This is no longer a Future Vision: Meeting the World’s Energy Needs with Solar Energy.

During the reworking of the Bavarian climate protection law, a general solar roof obligation for residential buildings has again been rejected. According to a recent study, solar cells installed on the world’s rooftops could potentially meet the world's energy needs.

A general solar roof obligation for residential buildings has again been rejected during the reworking of the Bavarian climate protection law. This means that when the bill comes into force next year, if all parties agree, the installation of photovoltaic systems will only be mandatory on the roofs of commercial properties at first. Considering the huge potential behind solar energy, this is a disappointing decision and one that squanders a huge opportunity to accelerate Germany’s goal of becoming climate neutral. After all, it’s not just visionary Elon Musk predicting solar technology to become the dominant energy source as early as 2031, with the immense potential of solar cells on the world’s rooftops examined in detail in a recent study published in the journal Nature Communications.

Solar cells could potentially supply around 27 trillion kilowatt hours of electricity worldwide

This paper was written by a research team led by Siddharth Joshi of University College Cork, Ireland, and discovered how solar cells could potentially supply around 27 trillion kilowatt hours of electricity worldwide. The calculation even considered different conditions for the sensible and cost-covering use of solar radiation across global regions. They found that around 40 percent of the world’s energy could be generated by photovoltaic systems installed on rooftops worldwide at less than nine euro cents (EUR 0.09) per kilowatt hour, which would more than compete with the cost of fossil fuels.

The team of scientists extrapolated data from house floor plans augmented via aerial and satellite photography using artificial intelligence. If the total space able to house photovoltaic systems on every building roof in the world, considering the specific solar energy potential of a region, was used for solar energy generation, mankind’s annual global electricity demand could be met. In 2019, global electricity consumption amounted to almost 23 trillion kilowatt hours which would, according to researchers’ calculations, be achievable with a roof area of around 200,000 square kilometers – with energy to spare. That would only correspond to the total area of a mid-sized U.S. state, country the size of Spain or, in terms of Germany, three Bavarias.

Energy generation with photovoltaics: Many investment advantages for homeowners

At least in Germany, the conditions for using a maximum roof area to generate solar energy are good. According to a recent Forsa survey, 68 percent of people between the ages of 20 and 50 in the nation indicated a desire to install a photovoltaic system on their roof – in addition to the 15 percent already running their home on solar energy. Other major advantages for homeowners include:

  1. The cost of investing in photovoltaic systems can be cushioned by tax savings, with homeowners feeding their solar power into the grid and selling it to grid operators considered entrepreneurs, which helps them save money on taxes especially in the first few years of operating a solar system.         
  • Public subsidies for private solar systems are extensive in Germany – as a rule, the installation is subsidized by the federal and/or state governments, although conditions vary by state. For example, special PV solar systems with their own storage are subsidized, with up to 150 euros per kWh available depending on size and yield.
  • Long-term advantages due to favorable energy costs: In view of ever-increasing energy prices, especially in Germany, investing in a photovoltaic system is worthwhile even without high feed-in tariffs – each kilowatt hour produced with PV itself theoretically saving a private system operator up to 1,100 euros for an average annual consumption of 3,500 kWh (assuming an electricity price of 32 euro cents per kilowatt hour).

Although these fascinating findings are theoretical and dependent on significant changing in markets across the world, they do add weight behind the possibility of a world powered almost entirely by solar energy. So, why not start now by installing your very own photovoltaic system on the roof of your home or business?

Image: Photo by Tom Fisk from Pexels


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Stefan Krokowski

Stefan Krokowski

Stefan is responsible for RESU sales in EMEA. He focuses on renewable energies since 2006 and digs into storage technologies since 2013.

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