Here’s Why Solar Systems Don’t Work

We have seen hundreds of companies pop up over the past few years aggressively selling solar systems in an effort to switch the population from carbon based fuels to renewal energy. As a seasoned solar engineer and current COO of The Solar Haven Nigeria, I have spent the last 6 years introducing Solar as a viable power alternative to Nigerian citizens.
Due to inconsistent electricity, many Nigerian families and businesses have upgraded their systems to solar. Some, however, are not happy with their purchase. Often my team meets people who have a poor impression of solar energy. Many of whom used low-priced solar installers. The typical complaint is simply “My solar doesn’t work”.
One thing I can say with confidence is that solar does indeed work. At The Solar Haven, we’ve installed systems in homes, schools, hotels, office buildings, and factories. All are operating with no issue. However, solar only works if it’s installed correctly.
The most common reason for a faulty system is “wrong system sizing.” This error happens at the first step of the relationship between the solar company and client. The first step to be completed by a solar professional before recommending a solar system is a “Site Energy Audit.”

A Simple Energy /Watt Meter
A Site Energy Audit is exactly what the name denotes. During a Site Energy Audit a solar professional visit the location to analyze and calculate the energy consumption of the proposed site. At The Solar Haven we use an “Energy Meter,” but energy consumption can also be calculated by manually adding up the power rating of each appliance and determining how many hours a day they are used.
Energy consumption is measured in Kilowatt-hour(kWh). For example, a 3-bedroom home with basic loads, excluding a heating and cooling system, water pump, etc. may demand at peak, 3–5kWh of Energy. Without this calculation many solar installers make the major error of installing the wrong system.
Wrong System Sizing occurs when the energy supply of a solar system is lower than the energy demand of the site. A solar system is a called a system because it consists of a Generation Unit (Solar Panels, Generators, Charge Controllers), the Transmission Unit (AC/DC Cables, Inverters) and the Storage Units (Batteries). Any imbalance in the 3 parts of the system will cause a partial system collapse. This means the end user will experience frequent system shut downs even when the equipment is new and the sun is shining brightly.
As an example, to properly equip the 3-bedroom home audited above, we have to first determine how much storage (batteries) is required for back-up purposes. For a demand of 5kWh the home will need at “least” 4 pcs of 12v 230AH Batteries (11.1kWh) at 50% Depth of Discharge. After determining the Storage capacity, then the installer uses that value to determine capacity of Solar Power needed. The home would have been analyzed for the average hours of full-sun equivalent that it receives over the course of a day for a year, e.g 5hrs.
So, for the Battery to be full by the end of the day we divide the Storage Energy demand by 5hrs. (5 kWh /5hrs). This gives 1kW of Solar Power needed daily to charge the panel. So, the installer must get at least 1KW Solar Arrays in the correct voltage to match the battery voltage.
Many installers and solar engineers make this mistake of incorrectly sizing the solar panels first. They match the energy demand to solar panels, which is backwards. The correct sequence is to first determine the energy demand to the batteries, and then the batteries to solar panels. And lastly the correct voltage must be selected. It should be the same across the solar system.

To be continued

Author
Suberu Habeeb Ayoade
COO
Solar Haven