Cost Comparison Case: Solar Street Lighting vs Traditional Street Lights

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This blog explores a compelling case study titled “Solar Street Lighting: Using Renewable Energy for Safety for the Turtle Mountain Band of Chippewa,” penned by Teri A. Allery. The study thoroughly evaluates solar street lighting vs traditional street lights and the cost dynamics between them. Allery’s research specifically scrutinizes the economic viability and energy efficiency of implementing solar powered LED street lights over conventional grid-connected systems. It’s a comprehensive investigation into the practicality and benefits of solar street lighting, seeking to address specific community safety concerns.

Solar street lights offer significant savings over time due to their minimal maintenance requirements and the absence of electrical energy costs.

An Introduction to The Turtle Mountain Band

The Turtle Mountain Band of Chippewa Indians calls the Turtle Mountains in North Dakota home, occupying a reservation spanning 72 square miles just 10 miles south of Canada. With over 30,000 enrolled members, about 5,800 reside within the reservation, and 2,500 on trust lands nearby. Despite being isolated and situated 120 miles from the nearest urban community, the reservation hosts a dense population of around 100 individuals per square mile.

The sole town within its boundaries is Belcourt, and its community faces a significant challenge with North Dakota Highway 281. This busy road lacks lighting, leading to numerous accidents and fatalities, casting a shadow over the community’s safety and well-being. Indeed, multiple accidents, including pedestrian fatalities, have occurred along a roughly 5.5-mile stretch. This tragic reality highlights the urgent need for improved safety measures along this dark highway.

In response, the Turtle Mountain Band recognizes the necessity of implementing a renewable and clean energy project. Specifically, it focuses on installing street lights along mile markers 239 to 245 to enhance safety.

It is here where the study holds immense value, evaluating the feasibility of solar street lighting vs traditional street lights. Cost comparisons must be considered as well, given the study’s purpose and the community’s circumstances.

Economic analysis highlights the long-term cost-effectiveness and sustainability of solar street lighting solutions compared to their traditional counterparts.

An Introduction to the Study

With the above in mind, the study dissects the potential replacement of existing grid-connected lights. It first compares existing power consumption with the anticipated outcomes post-implementation and then asserts the proposal’s effectiveness.

That said, the study’s explicit purpose and criteria must be noted. In the author’s own words:

“Ultimately, this research paper’s focus is to incorporate renewable energy specifically to take care of Mother Nature as well as the Turtle Mountain Band of Chippewa Indian people. There have been many deaths on North Dakota Highway 281, which it is the main road of the Turtle Mountain Band of Chippewa reservation. The highway has a high volume of traffic every day, in addition to many people who frequently walk this road. There is no walking or bike path along the road; most people tend to walk the shoulders of the road.

This research paper is a way to help protect these pedestrians with an idea of lighting the highway from the west end of Belcourt to one of are housing developments that is 5.34 miles to the west of town. This research paper will look at the various types of street lighting methods and provide recommendations for a suitable and economical project.”

Solar Street Lighting vs Traditional Street Lights: Street Lighting and its Types

Here, we should acknowledge that this exploration hinges on an array of factors, as the author notes. Most notably, it hinges on the history of street lighting and traditional street lights themselves.

Indeed, History of Lighting notes that this history dates back to when humans first started living together:

“Lack of natural light during nighttime in the urban environment was always a problem. From basic inconvenience that people cannot see where they are going to the greater chance of being attacked or mugged during the night. Because the problem was there since humans started living together, history of street light is maybe longer than we think.”

As such, for text economy, here we can highlight its key milestones:

  • The history of street lighting dates back to ancient times when Romans used oil lamps around 500 BC.
  • By 1802, William Murdock introduced gas lights fueled by coal gas.
  • In 1807, London pioneered the idea of lighting entire streets with gas lamps, which was later adopted by the United States in 1816, starting in Baltimore, Maryland.
  • Over time, improvements led to the shift from gas to more energy-efficient electric lights. Pavel Yablochkov’s Yablochkov Candle in 1875 was among the first electric street lights using arc lamps, followed by Paris switching 4,000 gas lamps to electric ones by 1881.
  • The United States caught on, installing 130,000 arc lamps by 1890.

Subsequent advancements refined these electric lights gradually. Today, a variety of lighting options exist, including traditional, efficient models and some older, less energy-efficient ones still in use. It is these advancements that have led to the emergence of solar photovoltaic street lights, where our comparison can begin.

Compared to solar street lights conventional street lights, with lower initial expenses, incur continuous costs in electricity and regular maintenance.

#1 Traditional Street Lighting

To contextualize the debate between solar street lighting vs traditional street lights, we can introduce the two.

Traditional street lighting involves illuminating roads and public areas using fixtures mounted on poles. These lights typically consist of a bulb, a reflector, and a transparent cover to protect the bulb. The bulb, often high-pressure sodium or metal halide, emits light when electricity passes through it. A reflector directs and enhances the light’s distribution. The functions of these lights are to provide visibility and enhance safety for pedestrians and vehicles during nighttime.

That said, traditional street lighting comes with two distinct costs. Installation costs include the price of the fixtures, poles, wiring, and labor. Operational costs encompass electricity consumption and maintenance expenses for bulb replacements and repairs. While traditional street lights offer reliable illumination, their operational costs can be significant due to energy usage and maintenance needs.

#2 Solar Street Lighting

In contrast, solar street lighting harnesses sunlight to power illumination for roads and public areas. These lights consist of solar panels, batteries, LED lamps, and a controller. Solar panels capture sunlight during the day, converting it into electrical energy stored in batteries for night use. LED lamps emit light using this stored energy. The controller manages the charging and discharging of batteries, ensuring optimal power utilization.

It is here where the key difference emerges; solar street lights operate autonomously, relying on renewable energy. This fact makes them eco-friendly and sustainable – and thus a viable option. As the study notes, the costs of solar street lighting vs traditional street lights differ fundamentally.

For solar street lights, installation costs involve the price of solar panels, batteries, LED lamps, a solar street light pole, and installation labor. Operational costs are primarily limited to minimal maintenance expenses, such as occasional battery replacements, as they don’t rely on grid electricity, reducing ongoing expenses significantly.

Indeed, the initial setup costs can be higher. However, long-term savings due to minimal operational expenses and eco-friendly energy usage make solar street lighting an attractive, cost-effective option.

Electrical Grid Systems

With street light types in order, another major factor emerges in electrical grid systems themselves.

An electrical grid system functions as an interconnected network transporting electricity between producers and consumers. Power plants or generating stations within this system convert kinetic energy into electrical power. Initially, this electricity is transformed into kilovolt amperes (kV) at a generating transformer. High-voltage transmission lines are then used to carry this electricity across distances within the grid. When reaching its destination, the electricity passes through a step-down transformer, reducing its voltage from high levels to lower ones suitable for specific customers or locations.

This step-down process ensures that electricity can be utilized effectively based on the varying needs of different consumers and locations. The power grid operates through this process, ensuring the efficient transmission and distribution of electrical energy across its network. It’s this function that makes grid types essential to solar street lighting vs traditional street lights comparisons.

#1 United States Major Grid System

The US relies on a vast power grid composed of three major interconnected grids—the Eastern, Western, and the smaller Texas (ERCOT) grid. These grids are interconnected by around 450,000 miles of high-voltage transmission lines and 5.5 million distribution lines, serving various facilities, homes, and businesses across the country.

However, the grid infrastructure is aging; as the study notes,

“The US power grid is over 100 years old and most of the necessary balance of the infrastructure is over 50 years old. To rebuild the grid, it is estimated to cost over $5 trillion dollars. The aging grid is vulnerable to extreme weather, natural disasters, electro-magnetic pulse weapons, and cyber-attacks. Instead of spending money on rebuilding the grid, a “smart grid” can possibly prevent the vulnerability of the current grid.”

#2 Micro Grid System

In turn, a microgrid system mirrors the structure of a traditional electrical grid but on a smaller scale. It can either operate alongside the main grid or independently as a standalone system by incorporating batteries or energy storage. Essentially, as the US Department of Energy notes, it’s a localized grid with its own control capabilities. If connected to the main grid, a microgrid can experience outages when the larger grid fails. However, when configured as a standalone system with backup batteries, it generates and stores its own energy during emergencies, such as power or weather-related outages. As such, these configurations largely inform solar street lighting vs traditional street lights comparisons.

Microgrids serve where it’s impractical or too costly to install distribution lines to individual homes or buildings or in areas where such lines are restricted. These systems vary in size; they can be as extensive as those utilized by the US military in remote deployments or as compact as powering streetlights, clusters of homes, or even entire districts, as envisioned in future urban planning. The scale of a microgrid is determined by the power requirements of the area it serves, providing flexibility in meeting specific energy needs.

There are numerous financial benefits of transitioning to solar-powered solutions for street illumination, particularly in the long term.

#3 Stand-Alone Power System

Finally, stand-alone power systems (SAPS) are self-contained electricity generators designed for remote areas far from the main grid, where connecting to the grid is costly. These systems produce power independently to cater to the energy needs of such remote locations. They encompass various generating sources or a combination of systems:

  • Solar photovoltaic units
  • Wind turbines
  • Geothermal heating units
  • Geothermal water pumps
  • Diesel or biofuel generators
  • Micro combined heat and power
  • Thermoelectric generators

SAPs also come with distinct use cases and benefits, as the US Department of Energy outlines:

“In remote locations, stand-alone systems can be more cost-effective than extending a power line to the electricity grid (the cost of which can range from $15,000 to $50,000 per mile). But these systems are also used by people who live near the grid and wish to obtain independence from the power provider or demonstrate a commitment to non-polluting energy sources.”

Evaluating the cost implications of solar street lighting compared to traditional street lighting, it’s essential to consider initial investment, ongoing maintenance, and operational costs.

Types of Solar Power Systems

Lastly, as we delve deeper into the solar street lighting vs traditional street lights comparison, we should also mirror the study. Specifically, we should outline the two main types of solar power systems:

  1. Solar glitter
  2. Solar photovoltaic array units

#1 Solar Glitter (MEPV)

Solar glitter, also known as micro-scale photovoltaic (PV), comprises tiny cells capable of capturing energy from diverse light sources to power devices in various flexible, moldable, or flat plate formats. These cells, sometimes as small as 100 micrometers wide and 1µm thick, possess the capability to generate electricity similar to larger PV cells or panels. Their function involves converting photons from sunlight or any light source into electrons or electricity. Their micro size facilitates adaptation to the shapes and contours of devices, blending seamlessly into their appearance and functionality.

There exist three distinct designs of these micro-scale PV cells:

  1. silicon back-contacted interdigitated finger pattern suitable for sunlight conversion without optical concentration
  2. radial pattern with similar attributes but a symmetrical design, allowing versatile placement
  3. ultrathin single-junction gallium arsenide (GaAs) cell for converting diffuse light into electricity for high-value applications such as mobile or space power

What sets these designs apart is their adaptability. They can be embedded into flexible PV modules, integrated into cost-effective micro-concentrator modules, or incorporated into various consumer electronic products. However, MEPV is still in its developmental phase, making it a less reliable option by comparison.

#2 Solar Photovoltaic Array (PV) Units

Solar photovoltaic (PV) units are the ones that often drive solar street lighting vs traditional street lights comparisons. PV units are established and reliable, offering to power highway solar street light projects like the one the study proposes.

PVs produce electricity directly from sunlight using certain semiconductor materials. When photons from sunlight strike these materials, they release electrons. These generate solar energy that travels through electrical circuits, powering devices or feeding electricity into the grid.

Currently, solar cells are predominantly crafted from crystalline silicon or thin-film semiconductor materials. Although silicon is costly, it exhibits high efficiency in converting sunlight into electricity. In contrast, thin-film materials offer a more economical option, but they are less efficient than silicon and require larger surface areas for electricity generation.

A solar panel comprises multiple small photovoltaic cells interconnected, enabling photons to dislodge electrons from atoms, initiating an electric current. Once these PV cells free electrons, the generated electricity flows through the system. Depending on whether the system operates on or off the grid, the electricity undergoes different stages, facilitating its distribution and utilization accordingly.

Solar Street Lighting vs Traditional Street Lights: Possible Street Light Systems for Highway 281

With all of the above in mind, the study concludes with three possible street light system proposals. As it does, it draws from the Global Energy Network Institute’s proposals, which include use cases for similar circumstances:

“Tribal lands contain enormous potential for renewable energy. In fact, according to the Intertribal Council on Utility Policy, the wind resources on Tribal lands in the Great Planes alone could power over 50 million homes.

[…] Developing renewable energy gives Native American Tribes a massive resource that could provide them with steady revenue and drive the development of the tribal infrastructure necessary for the Tribes to complete large projects.”

So, it is here where our solar street lighting vs traditional street lights comparison can truly come to a head.

#1 Traditional Lighting

Opting for traditional lighting for Highway 281 seems feasible by connecting lights to the nearby grid, considering the existence of a substation in the project area. However, the expense involved in installing new lights and extending the grid makes this solution highly costly. While the lights themselves aren’t exorbitant, significant expenses stem from initial installation, maintenance, and ongoing operation.

Each light pole installation could cost between $2000 and $3000, with an additional $1000 for electrician labor. The price of the light bulbs, particularly LED ones at around $110 each, influences long-term electricity and maintenance costs, given their lifespan of 10 to 15 years.

For a 5.5-mile stretch on North Dakota Highway 281, rough estimates predict a project cost totaling approximately $361,387, factoring in light pole expenses at an average of $2500, electrician labor costs of $750, and the use of 400W EQ LED light bulbs priced at $110 each.

A chart outlining the total cost of traditional street lights on Highway 281 without cost of electricity, giving data on solar street lighting vs traditional street lights costs.

Although feasible, this traditional lighting approach proves to be considerably expensive, making it a less cost-effective option for the project. The following chart outlines the cost of electricity per day, month, and year for this option:

A chart outlining the cost of electricity daily, monthly, and annually for traditional street lights on Highway 281.

#2 Solar Lighting with Micro Grid

Implementing solar street lighting with a microgrid system mirrors the installation process of traditional street lights, with additional costs for the microgrid unit. Comparing the total installation expenses of solar street lighting vs traditional street lights includes considering the annual electricity costs, factoring in the period when the generated electricity becomes free, post system payment.

A chart outlining the cost of traditional street lights with a micro grid on Highway 281 without cost of electricity, giving data on solar street lighting vs traditional street lights costs.

For a 10kW system, approximately 40 panels are used (equating to 4 panels per kW). In the case of the TMBCI project, requiring a 93kW system, approximately 372 panels would be necessary. Pricing for these systems varies, but a 10kW off-grid system generally costs between $32,000 to $54,700. Scaling this to a 93kW system involves multiplying the average 10kW system cost by 9 for a rough estimate. Considering the payback period in years involves the cost of light pole installation and the system itself.

A chart outlining how long it will take for the Highway 281 lighting project to pay itself off.

#3 Solar Lighting Stand-Alone Systems

Finally, calculating the cost for a stand-alone solar lighting system includes a $3500 expense for lights and poles, with an additional $1000 for installation, totaling around $48,400. Evaluating the payback amount involves considering the current electricity rate. Once the project is fully paid, annual electricity cost savings are evident as the system generates its electricity, negating the need for external energy purchases.

A chart outlining the cost of solar street lights on Highway 281, giving data on solar street lighting vs traditional street lights costs.

To calculate the payback period, the total project cost is divided by the yearly electricity cost saved or not needed. With the system self-generating electricity, the project pays off in a little over 4 years. Minor maintenance like bulb and battery replacements are anticipated throughout the project’s lifespan but entail negligible costs.

A chart outlining the cost of electricity daily, monthly, and annually for solar street lights on Highway 281.

Solar Street Lighting vs Traditional Street Lights: Comparing Costs of Alternatives

The comparison becomes the study’s central focus. Two alternative projects for Highway 281’s street light systems showcase close installation costs:

  • Traditional street lights at $361,387 solely for installation
  • Stand-alone solar street lights are at $484,000 for installation, devoid of ongoing electricity expenses.

The divergence lies in the post-payment scenario, where solar street lights eliminate electricity bills once the investment is settled:

A chart outlining the overall cost of the lighting project on Highway 281.

Conversely, traditional street lights incur an annual operational cost of $110,809 for purchasing electricity, a continuous expense. Here, the study does note that

“A solar street light system with a micro grid cost is expensive and has a long pay off rate. Although this alternative has a seven-year payback for the project, it is noted that the costs could rise if the land for the micro grid would have to be purchased.”

However, it does conclude that long-term costs favor this route. Indeed, in the post-payment scenario, stand-alone solar street lights emerge as the more cost-effective and eco-friendly option.

A chart outlining the cost comparison of alternatives for Highway 281, consolidating the solar street lighting vs traditional street lights debate.

Solar Street Lighting Illuminates the Path Forward

So, based on the calculated project costs, the recommendation for the Turtle Mountain Band of Chippewa is unequivocal. The study settles the solar street lighting vs traditional street lights debate in terms of both cost and efficiency. Installing stand-alone solar street lights along North Dakota Highway 281, between mile markers 239 and 245, emerges as the optimal choice.

The stand-alone system also aligns with the Band’s commitment to preserving the environment by harnessing clean energy. This commitment, the study notes, demonstrates their deep-rooted respect for Mother Earth and the tribal community’s safety. Unlike grand-scale solar PV farms or wind turbines, this solution addresses a community safety issue at a comparatively lower cost.

If you want to know more about solar lighting or a considering installing some yourself, don’t hesitate to reach out to EnGoPlanet. We are always there to answer all your questions.

References:

https://www.energy.gov/indianenergy/articles/solar-street-lighting-using-renewable-energy-safety-turtle-mountain-band

https://tmchippewa.com/

http://www.geni.org/globalenergy/research/renewable-energy-on-tribal-lands/Renewable-Energy-on-Tribal-Lands.pdf

http://www.historyoflighting.net/electric-lighting-history/history-of-street-lighting/

https://www.energy.gov/articles/how-microgrids-work

https://factmyth.com/factoids/the-us-is-connected-by-one-power-grid/

https://www.energy.gov/energysaver/grid-or-stand-alone-renewable-energy-systems

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