How many solar cells were made

Solar energy in Germany - an eventful history

What is solar energy?

Solar energy, i.e. with the help of the sun, can be used in two ways: in the form of heat (solar thermal energy) and by converting radiation energy (see irradiation map) into electrical energy (photovoltaics).

The Solar thermal uses the heating of collectors by the radiant heat of the sun. The solar energy absorbed in the thermally insulated tube system heats a carrier liquid. An oily mixture of propylene glycol and water ("antifreeze") or pure water can serve as a carrier medium. The energy absorbed by the carrier medium is used to heat domestic water or to support heating.

In the Photovoltaic the solar radiation energy is converted into electrical energy using the photovoltaic effect. (More on this under: How does a photovoltaic system work?). Individual solar cells generate only low voltages and currents. Only when the cells are connected to form modules and the modules are interconnected do technically usable voltages and currents arise.

What does "solar" mean?

In the scientific community of the 19th century, the adjective “solar” was derived from the Latin word “solaris” or “solarius” and means “relating to the sun, belonging to it, proceeding from it”.
In compositions such as solar cells or solar energy, “solar” serves as a defining word - here “cell fed by the sun” or “energy emanating from the sun”.


Increasing use of solar energy

Solar energy in Germany is a topic that causes both euphoria and disillusionment. The boom that photovoltaics has experienced in Germany over the past few years provides an occasion for euphoria. At the end of 2015, around 6% of the electricity required in Germany was generated by around 1.5 million photovoltaic systems. Disillusionment arises from the declining number of new buildings in recent years. For 2015 and 2016, an expansion of 2.4 to 2.6 gigawatts (GW) was required, and systems with an output of around 1.5 GW were implemented. In 2017 it was around 1.75 GW, even if the newly installed photovoltaic capacity was still below the target corridor. Returns were recorded for almost all system sizes - only small photovoltaic systems with an output of up to 10 kW were stable with almost 18% expansion.

Tip: Find out more about the costs, subsidies and tax aspects of photovoltaics here.

Influence of the EEG on the addition of photovoltaics in Germany

The Renewable Energy Sources Act (EEG) introduced in 2000 with its legally guaranteed feed-in tariff laid the foundations for the solar boom. German companies have made solar energy globally competitive. With the first amendment to the EEG in 2004, a rapid expansion of photovoltaics began in Germany; growth then stagnated at a high level from 2010 to 2012 (approx. 7.5 GWp per year). After 2012, the demand for PV collapsed by 80%. The Bundesverband für Solarwirtschaft e.V. (BSW) saw the cause in the fact that various EEG amendments have massively worsened the framework conditions for photovoltaics in Germany (source: BSW-Solar statement on the BMWi photovoltaic market analysis, Berlin, 13.03.2015)

As a result, the expansion targets set by the federal government of 2.5 gigawatts per year were clearly missed again and again. For 2015 and 2016, an expansion of 2.4 to 2.6 gigawatts (GW) was required, and systems with an output of around 1.5 GW were implemented. In 2017 it was around 1.75 GW, even if the newly installed photovoltaic capacity was still below the target corridor. Returns were recorded for almost all system sizes - only small photovoltaic systems with an output of up to 10 kW were stable with almost 18% expansion. A certain recovery can only be noted for the years 2018 with almost 3 GW and 2019 with almost 4 GW of photovoltaic additions.

The worsened legal framework had a devastating effect on the German solar industry: “The massive collapse of the internal PV market has long had serious effects on all stages of the value chain in the German PV industry. The number of employees in the solar industry has already more than halved, hundreds of companies have shut down their PV business operations or even had to file for bankruptcy, ”the BSW wrote in its 2015 statement. Of the once around 350 solar companies in Germany, there were only a few dozen left in 2019 - including SOLARWATT. A total of around 80,000 jobs were lost in the German solar industry.


PV expansion in numbers

yearExtension / MWpTotal / MWp

Source: Statista

PV energy continues at an all-time high in electricity production

Although the number of new builds is stagnating in Germany, the share of solar power in the German electricity mix continues to rise. This is mainly due to the increasing efficiency of the photovoltaic systems.

Share of renewable energies and photovoltaics in gross electricity generation in numbers

yearGross electricity generation total *Electricity from RE *Share of RE in%Gross power generation PV *Share of total in%

* Figures in billions of kWh

Swell: Total gross electricity generation and electricity from renewable energies - Federal Environment Agency, share of renewables and gross electricity generation from PV - calculated, share of PV in total gross electricity generation - Statista

Note on the numbers

Depending on the source, the exact information on gross electricity generation and the proportions of photovoltaics differ. Other lists use the net electricity generation (the amount of generated electrical energy, from which the internal consumption of the generating plants is subtracted) or the net electricity consumption as a reference value. However, all figures speak the same language: The share of renewable energies and also photovoltaics in electricity generation and consumption is increasing in Germany.

In 2019, according to Fraunhofer ISE, photovoltaic systems fed a total of 46.5 terawatt hours (TWh) into the German grid, for 2017 the value was still 38.6 TWh, in 2012 it was 27.9 TWh. Compared to 2012, the annual production increased by around two thirds.
The share of solar energy in the total electricity mix increased from 4.2% in 2012 to 7.0% in 2019 (according to Fraunhofer ISE 9% share of net electricity generation), all renewable energy sources together accounted for around 46% of the total in 2019 public net electricity generation.

The coalition agreement of the federal government of March 2018 provides for the share of renewable energies (RE) to be increased to 65 percent of gross electricity consumption by 2030. In order to achieve this goal, a steady annual PV extension of approx. 5 GW would be necessary. Around 150-200 GW of installed PV power is required to cover Germany's energy needs predominantly or completely with renewable energies. (Source: Fraunhofer ISE - Study "Current facts about photovoltaics in Germany")

What effects did the 52 gigawatt cap have on solar expansion?

The “52 gigawatt cap” stood in the way of the ambitious expansion targets for a long time. Section 49 (5) of the 2017 version of the EEG states: “If the total installed capacity of the solar systems ... exceeds 52,000 megawatts, the values ​​to be applied according to Section 48 are reduced on the first calendar day of the second calendar month following the exceedance to zero. "

In plain language this means: At the moment when the overall expansion target of 52,000 megawatts or 52 gigawatts has been reached, there is no longer any entitlement to remuneration for electricity fed into the grid. The feed-in tariff for new solar systems would therefore no longer apply, and excess solar power could then only be "given away" or marketed directly. According to a report by the Federal Environment Agency from 2020, the existing direct marketing offers for post-EEG systems and thus also for unsubsidized systems are not economical. According to the experts, this is primarily due to the marketing costs, which are allocated to a small amount of electricity in the case of very small systems and are therefore comparatively high.

Even if this legally guaranteed feed-in tariff is no longer as high as it was in the early days of the EEG, the income that can be generated still contributes to the refinancing of the investment in a solar system. It is all the more gratifying that the 52 gigawatt cap was abolished in 2020. It was not just representatives of the solar industry who feared that after the funding had ceased, there would have been another slump in the expansion of photovoltaics.