 GW) | Significantly less storage needed than TBPV — TBPV's bifacial rear-side gain deepens the duck curve beyond monofacial systems | Higher BESS requirement — bifacial rear-side gain amplifies midday surplus and duck curve severity |
| Grid Hosting Capacity | +46% on existing infrastructure | Baseline — constrained by overvoltage risk |
| Biodiversity & BNG | Wildflower strips beneath panel rows attract pollinators and aphid-eating natural enemies; increases natural enemy abundance ~44%, raises pest mortality ~54%, reduces crop damage ~23% vs monoculture (Dainese et al., 2019); supports mandatory 10% BNG | No habitat strips possible beneath racking; on-site BNG delivery constrained |
| Ground Accessibility | Full ground accessible — ~8% per row in clearance strips; natural vegetation can establish beneath | 40–50% of ground blocked by racking; sterile beneath panels |
| Capital Cost Premium | ~16% higher panel and mounting cost | Lower upfront cost |
All figures updated to use verified 2025 BESS cost benchmarks (BloombergNEF Dec 2025; Ember Oct 2025). Previous figures based on pre-2025 cost assumptions have been corrected.
Note on previous figures: Earlier versions of this campaign cited total system savings of £161–187bn. This was based on BESS cost assumptions of £250–300/kWh, derived from pre-2025 data. BESS costs fell 31% in 2024 alone (BloombergNEF) and have continued falling in 2025. The corrected figures of £25–35bn use the most current independently verified benchmarks and have been submitted in our fourth formal representation to DESNZ (02/03/2026). See full methodology →
VBPV outperforms TBPV in every season. The advantage is most pronounced in winter — exactly when the UK's energy needs are greatest.
| Season | VBPV Advantage Over TBPV | UK Grid Context |
|---|---|---|
| Spring | +19.32% additional energy | Demand recovering; VBPV morning advantage especially valuable |
| Summer | +14.77% additional energy | Lowest advantage season — TBPV performs relatively better in summer |
| Autumn | +20.27% additional energy | Demand rising; VBPV advantage grows as days shorten |
| Winter | +24.52% additional energy PEAK ADVANTAGE | UK demand at highest — VBPV critical for winter energy security |
Source: Badran & Dhimish (2024), University of York, Nature Scientific Reports. Full-year empirical measurement Feb–Dec 2023.
Seasonal figures note: Seasonal power gain figures are measured against the tilted monofacial reference system (TMPV) at 45° used in the Badran & Dhimish (2024) study. TBPV's bifacial rear-side gain amplifies midday generation beyond monofacial, increasing BESS demand further and strengthening the grid-matching argument for VBPV.
VBPV's agricultural compatibility directly addresses the core objection raised by local planning authorities, communities, and the NFU — that solar farms remove productive farmland from the food supply chain. With 80–90% of land remaining in active cropping, this objection is substantially neutralised.
Standard agricultural machinery operates between the rows without modification. Existing farm tenancy arrangements, crop rotations, and agri-environment scheme eligibility can all be maintained — removing the planning friction that currently delays or defeats conventional solar proposals on agricultural land.
For NSIPs and Section 78 appeals, VBPV's dual land-use case offers a compelling response to Inspectors weighing energy need against agricultural land protection under the NPPF.
England's first Land Use Framework (CP 1545, Defra, March 2026) shifts the planning question on Best and Most Versatile farmland from:
"Should solar be permitted here?"
to:
"Which solar technology genuinely retains agricultural productivity — and therefore meets the Multifunctionality Principle?"
The Framework explicitly endorses agrivoltaic systems on Grades 1, 2 and 3a land and establishes Multifunctionality as a formal government principle — with solar generation enabling continued agricultural production as its named example.
VBPV has a clear, evidence-based answer: 80–90% productivity retention, full machinery access, compatible with standard arable rotations. Conventional tilted solar (TBPV) does not — it removes productive farmland entirely for the duration of the lease.
Note: The Land Use Framework is not itself a material planning consideration for individual applications or NSIPs. It informs the strategic policy context within which planning decisions are made, and will feed into future revisions of the NPPF, National Policy Statements, and the Strategic Spatial Energy Plan (due Autumn 2027).