Maya Mountain Research Farm was founded in 1988 in a remote area that had no electricity. In 1994 we built our first small stand alone 12 volt system which ran two 12volt lights and 12 volt fan. That was a huge quality of life enhancer. Since then we have built larger systems for home use, and dozens of small battery based photovoltaic lighting systems in rural households, battery based lighting systems in 15 schools, one clinic and 12 ranger stations in protected areas, and two village level photovoltaic water pumping systems.
In this article we will look at the anatomy of a battery based off grid photovoltaic system. In following articles we will examine the system we have at the Main Building at MMRF, and photovoltaic water pumping.
A battery based photovoltaic system is stand alone, and not tied to the grid. Generally it is comprised of solar panels, to make the energy, a charge controller, to manage the amount of energy coming into the batteries, batteries to store the power, an inverter to take the Direct Current (DC) power of the batteries and convert it to the Alternating Current (AC) of lights and fixtures that are commonly available. Some systems may have input from a generator, or from a wind turbine, or from a hydro plant.
Solar Panels
Photovoltaic panels convert DC electricity from sunlight. Solar panels are generally either monocrystalline silicon or polycrystalline silicon. Monocrystalline panels are more common, and are slightly more efficient than polycrystalline panels at up to 20% efficiency. Polycrystalline panels tend to be a little bit cheaper and are a little less efficient, at 12-15% efficiency…
More than 35,000 homes and 600 businesses in Scotland have installed solar PV panels, but only because of lavish government subsidies. Now that these subsidies are being discontinued the question becomes whether solar PV in Scotland can stand on its own two feet. The data from operating PV arrays presented in this post show that the answer is a resounding “no”. With capacity factors of only 8-9% and seasonal generation ranges exceeding a factor of twelve, Scotland is in fact one of the worst places in Europe for solar, despite what its supporters claim.
