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More and more people want to invest in photovoltaic and battery storage systems. However, there are a number of myths that can cause disappointment among customers, according to a German consumer association.
Domestic demand for rooftop PV systems and residential batteries continues to grow. In order to meet the expectations of homeowners, Verbraucherzentrale NRW – a German consumer association – is trying to clear up false expectations about photovoltaic installations that could disappoint prosumers.
“It is important to be aware of the personal objectives of the use of photovoltaic energy and to inform yourself. This way you can avoid disappointment and use solar energy really efficiently,” says Sören Demandt, Digital Energy Transition Analyst at Verbraucherzentrale NRW.
The first mistake is to promise people that they can be self-sufficient with photovoltaic systems and storage systems. This is not true, because PV systems and home storage solutions can only cover a certain proportion of households annual electricity supply.
The degree of self-sufficiency that can be achieved ranges from 25% to 90%, depending on the level of energy consumption and whether or not storage is installed. Especially in the winter months, the amount of solar power that can be generated is far from sufficient, so you have to buy power from the grid, Demandt explains. Full self-sufficiency can only be achieved with additional seasonal storage, such as hydrogen.
“However, that is technically complex and hardly makes economic sense for a residential unit,” Demandt says.
Another misconception is the belief that a photovoltaic system is only worthwhile in combination with a battery. Some homeowners seem to believe that feeding solar power into the grid is not an economically attractive option.
“A photovoltaic system is economically worthwhile, even without storage,” says Demandt. "Whether installing a battery in addition to the photovoltaic system is feasible depends on several factors: mainly, the consumption profile of a home and electricity costs."
Therefore, owners should check their self-consumption levels without storage. They can compare the higher levels of self-consumption through battery storage with the actual costs of electricity.
Verbraucherzentrale NRW also rejects the idea that south-facing roofs are always better for PV systems than east-west ones. It is not just about generating as much solar energy as possible, but about generating electricity when it is needed. The annual yield of a photovoltaic system on a roof facing from east to west is only 80% compared to a roof facing south. However, the performance of east-west rooftop solar systems can be spread over an entire day, as the systems still receive a significant amount of sun in the morning and afternoon.
Many people who do not have roofs for photovoltaic installations often consider investing in plug-in solar devices. They can be installed on balconies or gardens. However, if tenants expect to be able to power appliances like coffee makers, they may be disappointed.
“These panels are especially suitable for covering the base load of the home,” explains Demandt. “Electricity is used directly, for example, for a telephone, an Internet router or an alarm clock radio”.
If more power is needed, it will be supplied by the grid. This is the case, for example, of a coffee maker that briefly needs about 2,000 W to heat water. Balcony PV modules alone could not achieve this, according to Verbraucherzentrale NRW. |
