A bright idea to reduce energy use

Tuesday, September 1, 2015

Purpose of the project

Sonae Sierra is constantly looking to improve the energy efficiency of its existing assets and has reduced electricity consumption across its portfolio by 40% since 2002 (its benchmark year). Nevertheless, in the pursuit of continuous improvement, the Company realised that there were irregularities in the energy consumption of its shopping centres that couldn’t be explained by local factors alone, and went to work on developing its own novel approach to optimising energy consumption. But how could Sonae Sierra develop a model to encompass every locally-specific characteristic?


Sonae Sierra developed Bright project to create its own model. Traditional benchmarking tools struggle to account for local or regional-specific factors, and shopping centres that are located in unfavourable climates are therefore often misinterpreted as inefficient. Bright project improves on these by allowing us to monitor the energy consumption of our shopping centres against a virtual simulation, identifying technical improvements and enhancing management practices.
The first task was to find building energy simulation software that could be adapted to deal with the necessary level of complexity. A dedicated internal team adapted a commercially available solution to create the “virtual standard shopping centre” (VSSC) tool. The tool allows Sonae Sierra to accurately predict the optimal energy consumption of every shopping centre in its portfolio.
The team developed two benchmarks: a reference benchmark and an operational benchmark. The reference benchmark calculates the optimal energy consumption of the shopping centre if it contained state-of-the-art equipment. The operational benchmark calculates the optimal consumption, based on the equipment the shopping centre actually contains. The model therefore indicates shopping centres that are underperforming due to their equipment, and those that are underperforming due to management practices.
The results of a pilot audit were analysed and shopping centres that were underperforming by the greatest margin were earmarked for on-site visits. The use of the reference and the operational benchmark allowed site visits to be targeted towards either technical performance or management practices. 


The results are impressive with a pilot audit at LeiraShopping producing significant results. Despite being awarded the highest energy efficiency certificate (A+), the centre was among the largest electricity consumers in our portfolio. Bright project identified a number of deviations from the optimal energy consumption of equipment such as chillers and air handling units. The findings where checked on site and a number of measures (representing an investment of $58,000) were implemented and monitored for a year. As a result, LeiraShopping reduced its electricity consumption by 29% between 2011 and 2013, which corresponded to financial savings of €139,000.
From the end of 2012 until the end of 2014, Bright project identified improvement measures at 28 shopping centres which, if implemented, could save a total of $4.9 million annually (based on average electricity costs). We estimate that around 40% of these savings will have a payback of less than one year, with the remaining within four years. Needless to say, the GHG reductions associated with these reductions are considerable. Moreover, Sonae Sierra has begun to offer this service to third parties.
What started as a process of fine tuning an internal benchmarking tool ended up unveiling a huge potential to improve energy efficiency and reduce costs across our portfolio. Furthermore, Bright project makes it possible to not only track the energy performance of our shopping centres, but also define yearly performance targets and support investment decisions at the corporate level.


Our Business Strategy encompasses a focus on a set of sustainability priorities with the aim of creating a virtuous circle whereby we address the primary sustainability risks facing our operations in order to safeguard our continued capacity to do business. One of the priorities has been the investigation on “ways” to reduce the environmental impact of our shopping centres as part of our long-term focus on Safe People and Eco-Efficiency. As an example, over the last two years we have developed the Bright and Dive projects, theoretical modelling tools that enable us to calculate shopping centres’ optimal energy and water consumption respectively in order to compare this with their real energy and water usage.

- Sonae Sierra