You would be wrong in assuming that a Solar Panel is just a Solar Panel. Here we break down what you need to know about Solar panels as part of your Grid-Tie, Hybrid or Off-Grid solar installation.
The simplest of your three options is Grid-Tie as opposed to Hybrid and Off-Grid which both bring many other factors into the equation when it comes to energy storage and efficiencies.
In my talks to clients of Straton Solar, I refer to Grid-Tie Solar Systems as the ‘hippy option’ for one reason only: If we all had to install Grid-Tie Solar (this is the option that feeds back into the grid when you are not self consuming power produced on your roof) then the need for load-shedding in South Africa would eventually disappear as millions of small power generating plants on roofs all over the country ‘donate’ electricity to the national grid.
At the end of the day we are paying for load shedding with increased electricity prices and continued shoring up of Eskom through our taxes – at least through Grid Tie we actually get to benefit with lower on site electricity prices.
The following number will differ largely based on a myriad of factors but (today) one can expect to pay around R0.70 per unit of grid-tie electricity produced over 20 years – imagine in 20 years time telling your neighbour that you pay R0.70 per kWh for electricity when he/she, at a nominal 8% increase per year, will be paying around R10.00 per kWh!
A Grid-Tie system consists of two main components:
- Solar Panels
- Inverter
The Solar Panels harvest the sun’s energy and send that energy to the inverter which converts the DC Power into AC Power and controls the distribution of that power to the home or the grid along with the ‘nice to haves’ such as reporting and historical data.
Let’s look at Solar Panels in this first article:
The prices of Solar Panels have dropped radically over the last number of years. Solar panel pricing and efficiency have not quite followed Moore’s Law and, in fact, follow “Swanson’s Law” which suggests that the cost of photovoltaic cells needed to generate solar power drops by 20% with each doubling of global manufacturing capacity. The Swanson Effect or Swanson’s Law is named after Richard Swanson who founded the American solar-cell manufacturer SunPower.
What we all need in a Solar Panel is a component that will be hyper-efficient, produce higher than average power than other Solar Panels (even 0.5% higher efficiency will produce massive savings over a 25 year period), robust and with a solid long term warranty.
Questions to ask your Solar Panel Installer:
- What is the highest Wattage Panel currently available?
- Are my panels from a Tier 1 Manufacturer?
- Are the panels you supply Monocrystalline, Polycrystalline or Thin Film?
- Are they sourced from the same batch?
- Are they connected in a string or optimiser based?
- Do you envisage any shadow falling on any part of a Solar Panel?
- What is the optimum angle for my Solar Panels and does my roof comply?
Those Questions are more fully explained below:
1. What is the highest Wattage Panel currently available? Solar panels have remained more or less the same size over the years but efficiencies in manufacturing have increased the output from 185 watts per panel to over 300 watts per panel. Straton Solar’s approach is to install the most widely available high wattage panels (BUT, not necessarily the latest high wattage panels available).
2. Are my panels from a Tier 1 Manufacturer? As the name implies Tier 1 Solar Panels are the better option. Tier 1 solar panel manufacturers are defined as those that: Have been producing solar panels for 5 years or more; Are either publicly listed on a stock exchange or have a strong and stable balance sheet; Have fully automated production and a high degree of vertical integration; Invest significantly in marketing their brand. Tier 2 and Tier 3 manufacturers are all those that don’t meet one or more of these criteria.
Typically tier 1 solar panels are 10-30% more expensive than tier 2 and tier 3 solar panels. One can reasonable expect a 25 to 30 year life from a Tier 1 Solar Panel. (1)
3. Are the panels you supply Monocrystalline, Polycrystalline or Thin Film? Monocrystalline solar panels contain cells that are cut from a single crystalline silicon ingot. The composition of these cells is purer because each cell is made from a single piece of silicon. As a result, mono panels are slightly more efficient than poly panels. They also perform better in high heat and lower light environments, which means they will produce closer to their rated output in less than ideal conditions.
Mono panels have a uniform black look because the cells are made from a single piece of silicon.
Polycrystalline solar cells are blended together from multiple pieces of silicon. Smaller bits of silicon are molded and treated to create the solar cell. This process is less wasteful because hardly any raw material is thrown out during manufacturing.
The blended makeup of the cells gives poly panels their iconic blue color. If you look at them up close, you’ll see the texture and color is uneven due to the way the cells are made.
Poly solar panels are slightly less efficient than mono panels due to imperfections in the surface of the solar cells. Of course, they’re cheaper to manufacture which means they cost the end-user less.
Thin film panels are usually deployed for large-scale utility projects and some specialty applications. Thin film panels are created by depositing a thin layer of conductive material onto a backing plate made of glass or plastic.
Thin film panels typically don’t see use in residential installs because they’re much less efficient than mono or poly panels. With roof space at a premium, residential customers go with more traditional crystalline silicon panels to maximize production from the space available to them.
However, thin film technology is less expensive to manufacture, and it becomes a more cost-effective option at a larger scale.
4. Are they sourced from the same batch? Solar Panels degrade over time – the norm is around 1% per year per panel. For this reason it is important to get Solar Panels from the same batch for each installation. Why? We are all familiar with the saying that a chain is only as strong as it’s weaker link and the same holds true for Solar Panels in a chain – solar installers call that chain a string. Strings of panels are connected together before feeding into the inverter (for most inverters) and these strings are subject to the ‘weakest link law’ wherein the lowest power producing panel dominates the power produced. Put it another way – if you string a 180W and a 300W panel together the output will match the lowest common demoninator (180W) solar panel. If Solar Panels manufactured this year are mixed with Solar Panels manufactured last year then all th epanels in that string will operate at 1% less efficiency from the onset.
5. Are they connected in a string or optimiser based? Solar Panels connected in a string are all subject to the “weakest link” theory and need optimum conditions for maximum efficiency. Some of those conditions include optimum installation aspect and angle. These depend on just where in the world you find yourself – more on this later.
Optimiser based Solar Panel Inverters can operate on a SINGLE Solar Panel level. This negates the “weakest link” theory and produces maximum efficiency over decades (remember that even 0.5% higher efficiency over 20 years is like compound interest on your bank account!). Optimiser based systems are more expensive to install and also offer greater flexibility and efficiencies from the ability to take advantage of East West orientations and over panelling to maximumk efficiency in a shady environment. What happens is that the inverter recognises an inefficient panel and can cut that out of the system until efficiency returns. Also, optimiser based systems keep a record of efficiency PER Solar Panel making troubleshooting quisker, easier and cheaper.
6. Do you envisage any shadow falling on any part of a Solar Panel? Shadow is the enemy. Do not decide to cut down a tree or cut away branches or shrubbery to install a system – vegetation grows back quickly and you will enter into a constant battle. As explained above shadow drops the efficiency of your entire system so if you do have shadow problems then rather over panel and install an optimiser based system.
7. What is the optimum angle for my Solar Panels and does my roof comply? The rule of thumb is to install Solar Panels at an angle equal to your Latitude. Strictly speaking your panels should be at Latitude – 15 degrees during summer and Latiude + 15 degrees during winter to take advantage of the lower and higher sun striking the panels at right angles.
The easier roofs (cheaper) to install on are NOT Slate, NOT Asbestos and have trusses connected with Nail Plates NOT Nails. Straton Solar has found that homes with nails connecting the trusses are mostly found in the older areas of Port Elizabeth like Central, Mill Park and Walmer.
(1) At the time of writing these were some of the Tier 1 Solar Panel manufacturers (listed in order of capacity): LONGi, Jinko, JA Solar (releasing some large wattage panels soon), Canadian Solar (Straton Solar recommended), Risen, QCells, Trina, First Solar, Talesun, Eging, Seraphim, Suntech, Astronergy, ZNShine, Jolywood, SunPower/ Maxeon, Jinergy, Jetion, LG, BYD, Waaree, Phono, Neo Solar, HT-SAAE, Adani, Vietnam Sunergy, Hengdian, Boviet, Hendigan, Ulica, Recom, Hyundai, Leapton, S-Energy, Goldi Solar, Heliene, Sharp and Swelect.
PLEASE NOTE: The Tier 1 Solar Panel Manufacturer list will change from time to time as more manufacturers enter the market, merge or close.
Video: Insider Solar Panel Secrets Revealed
More Info on Insider Solar Panel Secrets Revealed here: https://straton.co.za/solar/
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