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2022.12.11 12:54 GMT+8

Human Carbon Footprint: Efficiency dilemma of solar power

Updated 2022.12.11 12:54 GMT+8
By Tech It Out

In one hour, the Earth's atmosphere receives enough sunlight to power the electricity needs of every human being for a year. But because the Earth is so vast, that translates to about only 1,000 watts of energy per square meter of surface. 

Given the 20-percent efficiency of a solar panel, that means you put a one-square-meter panel under the sun and wait for about five hours. Then you can get one kilowatt hour. That's one unit of electricity on your bill. 

In comparison, a power plant can finish this job by burning just 300 grams of coal. For now, we have to rely on such inefficient ways to obtain such diluted energy. To compensate, we have to go big. Very big. 

When over 600 square kilometers of desert are covered with solar panels, it's a different story. Based in Talatan, Qinghai Province, China, Hainan Solar Park is one of the world's largest solar farms. But it's just a fraction of a more ambitious plan in Qinghai, which includes 2,000 square kilometers with an installed capacity of 154 million kilowatts, equivalent to seven Three Gorges power stations.

In fact, according to data from China's National Energy Administration, China has 323 gigawatts of solar capacity, around a third of the entire global total. More importantly, mass production and research progress here have cut the panel price by 75 percent in 10 years. But that doesn't mean we can solve the climate crisis by covering an entire desert. Engineering and economics aside, a massive solar farm will absorb more heat than the natural sand, change the region's climate, and dramatically transform the ecological landscape. 

The good news is we have a lot of desert and unused land around the world. But the bad news is few people live there. So we need to invest more in grids to transfer the energy to people who need it. How can we bring renewable energy closer to us?

Today solar panels can be found anywhere in China. Rooftops are just old-fashioned. If people want to avoid the worst of climate change, we need to be more creative about where we put solar panels. 

For example, fishermen like Liu Jianhua raised creative fish-pond-host solar farms in Changzhou, east China's Jiangsu Province. Solar power panels above ponds have little effect on the seafood. And selling electricity can make money. 

So it's a win-win for fishermen. Compared to a massive solar farm in the remote desert, this distributed system near people is a new trend. At present, floating photovoltaics like this have entered a period of rapid development globally. 

Due to good support policies and mature business models, the total installed capacity of Chinese floating photovoltaic projects has reached the first place in the world, mainly distributed in coastal and riverside cities.

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