You may have heard the term “efficiency” of the solar panel. If you have heard of it, but are unsure what it means, then this blog is for you. We are not only going to discuss what solar panel efficiency means, but also the ways of enhancing the overall efficiency of a solar photovoltaic (PV) system. Higher efficiency means more useful electrical energy from your solar power system.
WHAT IS SOLAR PV PANEL EFFICIENCY
Solar panel efficiency is a measurement of how much usable energy (electricity) the panel can produce out of the total amount of solar sun energy applied to the solar panel. More efficient solar panels will produce more electricity from the same size panel, as they convert a higher percentage of the total sun energy into electricity. On the other hand, a less efficient solar panel system will produce less electricity. A practical impact of solar panel efficiency is that the same physical size of solar panel array will produce more power with high-efficiency solar panels, than low-efficiency panels.
You must know that when we talk about the sunlight used by the panels to create electricity, we mean the sunlight that hits the solar panel. Currently, the cost-effective highest-efficiency solar panels available in the market can convert between 18 and 20 percent of the sunlight that hits them into electrical energy. This means they have 18 to 20 percent efficiency. The maximum efficiency of a solar cell can theoretically be up to 23 percent.
The efficiency of a solar panel is a rating, based on a standardized testing condition, so that different efficiency ratings can be compared across different solar panels regardless of the installation location, or physical size of the solar panel. Regardless of the efficiency rating of the solar panel, there are a number of ways in which the useful energy output of a solar power system can be increased, aside from installing more efficient solar panels. Let’s see how you can increase the useful energy output of your solar power system so that you get the highest benefit from the system for a longer period of time.
USING MORE SUNLIGHT
One of the ways to increase solar panel electricity production is to make sure that you’re using the maximum amount of sunlight available to the array. This can be achieved by removing nearby objects that might be shading the solar panels, or by using a solar tracking system to adjust the position of the solar panels to follow the position of the sun, or by periodically cleaning the solar panel array.
USING MORE OF THE SOLAR ELECTRICITY AT SUNNY TIMES OF DAY
For off-grid solar PV systems, there are situations when the solar PV system is able to generate electricity but there aren’t any electrical loads to use the energy so the available energy doesn’t get used. More of that energy can be used by running electrical loads during sunny periods, such as charging batteries for laptops and phones, laundry, baking, workshop saws or welding.
For grid-tied systems, if there aren’t enough loads connected to the PV system to use all the electricity while it is sunny, the excess electricity gets pushed into the grid and used by other nearby grid-connected customer loads. Since the electrical energy needs to travel a longer distance to reach other grid-connected customers, there are additional losses of energy as the energy travels through the wires. For that reason, running electrical loads at times when it is sunny, to minimize exported energy and maximize “self-consumed” solar power, can make use of more of the energy generated from the solar PV system.
A battery for energy storage can be added to a solar PV system to allow the battery to be charged while the sun shines. The battery energy can then be used at night and at times when the solar PV array is not producing enough power for the electrical loads.
Using battery storage can allow for more usage of the solar electric energy available during the day. However, battery storage systems require a considerable investment, which is often most economical or practical for off-grid systems, where the battery energy can be used at night instead of using a fossil-fuel generator, or for grid backup purposes, or for maximizing “self-consumption” in grid-tied systems in locations where the power price is much higher at night than during the day (not the case for most of Western Canada).
CHOOSE THE RIGHT SOLAR SYSTEM DESIGN FOR SYSTEM EFFICIENCY
You solar PV system consultant or professional can affect the efficiency of the overall solar PV system. The compatibility of solar panels, solar panel string design, solar inverters, and design of DC and AC circuits, can each have an effect on the overall efficiency of the system. For example, if a solar panel string configuration is partially incompatible with the connected PV inverters, the inverter may convert less of the solar panel electrical energy into AC electricity useful for common electrical loads, and power grids. It is important to involve people with solar expertise when planning and designing a solar PV system, to conduct a thorough needs assessment and a design that optimizes the overall efficiency of the PV system. If you make the right decision while buying, you will not need to make significant replacements, or purchases of additional components, before the end of the system design life.