Last edited: August 2018

Buying a Solar Power System in Tanzania

Step 1 – Selecting the solar company

As you can see on this page, there are many companies in Tanzania which are selling solar power systems. The first step is to ensure you are contacting a company which is providing the services you require. Check this page for the different types of systems.

In case you want SmartSolarTZ to bring you into contact with a suitable supplier, please use this contact form.

Step 2 – Stating your preferences

In order for the solar company to be able to ask you the right questions later, it is important for them to know about your expectations. It would be good to talk about:

• Performance of the system – When do you need power, maybe 24/7. How critical is it that you can always rely on the system, even in times of lots of cloud cover?
• Timeline – When do you expect the system to be installed? Especially larger systems often require to import components from outside the country.
• Budget – If you have a set budget, it could be good to share this in advance. This way you can ensure the company proposes a system which is aligned with what you can pay. In case you share your budget, do ensure that you ask for multiple quotes from different companies.
• Financing – Some companies provide options to finance your system. They pay for the system or for the electricity it produces over a set time period. If you are interested in a financed system it would be good to mention this.
• Time horizon – Do you want a system that lasts for the coming 2, 5 or 15 years?

Step 3 – Data collection

After stating your preferences to the solar company, they should ensure to gather sufficient data and information to start the design of a system that meets your requirements. Important data to provide the company with is:

• Energy usage – For a proper system design the energy usage is the most important figure. The best way to determine energy usage is always to measure it! In case of a grid connection, you can use your utility bills. If you are using a diesel generator you can use your diesel meter or base it on diesel consumption. If this is not possible, you can estimate the energy usage by performing a load analysis. In its simplest form, a load analysis multiplies the power rating of each appliance you use. This is then multiplied with the amount total amount of usage hours. The sum of all appliances provides you with your daily energy usage.
• Time of use – Aside from the length of using your appliances, it is usually also relevant to know when you are using the appliances most. If most of your energy consumption occurs during the day, you will require a different system compared to nighttime use. Also, the seasons matter. If you use more energy during the rainy season you will need a system suited for this.
• Future plans – Often it is much more expensive to upgrade a system in the future compared to building a slightly larger system from the get-go. Make sure that the solar company knows about any expansion plans you might have.
• Location of components – Especially for larger systems the solar company should plan a site visit. During the site visit the technician can determine which location/roof is best suitable for the solar modules. This is along with their pitch & orientation. Also it should be determined where the batteries and other equipment will be located. This way there is assurance of proper estimations of cable length and diameter.
• Communication – In order to include remote monitoring, you will either need to provide an internet connection (wifi/LAN) or have a GPRS signal from a telecom operator.
• Existing infrastructure – What is the quality of the existing infrastructure? Is there already a backup generator present? Can the current wiring be used for a future new system?
• Maintenance – Are there normally technicians or people around already performing maintenance on other equipment?
• Location – The solar company will need the exact location of the project in order to match it with local/regional weather and <irradiation data>.

Step 4 – System design

Based on all the gathered input it is now up to the solar company to recommend a solid system design. The system design also provides the input for the quotation.

A (slightly outdated) overview of the steps taken in designing an off-grid system can be found in this guide from African Energy here.

Step 5 – Comparing quotations

Comparing different quotations can be tricky. Depending on your own level of expertise and the total order value you could consider getting assistance in reviewing the quotations. SmartSolarTZ has been reviewing quotations for years and can provide you with the necessary insights to make an informed decision.

Step 6 – Installation

Normally the solar company will start preparations for the installation after receiving a down payment. Please note that not for all materials the stocks are from solar companies in Tanzania. Especially for a larger battery bank it possibly takes a long time to arrive. This is due to the start of the production, which is normally after the order has been received.
After installation, ensure a proper explanation of the whole system. Make sure that the relevant people are trained in the daily operation and maintenance of the system.

Step 6 – Remote monitoring

For larger systems and for critical function systems there is a strong recommendation to ensure that there is at least a connection to the internet with the inverter. This ensures that both you and the solar installment company can regularly check whether the system behaves according to expectation. If there is no internet, you can often still monitor the system locally by using a monitoring device. With monitoring it is possible to:

• Remotely identify (and sometimes fix) current or potential issues with the system
• Plan the use of appliances with the remaining battery capacity
• Get automatic messages in case your batteries are running low
• A history of high-quality data to see whether it is necessary to expand the system

Step 7 – Service and maintenance

Lifetime of a solar power system

The solar system lifetime depends on the use of the system, the brands used and the settings of different components. Generally speaking, you can expect the following lifetime if you are using high-quality brands and are performing occasional maintenance:
Solar Panels: 25 years, all Tier-1 solar panels are made to last a long time
Batteries: 3-8 years for Lead-Acid and 8-15 years for Li-Ion
Inverter/charger: 5-10 years
Charge Controller: 5-10 years

Service and maintenance of off-grid solar power systems

With Gel batteries or Li-Ion batteries a solar power system would not require much maintenance. It is good to clean the solar modules once in a while (with a soft cloth and ideally demineralized water). Aside from that, it is advisable to have a solar company check the connections and the voltages of the batteries. Flooded lead-acid batteries require the performing of equalisation charges at regular intervals and topping up the battery water. In case you do not do this yourself it is good to have the solar company come by at more regular intervals.

With an integrated generator into the solar power system, this part of the system requires more maintenance. Aside from the daily checks, changing the oil and filters at regular intervals (generally every 250-500 running hours) is important.

Service and maintenance of a grid-connected solar power systems

Aside from cleaning the solar modules (in case this is necessary), a grid-connected solar power system without batteries does not require any regular service or maintenance.