OXFAM Fair Trade: Batteries for PV self-consumption in HQ office building

The Oxfam Fair Trade headquarter (HQ), an office building located in Ghent, Belgium, has an annual energy consumption of 66,649 kWh of which 43% is covered by 306 photovoltaic solar panels in a surface of 1,456m², with a total capacity of 83 kWp. To increase its self-consumption, and reduce its consumption from the grid, Ampere Energy has installed three Tower S batteries, allowing the photovoltaic solar panels to cover up to 70% of Oxfam headquarters’ annual energy demand.

Fact sheet

  • Company: OXFAM Fair Trade
  • Location: Ghent (Belgium)


  • 4,800 kg CO2 emission reduction per year
  • Maximisation of the building’s self-consumption
  • Economic savings in the electricity bill
  • Oxfam is more socially responsible for trying to reduce its environmental impact

Fair trade and social responsibility

Since 1995, Oxfam functions as an international confederation composed of 20 non-governmental organisations (affiliates) working in almost 100 countries to fight against poverty and injustice. Every year its affiliates develop specific programmes helping more than 18 million people worldwide. One of the actions taken to fight against poverty and injustice implies equal trade relations for which reaching fair trade is a very important aspect. In this sense, Oxfam offers fair trade products supporting cooperatives and farmers, which is managed by the Oxfam Fair Trade headquarter located in Ghent. For Oxfam, social responsibility is a term that is related to Fair Trade because it involves making decisions that take into account, among other things, the environmental impact of its actions.

Oxfam offers fair trade products supporting cooperatives and farmers, which is managed by the Oxfam Fair Trade headquarter located in Ghent. For Oxfam, social responsibility is a term that is related to Fair Trade because it involves making decisions that take into account, among other things, the environmental impact of its actions.

Oxfam’s Ghent HQ has a PV plant for which Ampere Energy installed a storage system in April 2019, initially as a pilot in the WiseGRID initiative, helping to increase its self-consumption. Excluding the direct consumption from solar generation, the equipment of Ampere provides 27% of the total energy demand. These batteries, which are the model Tower S 12.5, are made up of lithium-ion cells, with 5 kW of rated power and 12 kWh of capacity (36 kWh in total) and have an estimated lifetime of around 17 years. Ampere has also integrated a new energy management system with advanced functionalities that helps maximise the building’s self-consumption.

An H2020 pilot turned reality – the European WiseGRID initiative

The storage system installed by Ampere was part of a pilot project under the European WiseGRID initiative in which two main challenges were pursued: making the most of self-consumption, increasing the energy independence of the building especially in hours without solar generation, and assessing storage possibilities in self-consumption systems, designing demand management price signals for customers. The Belgian cooperative Ecopower, partner of the WiseGRID Project consortium and in charge of supplying electricity to Oxfam, wanted to evaluate the possibilities of incorporating storage into the self-consumption facilities in the face of an imminent change of legislation in Belgium with the disappearance of bonuses for renewable energies.

Because of this, the three batteries were installed (initially as prototypes) at a total value of 30,000€ (under 1,000 EUR/kWh). The installation incorporated a new version of the battery power manager (developed by Ampere), which allows for remote management by an external application -in this case, a Virtual Power Plant-, to provide battery capacity to power grid balancing and adjustment services. This component, in the WiseGRID project, is called “Storage as a Service Virtual Power Plant” (Staas/VPP).

After validation of the pilot’s goal of integration into a VPP (in particular the one developed during the WiseGRID project) and its functionalities, the batteries remained in Oxfam’s installation as an active element to maximise the building’s self-consumption rate.

In terms of differences between the pilot and the resulting final installation, no relevant differences have been identified. Oxfam enjoys the advantages of the batteries installed by Ampere from the very first day of its implementation, with the possible interferences caused by the different flexibility service provision tests performed during the pilot.

The payback period foreseen in the initial study is 9 years if an electricity tariff without hourly discrimination is considered. With a different hourly rate, the economic benefit could increase, reducing the payback period. In addition, other revenues can be generated from the participation in energy markets, such as balancing services and flexible markets for demand management. Through the integration into a virtual storage facility, these batteries can modify their intended base behaviour to provide demand management or frequency regulation services, obtaining financial compensation for it, which would further decrease the payback period.

The intricacies of Ampere’s Integrated Energy Management System

The Ampere batteries work autonomously thanks to the built-in Energy Management System (EMS) entirely developed by the company. The new EMS includes different functionalities to maximise the building’s self-consumption:

  • Arbitration: depending on the contracted hourly discrimination tariff and using a demand forecast based on historical energy consumption, the EMS charges the battery in the cheapest hours and discharges it for consumption during the most expensive hours.
  • Self-consumption maximisation: in combination with a generation source (the PV plant), Ampere’s systems can be managed by a single device through direct connection between the hybrid inverter of solar generation and the batteries. This allows the EMS to autonomously decide, and based on optimisation, when to charge and discharge batteries throughout the day to make the most of solar generation, achieving higher levels of self-consumption and energy independence. If we add the arbitrage functionality to this, a considerable economic saving is achieved in the electricity bill for the customer.
  • Peak shaving: Ampere Energy’s equipment can limit power demand from the grid to a certain value above which the batteries would go into action to provide the extra consumption needed. This functionality could lead to significant economic savings.
  • Backup power line: possibility to connect a backup supply line, to maintain the power supply in case of incidents in the grid.
  • Feed into the grid: it allows to limit, at the user’s will, the amount of energy they can feed into the grid, from 100% of the available energy to zero
  • Remote management for Virtual Power Plant integration: the storage system installed in Oxfam was the first to have the remote management functionality for integration into the Virtual Power Plant developed in the WiseGRID project (Staas/VPP). This virtual storage plant can request to use the batteries punctually during the day to participate in grid services, considering that the alteration of the expected behaviour of the battery yields an economic benefit for the prosumer. In addition, Ampere Energy has its own virtual plant, called Amperia, currently in its last phase of development, which will serve as an integrator of all Ampere equipment in self-consumption facilities, being able to offer aggregated services of balance and flexibility where the legislation allows it.

In this last functionality, demand management can be both direct and indirect. In the direct mode there are no price signals, but a direct order of variation of the power delivered by the batteries, both to consume and to feed into the grid, for a certain period. This order is sent from the virtual plant, either the Staas/VPP plant or, in the future, Amperia.

The indirect modality would be through price signals. The EMS allows pricing by Real-Time Pricing (RTP), with variable energy prices for all hours of the day. Similarly, an energy supplier can design specific variable price signals for demand management and send them to Ampere equipment, which will vary their planning, accordingly, automatically seeking the greatest possible economic savings for the prosumer.

What the developers learnt through Oxfam’s project

It is very important to consider the exploitation model, the return on investment and the legislation related to energy and tariff schemes in each country when sizing and valuing an installation of this type, which includes self-consumption and storage with a high percentage of energy fed into the grid. Even if there are common European Union directives, the fact is that their transposition by each Member State gives rise to scenarios that may be very different across countries. In this regard, the collaboration with Oxfam was of great importance, as they allowed Ampere to make a previous on-site visit to see first-hand the facilities and assess the connection point. It was also important the collaboration with the cooperative Ecopower, as they are aware of the conditions that apply in Belgian legislation for self-consumption installations and energy feed into de grid.

Therefore, it is essential to establish close cooperation with local actors, who know first-hand the objectives that can be achieved and will benefit from the advantages offered by the installed storage systems. In the case of Ampere Energy, they had the advice and assistance from their Belgian partner Bernard Cernuta, CEO of New Technology.

Text: Creara (Madrid)
Content provider: Ampere Energy