Solar panels on half the world’s roofs could meet its entire electricity demand – new research

Solar panels on the roof are up to 79% cheaper than in 2010. This sharply decreasing costs have made photovoltaic solar energy on the roof even more attractive for households and businesses that want to reduce their dependence on electricity grids while reducing their environmental footprint.

But are there enough roof areas for this technology to generate affordable, low-carbon energy for everyone who needs it? After all, it’s not just people who own their own home and want to lower their bills who need such solutions. Around 800 million people worldwide without good access to electricity.

U.S new paper in Nature Communications presents a global assessment of how many rooftop solar panels we need to generate enough renewable energy for the entire world – and where to place them. Our study is the first to provide such a detailed map of global rooftop solar potential, assessing roof area and sunlight coverage on scales from cities to continents.

We discovered that we would only need 50% of the world’s roofs to be covered with solar panels to provide enough electricity to meet the world’s needs. annual needs.

Method

We designed a program that processed data from more than 300 million buildings and analyzed 130 million km² of land – almost the entire land area of the planet. It estimated how much energy could be produced from the 0.2 million km² of roofs present on that land, an area roughly the same size as the UK.

We then calculated the electricity generating potential of these roofs by looking at their location. In general, roofs at higher latitudes, such as in Northern Europe or Canada, can vary by as much as 40% in their generational potential over the course of the year, due to the large differences in sunshine between winter and summer. Roofs near the equator, however, typically only vary by about 1% in generating potential over the seasons, as the sunshine is much more constant.

A roof with solar panels in a nutshell
The location of the roof is important for assessing its potential to generate electricity when covered with solar panels.
Ecosolarceo/Pixabay

This is important because these large variations in monthly potential represent a significant consequence about the reliability of solar electricity in that region. That means places where sunlight is more irregular need energy storage solutions – rising electricity costs.

Hot spots

Our results identified three potential hotspots for rooftop solar power generation: Asia, Europe and North America.

Of these, Asia appears to be the cheapest location to install panels, where – in countries such as India and China – one kilowatt hour (kWh) of electricity, or about 48 hours of using your laptop, can be produced for as little as 0.05 pence. This is due to the panel’s cheap manufacturing costs and sunnier climates.

Meanwhile, the US, Japan and the UK are the most expensive countries for deploying rooftop solar. Europe takes the middle ground, with average costs across the continent of about 0.096 pence per kWh.

Rooftop solar panels look like they would be just as useful in low-population areas as they are in urban centers. For those living in remote areas, panels help to supplement or even replace the supply of potentially unreliable local grids. And for people in cities, panels can significantly Reduce air pollution caused by burning fossil fuels for energy.

Two people working on a solar panel on a roof
Rooftop solar panels may hold the key to expanding access to electricity to more remote regions.
Maria Godfrida/Pixabay

It is vital to point out that the global electricity supply cannot depend on a single generation source to meet the needs of billions of people. And thanks to the changeable weather and the day and night cycle of our planet, a mismatch between supply and demand of solar energy is inevitable.

The equipment needed to store solar energy for when it’s needed is still extreme duration. In addition, solar panels will not be able to supply enough power for some industries. Heavy fabrication and metal processing, for example, require very large flows and specialized electricity supply, which solar energy cannot yet supply.

Despite this, rooftop solar has enormous potential to reduce energy poverty and put clean, pollution-free power back into the hands of consumers around the world. If the cost of solar energy remains Reduce, roof panels could be one of the best tools to date to decarbonize our electricity supply.

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