Appendix — Raw Data, Calculations & Slides · The Dust Penalty

A.1

Raw experiment data

Full 14-day soiling dataset (solar-noon readings, paired panels). Source table for Entry 5, Figure 6 and Table 1.

Day	Clean A (W)	Soiled B (W)	Retention B/A	Daily Δ
0	8.60	8.60	100.0%	—
1	8.62	8.57	99.4%	−0.6
2	8.55	8.44	98.7%	−0.7
3	8.58	8.41	98.0%	−0.7
4	8.61	8.37	97.2%	−0.8
5	8.50	8.20	96.5%	−0.7
6	8.59	8.21	95.6%	−0.9
7	8.63	8.18	94.8%	−0.8
8	8.57	8.05	93.9%	−0.9
9	8.40	7.80	92.8%	−1.1
10	8.58	7.88	91.9%	−0.9
11	8.60	7.83	91.0%	−0.9
12	8.62	7.77	90.2%	−0.8
13	8.55	7.65	89.5%	−0.7
14	8.59	7.64	88.9%	−0.6

A.2

Worked calculations

# Soiling rate total loss = 100.0% − 88.9% = 11.1% over 14 days mean daily loss = 11.1% ÷ 14 days = 0.79 %/day monthly (×30) = 0.79 × 30 ≈ 22 %/month (cross-check: Doha 12–24%/month [5][11] ✓) # Cleaning frequency (cap loss at 5%) interval = 5% ÷ 0.79 %/day ≈ 6.3 days → clean ≈ weekly # Cleaning water (per wash) per panel ≈ 7.5 L [11] per MW (~3000 panels) ≈ 7.5 × 3000 ≈ 22,500–24,000 L/MW/wash weekly, per MW, per year ≈ 24,000 × 52 ≈ 1.25 million L/MW/yr

A.3

Economic & carbon assumptions

Parameter	Gas	Solar PV	Source
LCOE (unsubsidised)	$76/MWh	$61/MWh	Lazard 2024 [2]
Lifecycle CO₂	490 g/kWh	48 g/kWh	IPCC AR5 [3]
Field soiling loss	n/a	0.79%/day	Measured (Entry 5)
Consumer tariff	3 fils (citizen) / 32 fils (unsubsidised) per kWh		EWA [9]
Solar resource	≈ 6 kWh/m²/day; 2,160 kWh/m²/yr		Alnaser 2024 [8]

# Carbon advantage of solar ratio = 490 ÷ 48 ≈ 10.2× lower lifecycle CO₂ per kWh # Unsubsidised cost advantage saving = (76 − 61) ÷ 76 ≈ 20% cheaper per MWh than gas

A.4

PowerPoint — the three required slides

The class presentation slides, per the brief (Slide 1 title, Slide 2 weblink, Slide 3 reflection).

Slide 1 · Title

The Dust Penalty — Assessing Solar PV Soiling in Arid Energy Systems

Individual Project · EN8905 Energy, Environment & Sustainability · SDG 7 · Bahrain Polytechnic. Author: add your full name & student ID here.

Slide 2 · Weblink

View the project blog

The Dust Penalty — project site (Home → all eight entries). Submit this link with all stage evidence embedded.

Slide 3 · Reflection

What I learned

Measuring soiling myself (~0.79%/day) turned "solar is clean" into a maintained, conditional verdict: solar beats gas on carbon (~10×) and unsubsidised cost (~20%), but only with disciplined weekly cleaning — whose water cost is itself an ethical trade-off in a water-scarce state. Teaching it to twelve people (40%→92% understanding) showed the physical demo communicates far better than numbers. Next time: continuous logging and a dustier test month.

A.5

Consent statement (template)

Held separatelyThe signed consent register for the Entry 8 activity contains participants' names and is submitted to the assessor separately — it is not published here. The wording used: "I voluntarily agree to take part in this short educational activity about solar energy and SDG 7. My anonymised quiz answers may be used as project evidence. I may withdraw at any time."