VBPV vs TBPV Project Analysis Tool | Harvesting the Sun Twice

Parameter	VBPV	TBPV	Notes
Location	—
Panel orientation	Vertical E-W bifacial	30° S-facing bifacial
Specific yield (kWh/kWp/yr)	—	—	BifacialMAX / B&D 2024
Array density (kWp/ha)	—	120	TBPV: 30° tilt, 6m pitch
Row pitch (E-W)	—	6 m	Szarek et al. 2026 validated range 8–20m
DC:AC ratio	1.10	Fixed throughout
Calculation mode	—
Input value	—

Differential Metric	Value	Notes
Land differential (VBPV vs TBPV)	—
MWh differential (VBPV vs TBPV)	—
UK homes powered (VBPV output)	—	@ 3,100 kWh/yr average household

Parameter	VBPV	TBPV
Effective value factor (£/MWh)	—	—
Annual revenue (£/yr)	—	—
Value premium (VBPV over TBPV)	—

Parameter	VBPV + BESS	TBPV + BESS
Required BESS capacity (MWh)	—	—
BESS CAPEX (£M)	—	—
Annual peak-spreading revenue	—	—
Simple payback (years)	—	—
CAPEX saving (VBPV vs TBPV)	—

VBPV vs TBPV — UK Project Analysis Tool

Compare Vertical Bifacial PV (E-W agrivoltaic configuration) against standard South-facing Tilted Bifacial PV across UK locations. Enter your site area or target capacity to model energy yield, seasonal performance, time-of-use revenue, and BESS economics. Yield data validated against BifacialMAX modelling, London 51.51°N, June 2026. Full methodology →

Location

Calculation mode

Target AC capacity

DC installed capacity

—

VBPV row pitch (E-W inter-row spacing) 8m (Szarek min.) 20m 10m

Module 1 — Project Calculator VBPV-UK-ASSET-2026-05-01-001-V3

VBPV · E-W Vertical Bifacial

Land required

—

Density

—

kWp/ha

MWh/yr

—

Cap. factor

—

TBPV · South-facing Tilted Bifacial

Land required

—

Density

120

kWp/ha ref.

MWh/yr

—

Cap. factor

—

120 kWp/ha · 30° tilt · 6m row pitch · Badran & Dhimish 2024

Land differential

—

MWh differential

—

UK homes (VBPV output)

—

@ 3,100 kWh/yr

Peak window analysis — share of daily output

Morning peak

06:00–10:00 BST

VBPV

—

TBPV

—

East face captures rising sun

Evening peak

16:00–20:00 BST

VBPV

—

TBPV

—

West face captures afternoon sun

Midday surplus

11:00–15:00 BST

VBPV

—

TBPV

—

Low demand — surplus needs BESS

Combined peaks

Morning + evening windows

VBPV

—

TBPV

—

VBPV is "peak-first" by design

Daily output profile — normalised shape · BST

VBPV (E-W twin peak) TBPV (S-facing single peak) UK grid demand (right axis)

Szarek et al. 2026: VBPV delivers +46% grid hosting capacity. TBPV noon surplus coincides with minimum grid demand and requires BESS to reach peak markets.

Module 2 — Seasonal Performance · Badran & Dhimish 2024 VBPV-UK-ASSET-2026-05-01-001-V3

Badran & Dhimish (2024) — seasonal crossover finding

VBPV outperforms south-facing tilted bifacial PV in winter months at UK latitudes. Low solar elevation angles mean vertical panels receive near-optimal direct irradiance November–February, with additional gains from snow albedo on the rear face. The summer deficit is real but occurs when grid demand is lower and electricity commands lower market value. Study location: University of York, 53.9°N. Source: Int. J. Low-Carbon Technologies, Oxford Academic (2024).

VBPV outperforms in

5 months

Oct, Nov, Dec, Jan, Feb

Peak winter advantage

+34%

VBPV vs TBPV kWh/kWp in Dec · York

Peak summer deficit

−25%

VBPV vs TBPV kWh/kWp in Jun · York

Annual net (selected location)

—

kWh/kWp VBPV vs TBPV

Monthly production — VBPV vs TBPV kWh/kWp

Shaded months = VBPV ≥ TBPV · ratio line = VBPV as % of TBPV (right axis)

VBPV kWh/kWp TBPV kWh/kWp VBPV/TBPV % ratio

Monthly profile derived from Badran & Dhimish (2024) irradiance weighting at 53.9°N, applied to selected location's annual specific yield. Full citation: Badran, G. & Dhimish, M. (2024). Comprehensive study on the performance of vertical bifacial photovoltaics: a UK case study. International Journal of Low-Carbon Technologies, Oxford Academic.

Module 3 — Revenue · Time-of-Use Pricing VBPV-UK-ASSET-2026-05-01-001-V3

Time-of-use revenue model

VBPV generates into high-value morning and evening demand peaks. TBPV generates into low-value midday — sometimes at negative wholesale prices in high-solar summers. Adjust prices below to match your PPA, wholesale exposure, or CfD structure. Default values are representative UK half-hourly wholesale averages (2024–25).

Morning peak (06–10h) £/MWh

Daytime (10–16h) £/MWh

Evening peak (16–21h) £/MWh

Night (21–06h) £/MWh

VBPV value factor

—

£/MWh generated · annual avg

TBPV value factor

—

£/MWh generated · annual avg

VBPV value premium

—

% more revenue per MWh vs TBPV

Annual revenue gap

—

£/yr VBPV vs TBPV at project scale

VBPV annual revenue

—

£/yr at project scale

Annual MWh

—

£/MWh eff.

—

Winter VF

—

TBPV annual revenue

—

£/yr at project scale

Annual MWh

—

£/MWh eff.

—

Winter VF

—

Monthly revenue — VBPV vs TBPV (£)

Winter months show strongest VBPV advantage — both higher value factor and seasonal production crossover occurring simultaneously

VBPV revenue TBPV revenue

Module 3 — Agricultural Value & Co-benefits VBPV-UK-ASSET-2026-05-01-001-V3

Agricultural value — the dual-income case

Why solar revenue alone understates the VBPV case

TBPV occupies agricultural land entirely — crop income is lost for the project lifetime. VBPV maintains ~78% crop irradiance between E-W rows, preserving proportional food production income. The combined income per hectare (solar + agricultural) is the correct comparison for land occupying Best and Most Versatile farmland. Enter your site's typical crop income below to see the full dual-income picture.

Crop income (£/ha/yr)

UK arable refs: wheat ~£280, OSR ~£340, vegetables £600–1,200+. Use Farm Business Survey or FBS regional average for your crop type.

VBPV crop retention (%)

Default 78% · Szarek et al. 2026 range: 70–85% at 8–12m pitch. Adjust for your pitch and crop type.

TBPV crop retention

Panels cover ground — no meaningful arable cropping possible beneath fixed-tilt arrays

VBPV combined income/ha

—

£/ha/yr · solar + crop

TBPV solar income/ha

—

£/ha/yr · solar only · no crop

Combined income advantage

—

£/ha/yr VBPV over TBPV

Total annual dual-income

—

£/yr · VBPV project scale

VBPV — dual income breakdown

Solar income

—

£/yr

Crop income

—

£/yr · at 78% retention

Combined

—

£/yr total

Agricultural income calculated as: site area (ha) × crop income (£/ha) × retention (%). Szarek et al. 2026: 79.9–82.5% irradiance retention at 10–12m pitch.

TBPV — solar-only income

Solar income

—

£/yr

Crop income

£0

£/yr · land under panels

Combined

—

£/yr total

TBPV displaces all agricultural production. On BMV (Grade 1, 2, 3a) land, this income loss persists for the full project lifetime (25–40 years).

Campaign framing: The UK Land Use Framework and Strategic Spatial Energy Plan currently assume solar prevents food production — treating VBPV and TBPV as equivalent in land-use terms. The dual-income figures above show why this is incorrect. VBPV generates meaningful agricultural income alongside solar revenue. DESNZ letter TOB2026/04355 (Adrian Collins, 29/04/2026) acknowledged that agrivoltaics "may have an important role to play" — this section quantifies that role in £/yr terms.

Crop income is indicative. Actual farm income depends on crop type, rotation, yield, commodity prices, and subsidy regime (BPS/SFI). Use Farm Business Survey (FBS) regional averages or a site-specific farm business assessment for formal representations. Agricultural income retention percentage: Szarek et al. 2026 (70–85% range at E-W pitch 8–12m). Canopy-style APV systems may achieve higher retention — consult Dual Harvest Agrivoltaics for site-specific assessment.

Non-financial agricultural co-benefits

VBPV delivers agronomic benefits that have no TBPV equivalent

Beyond income, VBPV E-W rows create measurable agronomic advantages that are absent from fixed-tilt south-facing arrays. These benefits are unquantified in current UK planning policy but are increasingly supported by peer-reviewed evidence.

🌬 Wind protection

Up to 40%

wind speed reduction between E-W rows

VBPV rows act as windbreaks along the prevailing wind direction, reducing soil erosion and crop moisture loss. Twice the protection of conventional tree windbreaks (20%).

Williams, Hashad & Zhang (2026) · Agricultural and Forest Meteorology

TBPV: no windbreak effect

🌱 Soil structure

Maintained

annual cultivation continues between rows

VBPV allows continued ploughing, drilling, and cultivation between E-W rows, maintaining soil biology, organic matter, and drainage. TBPV panels shade and compact the ground beneath — preventing cultivation, concentrating rainfall runoff from tilted panels, and degrading soil structure over the project lifetime (25–40 years).

VBPV driven-pile foundations · no concrete in soil · full reversibility at decommissioning

TBPV: compaction, runoff channelling, 25–40yr

☀️ Albedo synergy

+ve loop

crop canopy reflects energy to rear face

Crop canopy between E-W rows reflects diffuse radiation onto VBPV rear faces, boosting generation. Snow cover amplifies this further in winter months — a synergistic effect that grows with crop density. Contributes to VBPV's winter performance crossover.

Szarek et al. (2026) · Applied Energy · University of Turku

TBPV: no rear-face crop albedo path

🏡 BMV preservation

"Leave no trace"

reversible · soil baseline maintained

VBPV driven-pile foundations leave no concrete in soil. "Leave no trace" planning condition: baseline MP soil assessment at commissioning + annual drip-line monitoring + soil report at decommissioning. Full reversibility supports BMV Grade 1–3a land classification.

NPPF BMV protection · Paul Wright (leave no trace methodology) · Alex DePillis (drip-line monitoring)

TBPV: compacted soil, concrete bases, 25–40yr

Sustainable Farming Incentive (SFI) compatibility: VBPV's continued agricultural use may support ongoing SFI scheme eligibility — subject to Natural England and DEFRA guidance applicable at the time of application. TBPV projects typically cannot maintain SFI payments as agricultural activity ceases. This income stream is not modelled above but could represent a further £40–150/ha/yr depending on actions selected. Verify current SFI action rates at gov.uk/sfi.

Crop income is indicative. Actual farm income depends on crop type, rotation, yield, commodity prices, and subsidy regime. Use Farm Business Survey (FBS) regional averages or a site-specific farm business assessment for formal representations. Agricultural income retention: Szarek et al. 2026 (70–85% at 8–12m pitch). Wind speed reduction: Williams, Hashad & Zhang (2026), Agricultural and Forest Meteorology. Soil structure: VBPV allows continued annual cultivation; TBPV prevents cultivation and concentrates rainfall runoff for the full project lifetime. Canopy APV systems may achieve higher crop retention — consult Dual Harvest Agrivoltaics Limited for site-specific assessment: harvestingthesuntwice.org

Module 4 — BESS Analysis VBPV-UK-ASSET-2026-05-01-001-V3

BESS sizing and payback model

TBPV generates 61% of output in the low-demand midday window — requiring substantial battery storage to reach peak markets. VBPV's peak-aligned output needs significantly less storage. This model calculates BESS capital cost, annual revenue from peak-spreading, and simple payback for each configuration. Price spread used from the Revenue tab.

BESS installed cost (£/kWh)

TBPV shift fraction (%)

VBPV shift fraction (%)

System lifetime (years)

VBPV BESS capacity

—

MWh · daily cycling basis

TBPV BESS capacity

—

MWh · daily cycling basis

CAPEX saving (VBPV)

—

£M less BESS capital vs TBPV

Price spread (ToU tab)

—

£/MWh evening peak − daytime

VBPV + BESS economics

BESS CAPEX

—

£M outlay at yr 0

Annual revenue

—

£k/yr peak-spreading

Simple payback

—

years

TBPV + BESS economics

BESS CAPEX

—

£M outlay at yr 0

Annual revenue

—

£k/yr peak-spreading

Simple payback

—

years

How to read the cashflow chart: Both lines start negative (CAPEX outlay at year 0). A higher position means better — either less capital spent or more recovered. VBPV starts higher because it needs significantly less BESS capital. Both lines cross zero (break-even) at approximately the same year. After break-even, TBPV rises faster because its larger BESS generates more annual peak-spreading revenue — but required 2–3× more upfront investment to get there.

BESS cumulative cashflow — 15-year project life

VBPV + BESS (lower CAPEX) TBPV + BESS (higher CAPEX) · CAPEX annotated at year 0 · dashed = break-even

BESS cost reference: £80–200/kWh installed (UK utility-scale 2025–26). Default £100/kWh reflects competitive LFP procurement — Ember (Oct 2025): all-in project CAPEX ~$125/kWh; BloombergNEF (2025): battery pack prices ~$108/kWh. UK-specific projects with higher BOS/grid connection costs may trend toward the upper end of range. TBPV shift fraction 35% = 61% midday output minus ~26% direct grid consumption. VBPV 15% = residual daytime output not captured at peak. Round-trip efficiency: 85% throughout. Simple payback shown — NPV analysis recommended for investment decisions. Next2Sun BESS field data referenced (percentage figure independently unverified).

Indicative modelling tool. VBPV density model: 1,950÷pitch kWp/ha (first-principles: Huasun M6 470W, 2.41m bay, N2S Standard single panel). TBPV: 783 kWp/ha reference (30° tilt, 2m wide tables, 6m row pitch, GCR 0.33 — representative UK utility-scale). Yield data: BifacialMAX validated runs, London 51.51°N, June 2026 (TBPV: 1,118 kWh/kWp/yr; VBPV N2S Standard: 934 kWh/kWp/yr; albedo 0.20, HJT 70% bifaciality, P=12m). Revenue model applies normalised hourly profiles — not site-specific dispatch modelling. DC:AC ratio fixed at 1.10 throughout. Not a substitute for a site-specific Energy Yield Assessment (EYA) or full financial model.