Control house storage according to network status
Electricity storage units in the basement can also be controlled remotely – and can absorb energy from wind and solar parks that is currently not needed. In the future, many such storage facilities will be able to reduce bottlenecks in the electricity grid – by storing energy temporarily.
Intermediate storage of regional excess electricity supply
Today, home storage systems are already helping some users to improve their supply of electricity from their own photovoltaic systems and reduce their energy costs. The battery enables the household to influence its electricity exchange with the grid and thus adapt to the local electricity supply – without restrictions in comfort.
If many storage facilities are combined, they can also be used to temporarily store regional energy surpluses and relieve the power grid – without having to regulate wind power or solar plants in this area. Storage units switch uniformly to charging mode, households receive more electricity, and the electricity grid can absorb more renewable energy without the client having to switch household appliances on or off. The prerequisite is that home storage facilities can “plan” congestion-related specifications of the network operator. This becomes interesting for the storage owners if they remunerated for it.
EnBW is researching how to use household storage not only for its own consumption but also for the electricity grid.
Milestones
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Spring 2016
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Development of the concept
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October 2016
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Start of testing: Three battery storage units installed for test client
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Summer 2018
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End of measurement and evaluation
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At a glance
Name: House accumulator as controllable consumption device
Status: Pilot operation
Goals: Testing of home storage facilities for a more flexible electricity grid; creating the conditions for grid-stabilizing home storage facilities to be recognized as “controllable consumption device”
Comments on the project
Optimising one’s own household with storage systems – this is what many players in the market are dealing with. What is new about our project is that even households without their own electricity generation can contribute to the integration of more renewable energy.“
Three test households
In three test households, EnBW is investigating how home storage can be controlled depending on the grid status and the electricity supply. In addition to an intelligent meter, the company has installed three identical storage units with a capacity of 25 kilowatt hours each.
At the heart of the tests is a control algorithm that temporarily stores regional excess electricity in household batteries. In the test households, EnBW is investigating how the use of home storage can prevent the shut-down of regional plants that generate renewable electricity.
The households have been selected in such a way as to cover three frequent uses and to allow the concept to reach as many users as possible.
The first household is a client who does not have any particular consumers or production facilities. This case represents the basic scenario and serves to show how a household that does not have a solar system can nevertheless contribute to the energy revolution with a battery storage system. This household will be used to clarify fundamental questions. The researchers would like to determine how well the consumption of the client can be predicted. This is necessary so that the state of charge of the battery can be controlled in such a way that the household can always be supplied from it. The optimum design of the battery in terms of capacity and performance is also tested here.
In the second pilot household, a heat pump is supplied via the battery in addition to the usual electrical appliances. Because of their technical design, heat pumps have only limited flexibility. This is to be increased via the home storage. The increased power requirement of the heat pump affects the battery capacity required. This will also be analysed in the course of the project.
The third household has a PV system. Here, it is being investigated how to increase the consumption of self-generated energy whilst relieving the grid with battery storage. In this case, the battery has a double function.
Set-up and objectives in the three test households
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1
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2
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3
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System
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1
Household with battery storage
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2
Household with battery storage and heat pump
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3
Household with battery storage and domestic production
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Objective
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1
Creating basis for recognition according to §14a
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2
Flexibilisation of the heat pump through battery and testing of a common measurement
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3
Developing and testing forecasts; testing compatibility with the Renewable Energy Sources Act
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In all three scenarios, the data and experiences collected are used to determine whether and under what conditions a battery can pay off as a controllable consumption device for the client and also for EnBW – i.e. at which battery price or with which reimbursements.
Creating a legal basis
This model works only if the legislator creates a basis for it: The Energy Industry Act (Section 14a) stipulates that less grid fees must be paid for controllable consumption equipment in the low-voltage grid – provided they have a separate point of delivery. In addition to electric cars, permanently installed heaters for room heating or hot water preparation have also been recognised by the legislator as controllable consumption devices but not home storage units. The recognition of these would better utilise the potential of home storage for the energy system.