The sun and the wind are impossible to control. If they are to become the pillars of the new energy world, the power system will need a lot of flexibility. But what does that mean? Where does flexibility come from? And how does it work?
When the sun is shining, EV-chargers automatically start charging electric cars. When the wind is strong, the heat pump starts up, taking advantage of cheap electricity. This is how flexible small consumers could help keep electricity generation and consumption in balance at all times. This principle will be essential for a stable power supply. But how can residential and commercial electricity consumers actually contribute to the overall stability? In what ways are they already doing this today? And could this well-intentioned adaptation lead to unwanted effects?
“According to EU calculations, the demand for flexibility will increase by 133 percent between today and 2030, and by another 25 percent between 2030 and 2050,” says Michael Villa, Managing Director of the European industry association smartEn. Members of this association are working on making consumer-side flexibility usable for the power system. It will require technical solutions for controlling flexible loads, service providers that unite various players, and financial benefits for shifting energy consumption. For Villa, consumers are the key to a cost-effective energy transition because they are particularly good at providing flexibility throughout the day. “Tomorrow’s energy system will be based on renewable sources and will require a very high flexibility on a daily, rather than weekly or seasonal basis,” he says.
The term “grid-serving” is often thrown around in discussions about flexibility, but it’s rarely used correctly. With the exception of a few pilot projects, flexible loads are generally unaware of the grid status. They’re optimizing completely different target figures. The VDE study “Flexibilization of the Energy System” distinguishes between three different functions of flexibility.
The first and easiest way to benefit from flexibility is optimizing on-site consumption. This function has been standard for home energy systems for years. People who link their PV system to a battery, heat pump and electric car, usually also use a Home Energy Management System, or HEMS for short. Its primary goal is to minimize the amount of electricity drawn from the power grid by first using self-generated solar power. The E-Smart complete system by M-TEC combines battery storage system, heat pump, EV-charger and an additional heating element for hot water production, for example. A visualization shows where the energy comes from and where it goes. The E-Smart energy control center can be controlled via smartphone, for example to configure settings.
Charging solutions that use the same grid connection for several EV-chargers also qualify as optimization of on-site consumption. They ensure that the given capacity of the grid connection is not exceeded during the charging process – because laying a new cable is expensive.
Just like any other market, the electricity market ensures that supply and demand in the power grid automatically respond to each other. The VDE study refers to this other type of flexibility as “system-oriented”. The basic principle is this: When there is plenty of sun and wind, electricity on the European Energy Exchange EEX becomes cheaper. Normally, end customers aren’t aware of any of this, because most energy suppliers provide their electricity at a fixed price. One of the pioneers for dynamic electricity tariffs is Tibber: The company directly links the commodity price to the market value of electricity. Such a pricing model can be beneficial to consumers, provided they are able to respond to the price signals. The HEMS shifts the heating time of the heat pump or the charging time of the electric car according to the electricity tariff.
In Germany, more and more electricity suppliers are starting to implement the same model, and by 2025 at the latest, all suppliers will be obligated to offer at least one dynamic tariff that responds to the market conditions. A smart meter is generally required for tracking and billing consumption. The amount of money that can be saved with this system varies greatly. According to a study conducted by r2b energy consulting, under ideal conditions, the cost of charging an electric car in winter can be reduced by 88 percent. In the summer, however, the savings are significantly lower because the car is usually not plugged into the EV-charger during the midday peak of solar power. In order to pass on these cost advantages to their customers, some system manufacturers, such as M-TEC, also offer a flexible electricity tariff.
When several home energy systems are pooled together and reach a considerable size in terms of total output, the systems can market their combined electricity – so not only do owners get cheaper electricity, they can also sell it back to others. Aggregators, such as Next Kraftwerke, exist to handle this transaction. The B2B service provider ISON provides support in coupling decentralized systems to the electricity market. “We offer home energy solution providers, energy suppliers and hyperscalers the possibility of enhancing their product range by connecting it to the energy market,” says Sebastian Mahlow, Managing Director of ISON. Hyperscalers provide easily scalable cloud services with high computing power, that are also becoming more active in the energy industry.
ISON’s service includes locally installed hardware for measuring, controlling and forecasting residential electricity supply and demand, as well as demand-side management. “We control either the manufacturer’s HEMS or cloud interface, or devices such as EV-chargers or heat pumps directly,” explains Mahlow. The end customers are part of a pool that takes part in the electricity market. “This accelerates the systems’ amortization by around four years on average,” Mahlow cites one benefit. The end customer usually isn’t aware of these meshing interfaces, because ISON acts as a white label supplier in the background. For the end customer, the entire process – from purchasing a home energy system to billing for the electricity used – is handled by their usual suppliers.
The open source software platform OpenEMS is also designed to bring together electricity markets and hardware. It’s like Linux for HEMS, and thanks to its open interfaces, it is compatible with devices from any manufacturer. This allows practically all EV-chargers, heat pumps and battery systems to be freely integrated into a single overall system. “Only when people have real freedom of choice can market competition flourish,” explains Christof Wiedmann, member of the board of directors at the OpenEMS Association. As the name implies, it’s not a company – making it consistent with the open source concept. Various developers and companies are involved in OpenEMS, including storage system manufacturer Fenecon, which also uses the platform for its residential storage systems. Combined with the hardware, service and branding of Fenecon, OpenEMS becomes Fenecon energy management FEMS. OpenEMS can also respond to dynamic electricity tariffs or grid charges – provided there are any of the latter.
At certain times, the capacity of a transmission or distribution grid may be at risk of being exceeded. This is where grid operators intervene. An established win-win principle for this are special tariffs for heat pumps in the distribution grid, where distribution grid operators offer a discount on grid charges. In return, they can turn off devices on an hourly basis when the grid is at risk of congestion. The house still stays warm – after all, the systems are equipped with heat storage systems.
There’s another, brand new regulation in Germany: The amended Section 14a of the German Energy Industry Act (EnWG) allows grid operators to curtail EV-chargers and heat pumps when there is a risk of grid congestions at certain points. However, this requires the devices to have the necessary interface. In return, grid operators cannot refuse to connect such consumers on the grounds that they could overload the grid. The German Association of Energy Market Innovators (bne) describes the amendment as a “balanced compromise”. But according to the association, it will take some more time for it to take effect. Especially the necessary control devices on the consumer side and the measurement technology on the supplier side are still scarce.
Consumer-side flexibility and its integration into the energy system is an important topic at EM-Power Europe , the international exhibition for energy management and integrated energy solutions, taking place in Munich from June 19–21, 2024. Learn more at the exhibition booths of M-TEC, ISON, Next Kraftwerke, OpenEMS Association, the associations bne and smartEn and many other innovative companies. The exhibition will also focus on the modernization and digitalization of the power grid into a flexible smart grid, system integration of decentralized systems, advanced metering infrastructure, energy monitoring and management and energy as a service. Flexibility will also be an important topic at the EM-Power Europe Conference on June 18 and 19, 2024, in Munich.
EM-Power Europe is part of The smarter E Europe , the continent’s largest alliance of exhibitions for the energy industry. 2,800 exhibitors and 115.000+ energy experts are expected in Munich from June 19–21, 2024 at the four concurrent exhibitions Intersolar, ees, Power2Drive and EM-Power Europe.
