Is solar energy environmentally friendly

Photovoltaics: How environmentally friendly is solar energy really?

  • Clean, cheap and well hidden on the roof: solar power enjoys a particularly high reputation among modern energy sources.
  • What does it mean, how environmentally friendly and cost-effective is photovoltaics really?
  • The most important questions and answers.

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Along with wind power, solar energy is considered to be the energy source of the future: Last year not only did the demand for photovoltaics increase, the prices for solar power also fell. The International Energy Agency (IEA) recently revised its previous forecasts for the cost development of solar energy downwards again and spoke in its current report of increasing demand. So far, wind and solar energy have made up around 42 percent of electricity prices in Germany, and around 21 percent in the EU.

Accordingly, solar energy is being researched from many perspectives - how photovoltaics, for example, can be designed to be as environmentally friendly as possible, how it becomes the safest possible source of supply and does not contain any other pollutants.

Here you will find the most important questions about solar energy and their answers from the point of view of science and consumer protection.

How environmentally friendly is solar energy really?

In science, photovoltaics are very environmentally friendly, even in comparison to other renewable energy sources such as biomass, geothermal energy and hydropower. Compared to fossil energies, the differences in CO2 intensity are considerable: while solar power releases around 60 grams of CO2 per kilowatt hour, fossil power plants such as lignite and hard coal release around 1,000 grams.

And even this output could be reduced, says Harry Wirth, division manager for photovoltaics, modules and power plants at Fraunhofer ISE, in an interview with our editorial team. The more renewable energies are already used in the production of the photovoltaic modules, the better the environmental balance of the solar system. If modules are imported from abroad, for example, the emissions that are emitted for a product increase.

In addition, there is a return policy for photovoltaic modules in the EU, so manufacturers must undertake to guarantee a certain quota of free returns. "Overall, the industry has taken recycling very seriously," says Wirth.

Thanks to a special recycling system, the modules did not end up in the usual landfills, but were instead forwarded to certain companies that separate and reuse the individual substances. However, some parts of the modules cannot yet be recycled to cover costs, explains Wirth, including copper, silicon and small amounts of silver, for example. But here, too, research is being carried out to further increase the recycling rate.

Do solar systems contain dangerous substances?

In fact, some photovoltaic modules contain small amounts of lead, some of which is found in the solar cells themselves or in the material with which they are soldered. Wirth estimates the market share of such modules to be relatively high, also because photovoltaic modules do not yet come under the relevant EU directives that prohibit the use of lead in products.

"Today it is technically no longer a problem to do without lead," says Wirth. There are many products and technologies that can do without lead in solar systems. For example, solar cells are glued instead of soldered in order to dispense with lead in module production.

How do you tell the difference as a private consumer? Some companies already advertise lead-free modules, otherwise Wirth advises: "Just ask the manufacturer - that will also generate the demand that the market needs in this area."

How environmentally friendly are solar systems?

Julia Wiehe is a scientist at the Institute for Environmental Planning at Leibniz University Hannover and is concerned with how renewable energies can be used particularly efficiently and at the same time in a manner that is environmentally friendly. The most sensible use is still on the roof, since solar cells here have no impact on the landscape and nature.

However, the existing potential for roof areas in Germany has not yet really been used. This is also due to the fact that the so-called self-consumption levy makes it economically more worthwhile for some system operators to limit their system to a certain size. However, says Wiehe, a nature-friendly energy transition is only possible if all usable roof areas are actually available for photovoltaics.

Is photovoltaics expensive?

All in all, solar power is becoming cheaper and cheaper and whoever can obtain it from self-consumption pays significantly less for it than for electricity from fossil energy sources. However, this price saving does not necessarily apply to small systems. For example, a study by the University of Technology and Science (HTW) Berlin on behalf of the consumer advice center in North Rhine-Westphalia found that smaller photovoltaic systems have even become more expensive in the past year.

According to these calculations, solar systems with an output of up to four kilowatts are hardly profitable. Here, consumer advocates advise occupying as much of the available space as possible with modules in order to make the system more profitable. In contrast, the costs for larger systems with a capacity of twelve kilowatts or more have been reduced by around five percent.

For whom is photovoltaics worthwhile?

From a legal point of view, it is easiest for homeowners to invest in their own solar systems. "If you see that you have a pitched roof on your house that is roughly oriented to the south, the chances of a profitable photovoltaic system are initially quite good," says Wirth.

In general, a system is even more worthwhile if a lot of solar power can also be used directly by the owner. For an initial orientation of how high the return on your own system would be, Stiftung Warentest, for example, offers a return calculator that includes various factors such as the expected electricity yield, the acquisition costs, the proportion of self-consumption and the development of electricity prices.

Sources used:

  • Conversation with Dr. Julia Wiehe, Leibniz University Hannover, Institute for Environmental Planning
  • Conversation with Dr. Harry Wirth, Head of Photovoltaics, Modules and Power Plants, Fraunhofer ISE
  • Statista: Germany leads the way in wind and solar
  • Current facts about photovoltaics in Germany, Fraunhofer ISE, version from September 22nd, 2020
  • World Energy Outlook 2020, IEA (2020)
  • Environmentally friendly energy supply from 100% renewable energies 2050 (EE100), Institute for Environment Leibniz University Hannover
  • Photovoltaic price index, North Rhine-Westphalia consumer center
  • Return calculator for solar systems, Stiftung Warentest
  • pv-magazine.de: "Price index: Falling solar subsidies threaten the profitability of small photovoltaic systems",
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