Solar Energy

by Bryan A. Thompson

Last Updated 2/12/2003

Overview

Solar energy isn't reliable, efficient or non-polluting.  It isn't free - it isn't even cheap.  However, it is sustainable.  It takes a huge amount of roof area.

 

Energy, Density, Weight, etc

See the Fuel Comparison Chart (or as an Excel File) for more information.

 

Energy Efficiency and Energy Costs

See the Energy Efficiency Comparison Chart (or as an Excel File) for more information about how the generator compares to other forms of energy consumption.

Irradiance from the Sun varies with the season and your location on Earth.  Panels are rated at an Average irradiance of 1000W/m^2.

Example: 

This info is from the data sheet for BP MSX120 120W panel.  It costs $552 and weighs 28.6lbs.  .991 M x 1.108 M=1.098M^2.  Output = 120W.  Output = 109.29W/M^2.  Efficiency = 10.929%.  Expected life is 25 years.  Operating Cost = $22.08/year or $0.0025205/hr. 

It's still necessary to store the energy in batteries, and to convert the energy to 120VAC.  Both of these conversions mean that it's even less efficient than the figure above indicate.   

Solar for Renters

Even though the landlord won't let you put solar panels on the roof, it's still possible for renters to harness solar energy. 

Solar panels are fairly large, so they're more practical if you rent a home, but it's still possible to capture enough energy to recharge smaller batteries in an apartment if you have a sunny window or balcony. 

 

Conclusion

I see no need for solar energy for renters.  Backpackers might use it to recharge small batteries.