OptimaSolar Worblental – A Cooperative Success Story in Renewable Energy

Integrating electric charging stations and water heaters into the development’s energy management system requires careful planning and configuration to achieve the best possible results. In addition, billing for 50 apartments—particularly responding to customer inquiries—is relatively time-consuming. For this reason, Gerber AG Energietechniktook over the Utzigenrain property effective January 1, 2023. The company handles billing, conducts periodic system inspections, and provides recommendations for optimizing self-consumption.

The metering concept took into account not only the meters for the individual apartments, but also the photovoltaic system, the electric vehicle charging stations, and the water heaters. The first MID meters from smart-me AG were successfully integrated into the project in 2018. To manage peak loads and maximize self-consumption, the project utilizes the intelligent energy management system from smart-me, flexible rate models in smart-me Billing, and (as of the end of 2023) the load control system from Loxone. These systems help distribute and optimize electricity consumption to prevent overloads and thereby reduce electricity costs for residents.

The most common strategy for increasing self-consumption is to control hot water production. However, every apartment in Utzigenrain has its own water heater, which makes optimization complex. Not only must current PV production and the water heaters’ electricity demand be taken into account, but logic must also be developed to determine when and at what level the water heaters should be activated in order to optimize self-consumption.

While simple optimizations can be implemented using the “If/Then” actions in the smart-me Cloud, a third-party system is recommended for more complex optimizations. The 50 water heaters in the housing development will therefore be controlled using Loxone in the future. When the PV system produces more energy than is currently needed in the households—that is, when a “surplus” is generated—the electric water heaters in the households are used to store hot water. The logic is set up so that the electric heating element of the water heaters is always activated whenever sufficient surplus electricity is available; grid power is used for this purpose only in an emergency. Instead of feeding the surplus electricity back into the grid at an unattractive price, it is now used for hot water production. This increases self-consumption, and the locally generated solar energy is stored in the hot water. Even more important, however, is the reduction in peak load(s) s achieved by the staggered activation of the water heaters, which results in significant cost savings.

The smart-me energy management system continuously monitors current energy generation and consumption. This information is transmitted in real time by Loxone. Loxone then sends control signals to the smart-me meters, which regulate the boilers via their digital outputs. Data is transferred from smart-me to Loxone via an automated API interface and incurs no additional costs.

The investment in Loxone will pay for itself within 3–4 years. Markus Streit has provided a detailed overview of peak load distribution and the resulting costs on the smart-me web portal. He used this data to demonstrate to the homeowners’ association the cost-effectiveness of further optimizing boiler loads with Loxone.

Another optimization involves the control of the electric vehicle charging stations. The management (EGU) has provided the basic installation and the ribbon cable, while the owners purchase the individual charging stations. The real-time data gives users precise insight into the charging current currently being used—that is, whether it comes from the PV system or the grid. Since the charging stations are billed at high, low, and solar rates, users have an incentive to charge their cars only when there is a PV surplus. As a result, over 80% of charging is done with locally generated PV electricity. This means that electricity from the PV system is used directly to charge electric vehicles, further reducing the amount of electricity drawn from the grid.

The charging speed of electric vehicles can also be adjusted. The Zaptec charging stations used can be controlled by Loxone at four different levels. If the PV system generates less electricity or electricity consumption in the complex increases, the charging power of the vehicles can be reduced to avoid expensive peak load(s) .

The overarching goal of the OptimaSolar Cooperative is to encourage the public to invest collectively in solar power generation and to meet their own electricity needs with renewable energy. The project continues to grow, and additional cooperatives have already been established in other regions based on the same model.

Legislators are also taking action, and in the future, it may become possible to form self-consumption groups (CSC) regardless of location. A new article, Art. 17bbisa of the Electricity Act (StromVG), is intended to enable the formation of local electricity communities (LEG), in which neighborhoods, renewable energy producers, and storage operators can join forces to supply each other with electricity. This addresses a need similar to that of self-consumption consortia (CSC), but does not require access to the public grid. Participants must be located within the same grid area and at the same grid level. This is intended to promote the expanded deployment of renewable energy generation facilities—particularly photovoltaic systems—to make their operation more profitable and to utilize the generated electricity locally. Since energy cooperatives often operate more flexibly and agilely than energy utilities, they can drive innovation in the energy sector. They can test new technologies, build efficient energy infrastructures, and develop business models that meet the needs of society.