OptimaSolar Worblental – A renewable energy cooperative success story

The integration of e-charging stations and boilers into the energy management of the complex requires careful planning and configuration in order to achieve the best possible results. In addition, the billing of 50 flats, in particular responding to customer enquiries, is relatively time-consuming.

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

The metering concept takes into account not only the meters for the individual flats, but also the photovoltaic system, the e-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 tariff models in smart-me Billing and (by the end of 2023) the load control system from Loxone will be used to deal with peak loads and maximise self-consumption. These systems help to distribute and optimise electricity consumption in order to prevent overloads and thus 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 production and the electricity demand of the boilers be taken into account, but logic must also be developed to determine when and at what level the boilers should be switched on/off in order to optimize self-consumption.

While simple optimizations can be implemented with the if/then actions of 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 regulated with Loxone in future. If the photovoltaic plant produces more energy than is currently required in the households, i.e. a “excess” is generated, the electric boilers are used as hot water storage tanks in the households. The logic is set up so that the electric use of the boilers is always activated when sufficient surplus electricity is available; grid electricity is only used 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 switching on of the boilers and thus the considerable cost savings.

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

The investment in Loxone will amortize within 3-4 years. Markus Streit has a precise overview of the peak load distribution and the resulting costs in the smart-me web portal. He used this data to show the community of owners the profitability of further optimizing the boiler loads with Loxone.

A further optimization concerns the control of the e-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, i.e. whether it is coming from the photovoltaic plant or from the grid. As the charging stations are also billed with high, low and solar tariffs, users have an incentive to only charge their car when there is a photovoltaic excess. This means that over 80% of charging is done with locally produced photovoltaic electricity. As a result, the electricity from the photovoltaic plant is used directly for charging the electric vehicles, further reducing grid consumption.

The charging speed of the electric vehicles can also be adjusted. The Zaptec charging stations used can be regulated by Loxone with four levels. If the photovoltaic plant generates less electricity or the electricity consumption in the building increases, the charging power of the vehicles can be reduced to avoid expensive peak loads.

The overall aim of the OptimaSolar cooperative is to encourage the population to invest together in photovoltaic production and cover their own electricity needs with renewable energies. The project continues to grow and similar cooperatives have already been founded in other regions.

The legislator is also moving and it may be that in the future it will be possible to create associations for self-consumption (ZEV) regardless of their location. A new article, Art. 17bbisa 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 own consumption (ZEV), 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. As 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.