The announcement of the latest climate agreement in the U.S.
brings good news for the solar streetlighting industry as spending on solar
projects is expected to increase dramatically. However, because solar
streetlighting is still a relatively young market, the space is rife with myths
and misinformation. Similar to a previous blog
post on the most common myths about off-grid power in general, this blog
will have Clear Blue’s team of experts take a look at some of the most commonly
heard myths, advertised in the solar street lighting market, to see what is
truth and what is fiction when it comes to solar street lights.
Firstly, be wary of streetlight manufacturers suggesting
that because they use Nickel Metal Hydride (NiMH) batteries, their systems will
have optimal performance and longest system life, as this is misleading. The main
advantage of NiMH batteries is that they are cheap to source. However, this
does not mean they are the most efficient, reliable batteries on the market.
The Advantages and Disadvantages of NiMH batteries. Learn More.
In reality, the life of NiMH
batteries can be significantly reduced when improperly charged, in which
case they will have poor performance. While typically more expensive, Lithium-Ion
batteries have a much higher energy density, meaning they are more efficient
than NiMH batteries. Li-ion batteries tend to perform better than NiMH
batteries and hold their charge for much longer. In addition, Lithium batteries
have a life cycle of about 5 years, compared to the 2-5 year cycle of NiMH
The Advantages and Disadvantages of Lithium-Ion
batteries. Learn More.
Overall, both technologies have their advantages and
disadvantages. So, don’t be fooled by the myth that NiMH are more reliable and
long-lasting than other batteries.
Lumen Output and Fixture Life
In addition, there are many myths in the industry about the
lifespan of a lighting system and its ability to produce a certain light level.
By digging a little deeper, these myths can easily be dispelled. One common
claim is that a lighting system has a 20-year lifespan, meaning it can maintain
a light level for nearly 200,000 hours.
However, this claim is highly exaggerated and clearly misleading.
In most cases, lighting specifiers, including engineering companies and
municipalities, will request a Light Loss Factor (LLF) of 85%. At 200,000
hours, the light loss factor will be far lower than 85%. As a result, 200,000
hours is a meaningless value. A light cannot maintain its luminance for nearly
Such a number is based on the ‘calculated lumen maintenance,’
which is extremely different from ‘reported lumen maintenance’ and is not an
accurate reflection of how long the light will actually last. The data that is
calculated in the lab tests is very different from what will work in practice,
and calculated lumen maintenance thus cannot be used to infer light life
In fact, according to IES TM-21-9, the Illuminating Engineering Society (IES) does not
recognize any lighting projection that is beyond 6 times the practical test period,
which is between 6000 and 10,000 hours. Therefore, anything beyond the 60,000-hour
level cannot be verified, and the IES states a lack of confidence in data
beyond a 5-year projection. When suppliers advertise claims such as a light
with a 20-year lifespan, it cannot be backed up. It is important to have
quality conversations with your supplier to understand better the true
capabilities of their products and what they can offer.
Hardware is another common area where customers in the solar
street lighting business can be misled. The so-called ‘all-in-one’ streetlighting
suppliers will offer lighting systems which they claim have ‘lighter, more
simple designs.’ What this actually means is that the lighting systems are
cheaper to source, less durable and less reliable. As a result, customers
should be wary of lighting hardware with such designs and make sure to source
quality hardware that is managed remotely for increased reliability. Moreover,
when suppliers advertise that their systems are ‘designed to’ a certain
standard, it does not necessarily mean it has actually met that standard.
Monitoring vs. Smart Management and Control
As discussed in a previous blog
post, there is a critical difference between monitoring and control. System
monitoring provides helpful data but does not reduce overall costs. On the
other hand, management and control capabilities save significant costs by
eliminating on-site maintenance visits and provide high reliability.
In the solar street lighting market, claims about system
control should be evaluated closely. Access to data from the lighting system is
different from being able to control the system’s settings remotely. And simply
because energy can be transferred from the solar panels to the batteries for
storage does not mean there is remote system control. In fact, this is a basic
function of most off-grid systems, regardless of their software capabilities. Without
the ability to actively manage the system, monitoring does not significantly
lower costs, as a technician still must go to the site.
All-in-one solar streetlighting manufacturers sometimes bypass
IES standards to provide cheaper products. For instance, as per IES
recommendations for roadway applications, the angle of the light to the surface
(also known as the nadir angle) should be less than 10 degrees. However, in
order to correctly angle their solar panels for optimal solar energy
generation, all-in-one solar streetlight manufacturers will deliver systems
with a nadir angle of 25-30 degrees which produces significant glare. By
avoiding the reputable standards of the IES, costs are reduced, yet the quality is
sacrificed. Unless otherwise requested by the customer, Clear Blue’s lighting
systems are designed using Lighting Analysts software and adhere to IES
Recommended Practices (RP) 8-18 or 8-21. As a result, Clear Blue’s customers
are sure to receive the highest quality street lighting products.
Ultimately, when approaching the solar street lighting
market, it is important that customers have accurate information from lighting
experts so they can make informed decisions and purchase the solution that best
suits their needs. By avoiding these misconceptions, customers will be able to
find high-quality street lighting products that suit
their application’s needs.
If you have any questions about the standards or quality of
products that Clear Blue provides, reach out to our expert team by email: firstname.lastname@example.org, and we will be happy
to answer any of your questions around batteries, lumen output, hardware
compliance, remote management or IES standards and show you why Illumient SMART
solar street lights are a market leader.