Solar energy is the most abundant energy available to human beings. It is estimated that over the past billion years, the sun has consumed 2% of its total energy. There is enough remaining to supply life on Earth for billions of years. As a clean energy, PV will not cause pollution or affect the ecological balance. Solar energy is also equitably distributed on the earth – there is solar energy everywhere, which can be exploited and utilized.

Over the past few decades, solar technology has progressed dramatically. Ten years ago, the price of solar panels was $5 per watt, while nowadays it is about 25 cents per watt. It’s reasonable to expect that in the next two to three years PV will become the most economical power source in most parts of the world. A report by Energy Watch Group suggested that in 2050, the global power can be totally supplied by clean energy, in which 69% comes from PV, 18% from wind power and 8% from hydropower. In order to achieve that result, 1,000GW of solar energy must be installed each year for 25-30 years continuously to meet the electricity demand worldwide. Since 25-30 years is the expected lifetime of a solar module, the cycle of 1,000GW per year will need to continue.

Midnight sun

When solar power is cheap enough and the manufacturing is fully clean, it can also undertake another more important task: to restore the earth’s ecosystem. We can imagine a scenario in which solar energy is used to desalinate seawater on a large scale, and cascade pumping projects are built to lift fresh water to irrigate into desert areas to awaken vegetation and turn desert into oasis. Once plants are restored, carbon dioxide in the air can be captured. It’s calculated that if 70% of Earth’s desert areas can be turned into oases, then all carbon emissions generated by human activities in history could be absorbed.

Out of your imagination? Next, I will let you know the solar PV technology improvement shall enable everything to be realized.

Solar energy combined with energy storage means that excess electricity generated during the day could be utilized at night. There are many ways to combine solar with energy storage. For example, if a region has abundant water resources, we could use pumped storage. This technology is already mature and cheap.

EVs as grid assets

Another means is electric vehicles. During the day, solar power is used to charge electric vehicles; at night, these electric vehicles can release the excess energy back to the grid. Today, the world’s annual electricity consumption is 26 trillion kWh, about 70 billion kWh per day. If it doubles in 20 years’ time, the global daily power demand will be close to 140 billion kWh per day. By then, the world’s electric vehicle amount is very likely to grow to 1 billion with the storage capacity of 70 billion kWh per day, which is enough to balance global electricity demand at night.

Taking the ultra-high voltage grid as the backbone network, global energy interconnection can be enabled to balance all sorts of renewable power energy supply and work continuously to meet global demand during the day and at night.

To put it simply, the mode of how global energy interconnection works is: renewables plus ultra-high voltage grid plus smart grid. Through the global energy interconnection, solar power generation in the daytime area can be transmitted to the night region, which can realize continuous power supply around the world.

We have 100% confidence that solar would change the world. Solar energy is infinite and cheap, and its intermittency issue can be solved in many ways in a few years to come.

This is an edited extract from Longi president Zhenguo Li’s speech at the Future of Technology Summit in Washington DC in April.