How about producing solar electricity on your warehouse's roof?

Posted on May 29, 2008 by Matthieu Desiderio

Updated from May 14, 2008 version

It appears that more and more suppliers tend to take into account environmental concerns in their supply chain management. This trend towards a “greener” attitude from well-known brands is thus more and more encountered, especially in the retail distribution sector. Carrefour, a French major player in retailing distribution, in association with the French Logistics provider, Faure & Machet, has recently been an example of this phenomenon by establishing a warehouse of 54,000 square metres in in the South of France that complies with the most advanced environmental standards.

The Carrefour/Faure & Machet approach

Implemented in Nîmes, this scheme is unique. Indeed, the very specific and innovative design of this building make it the only experimentation in Europe at the moment!

The warehouse has been designed with a whole range of state-of-art technological devices that substantially reduce the environmental footprints of the construction. More specifically, we can point out devices such as: water solar-heating systems, energy-saving lightings, double glazing windows and also fans used for recycling purposes. Moreover, the layout of the warehouse has been purposely designed to minimize the number of forklift vehicles movements and to favour recycling through the construction of a waste container on-site. It is to note that the building conception was made by NG Concept, the warehouse engineering branch of FM Logistic.

The most impressive aspects of this construction definitely remain the large amount of solar cell panels laid out on the roof of the warehouse. With a number of 2,650 panels, it is acknowledged to be the largest photovoltaic power station implemented on a roof in Europe. Moreover, it is to note that, because of its 300 days of sunshine per annum, the location is quite ideal for such a scheme.

The scheme in figures

In total, the 2,650 solar cells occupy a 30,000 square-metre-wide surface, totaling 80% of the warehouse’s roof. By converting solar radiation directly into electricity, these panels are expected to generate more energy than the 1 million kWh needed on-site for daily operations. Over a year, production can reach 1.65 millions kWh; in other words, the solar cells can generate the equivalent of the yearly energy consumption of 500 households. Economically speaking, the whole device costs €8.2 million.

As a rule, French local Government provide a substantial financial support for such undertakings in order to promote use of renewable energy. For instance, Carrefour, which put in place a similar project – to a smaller extent though – on the roof of its Nîmes supermarket, took advantage of a Central State subsidy which represented 40% of the €300,000 required to set up the whole scheme.

As a matter of fact, Faure & Machet is not responsible for the energy production and has no direct use of it. FM Logistic receives a €15,000-fee per month so that Laudun Energy can use the warehouse roof to produce electricity. Laudun Energy, which made the initial investment of €8.2 million, is the company responsible for the electricity production. Another provider got involved to set up the entire installation: Urbasolar.

The electricity produced is then sold to EDF, the French electricity supplier, and not used to run the on-site operations. This financial device is directly due to EDF’s choice to promote and favour the use of “greener” electricity, that is to say, produced from any sorts of renewable source. Thus, the French electricity provider buys over at a higher rate electricity produced with photovoltaic cells. Therefore, from FM Logistic viewpoint, it is definitely more interesting to sell out – via Laudun energy – the electricity produced at the price of €0.57 per kWh, and to buy the electricity needed for the platform operation at a 6-time lower rate of €0.10 per kWh. A brief calculation shows that in about 10 years, Laudun Energy will have paid back its initial investment. The initial contract foresees that FM Logistic will own the system, once the solar panels have been operated for 25 years. Moreover, Urbasolar is supposed to perform maintenance, and ensure a cleaning and a complete check-up once or twice a year. The profitability threshold will thus depend on the cost of these services.

According to the project managers’ point of view, most of existing warehouse roofs can be similarly equipped to produce electricity. Since the technology used in the FM Logistic-Carrefour scheme is very light (5 kilogrammes per square metres), no changes in the warehouse frame were needed. In 2009-2011, the warehouse will be extended to 90,000 square metres, built over a 19 hectares lot – being presently 15 hectares.

Fast facts about FM Logistic

2007 turnover: €600 million (58% in warehouse management, 23% in freight transport, 17% in products-packing and –manufacturing activities);
Surface operated: 2 million square-metres; and
Payroll: 13,000 employees.

Solar cells when compared with other electricity production means

The French Environment and Energy Management Agency (Ademe) released in 2007 the following table showing the equivalent amount of CO₂ (in grams) that are rejected in the atmosphere to produce 1 KW.h of electricity for various technologies (nuclear, hydraulic, etc.). These outcomes have been established by taking into account the whole of the lifetime cycle of the specific technologies, including design and construction, transport, direct operations, etc.

Technologies	Direct operations	Rest of lifetime cycle	Total (equivalent grams of CO₂ per KW.h produced)
Nuclear	0	5	5
Fuel/Gasoline	646	175	821
Wind	0	3 to 24	3 to 24
Photovoltaic	0	60 to 250	60 to 250
Coal (600 MW)	887	114	1001

It is to note that the uncertainty for wind and photovoltaic depends on the nature of electricity used in the construction phase of the different systems (nuclear, gasol, coal, etc.).

Basically, since each country has its own and specific way of producing energy, it means that depending on the country considered, photovoltaic cells schemes do not display the same level of pertinence. For instance, in Germany where more than half of the electricity produced comes from coal power stations, solar cells are an interesting alternative. Indeed, Germany is a leading country in Europe with regards to the amount of solar technologies projects. The existing installations already generate a total of more than 1 GW.h per annum (compared to 23 MW.h p.a. in France in 2007, the Earth Policy Institute estimates that this figure reaches 12.4 GW.h per annum for the whole world).

References

Article: Produisez de l’électricité solaire sur le toit de votre entrepôt, Nathalie Arensonas, Transports Actualités, Apr. 2008: here
Report: GUIDE DES FACTEURS D’EMISSIONS (Version 5.0) – Calcul des facteurs d’émissions et sources bibliographiques utilisées, Adème, Jan. 2007

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