ASKING THE RIGHT QUESTIONS: SOLAR STREET LIGHTS PROS & CONS

In this blog we give you our tips on some useful pros & cons questions you should ask your solar street light provider. Apart from the fact that many solar street light companies always emphasize the wide applicability of their products, when thinking about the actual needs and problems solar powered street lights should resolve for you, the key is in understanding your individual situation and unique project circumstances.

Simply stating the benefits of solar street lights to a diverse pool of potential users is not enough. In a reverse logic, it is much more appropriate for solar lighting companies to take the user perspective by conducting a deeper analysis of each individual problem and the context in which it takes place: “Who needs solar street lights and why?”

Why don’t we start by looking at how the problem will be solved for you in the first place: “Do you want to improve energy efficiency and reduce your electricity bills to zero? Do you prefer to see long-term ROI by using clean energy for LED light? Do you aim to reduce your carbon footprint and benefit from renewable energy subsidies? Do you perceive solar energy lights as a reliable standard in the street lighting industry?”

Simply put, you need to know all the positive and negative aspects of the solar LED lighting system, how it functions and how smart technology can ensure performance reliability and cost efficiency over the product lifetime. Asking the right questions is crucial!

Let’s get into the pros & cons of solar street lights and some questions that may help you save money and improve your decision making process.

Solar Street Lights: Most Important Questions for Customers

Each street light model you choose to implement must undergo thorough analytic approach in determining the most feasible solar system components (LED light, solar panel and battery capacity), technical product specifications, solar controller and communication network, system design and overall energy outputs for your preferred type of solar energy light.

  • What is the application of your solar energy light? Is it going to be installed on a sidewalk, in a park, on an airport, at University campus, at a parking lot, on a roadway, on a bridge, in a residence, at industrial facility or another place? All of these locations may require unique considerations when developing your solar street light project.
  • Is it going to be a retrofit solution (if yes, will it be off-the-grid or on-the-grid solar retrofit solution) or completely new pole installation? These questions need to be closely discussed with the solar provider so that you are aware of all the peculiarities of the solar lighting project you are trying to implement.
  • Communicate your energy needs to the solar light provider in terms of expected hours of light per day, energy conservation objectives per year, movement and frequency in the desired location. If the solar provider optimizes the solar system components properly (solar panel wattage and optimal angle, LED light wattage and battery amperage) in relation to your energy needs and the pole height, you should not overpay the battery and solar panel capacities, because system optimization means doing more with less.
  • Ask for calculations on solar irradiance and insolation for your specific location based on the selected solar system specifications and configurations. These calculations will clarify the solar energy potential of your location. Check this Q&A on solar irradiance for more info on the topic.
  • Ask for full on-site and off-site support by the solar provider, solar installers and/or other involved contractors during all phases of the solar project implementation. For example, transportation costs are much lower if the pole has a modular design, which is good to know from a customer point of view when choosing which solar street light model to implement.
  • Ask for training of software usage if your solar street light has remote management control and monitoring system.
  • Finally, consider also the costs of maintenance and servicing, always ask for a long-term solution regarding these important issues with precise cost estimates.

Asking the Right Questions Part 1: Solar Energy Lights CONS

The main disadvantages of solar street lights include the following:

1. The initial investment for solar LED street lights is higher than for traditional street lights.

Your questions to the seller:

- What is the expected return on investment and at what rate per year?

You need to ask for financial analysis of the expected ROI of the solar lighting project that will include the following main categories: insolation parameters, energy generation in kWh per month and per year, servicing and maintenance, installation and miscellaneous. Solar calculations are the backbone for the financial feasibility of your street lighting project!

- What is the guarantee for the battery, the solar controller, the solar panel (ask for linear performance guarantee), the LED lights, the system electronics and the pole?

It is important to have everything laid down to you upfront so that you can conduct your own calculations on the feasibility of the solar lighting project. Each of these essential components of the street light has unique characteristics and functions which are highly significant to the long-term durability of the product. You can find useful information on the main components of solar LED street lights in this paper.

2. The dust, snow or moisture can pile up on the solar panels and reduce the energy generation.

Your questions to the seller:

- Do you provide servicing related to cleaning the dust, show or moisture from the solar panels?

- How often do we need to make sure that the solar panels are cleaned to have the maximum performance and energy generation?

If you are having solar street lights in a windy or dry, desert like location or in northern regions with lots of snow, ask for a better estimation of the expected periodical cleaning of the panels, including other measures for mitigation of these external conditions.

3. The rechargeable batteries need to be replaced several times.

Your questions to the seller:

- When would I need to replace my solar battery? How often this should be done and what is the replacement cost per pole?

- What actions are important during the performance of the solar street light for preservation of battery life?

It is best to ask for a brief training of how batteries work and what do’s and dont’s are relevant to increase the battery life cycle.Each type of battery has certain quality, however if your solar street light system is managed remotely by a dedicated cloud software with real-time data analytics, including interpretation and monitoring by solar industry professionals, your solar battery can last up to 10 years. Regardless of what solar providers tell you, without smart technology and close monitoring, on average solar batteries last 3–5 years (battery replacement costs around 600 USD per unit).

Important note: It is always better if the solar battery is placed underground during installation of the solar system since temperature fluctuations are less severe under the Earth’s surface. Such placement prolongs battery life and keeps the battery temperature below dangerous levels during severely cold or extremely hot weather.

4. The performance of solar energy lights is dependent on the weather, without sunlight there is no more than 5 days of solar system autonomy.

Your questions to the seller:

- How long can my solar street lights operate without sunlight?

- How can I improve my solar street lights energy generation to counter prolonged bad weather periods?

- When should I go for solar on grid system instead of solar off-the-grid installations?

In case of large installations of solar street lights in locations that cannot generate enough solar energy (locations which are not much exposed to sun — shading, extreme climate), you can opt for a solar controller with back up grid power. This device controls the amount of power that is pulled from the electric grid to ensure that grid power is only drawn when needed and that maximum solar energy is first obtained. With both solar and grid available to charge the batteries, your solar street lights will have enough power even when there is not enough sunlight. Another option for solar on grid systems is to feed in the solar energy obtained during the day in the grid and to pull energy from the grid to power the LED lights during the night. The energy efficiency of solar street lights and the difference in feed in tariffs make this option profitable.

In case of off-the-grid solar installations, the best solution to counter bad weather and achieve maximum autonomy is to usecloud software for remote management of each street light unit. Weather predictability algorithms are another very innovative feature which is included in the most reliable remote management systems. Weather predictability will help you optimize your solar lighting system and predict lower energy periods in order to ensure LED light performance even during prolonged bad weather events. Increasing energy efficiency and conserving additional power through motion sensors and dimming functionalities with pre-set lighting schedules will significantly improve the autonomy of your solar street lights. With careful system optimization based on weather predictability algorithms and gathered solar off-the-grid data, you street lights can have up to 365 days of autonomy (be functional regardless of the weather).

Asking the Right Questions Part 2: Solar Energy Lights PROS

The main advantages of solar street lights include the following:

1. Solar LED street lights are highly cost effective and energy efficient in the long-run.

Your questions to the seller:

- How do I decrease battery replacement and other maintenance costs to achieve higher ROI?

- What savings should I expect from solar street lights compared to traditional lights?

Remote management system is the key to always knowing what is going on with each component of your off-the-grid solar lighting system. With no remote monitoring tools in place, you would always have to send a technician to check each unit on-site and you will never have in-depth information in real-time on your system status. The better monitoring and control you have of your solar lighting system, the more savings you will have from free clean energy.

With optimized solar LED street lighting system you will experience economies of scale of light performance and higher reliability than traditional street lights, better illumination, decreased maintenance costs (no need to replace bulbs and allocate resources for expensive on-site system checks) no CO2 emissions, free energy, remote control and monitoring functions that will boost your ROI. Over a 15 year period, smart solar street lights can generate combined savings (including free energy generation, energy savings through optimization and increased light performance as well as reduced maintenance costs) between 1500–2000 USD per street light unit.

2. Solar LED street lights do not incur high installation costs and have much less systems to install.

Your questions to the seller:

- How long does it take to install one solar street light unit? How does the solar panel positioning affect the energy generation by the system?

- What is the step by step installation procedure?

- What are the solar system’s safety procedures in case of a problem or malfunction? How do I know when something is wrong with my solar street light system?

Finding the optimal angle for solar panels is very important for increasing their exposure to the sun and for highest energy performance. The optimal angle for solar panels depends on your installation location. Always ask for supporting documentation and installation guidelines so that you are fully aware of the procedures and the lead time for completion of this activity. The installation of one solar powered street light unit will take no more than a day, while the project preparation takes longer depending on the the number of installations, the location, logistics, product specifications and other parameters.

Having a dedicated remote management system which is connected online with your solar street lights is the most convenient way for real-time monitoring of your off-the-grid system functionalities. Alarm notifications with pre-set value thresholds is a very good way to keep track of how your solar lighting system operates and what is the current status. To find out more about the benefits from having a remote management system for your street lights, check our previous blog on how much smart technology improves solar street lights.

3. Solar LED street lights provide higher output when compared to traditional sodium lights.

Your questions to the seller:

- What is the replacement cycle for LED lamps?

- If I dim the LED lights to 50% how much energy will I save? Do LED lights provide enough brightness at 50% capacity for convenient illumination?

LED lights translate 80 percent of electrical energy into light while the rest is wasted as a heat. In traditional sodium lamps, 80% of the energy is wasted as heat and only 20% is utilized. The life cycle of LED lamps is equal to 11 years of continuous illumination or about 22 years of 50% operation. Contrary to traditional lights, LED lights do not burn out, but as time goes by their illumination lowers down and their brightness decreases. Therefore, you do not have to worry about regular LED replacements. The main differences between solar powered street lights and traditional lights are explained here.

4. With the right monitoring technology and system optimization parameters, solar energy lights can be fully autonomous regardless of the weather conditions.

Your questions to the seller:

- Does this mean that I can have solar LED light all year long and need not to worry during rainy days and winter periods?

- What is the cost per month to operate solar street lighting system monitored by smart technology? What are the savings generated from such smart applications versus the additional costs?

The benefits of using smart technology to operate your off-the-grid solar lighting system significantly outweighs the cost. For example, if you have installed 1000 solar street lights, by prolonging battery life from 5 to 10 years, meaning you will need to change them once in 10 years, you will save 600.000 USD. The cost of using remote management system for operating your solar street light system is less than 30 USD per pole, meaning that in a 10 year period the total net savings from using smart technology, which would double your solar battery life, would be 300.000 USD. The reliability of solar street lights achieved by smart technology increases the confidence in the solar industry’s future.

5. Solar street lights are sustainable and environmentally friendly, utilizing renewable energy sources.

Your questions to the seller:

- What are the available financing and subsidy schemes for renewable energy projects available in my country?

Renewable energy replaces the need for producing electricity by using fossil fuels, which cuts greenhouse gas emissions and facilitates sustainable development. That is why most of the countries are eligible for international green energy financing schemes and grants while local governments provide different subsidy frameworks for implementing renewable energy projects.Check this comparative study on energy financing schemes in EU countries. Solar street light companies may also be able to offer you convenient financing programs for your street lighting project with affordable terms dependent on the project’s expected energy outputs.

We hope we have helped you learn more about the advantages and disadvantages of solar street lights and what information to ask from the solar companies when considering this product. Overall, the pros of solar energy lights far outweigh the cons, especially if you are looking for lighting solutions that are energy efficient, have lower overall costs, are environmentally sustainable, and last a long time if supported by smart technology. Follow our next blog on solar street lights applications.