Want to go solar? Here’s what you should no

By Asad Ullah Kamran

Eventually, we’re all going to have to rely on the sun. That much is an unfortunate (or fortunate depending on how you look at it) fact. Pakistan has continued to lag behind in electricity production over the decades with coal, oil, and hydel production all failing to effectively meet demand. And if the infrastructural problems were not enough - there are the environmental realities that make our reliance on the sun inevitable. In such a situation, while commercial use might be a little far, a lot of domestic users in the country have already become early adopters of solar technology. Seeing homes, mosques, small businesses, parks, and street lights powered by solar panels is a common enough sight all over the country. Surprisingly the technology has even permeated in lower-income neighbourhoods as well as smaller cities. And why would it not? With electricity a growing cost, the unit economics of going solar more than make sense. There is very much a future, in fact, where middle and upper-middle class households should be powered by solar energy to the extent that they also have cheaply available electric cars that they can fuel through the sun and run completely off the grid. Energy from the sun is being wasted until we use it. But what does a person need to understand before they make the decision to go solar? What are the different kinds of options available? If you’ve been considering getting a solar energy solution for your home, there are some things that you should know before making your decision. Pakistan has been experiencing load shedding for over a decade now, this makes it an ideal market for residential solar solution providers. Solar technology has a high initial investment cost, but it has a cheap running cost and a long service life. The ability to finance a PV system reduces the initial cost of purchasing the system and distributes the cost over time while the system is already saving money on power bills. This makes solar more accessible to people who can’t afford to pay for the system all at once. Although essentially when looking at the solar energy solution the ideal goal is maximising the efficiency in terms of cost and benefit. Whether or not the investment is worth it or not, to do this start with the data around as in your utility bills.

For going solar it is important to understand your own requirements in terms of units consumed and having an estimate range you’re willing to spend. Now to get an idea of what you’re consuming is to look at your utility bill, use the data for the entire previous year to get a more accurate assessment.

The economics of going solar

If, for instance, you’re looking for a 5kW system for your home it is important to ask the right questions before making the purchase. After taking into consideration multiple sources, a 5kW system costs around Rs700,000 to 1,000,000 and is expected to produce anywhere from 6,000-7,000 units in the year. To calculate the per unit cost of electricity you’re getting from the system, multiply the annual units produced by the system over the span of it’s warranted life span, usually solar panels last over 25 years. Using 6,500 units as a benchmark annually for a system and costing Rs850,000 for this calculation, we get an approximate 162,500 units over the course of systems life, dividing the total cost of the system by this number would give the per unit cost of Rs5.23 per unit.

The benefit from going solar is very evident, if you just take a look at the utility bill. For the period of 12 months stretching from March last year the total electricity I consumed was 6,261 units at an average cost of Rs 24.87. The benefit is quite obvious from here on out as the difference between the cost per unit is Rs 19.64.

Furthermore, any further increase in the energy prices in the future would only help you save more costs. Now if the system in an annual year produces 6,500 units whilst considering the annual consumption remains constant, the system would yield an annual benefit of Rs127,663. Using this calculation you can figure out the time it would take for the system to pay for itself, by dividing the total cost of the system by the annual benefit. The payback period for the system would take six to seven years based on the numbers from the example above.

Using the numbers from the example above you can safely conclude that going solar is

not a bad investment however the upfront cost you have to bear for the system is substantial. It should be considered as a long term investment and the eventual return on investment will pay for itself and help you cut costs over the system’s life. Using the figures from the example above you can save approximately Rs 2.3 million over the life of the system and if energy prices increase which is likely the monetary saving will increase and the payback period would also reduce significantly.

This disclaimer should be noted before making any decision, these numbers are rough estimates for simplicity, the costs as well as yearly output of the system is dependent upon a multitude of factors. However, that does not make these calculations invalid the arithmetic of getting these numbers would remain the same.

Where to start?

This is simple. Who do you go to for solar panels? Advertisements in print media, online searches, and chatting to people who have previously installed PV systems are all good ways to find PV system providers in your area. Another option is to contact solar organisations and obtain quotes from various providers through their members. Companies that provide solar installation services have websites that may be easily found, and there are several solar associations in Pakistan.

Component manufacturers and local distributors usually publish lists of approved installers of their products. When picking a vendor/supplier, go for the one that offers the best quality at the best price. Providing the ability to register for net metering is a nice bonus, but it shouldn’t be the only factor to consider when choosing a provider.

It is vital to mention all basic things in choosing the most effective offer. Some components, such as a data logger, are useful add-ons but not critical to the PV system’s operation; however, an offer containing options such as an operation and maintenance contract, warranty extensions, and insurance policy for the PV system can be added benefits, and such offers can be given preference if the system’s quality is comparable.When comparing similar deals, go with the firm that has local representation and/ or is willing to give after-sales services. Furthermore, emphasis should be given to a firm that provides a realistic time period for installing the solar PV system, as well as enough technical capability and qualified and skilled people.

Getting familiar with basic technicalities

Although the engineering side of it can seem daunting, it is relatively simple if you break it down to the most fundamental parts that go into installing a solar system. When installing a solar energy system, the most crucial decision to make is which materials to utilise or which business to entrust with the project. Cost is important, but it’s also important to be sure that the system being built can satisfy load requirements, that its long-term endurance is assured, and that the roof has adequate room for solar panels to be put.

The most fundamental or core aspect of any solar system are the solar panels (also known as photovoltaic or PV modules) , the actual devices that convert sunlight into electricity. To maximise the amount of electrical power that may be generated, a number of modules are joined together. The array refers to the full collection of modules. On the market, there are two primary types of modules.

Crystalline silicon (c-Si) cells have a high efficiency rate, as well as a high level of stability, manufacturing simplicity, and dependability. Other advantages include great heat resistance and minimal installation costs.

They’re further split into mono-crystalline and poly-crystalline varieties. Poly-crystalline modules are utilised more commonly than mono-crystalline modules, despite the fact that they are slightly less efficient.

The pricing contrast between these two kinds, on the other hand, compensates for the modules’ inefficiency. Compared to c-Si wafer cells, thin-film solar panels are less costly. They are more flexible and easier to handle since they are available in thin wafer sheets. They’re also less prone to breakage than crystalline silicon (c-Si) modules, although they’re less efficient.

The next critical component would be the inverter. The link between the solar system and the public distribution grid is represented by the inverter. It transforms the PV system’s direct current (DC) into alternative current (AC) (AC).

Grid-connected, stand-alone (off-grid), and hybrid inverters are available. Grid-connected inverters, as the name implies, are directly connected to the public energy grid via the in-house electrical network.

Now, the key plus point of a grid connected inverter is the fact that for instance if you’re not in your home and not utilising any energy, the excess electricity produced by the solar system would be sold to the local DISCO. This would directly have a positive impact on the energy bills as all the units sold to the grid would be netted against the units consumed during the period the solar panels aren’t working.

Off-grid solar inverters with utility backup or grid-tied solar inverters with additional battery storage is another approach depending upon personal requirements. In the scenario that you don’t want to be connected to the grid for any reason you can also utilise batteries that can support the load during non production hours of the system. However batteries entail additional costs and maintenance consequently affecting the overall cost of the system.

A hybrid solar inverter combines the benefits of both grid-connected and off-grid inverters. In basic terms, a system with a hybrid solar inverter prefers solar input and can both export to the grid and power in-house loads. These inverters function in off-grid mode when the grid is unavailable, providing battery-stored power to address the load of the house.

There are several crucial criteria to consider during the installation process of the inverter. The inverter should be installed closest to the solar panels, this reduces the

The amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year. Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation. This energy can be used to generate electricity or be stored in batteries or thermal storage. The most common kind is PV, which is utilized in solar panels. When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow.

Figure 1. Grid connected inverter

loss of the solar PV system by using shorter DC cabling. Inverters are large, expensive pieces of equipment that get somewhat hot during operation. Appropriate ventilation is required to attain improved performance. Always adhere to the manufacturer’s external requirements, notably the maximum humidity and ambient temperature.

Now in case you opt for a battery storage facility along with your system it is important to understand how to go about it. The following is a quick summary of the many types of batteries that may be used to store electricity generated by solar power systems. For backup purposes, traditional lead acid batteries are utilised in the majority of solar household systems. New deep-cycle/OpzS and OpzV lead batteries, on the other hand, should be favoured.

Deep-cycle batteries are built to do deep discharges on a regular basis, utilising the majority of their capacity. The OpzS and OpzV batteries include tabular plates that are specifically intended for all industrial applications that need minimum maintenance and average and extended discharges. The lead selenium alloy tabular design ensures long working life, little maintenance, and maximum performance in cycle and standby applications.

With proper care, deep-cycle batteries can last 4-5 years; however, lead acid batteries typically last one to two years, and battery life varies depending on the frequency and pattern of usage as well as maintenance.

The considerations into the mounting structure should be made carefully, PV modules deployed to produce power from sunlight are supported by solar mounting frames. These structures position the solar panels at an angle that allows them to catch the most sunlight. A rule of thumb to remember when looking at structures is the size you’ll need to accommodate the PV modules required by the system, you’ll need approximately 8-12 square feet per kW.

Other tips that you should keep in mind are when choosing a mounting option it should be corrosion-resistant and statically tested. Verify that the chosen mounting system meets the module manufacturer’s criteria. Consider the maximum wind loads in your area. Throughout the life of the solar panels, the structure should be protected against corrosion by two coats of paint: red oxide and galvanised paint.

Unlike in the past, manufacturers now provide flat roof mounting options that are simple to install. Frames are now typically lightweight, aerodynamic, self-supporting, and free of roof penetration issues. Drilling holes into the module frame should be avoided while installing the modules. Before drilling any holes, check with your module’s manufacturer for warranty information.

Wiring is perhaps one of the most critical aspects of ensuring the safety and reliability of the system, and to avoid any unnecessary electrical short circuits. DC wires should be selected carefully for connecting panels to the inverters. Wires are rated according to the current rating (Amps) that can safely pass along it, higher the current, thicker will be the wire. Allow at least 35% margin in the rating of wire and the load. Consult a qualified electrician, having knowledge of DC wiring and solar system to decide the best wires for the system The distance between the inverter and the panel should also be minimum to minimise losses

The current state of affairs in both the economic and political domains has been dismal and disappointing on all fronts and has contributed to worsening the already trembling economy. Long power outages throughout Pakistan have become somewhat of a new norm going back to before the vote of no confidence. Although as per NEPRA the energy supply is adequate enough to deal with the demand, and in some scenarios more than the demand. However despite this stance power outages have not subsided. The energy sector of Pakistan is an extremely fragile and volatile environment that’s further exploited for political gains at the cost to private and state owned enterprises. Given the dismal situation in terms of availability of energy, private consumers have started leaning more towards renewables, particularly solar energy to meet their domestic needs. Furthermore by installing net metering and selling the excess units to the local DISCO citizens are able to cut down on their electricity bills and at the same time add to the somewhat constrained supply. At the recent Pakistan Energy Reform Summit 2022 issues in the energy sector that directly affect the overall economic health of the country was a key topic. And as per the government officials that addressed the private sector entities the importance of and increased reliance on renewables was pointed out. In order to stimulate the use of alternative energy, Prime Minister Shehbaz Sharif has ordered the repeal of the previous PTI government’s 17 percent general sales tax on solar panels. It’s a positive step in the right direction toward lessening the country’s dependency on fossil fuel resources.

Conclusion

To summarise the points and information given above, keep in mind that the PV system will only cover a percentage of your household’s power usage. As a result, it’s critical to establish an approximate estimate of the entire capacity of the PV system you’ve installed – based on the available roof space – and match the PV energy production to your usage.

To size the system, determine the load you want to run on the PV system, the number of hours you want to run it for, and the maximum load that can be operated on the system at any given moment.On the basis of this information, the vendor will be able to size a system for you. You can obtain numerous bids for your system from various vendors to determine which system best matches your needs.

Furthermore, whenever the PV system generates maximum power and achieves peak capacity, you may enhance your home’s demand pattern to maximise the benefit of the system. Managing your load in this manner will allow you to get the most out of your solar system. n

Figure 2. Stand alone inverter Figure 3. Hybrid inverter.