Light Bollards: Hard-Wired vs. Solar

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Outdoor lighting creates safety and security for pedestrians in low-light conditions, and accentuates the beauty of buildings and landscaping. Light bollards are useful along paths where lamp standards would be impractical or undesirable. Their low profile minimizes light pollution while still illuminating people and pathway, preventing accidents. Outdoor bollard lights can be installed with either a hard-wired electrical grid, or they can stand alone as solar bollards. Which electrical source is beset depends on the size and scope of the project; although the lights themselves may provide the same benefit, there are pros and cons to each approach.

Hard-wired electrical bollards

Hard-wired electrical bollards are any that require wiring to be lit. Most of the time, this wiring is run underground in conduits that connect to a central electrical box. The bollard may have simple on/off capability or might be wired for “smart” services, including central control, dimming, or diagnostics.

As with any electrical work, local regulations and permitting are important to consider while planning a hard-wired grid installation. In many jurisdictions, this sort of work needs both a trades permit and city inspection, because there are several issues that an experienced electrician can foresee that might cause trouble for an inexperienced worker.

Outdoor wiring is built to be stable against interruption. Depending on soil, voltage, and geographical considerations, wiring trenches can be dug anywhere from 6 to 24 inches down. Trenching historically required opening the earth, possibly disturbing hardscape—such as asphalt, concrete, or paving stone—but with the development of trenchless technology like micro-tunneling, hardscape surfaces can be left relatively undisturbed. This is less disruptive but comes at a higher cost. Conduits made of metal, PVC, or insulation protect the wiring underground. Circuits are installed with a ground fault circuit interrupter (GFCI) that will cut the power if someone digs into the wire.

Electricians calculate voltage drop when planning the grid. This describes a phenomenon in which wiring length affects available power. This is rectified through using proper wire gauges and careful planning of where lights go. Voltage drop issues require putting fewer fixtures on long wires.

In recent times, low-wattage LED bollards have allowed hard-wired bollards to provide energy savings over more traditional outdoor lamps. A 2012 study at the San Diego State University ran a pilot project to compare the cost of energy for LEDs vs. HID (high-intensity discharge) lighting bollards. Measuring demand between the two lamps produced the following output:

The study further showed that the total cost of energy per bollard per year was $60.00 for the HID, compared to $14.00 for the LED bollards, with no loss of illumination on the pathways.

The substantial energy savings provided by the LED bollard has ushered in the a wide-spread adoption of solar energy as an on-site source of electricity for lighting. In some places, this solar energy is switched over as the electrical source for a wired grid. A large panel feeds its output into centralized storage, and a control module monitors and provides power to the system.

The development of intelligent technologies, as well as improved panels and batteries, have allowed stand-alone solar bollards to generate and manage their own energy profiles. These discrete solar light bollards can go off-grid, yet still provide practical solutions to the need for outdoor lighting.

Solar light bollards

Outdoor bollard lights with onboard solar panels are self-sufficient, not needing a lighting grid to support them. This allows for easier installation into existing hardscape surfaces. Only the bollard footing need be planned, so no trenching is necessary.

Home-consumers have had a residential version of these bollards for years: solar path-lights for the garden, available at the hardware store, which store energy and cast a little light for a few hours after sundown. This technology is not enough to make stand-alone solar useful for larger sites with greater lighting needs, especially in environments they might be vulnerable to vandalism.

Innovative enhancements to the materials and design of bollards, batteries, and LEDs have allowed engineers to design light bollards for use in public spaces. These bollards are durable, with greater energy storage capacities, and they produce enough light to illuminate larger areas.

Smart solar bollards are a further development that finally brings grid-level control to stand-alone bollards. Advances in computing technology allow a site manager to program stand-alone solar lights, similar to what might be done with a grid, so that they are brightest when needed—generally in the hours near sunset and dawn. An additional benefit is that the bollards can also sense and respond intelligently to their environment without the site manager’s oversight. The onboard system on our solar bollards watches weather patterns and battery levels, and conserves energy when there has been a stretch of dull weather by adapting power output.

This smart-conservation allows the bollard to continue to cast light even if there are one or more days in which it does not receive sunlight. This autonomy function will move the bollard into a power-saving mode. If starting with a full battery, the bollard can run for up to two weeks without receiving any sunlight. In Seattle, a place known for overcast skies, the solar light bollard will generally experience three autonomous days in the summer and fourteen over the course of the winter.

Of course, the location of the bollard does matter. Locations very far north, which experience only a few hours of sun per day in winter, or spots where the bollard is mostly in shade, may prevent the bollard from getting enough light to function optimally. These situations might require hard-wired bollards. However, with smart-technology and LED lights, there are far fewer situations in which electrical grids are needed than there were a decade ago.

A comprehensive lighting plan

Lighting bollards are an important part of a comprehensive site plan. Illumination helps protect against injury and criminality, yet sites are also concerned with reducing light pollution so that plants, animals, and people get required dark hours. Bollards can help with both, providing pathway lighting that allows people to see each other and tripping obstacles without causing the same glare and light-trespass as standards and sconces installed higher. Hard-wired grids provide reliability in shade and in dark-sky situations. With advancements in technology like LED lighting, battery retention, and onboard intelligent monitoring systems, independent solar bollards are becoming an increasingly viable solution for projects, easily added to existing hardtop and new installations, and requiring less construction during install.