Deep in the sun’s core, two protons of hydrogen atoms collide violently. Under 【C1】_____pressure they fuse together and release vast amounts of energy in a process known as nuclear fusion. Travelling at the speed of light, some of this solar energy【C2】__Earth, where it powers our planet. From kettles to cars, almost all of the energy that we rely on originates from the sun. To【C3】__our increasingly electrified lives, there is an abundance of clean and renewable energy sources that we can【C4】__. And technology is at the cutting edge of harnessing this renewable energy more【C5】_____.

Solar panels are one of the most ubiquitous renewable energies, already【C6】_____more than 3.5 percent of the world’s electricity. But there is【C7】__for improvement: Capturing just one hour of the world’s sunlight would power the planet for a year. Not only are more solar panels being【C8】__, but technology is also finding ways to make them more efficient. Placing hexagonal lenses into a panel’s protective glass coating, for example, can【C9】__the incoming light to achieve an efficiency rate of about 30 percent, compared to an industry standard of 15-22 percent. Adding thin【C10】_____of silicon to both sides of a solar cell increases its efficiency to around 25 percent.

However, with silicon, one of the most energy intensive【C11】_____of traditional solar panels, science has developed an alternative using perovskite crystals. Another big【C12】_____ has been PERC (Passivated Emitter Rear Cell) technology, that【C13】_____unabsorbed light back into the solar cell for a second chance at conversion into electricity.【C14】__, PERC enables solar panels to be bifacial—capturing sunlight on both sides with sun-tracking technology moving the panel to ensure【C15】_____exposure.

Among the most recognizable forms of renewable energy is wind power, with wind turbines an【C16】_____common feature of both landscapes and coastlines. Wind already generates more than six percent of global electricity, and technologies are being developed that will make wind turbines cheaper, more efficient, and more【C17】__. A key focus has been on the blades that catch the wind’s kinetic【C18】__, with technological improvements, 【C19】__3D printing, enabling blades to be【C20】_____longer and lighter for greater efficiency.

【C19】