OptimaSolar Worblental – A Success Story of a Renewable Energy Cooperative

Integrating e-charging stations and boilers into the complex’s energy management system requires careful planning and configuration in order to achieve the best possible results. In addition, billing for 50 apartments—and, in particular, responding to customer inquiries—is relatively time-consuming.

Gerber AG Energietechnik therefore took over the Utzigenrain property on January 1, 2023. It is responsible for billing, conducts periodic system checks, and makes recommendations for optimizing self-consumption.

The metering concept takes into account not only the meters for the individual apartments, but also the photovoltaic system, the electric vehicle charging stations, and the boilers. The first MID meters from smart-me AG were successfully integrated into the project in 2018. The intelligent energy management system from smart-me, flexible rate plans from smart-me Billing, and (by the end of 2023) the load control system from Loxone will be used to manage peak loads and maximize self-consumption. 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 the heating of hot water. However, each apartment in the Utzigenrain has its own boiler, which makes optimization complex. Not only must the current photovoltaic output and the boilers' electricity demand be taken into account, but a logic must also be developed to determine when and at what level the boilers should be turned on or off in order to optimize self-consumption.

While simple optimizations can be implemented using the if/then actions in the smart-me cloud, the use of a third-party system is recommended for more complex optimizations. The 50 boilers in the development will therefore be controlled using Loxone in the future. If the photovoltaic system produces more energy than is currently needed in the households—that is, if a “surplus” is generated—the electric boilers are used as hot water storage tanks in the households. The system is configured so that the boilers’ electric heating function is always activated when sufficient surplus electricity is available; grid electricity is used only in emergencies. Instead of feeding the surplus electricity into the grid at an unattractive price, it is now used to heat water. 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 loads due to the staggered activation of the boilers—and the resulting considerable cost savings.

The smart-me energy management system continuously monitors current energy generation and consumption. This information is transmitted in real time to Loxone. Loxone then sends control signals back to the smart-me meters, which regulate the boilers via digital outputs. The data is transferred from smart-me to Loxone via an automatic API interface and does not incur any additional costs.

The investment in Loxone will pay for itself within 3–4 years. Markus Streit has 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 community of owners the benefits of further optimizing boiler loads with Loxone.

Another optimization involves the control of the electric vehicle charging stations. The administration (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 actually being used—that is, whether it is coming from the photovoltaic system or from 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 excess photovoltaic power. This means that over 80% of charging is done using locally generated photovoltaic electricity. As a result, the electricity from the photovoltaic system is used directly to charge the electric vehicles, further reducing grid consumption.

The charging speed of electric vehicles can also be adjusted. The Zaptec charging stations in use can be controlled by Loxone at four different levels. If the solar power system generates less electricity or electricity consumption in the building increases, the charging power of the vehicles can be reduced to avoid costly peak loads.

The overall goal of the OptimaSolar cooperative is to encourage the public to invest collectively in solar power generation and meet their own electricity needs with renewable energy. The project continues to grow, and similar cooperatives have already been established in other regions.

The legislature is also taking action, and it may be that in the future it will be possible to form associations for self-consumption (CSC) regardless of their 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 fulfills a need similar to that of the association for self-consumption (CSC), but may also make use of the public grid. The participants must be in the same grid area and at the same grid level. This is intended to promote the increased expansion of renewable energy systems, particularly photovoltaic plants, so that they can be operated more profitably and the electricity generated can be used locally. Since energy cooperatives are often more flexible and agile than energy suppliers, 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.