SOLAR OR GENERATOR: WHICH SHOULD YOU BUY?

If you haven't read my previous article, “How My Friend Wasted ₦12 Million by Buying the Wrong Generator,” you may want to read it first.

⚠️ How to avoid spending either ₦21.5 million or ₦7.7 million for similar purpose

My 4 KVA Hybrid system with tabular batteries

What do you want to use that electricity generator you intend to buy for? What's the total cost of ownership (TCO) of your choice? If you answer these questions correctly, you are good to go. Let’s look at the factors together !!

Several times, people ask me the same question: "Should I continue using my generator or should I install a solar power system instead?" Some people argue that solar is the best option, while others vote for generator. This reminds me of the story of six blind men who touched different parts of an elephant and gave a verdict based on the parts that they touched. Initial cost of the purchase shouldn't be the sole criterion; to get it right, total cost of ownership (TCO) and the aim for the purchase must be considered.

TOTAL COST OF OWNERSHIP
This is a major factor; it's the comprehensive financial estimate of the direct and indirect costs associated with an asset over its entire lifecycle. It goes beyond the initial purchase price to reveal the true, long-term profitability of a purchase. To choose wisely, let's compare both systems (solar and generator), using practical Nigerian conditions over a period of ten years. This will guide anyone to choose wisely. We will consider an average home or an MSME (Micro, Small and Medium Enterprise), where about 5 KVA generator or solar is commonly used to complement the grid supply.

GENERATOR
Total cost of ownership of a generator
includes:-

• Purchase price
• Transportation and installation
• Fuel (petrol or gas)
• Engine oil
• Routine servicing and repairs
• Replacement parts
• Insurance (if applicable)
• Grid (public electricity) supply.
  To get the total cost of ownership, you add all the listed items; the sum is your TCO.

My 4 KVA Hybrid Inverter (picture taken before installation)

SOLAR SYSTEM
Total cost of ownership of a solar system includes:-

• Purchase price of solar panels, inverter, batteries, mounting structure, cables, circuit breakers and miscellaneous materials.
• Transportation of the purchased materials.
• Installation
• Battery replacement
• Inverter repairs or replacement (if needed)
• Panel cleaning and routine maintenance
• Grid (public electricity) supply.
  Just like the generator example, you add all the listed items to determine the TCO.

10-YEAR CASE STUDY
Suppose a family needs electricity for 10 years:-

Generator

• Purchase and installation: ₦2,000,000
• Fuel: ₦3,000 per day (₦3,000×365×10)= ₦10,950,000 (10 year average)
• Grid supply: ₦50,000 per month (₦50,000×12×10)=
  ₦6,000,000 (10 year average)
• Servicing/repairs: ₦250,000 per year (₦250,000×10)=₦2,500,000
  (over 10 years, the engine should be overhauled about five times, depending on usage and the alternator repaired due to wears and tears, caused by rotating parts)
  Total: ₦21,450,000

Solar System

• Purchase and installation: ₦5,500,000. A hybrid inverter with lithium batteries is highly recommended because it uses minimal public electricity when there's sunshine. The hybrid inverter is the best option because it's designed to charge the battery and also maximise the use of sun energy. This leads to minimal usage of grid supply.
• Grid supply: A hybrid inverter can drastically reduce average monthly consumption to about ₦10,000 average (₦10,000×12×10)= ₦1,200,000 (10 year average)
• Maintenance: ₦100,000 per year (₦100,000×10)= ₦1,000,000 (maintenance cost is low because the lifespan of a quality solar panel is 25-35 years; while a good quality inverter lasts 10-15 years. Cleaning of solar panels is the most required task, especially in dusty environment)
  Battery replacement: (nil: lithium batteries, which is highly recommended, last 10 to 15 years)
  Total: ₦7,700,000

Above tabulations show that solar is cheaper than generators, based on the respective total cost of ownership. Although the solar system costs more initially, its total cost of ownership over 10 years is much lower than the generator. This concept is especially useful when comparing generators with solar systems; but looking only at the purchase price can be misleading. Other factors should be considered before a purchase decision is made.

THE IDEAL SITUATION
An ideal situation is a hybrid system consisting of a grid, a generator and solar; this is what many engineers recommend. In this setup, solar handles daytime loads, while the generator is reserved for extended cloudy periods or night, when the energy stored in the batteries is exhausted.

The choice of solar panels is also important; in cloudy and rainy weather, monocrystalline TOPCon (Tunnel Oxide Passivated Contact) or monocrystalline PERC solar panels are used. TOPCon cells feature an ultra-thin oxide layer that minimizes electrical losses, allowing them to capture diffuse or scattered light under heavy clouds much better than older panel types. Another type of high-efficiency solar panel is the bifacial; many modern monocrystalline panels are "bifacial", meaning they can absorb ambient light from both the top and the bottom of the panel, maximizing energy capture during cloudy days.

ADVANTAGES AND DISADVANTAGES
Below is a breakdown of the advantages and disadvantages of both:-

GENERATOR
Advantages:-

• It's reliable day or night, as long as fuel is available.
• It has power output for heavy appliances such as freezers, pumps, AC units, welding machines, power tools, cookers, etcetera.
• Its operation is easy to understand.
• It works effectively and efficiently during long cloudy periods or rainy seasons.
• It runs for many hours or continuously if you keep refueling.
• It's suitable for emergency backup, construction sites, events, shops, etcetera.
• It can be bought in many sizes and fuel types, giving flexibility.
• Servicing and replacement parts are widely available.

Disadvantages:-

• Recurring fuel purchases, which can become expensive over time.
• Exhaust fumes causing air pollution and greenhouse-gas emissions.
• Noise pollution, often enough to disturb the neighborhood, or business environments.
• Requires regular maintenance such as oil changes, spark plug / injectors replacement, engine checks, etcetera.
• Availability of fuel can be uncertain during shortages or price spikes.
• Difficult to use safely indoors or in poorly ventilated spaces because of carbon monoxide risk.
• The total cost of ownership is high

SOLAR
Advantages:-

• Uses sunlight; no fuel costs.
• No smoke, exhaust, or noise
• Cuts or eliminates electricity bills depending on system size and usage.
• Very low operating cost; no fuel purchases and elaborate maintenance.
• Works well for homes, offices, internet equipment, lights, fans, and moderate loads.
• Has strong long-term value because panels typically last many years with relatively little maintenance.
• You can start small and expand if the design allows it.
• Ideal in areas with good sunshine, which makes it especially attractive in many tropical areas.

Disadvantages:-

• High upfront cost
• Sunlight determines the output; no generation at night and output falls in cloudy or rainy weather.
• Requires large roof or ground space for panels.
• Not ideal for very heavy loads unless the system is carefully sized.
• Performance can be reduced by dust, shade, or poor maintenance.
• In some cases, building rules or mounting limitations can restrict installation.

SO, WHICH SHOULD YOU BUY ⁉️
There is no single power solution that fits every Nigerian household or business. The best choice depends on your energy needs, budget, and long-term plans. A generator may cost less to buy, but years of fuel and maintenance can make it much more expensive to own. A properly designed solar system requires a larger initial investment, yet its lower operating costs can make it the more economical option over time. Before spending your money, determine why you need it, calculate the cost of ownership; not just the purchase price.

If you had a budget of $1,000, would you choose a generator or a solar system? What are the reasons for your choice?

📣 The costs used in this article are estimates based on prevailing Nigerian market conditions and are intended for educational comparison. Actual costs vary with location, fuel prices, equipment quality and usage.

Coming Next
“Why many solar installations fail after one year”. I'm releasing this vital information based on hands-on experience ….
Stay tuned.

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