Sustainable investing starts with calculations

Connecting a rechargeable battery to a power station is good for the electricity grid, but is it also good for the power station? And what is the best solution, then? BECC Energy Hub called in expert advice to answer that question, including identifying the right partners to build and manage such a battery.

Business case

Robert Kleiburg, CEO of Recoy: "Everything starts with the customer's vision of the need for flexibility in the energy system. We guide the steps to convert that vision into a business case, and when purchasing this battery, we also participated in selecting the model and supplier."

The need for flexibility stems from the advances in solar and wind farms in power generation. Production from these two significant sustainable sources depends on weather conditions. Therefore, it is usually out of sync with the electricity needs of companies, public facilities, and households. With this variable supply, network operators still have to guarantee that alternating current with a voltage of 230 Volt and a frequency of 50 Hertz will come from the socket. This is only possible if other producers absorb the fluctuations in sun and wind.

BECC's decision to use its own battery to stabilize the electricity network sounds simple, but such an installation expansion requires much thinking and calculating. So Recoy analyzed the conditions under which the investment would be profitable.
Kleiburg: "Consumers are now also offered a price that varies per hour from some suppliers. You have to adjust your consumption accordingly. For a battery like BECC's, it works both ways. You want to charge at a low electricity price and discharge at a high price."

Those who want to respond to this must be alert 24 hours a day. It is not possible to do that manually. Based on five years of experience, Recoy has developed algorithms that respond to current and expected price developments. BECC's battery can switch every 15 minutes or every hour, depending on the market segment. In practice, the calculations predict this is sufficient flexibility to recoup the investment in the long term.

Consumers are now also offered a price that varies per hour from some suppliers. You have to adjust your consumption accordingly. For a battery like BECC's, it works both ways. You want to charge at a low electricity price and discharge at a high price.

Robert Kleiburg, ceo van Recoy

Capacity

Recoy advised BECC to use a 10 Megawatt battery from Alfen with a storage capacity of 20 Megawatt hours. That is enough to charge or discharge at full power for two hours. That seems like a short period, but BECC is not alone in balancing the electricity grid by quickly responding to peaks and troughs. There is enough variety to keep the battery working daily during dark December days and sunny summer weeks.

Kleiburg: "The puzzle is to look as closely as possible at where the attractive markets are. We opted for 10 megawatts and 2 hours. In the United States, you also see installations with 4 hours of storage capacity. In Europe, 1 hour also occurs."

The choice of the supplier was made through a tender, which resulted in five bidders. Recoy also advised on the trade-off between those five. Delivery time was an essential point for BECC. In addition, the price and the predicted wear and tear played a role. All batteries have a guaranteed number of charge and discharge cycles, with capacity decreasing over time. The choice fell on supplier Alfen, partly due to environmental considerations. BECC's battery comprises lithium, iron, and phosphate (LFP). An alternative technique works with nickel, magnesium, and cobalt (NMC). Cobalt extraction, in particular, is controversial because child labor is often used. Kleiburg: "LFP is the least problematic and also better when it comes to fire safety."

Gravel Path

The original energy storage battery initiatives used sea containers, but BECC currently boasts 56 square cabinets, each measuring around two meters high. On an empty gravel path at the site's edge, they stand in a line that extends 70 meters. "Very high tech, but you can't tell," according to BECC's Gertjan de Jong. Like solar and wind farms, the distribution across 56 boxes ensures the installation keeps working even if one of the parts breaks down. In addition, each battery cabinet in the climate-resistant housing has built-in heating and cooling. Therefore it is unnecessary to erect a shed around it.

A jungle of regulations

Connecting a storage battery to a power plant is technically complex and requires close cooperation between suppliers, installers, and licensing authorities. After choosing Alfen as the supplier and Greenchoice/Spectral for management, Guus Bengsch of Green Energy Storage from Breda came into the picture as an external project leader to make ends meet. Bengsch: "You add something to an operational center, so there is a lot to do, and almost everything is customized. This also applies to the regulations because new developments, such as battery storage, do not automatically fit into the jungle of rules and regulations. Of course, it says something about the storage of batteries, but then you are talking about a warehouse with telephone batteries, for example. So I sometimes have to explain that those regulations are irrelevant to our project."

It was also his job to coordinate the activities of all parties involved so that the installer Modderkolk, for example, received the correct materials at the agreed times and that sufficient workspace was available on site. "In such an integration project, the people and the systems must work together. That means a lot of figuring out and fine-tuning. But, thanks to the cooperation between individuals, it all went well."