Where to find energy for those who live on boat

Let's find sources of energy  for mooring in tropical place with 28-30C during the day time and 24-27 at night.

Energy Requirements

1. Per Person: 1 person: ~1200W/day (basic needs). 2 people: ~1600–2000W/day.  With limited AC: ~3300W/day.

2. AC Usage: Air conditioning adds ~1500W/day during summer months. Without AC, energy needs are manageable with solar and wind, but AC requires supplemental power.

Problem with boats, we have very limited space and surface area.

Reasonable installations of solar panels. I have seen three different installations: a. on top of bemini b. on the deck  c. on the side of starboard or portside.

On top of bemini or metal carcass typically there is around 1.5m by 2.5m, which is 3.75m2 could give us around 500W in ideal situation  at mid-day and 300W on different sun angles. Please see how I got this on that page (click here).

You could try to optimize tilt angles to get maximum out of solar panel. But practically on boats you most likely limited to 0deg or horizontal orientation. Thus use this calculator to get realistic numbers of power you might get from your solar panel.

Solar Power Potential. Surface Areas and Energy Output

• Bimini or Metal Carcass (Top):

  • Area: ~1.5m × 2.5m = 3.75m².
  • Ideal output: ~500W at midday, ~300W at suboptimal angles.
  • Daily energy: ~1300–1400W (assuming 2 ideal hours + 3 suboptimal hours).

• Deck Surface:

  • Area: ~1–1.5m² (limited by obstructions).
  • Additional energy: ~500W/day.

• Sides of Boat (Port/Starboard):

  • Area: ~3m² per side (ideal conditions only).
  • Output: ~1000W/day per side.
  • Practicality: Limited in tight marinas; better in open moorings.

Total Solar Output:  Maximum Possible: ~3000–4000W/day (using all available space).

• Realistic Average: ~1300W/day (bimini area only) to ~2000W/day (with deck and some side panels).

Efficiency Losses

• Charging and Storage Losses:
  • Battery charging: ~15% loss.
  • Controller/inverter efficiency: ~80% overall.
  • Self-consumption of controllers: ~12W/day.
• Net Usable Energy:
  • Bimini area: ~1000W/day (DC-only usage).
  • With deck panels: ~1500–1800W/day.

Wind Power

• Typical Wind Generator Output:
  • Low wind (<10 knots): ~40W.
  • Medium wind (10–20 knots): ~100W.
  • High wind (20–30 knots): ~150W.
• Daily Energy Contribution:
  • Good windy day: ~400–1000W.
  • Nighttime advantage: Wind complements solar by generating power when sunlight is unavailable.

• Fuel Consumption:
  • 3kW generator: 200ml/hour ( 0.2L/hour).
  • To generate 1500W/day for AC: ~1 hour/day → ~6L/month.
• Role:
  • Backup for high-energy demands (e.g., AC).
  • Minimal use to conserve fuel while relying on renewable sources.

Energy Balance Without Air Conditioning

• Energy Needs: ~1600–2000W/day for two people.
• Renewable Sources:
  • Solar: ~1300–1800W/day.
  • Wind: ~400–1000W/day.
• Total Renewable Energy: ~1700–2800W/day.
• Feasibility: Achievable without diesel generator if energy consumption is optimized.

With Air conditioning

• Energy Needs: ~3300W/day (including ~1500W for AC).
• Renewable Sources:
  • Solar: ~1300–1800W/day.
  • Wind: ~400–1000W/day.
• Shortfall: ~600–1300W/day.
• Solution: Use diesel generator for ~1 hour/day to cover the shortfall.

1. Maximize Solar Panel Installation:

   • Install panels on the bimini (primary source).
   • Add panels on the deck (secondary source).
   • Consider side panels if moored in open areas.

2. Optimize Panel Angles:

   • Adjust panels to be as perpendicular to the sun as possible.
   • Use adjustable mounts if feasible.

3. Incorporate Wind Power:

   • Install a reliable wind generator for nighttime and low-sunlight conditions.
   • Choose a model rated for consistent performance in medium winds.

4. Minimize Energy Losses:

   • Use high-efficiency charge controllers and inverters.
   • Turn off the inverter when not needed to reduce self-consumption.

5. Use Diesel Generator Strategically:

   • Reserve for high-demand periods (e.g., AC).
   • Run for short duration to minimize fuel consumption.

6. Energy Conservation:

   • Use LED lighting and energy-efficient appliances.
   • Limit AC usage to essential times (e.g., hottest part of the day).

For a boat in a tropical environment:

• Without AC: A combination of solar (1300–1800W/day) and wind ( 400–1000W/day) can meet the energy needs of two people.
• With AC: Supplemental power from a diesel generator (~1 hour/day) is necessary to cover the additional ~1500W/day required for air conditioning.

By optimizing panel placement, incorporating wind power, and using the diesel generator sparingly, you can achieve a sustainable and reliable energy system for your boat.

Final Answer: A realistic energy setup for a boat in a tropical environment involves maximizing solar panel installation (bimini, deck, and possibly sides), adding a wind generator for nighttime power, and using a diesel generator (~1 hour/day) to supplement AC usage during summer months. This approach balances renewable energy sources with minimal reliance on fossil fuels.