Climate change, transition to clean energy, fossil-fuel phase-out, nuclear power phase-out – These are all terms that come to mind when talking about renewable energies. In a short fact check, we want to take a closer look at the most frequent questions regarding effectiveness, costs, efficiency and environmental friendliness of PV energy.

Is it effective to use PV energy and renewable energy sources?

Does PV energy make a meaning contribution to the supply of electrical power?

Yes, Germany is a good example: In 2019, PV energy contributed about 8.2% of the total power consumed in Germany. All of the renewable energy resources together contributed about 43%. PV energy is becoming increasingly important and will become a core component of a sustainable energy future.

PV energy is just a German phenomenon?

No. Germany has indeed played a pioneering role in some areas of PV energy, but in the meantime, PV energy is used all over the world. As of 2019, there were 1.7 million PV plants in Germany with an output of 49 GW. Just in 2019 alone, there were an additional 115 GW installed around the world. China is the forerunner with new installation, followed by the US, Japan and Germany.

PV energy Diagram

Economic aspects of the PV industry

The German PV manufacturers are under enormous pressure, especially from the Chinese competition. Yet, the PV industry in Germany employed about 24,000 people in Germany in 2018 [BSW]. Many of these jobs involve manufacturing inverters and installation. In addition, there is a steady demand for intelligent solutions to manage and monitor PV plants and their yields. Medium-sized companies like Solare Datensysteme GmbH have focused on this sector and provide smart solutions for the international market.

What does PV energy cost us?

Nuclear power is cheap?

This is only true when nuclear waste disposal and the risks of accidents are not factored into the equation. The Fukushima Daiichi nuclear disaster will cost well over $100 billion. And this does not even take the human tragedies into account. (
If you are interested in nuclear accidents and their costs over the last decade, here is an overview ( (German)).

To date, there is no solution on how to “dispose” of nuclear waste. The disposal of nuclear waste is a bit of misnomer. It takes 10,000 to millions of years for nuclear waste to no longer be radioactive. German states dispute where “suitable” storage can be found. One site needs to be defined by 2031.

And at the same time, there is increased support for using nuclear power plants to meet climate protection targets. Here it is important not to overlook the risks of nuclear power and that there are alternative sources.

Using PV power directly – self-consumption

The range of potential applications of PV power has increased greatly in recent years (Link last blog article), especially in regard to self-consumption. When one uses the power directly, there is no need to buy electricity from power plants. At the same time, one is not affected by future power price increases.

An example: Take, for example, a four-person household that consumes 4500 kWh a year and has a 5-kWp PV plant on their roof. This PV plant provides the household with about a third of their yearly consumption (ca. 1500 kWh). The results in a savings of about 460 EUR per year with an average electricity price of 30.85 cents per kWh (or about 9250 EUR during the 20-year plant operating life).

Are PV plants efficient?

How efficient are PV plants, for example, in Germany?

There is a performance ratio value (PR value) to calculate the efficiency. The PR value is the ratio between the maximum achievable yield and the actual amount of PV power produced. The efficiency of a plant can be determined from this value. The higher the percentage, the more efficient the PV plant is. (More information available at:

A new PV plant in Germany achieves a PR values of 80 to 90%. (Source: ISE

Another indicator is the specific yield. The specific amount is calculated from the ratio of the power yield kWh in relation to the installed capacity kWp. Last year, a good average value was 1100kWh/kWp and about 1350 kWh/kWp the maximum. In southern Spain or Northern Africa, the specific yield can be as high as 1600 kWh/kWp (Source: ISE).

PV energy Diagram

Specific annual yields for roof-top photovoltaic pants in Germany from 2012 to 2019. The bars indicate the areas in which the specific yields of good photovoltaic plants should lie in the individual years. (Source: ISE )

Module power

The module power output is another factor for yields. The more output that a module has, i.e. the amount of sun that can be converted into power, the higher the efficiency. Efficiencies of up to 24.58 percent can now be achieved. The prices of the modules thus continue to fall indirectly.

Cell type Efficiency
Monocrystalline 20 – 22 %
Polycrystalline 15 – 20 %
Amorphous silicon 8 %
CIGS cells 12 %
GaAs cells 25 %
Dye-sensitized solar cells 2 – 3 %

Are PV plants environmentally friendly?

Do PV plants make an effective contribution in reducing CO2 emissions?

When producing power, a PV plant does not produce any CO2.
In order to obtain a comparable value, one has to take CO2 emissions during production and disposal into account.

PV energy Diagram

Average CO2 equivalent emissions of different power producing technologies [EnAg] (Source: ISE)

Here is a look at global CO2 emissions from electric power production (gCO2eq/kWh):

Does PV energy reduce CO2 emissions?

Last year, 2019, CO2 emissions were 44% lower than those from 1990. The biggest factor here was the decline in the number of coal-fired power plants by around 25 % compared with 2018. In addition, the expansion of renewable energies, which recorded a growth rate of 9 % in 2019, contributed to a healthier environment. (Source BDEW).


The numbers show that we are on the right path, but there is still more to do.
PV energy makes an important contribution in reducing CO2 emissions. PV energy makes a relevant and increasing contribution to the electric power supply. And PV energy efficiently supplies electricity for public energy supply.
Yet, there is still a ways to go. To achieve the government’s climate targets, it is necessary to continually expand renewable energy sources. This cannot be achieved without a contribution from the general public. One must not forget, however, that the general public ultimately benefits most from an effective climate policy.