Inovus Solar has announced the first installation of its LED-based On-Grid Solar Street Light poles in a Boise, Idaho big-box retail store called WinCo Foods. The poles have integral solar panels and inverters that supply electricity onto the grid during the day, essentially reducing the cost of electricity used by the store during peak periods, while the grid powers the solid-state lighting (SSL) at night when rates are lower.

The WinCo installation includes six Inovus light poles equipped with LED-based Evolve luminaires from GE Lighting that are located around the perimeter of the parking lot. Inovus also includes wireless communications capability in the poles that allows for adaptive control – for instance dimming the lights late at night to compound the baseline energy savings attributable to SSL.

WinCo projects that the on-grid solar SSL installation will save 24,000 kW/h per year, and eliminate 16,000 pounds of CO₂ emissions. WinCo hopes the pilot installation leads toward using the LED and solar combination at all new stores and to retrofit other locations over time.

On- or off-grid solar

While Inovus has been active in off-grid solar products and is a founding member of the Consortium for Solar Lighting, the on-grid product provides more flexibility in terms of powering high-wattage luminaires. Inovus Business Development Manager Reid Carley said that the on-grid poles can utilize luminaires rated from 40W to more than 400W.

Off-grid products require a solar system and batteries that can keep the lights lit all night, and obviously incur no electricity cost. But there are limits to the amount of power that can practically be harvested and stored. The on-grid products simply offset other electrical usage during the day while using power at night when the electrical rates are lowest.

The Inovus on-grid pole design is quite different from most other solar LED systems. Typically such systems use a rectangular panel mounted on top of the pole. Inovus skins its poles with a flexible thin-film solar collector that essentially blends into the pole. Inovus notes that the integral panels are more reliable than traditional panels, especially in windy conditions, and the company believes the design is more aesthetically pleasing.

Inovus estimates that SSL alone can provide 50-60% in energy savings relative to legacy light sources such as high-pressure sodium or metal-halide lamps. The combination of adaptive controls and solar generation can bring savings to 70-100% according to Inovus. The company asserts that the WinCo installation is delivering 80% savings.

Inovus worked with an unnamed partner on the wireless communications scheme. Carley said it is based on the IEEE 802.15.4 standard that also underlies ZigBee. Carley also said that the Inovus implementation had extended the technology to support higher data rates and more-reliable wireless links. The wireless capability supports centralized scheduling of individual lights or groups of lights, in terms of on or off times and dimming levels.

WinCo promotes itself as a green business and in fact has a section on its website that highlights its green initiatives. The site notes that the company will choose LED lighting whenever possible. The rationale is saving energy and the fact that SSL doesn’t contain mercury or emit UV light.