Use of English - Multiple Choice

Storing Green Power

Renewable energy is becoming more common around the world, but one major problem still needs to be (0) SOLVED. Solar panels and wind turbines only produce electricity when the sun is shining or the wind is blowing, so power companies must find ways to store extra energy for later use. One difficulty is that demand for electricity can (1) .......... greatly during the day, while renewable supply may suddenly drop. This means storage systems must be able to (2) .......... with both short-term changes and longer periods of low production. Batteries are one possible solution, but they can be expensive to produce and may wear (3) .......... over time. Another issue is scale. A battery that works well in a home may not be suitable (4) .......... a whole city. Engineers are therefore looking into other methods, such as pumped hydro, which involves moving water uphill when there is spare electricity and releasing it later to generate power. However, this depends (5) .......... local geography and can be difficult to build. In the end, no single technology is likely to (6) .......... all the answers. Experts believe progress will rely (7) .......... combining several storage methods and improving energy networks. If these systems are developed successfully, renewable power will become a more reliable part of everyday life, rather than a source of (8) .......... uncertainty.