Experts from the Solar Center Berlin: “Defined interfaces are necessary”
Community electricity supply differs from previous models. What are the advantages and disadvantages compared to tenant electricity?
Elisa Förster : The GGV is easier to implement, especially for smaller condominiums where tenant electricity isn't cost-effective. Furthermore, individual tenants retain the option of keeping their current supplier and choosing freely. This is different with tenant electricity. All participating residential units then have the same supplier for their residual electricity. Tenant electricity, on the other hand, offers more revenue options for operators. They can then link solar power to grid electricity for calculation purposes and sell it as a single tariff. The procurement of residual electricity then generates additional revenue. In addition, there is the tenant electricity subsidy, which isn't available with the GGV.
Jessica Grunert : Furthermore, with a GGV, some supplier obligations are eliminated. And users don't have to cancel their existing electricity contract; they simply receive additional, affordable electricity from the roof. This is an advantage of GGV over tenant electricity, especially in existing buildings and condominiums. It can be very economically attractive if the billing is handled independently. A disadvantage of GGV is that the parties each receive two bills, and smart metering systems must be available.
What about the technical effort?
Jessica Grunert : For tenant electricity, a physical or virtual totalizer can be used. With the GGV (general electricity distribution system), it's always a virtual model. This eliminates the need to install a physical totalizer. This takes up a lot of space and is also expensive. Although in Berlin, for example, there is a subsidy for this.
Tenant electricity is usually implemented with an external service provider. Is such a service provider also necessary for the GGV?
Jessica Grunert : Unfortunately, at the moment, yes. Many metering point operators with primary responsibility don't yet offer metering and the necessary balancing themselves. In such cases, either a competitive metering point operator must be used, or, for example, a balancing service provider is required to allocate the individual electricity quantities and report them to the grid operator. A service provider is not necessarily required for the billing itself; this is less complex than with tenant electricity.
Homeowners want to invest in photovoltaics – but need financing
Which solution – GGV or tenant electricity – is more cost-effective for users?
Jessica Grunert : That always depends on the framework conditions: In a pilot project in Berlin, for example, the GGV is very inexpensive for users: PV electricity can be offered for 17 cents per kilowatt hour.
Elisa Förster : With tenant electricity, the price depends heavily on whether a third-party provider is involved. Typically, this involves a mixed calculation, where users receive the total electricity for, say, around 30 cents per kilowatt hour. However, with a shared ownership agreement, a residual electricity supply is also required, which is more expensive than solar power from the roof. If a condominium association implements a tenant electricity concept itself without a service provider, the price will likely be similar to that of a shared ownership agreement.
What is the tax classification of solar power supplied under a GGV?
Jessica Grunert : Essentially, the same exemptions and limits apply as for tenant electricity—such as the zero tax rate for PV systems on residential buildings or the income tax exemption up to 30 kilowatts per unit and a maximum of 100 kilowatts per operator. The same tax allowances apply to trade tax as for tenant electricity, amounting to €24,500 in profit per year. However, tax advice should always be sought in individual cases.
Renewable Energy Association calls for new concepts for solar energy in Lower Saxony
Are there other models besides tenant electricity and GGV?
Elisa Förster : Yes, for example, collective self-sufficiency, the so-called single-meter model. Here, the condominium association operates the solar system and purchases all the remaining electricity jointly. To the grid operator, the entire building is a single consumer, and the electricity bill is paid. The condominium association then bills each other for the electricity consumption of the individual apartments. It works like central heating: a shared supplier, internal distribution, no electricity supply contracts. However, it requires everyone to participate. And it's a model primarily for smaller condominium associations. All residents have the same electricity supplier.
The interview was conducted by Sven Ullrich.
In the first part of the interview , Elisa Förster explains how the communal building supply works and what technical requirements are necessary for it.
The SolarCenter has created a flyer on the topic of shared building supply , which is available for download on the advisory center's website. The SolarCenter is a product- and manufacturer-neutral information and advisory center on solar energy – funded by the Berlin Senate Department for Economic Affairs, Energy and Public Enterprises and implemented by the Berlin-Brandenburg regional association of the German Solar Energy Society.
erneuerbareenergien
