Reduce Energy Costs Today By Upgrading To High Efficiency LEDs

Published 19 Jan 2023

Raytec Bay Lighting Solutions

LED Lighting

SPARTAN Mid Power Bay & Linear High Output

Raytec have recently launched the SPARTAN Mid Power Bay & SPARTAN Linear High Output lighting which utilise optics, high-efficiency LEDs, and cutting-edge driver technology.

These new products offer Thorne & Derrick’s customers greatly improved flexibility when it comes to designing lighting schemes that would typically utilise bay style light fittings, and can help to significantly reduce energy costs and capital expenditure.

Did You Know? Halogen and fluorescent bulbs are the least energy-efficient bulb on the market and there are more accessible energy saving alternatives to use. According to the recent press release, the government plans to start phasing out high-energy fluorescent light bulbs in September 2023 as part of the energy-saving efforts to tackle climate change.

Upgrading To High Efficiency LEDs

💡Find out how Thorne & Derrick together with Raytec can help you explore how switching to ATEX LED lighting can deliver significant cost savings 💡

Historically, bay and area lighting applications with mounting heights of 6-12 metres would use traditional 250W or 400W SON, Metal Halide (MH), or Mercury Blended (MBF) fittings. However, these light fittings are inefficient and offer little in terms of light output control.

In this article, Raytec compare the SPARTAN Mid Power Bay and SPARTAN Linear High Output against traditional 250W SON wellglass fittings. We also explore the energy and capital expenditure savings that can be achieved by switching to LED.

SPARTAN Mid Power Bay & Linear v Wellglass Fitting

Let us start by looking at a typical warehouse application, with luminaires mounted at 6m, and requiring 300lx on the ground.


Using a scheme of traditional 250W SON wellglass fittings, 45 luminaires have been used to provide 346lx on the ground, delivering a uniformity of 0.71. However, the inefficiency of the SON wellglass means this scheme has a high total power consumption of 12.4kW.

Efficient Bay Lighting Table Lighting Design Wellglass

Efficient Bay Lighting Table Lighting Design Wellglass

The design of a wellglass means that a lot of light is dispersed out to the sides of the unit; not necessarily where it’s needed, meaning a lot of light is wasted.

Now let’s compare these results with two further schemes using Raytec’s LED bay lighting solutions. For each of the comparisons, the same warehouse dimensions are used, as well as the same 6m mounting height.


In this second example, we’re using Raytec’s 12,500lm Mid Power Bay as a point-for-point replacement for the 250W SON wellglass lamp. This means the same number of fittings (45 luminaires) and formation (9 rows of 5 luminaires) is used.

Efficient Bay Lighting Tables Lighting Design Mid Power

Efficient Bay Lighting Tables Lighting Design Mid Power

This solution achieves a higher lux level of 359lx, while maintaining a good uniformity of 0.60. Critically though, the Mid Power Bay can deliver significant energy savings. The total power consumption has dropped to 4.5kW – a reduction of over 63%.

Let’s look at the numbers in more detail and see what this reduction in consumption equates to in terms of actual cost savings. These calculations assume an energy price of 20.5p/kWh* and that the light is switched on for 10 hours per day.

*Average Industrial business energy rate not including VAT taken from Department for Business, Energy and Industrial Strategy.

Light Fitting No. of Light Fittings Wattage Kilowatt per Day Savings
250W SON 45 275W (per fitting) 123.75 kWh/day
SPZ MPBY12K5 45 100W (per fitting) 45 kWh/day
Using SPZ MPBY12K5 offers customer: Energy Saving 64% (£5,892/year)
CO2 Emission Reduction 64% (15.08 ton reduction)
Yearly Payback 2.8 years

Using the 12,500lm SPARTAN Mid Power Bay delivers an energy saving of 64% (£5,892) a year. Also note that using a luminaire with a more efficient light output reduces the CO2 emissions of the lighting scheme by 15.08ton, offering greatly improved environmental benefits.

The directional nature of an LED light source, combined with Raytec’s choice of optics and beam angles, ensures the light can be targeted exactly where needed to provide the most efficient light scheme.

Raytec Spartan Linear WL168 Zone 2 Hazardous Area 7,048 Lumens


The third example offers an alternative solution to the traditional bay style fitting and utilises Raytec’s new Linear High Output luminaires. In this scenario, the target lux level is achieved using 9 fewer fittings than in scheme A and B. Using 36 luminaires, with a 9×4 luminaire layout, achieves 333lx on the ground while still delivering a uniformity of 0.62.

Efficient Bay Lighting Tables Lighting Design High Output Linear

With a total energy consumption of 3.5kW, even greater savings can be achieved compared to the 250W SON solution. With fewer luminaires required to achieve the target lux levels, SPARTAN Linear High Output also helps to reduce the initial capital expenditure, thanks to lower procurement and installation costs.

For larger installations, the extent of these savings will grow exponentially and help end-users to significantly reduce both their initial outlay and ongoing running costs.

Light Fitting No. of Light Fittings Wattage Kilowatt per Day Savings
250W SON 45 275W (per fitting) 123.75 kWh/day
SPZ-WL168-HO 45 100W (per fitting) 45 kWh/day
Using WL168-HO offers customer: Energy Saving 71% (£6,620/year)
CO2 Emission Reduction 71% (16.94 ton reduction)
Yearly Payback 2.5 years



Thorne & Derrick can offer a comprehensive range of bay and area lighting solutions including hazardous area lighting, which can provide customers with significant capital expenditure and energy savings.

The new Linear High Output breaks the mould of conventional bay-style fittings. The luminaire provides a compelling solution both in terms of performance and cost-effectiveness.

Don’t hesitate to get in contact with us to discuss your requirements, or to utilise our free lighting design service to ensure you achieve the most efficient and cost-saving lighting solution for your application.

Hazardous Area Lighting

Hazardous Area Lighting Design


Thorne & Derrick International, based in the UK, are Preferred Distributors and Stockists for the Raytec SPARTAN range of ATEX lighting using LED technology for the illumination of hazardous area locations and potentially explosive atmospheres.

SPARTAN is a full range of Ex LED luminaires and lighting approved for all ATEX and IEC Ex Zone 1 and Zone 2 hazardous area environments, including UL /CSA C1D2 installations. The hazardous area lighting products are designed for the most extreme environments – Flood, Linear, Bulkhead, Bay and Crane luminaires with emergency and industrial lighting versions are also available from Thorne & Derrick International.

ATEX Lighting Hazardous Area Lighting Zone 1 Zone 2 ATEX