How new lighting can generate positive cash flow immediately

Not only is new lighting in this Netto warehouse reducing energy costs by 40%, but it has vastly improved colour rendering — and there is a host of other benefits

Business looking for new revenue streams would be well advised to look at their lighting installations and consider the benefits of one-for-one replacement.

So efficient is today’s lighting compared with that of just seven years ago that a replacement programme can readily deliver energy savings of 40%.

In addition, the use of sensors for detecting daylight and the presence of people can achieve further energy savings of 70%.

Put those two savings together, and the overall result can be a reduction in lighting energy consumption of over 80%.

Those figures come from David Trueblood, joint managing director of Riegens Lighting, who also puts those savings into a wider perspective. Since 20% of electricity generated is used on lighting, an 80% reduction in lighting consumption reduces total electrical consumption by 16%.

Payback can be quite short, as illustrated by a project carried out by Riegens for a warehouse of supermarket chain Netto. A total project cost of £82 500 is delivering annual savings of £36 900, even without the effect of daylight and presence detectors — giving a payback of 2.2 years and substantial long-term savings.

The project was at Netto’s head office in Pontefract, West Yorkshire, which was opened 15 years ago and has been extended twice. All construction was completed on a design-and-build basis.

David Trueblood acknowledges that even that rapid a payback might deter many companies from carrying out such work. However, Government-supported interest-free loans are available with repayment periods that can be tailored to give positive cash flow from day one.

For this particular project, David Trueblood explains that the potential for a Carbon Trust Loan was £99 106, a figure which was increased to £132 000 from July this year.

He then tells us that the repayments required on a loan of £99 106 would be £2752 a month. That repayment is to be compared with a monthly saving in electricity costs of £3075. The cash-flow benefit is immediate, and at the end of the repayment period, all the energy-saving benefits would be enjoyed.

David Trueblood stresses that the analysis above does not take into account the savings that can be achieved by daylight and presence sensors — which Netto estimates to be achieving additional savings of 30 to 40%. The project is also eligible for Enhanced Capital Allowances.

The previous lighting in Netto’s warehouse comprised 400 W SON (high-pressure-sodium) high-bay fittings. There were 250 of these fittings, and they were replaced on a one-to-one basis with HB-Eco luminaires, each with four 55 W fluorescent tubes having a colour temperature of 4000 K.

The previous lighting had a power consumption of 106 kW, including control gear, compared with just 64 kW for the new lighting, including control gear.

This warehouse is a 24/7 operation, so energy calculations are based on 8736 h a year. On that basis, the previous SON installation had an annual energy consumption of 928 MWh, compared with 559 MWh for its replacement. Energy costs have been reduced from £92 820 a year to £55 910 — a saving of £36 910.

Not only are the new lighting fittings more efficient, they can also switched on and off more readily than SON lamps, which take several minutes to strike and reach full brightness. The ability of the new lighting to be switched on an off as required opens up the possibility of saving energy using integral occupancy and daylight sensors — increasing annual energy savings to around £50 000.

Savings continue to pile up with the ability to include integral emergency lighting in the fluorescent fittings obviating the need for a separate system for emergency lighting, as would be required with HID lighting.

Maintenance costs are also reduced sharply by virtue of the fluorescent tubes having a life of 16 000 h before they need to be replaced — compared with about 9000 h for HID lamp..

In addition, the occasional failure of a single lamp in a luminaire containing four lamps will have only a minimal effect on light levels in the immediate area, so replacement will not be required immediately. In contrast, the failure of a single HID lamp dramatically affects light levels over a wide area, so the lamp has to be replaced immediately.

The success of the new lighting in the warehouse prompted Netto to analyse office lighting at its Pontefract site.

The main office lighting was provided by switchstart louvred fittings with four 18 W T8 lamps in them. There were 255 such fittings, plus 41 louvre fittings with three 18 W T8 lamps and 13 downlighters with two 26 W lamps. All areas were over lit, especially corridors at over 700 lx.

To minimise disruption, the requirement was for point-for-point replacement. Most of the new lighting was Arbos DI fittings with 40 W PLL HF lamps. There were also to be some louvred fittings with two and three 14 W T5 lamps and two downlights with 17 W lamps.

The overall benefit would be to reduce installed load from over 27 kW to less than 13 kW and to reduce annual costs from £19 791 to £10 500, a saving of £9291 — even without sensors. Adding sensors could be expected to increase energy savings by 40% to £13 000.

Mike Garlinge, head of building and development at Netto, is very enthusiastic about the energy-saving potential of new lighting. He says, ‘Although we can’t do anything about the rising cost of energy, we can do something to reduce our energy consumption. Energy efficiency has always been a key focus area for us, with heat reclaim, low-energy lighting and BMS in 80% of our stores — putting Netto amongst the most efficient retailers in Europe. However, the benchmark continues to develop, and it was clear that we needed more than just a low-energy lighting solution for our warehouse. We contacted our lighting partner Riegens, which came up with the ideal solution in terms of energy savings, low maintenance and illumination levels.

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