Energy Alternatives
Online Store Resources Company E-services
Home Solar Wind Micro Hydro Batteries Inverters Water Pumping Lighting Appliances Catalogue Check Out Cart Home Email

Solar Photovoltaic (PV)


Photovoltaics are the simplest form of alternative energy. There are no moving parts in photovoltaic modules and little maintenance is required. A photovoltaic module converts the sun’s energy into electricity which is either used immediately (grid intertie or water pumping) or is stored for future use (batteries). Solar electric systems are modular, allowing you to start with a small system. As your power requirements grow, you can easily add more modules.

Types of solar cells

Single Crystal
Single crystal silicon cells are extremely thin wafers of silicon cut from a single silicon crystal. These are the most efficient type of silicon cells and have a life expectancy exceeding 25 years. The cells are fragile and must be mounted in a rigid frame. You can tell it is a single crystal due to the uniform, rounded individual cells.

Multi Crystal

Multi crystal silicon cells are also extremely thin wafers of silicon but are cut from multiple crystals grown together in an ingot. They are similar to single crystal cells in life expectancy and fragility. However, they are slightly less efficient than single crystal cells and require more surface area to produce a given amount of electricity. These types of cells are usually square and will have a varied appearance.

Amorphous Silicon(a-Si)
Amorphous silicon cells are made by depositing a micro thin layer of silicon directly onto a sheet of stainless steel. Because amorphous absorbs light more efficiently than its crystalline counterpart, the amorphous solar cell thickness can be 100 times less, thereby significantly reducing cost of materials. By utilizing a flexible, stainless steel substrate and polymer-based encapsulates, products utilizing this technology can be very lightweight, flexible, and durable. No parts are broken during shipping and units are easy to transport to remote rural areas, thus saving on shipping costs.

New Technologies

Innovative new technologies that will allow us to capture energy from the sun will undoubtedly be hitting the market in years to come. Energy Alternatives is constantly reviewing new technologies.

How to Choose
There are many different considerations when selecting a specific type of solar panel. Energy Alternatives only sells PV modules that have an extensive, proven track record and a solid company backing the product. Generally speaking, the larger the module, the better the cost per watt. Crystal type panels are most common for stationary applications. Amorphous cells are approximately twice the physical size as crystal type cells but are much more durable and shade tolerant. Their unique construction makes them virtually unbreakable.

Sunshine and Shading
PV modules produce electricity in proportion to the amount of sunlight falling on them. In full overhead or “peak” sun (1000 Watts/m2) they will produce their rated power. Reduced sunlight caused by clouds or location will diminish the amount of electricity generated. Modules will produce electricity even when there is no direct sunlight. A cloudy sky with an occasional blue patch will often be equivalent to approximately 50% peak sun. A cloudy day with rain in the forecast will produce approximately 10% to 20% peak sun. Reflected sunlight from snow or water can also increase the output of solar panels.

It is very important to note that shading even one cell of a module will reduce the output of the entire module. The only exception to this found in the Uni-Solar modules which have built-in diodes between the cells to reduce the effect. However, it is better to mount solar modules so shading is avoided.


It is a common misconception that heat is required for PV modules to produce electricity. High temperatures actually decrease the power output. Warmer climates require PV modules with a higher maximum voltage than those used in cold climates. Cold temperatures decrease resistance and increase voltage. Modules with a lower voltage rating are ideal in colder climates such as Canada.

Size and cost

There are two primary factors that determine the size of your solar array:

• The daily power consumed by your electrical loads.
• The sunlight levels (insolation) available at your particular location.

Insolation or sunlight intensity is measured in peak sun hours. A full sun hour is equal to the amount of sunlight striking the earth in one hour when the sun is directly overhead in a clear sky. Bright sunshine hours do not equal peak sun hours. Bright sunshine first thing in the morning or just before sunset is not the same as bright sunshine at noon from a PV module’s perspective.

The lower the sun is in the sky, the more atmosphere the light must pass through. Water molecules and other gases in the atmosphere reflect and absorb some of the light passing through it, reducing the insolation. Smog or other pollutants will also block or reflect sunlight. Most of the sun’s energy is delivered between 10 a.m. and 3 p.m. when the sun is highest in the sky.

Location - getting the best sun
Your PV array is a valuable investment. To achieve the best performance from your array it should be aimed in the direction of the most sunlight and angled correctly for the season. The array should be adjusted to the latitude plus or minus 15° from summer to winter for optimal output. If your mounting structure is not seasonally adjustable the modules should be mounted to achieve maximum output during the period of highest usage. For example, if you use your cottage during the summer months your array should be angled accordingly.

PV modules should always be aimed in the direction where they receive full exposure to sunlight. In areas with little or no shading, modules should face true south (not magnetic). True south is calculated by using the magnetic declination information for your site (available on most maps) and adjusting your compass accordingly.

New technology allows for PV arrays to be located much further away from the battery bank. If your site dictates a longer transmission distance, please contact your local dealer or Energy Alternatives for design details.




Purchase Products Online:

Solar Modules:

CMHC (Canadian Mortgage and Housing Corporation) guide to Photovoltaics. This excellent publication covers off-grid and on-grid PV systems and is essential reading for those who are new to PV.

An introduction to Photovoltaic Systems
Every day, the sun delivers energy to the earth free of charge. You can use this free energy thanks to a technology called photovoltaics, which converts the sun's energy into electricity.

Photovoltaic Systems : A Buyer's Guide

Solar-Electric Systems Simplified - HomePower Article. Whether you are the rookie who wants to understand how solar-electric systems work, or that better describes your spouse, friend, or prospective customer,
this article explains the guts and bolts of the three most common options in solarelectric systems: grid-intertied, grid-intertied with battery backup, and off-grid.


Solar Energy Society of Canada, Inc.

Canadian Solar Industries Association

US Department of Energy Photovoltaics Program

US National Renewable Energy Laboratory

Contact Energy Alternatives - (250) 846-9888 • Smithers, British Columbia Canada V0J 2X2
© Copyright 2013 EA Energy Alternatives Ltd.
Design & Resources - Articles, Troubleshooting, Education, FAQ's, System Design, Design Tools, Conservation, Catalogue Download.
Company - Installations, About EA, Testimonials, Privacy Statement, Homepage s
Catalogue - Systems, Photovoltaics, Wind, Microhydro, Inverters, Batteries, Battery Chargers, Balance of Systems, Pumps, Generators, Books & Education