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Solar Disaster Relief Calculator

Size a portable solar system for field deployment — enter mission type, equipment, and location — get panel array, battery size, system weight, and diesel cost comparison.

Deployment configuration
people
days
°
Equipment checklist
Portable solar system for field deployment
15.2 kW array — 76 × 200W flexible panels
Daily energy needed59.0 kWh/day
Location PSH5 hrs/day
Battery bank (overnight critical loads)7 kWh LiFePO4
Total system weight383 kg (845 lbs)
— Panels weight266 kg
— Battery weight42 kg
— Equipment weight60 kg
Transport fitFits in 20ft container
Solar system cost$75,900
Diesel generator comparison (14 day deployment):
Diesel fuel needed:258 litres
Fuel cost:$310
Generator rental:$1,120
Total diesel cost:$1,559
Daily diesel savings with solar:$102/day
CO2 avoided vs diesel: 692 kg CO2 over deployment (0.69 metric tons). Diesel fuel logistics in disaster zones also costs $0.50-2.00/litre extra for transport — solar eliminates this entirely.
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How to Use This Calculator

Select deployment type and location

Start by selecting your mission type — medical clinic, water purification, communications hub, emergency shelter, or a combined station. Each has a different base power requirement. Enter the deployment latitude: locations near the equator (disaster zones in Southeast Asia, Central America, Sub-Saharan Africa) receive 5.5-6.5 peak sun hours; Mediterranean or Southern US deployments receive 4-5 hours. Latitude directly affects how many panels are needed.

Check off your equipment

Each equipment item shows its wattage and weight — both matter for field deployment. The calculator tracks total system weight to determine whether your setup fits in a standard 20-foot shipping container (max ~5,000 kg payload) or requires a 40-foot unit. Ventilators and vaccine refrigerators are the highest-priority loads and are sized as critical backup loads for the battery calculation.

Compare solar vs diesel

The diesel comparison is the key decision metric for relief organizations. Solar has higher upfront cost but eliminates fuel logistics in crisis zones — where diesel delivery can cost $1-3 per litre premium over market price, plus security risks for fuel convoys. For deployments of 10+ days, solar typically becomes cost-competitive. For 30+ day deployments, solar is almost always cheaper and operationally simpler.

The Formula

Daily kWh = (Base deployment kW × 8 hrs) + (Equipment watts × 16 hrs) ÷ 1000 PSH = 6.0 if lat ≤15° / 5.0 if lat 15-30° / 4.0 if lat 30-50° System kW = (Daily kWh × 1000) ÷ PSH ÷ 0.78 (field efficiency factor) Panels = System kW ÷ 0.2 kW per panel (200W portable panels, round up) Battery kWh = (Critical load watts × 8 hrs) ÷ 1000 ÷ 0.80 DoD System weight = (Panels × 3.5 kg) + (Battery kWh × 6 kg) + Equipment weight + 15 kg inverter Diesel litres = Total kWh ÷ 3.2 kWh/litre Diesel total cost = Fuel cost + Generator rental ($80/day) + Logistics premium

Field efficiency (0.78) is lower than a permanent installation (0.80-0.85) to account for suboptimal panel orientation, dust accumulation in the field, and heat degradation. Portable 200W flexible panels are specified because they are lightweight (3.5kg vs 10kg for rigid panels), fold for transport, and can be mounted on any surface including tent frames and vehicle roofs.

Example

Field Medical Clinic — Haiti earthquake response, 30 patients, 14-day deployment

A field medical clinic with ventilator, vaccine refrigeration, LED lighting, communications, portable ultrasound, and a laptop. Deployed at latitude 18°N (Haiti) for a 14-day earthquake response mission.

DeploymentMedical clinic (5 kW base)
EquipmentVentilator, vaccine fridge, lighting, comms, ultrasound, laptop
Latitude18° (tropical, 5.0 PSH)
Duration14 days

Result

Daily energy need~29.5 kWh/day
Panel array8 kW — 40 × 200W flexible panels
Battery bank6 kWh LiFePO4 (overnight critical loads)
Total system weight~320 kg — fits in 20ft container
Diesel equivalent cost~$2,400 (fuel + rental + logistics)
Solar system cost~$7,600 (reusable)
CO2 avoided~359 kg vs diesel

The solar system costs more upfront for a 14-day deployment, but it's reusable for dozens of future deployments — making the per-deployment cost roughly $380 after 20 uses, compared to $2,400 for diesel every time. For organizations with recurring deployments, portable solar is the clear economic and operational choice.

FAQ

Solar becomes operationally and economically superior to diesel in three key scenarios: (1) Deployments of 30+ days — fuel costs accumulate quickly, and solar pays back within the deployment. (2) Remote or insecure locations — fuel convoys are vulnerable, expensive, and dangerous. Solar eliminates fuel logistics entirely. (3) Recurring deployments — the same solar system can be used for dozens of missions over its 10-15 year life, amortizing the upfront cost across all deployments. For short (7-day) deployments in accessible locations, diesel generators remain practical.
Flexible lightweight panels (200W, ~3.5kg each) are the preferred choice for humanitarian operations. They fold for compact shipping, can be mounted on tent frames, vehicle roofs, or deployed on the ground, and survive rough transport conditions better than rigid glass panels. Monocrystalline flexible panels from brands like Renogy, SunPower, or Goal Zero offer 20-22% efficiency in a portable form factor. For larger permanent-ish deployments (30+ days), lightweight rigid panels (10kg, 400W) are worth the extra weight for better durability and efficiency.
Size the battery for your critical loads overnight — typically ventilators, vaccine refrigeration, minimal communications, and emergency lighting. Non-critical loads (water pumps, ultrasound for scheduled procedures) can be shut down overnight or run only when solar is producing. As a rule of thumb: (Critical watts × 8 hours) ÷ 1000 ÷ 0.80 DoD = kWh needed. For a ventilator (150W) + vaccine fridge (75W) + comms (200W) + emergency light (50W), that's 475W × 8hr ÷ 1000 ÷ 0.8 = 4.75 kWh — round up to 5 kWh. LiFePO4 batteries are strongly preferred for their stability, safety, and 2,000+ cycle life.
Weight depends on your transport method. A light pickup truck can carry 500-800 kg payload; a standard military or aid truck carries 2,000-5,000 kg. A standard 20-foot shipping container holds approximately 25,000 kg but has about 33 cubic meters of volume — usually the volume constraint is binding before the weight limit. Helicopter sling loads are typically limited to 1,000-4,000 kg depending on the aircraft. The calculator flags when your total system exceeds 1,500 kg (light truck limit) or 5,000 kg (container limit) to help with logistics planning.
Major humanitarian organizations increasingly deploy portable solar: the International Committee of the Red Cross (ICRC) powers field hospitals with solar; Médecins Sans Frontières (MSF/Doctors Without Borders) uses solar in many field missions; UNHCR deploys solar microgrids in refugee camps; USAID and other government agencies fund solar for water and health programs. Companies like Sievert, Renovagen (roll-out solar), and SunTransfer specialize in humanitarian solar deployment. The UN Environment Programme estimates humanitarian solar capacity has grown tenfold since 2015 as costs have fallen and reliability has improved.

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