Electricity generated from renewable energy of solar panels on roof-tops or part of a solar farm is an intermittent process and it depends on the availability of the sun, the main source of the solar energy, which is high in the summer days and low in the winter. It obviously disappears at night when it is mostly needed to light houses and run all electrical appliances.
The biggest challenge for the excess electricity produced during the day and not consumed becomes a burden for the grid and need to be stored for night use. Many countries like Germany, Australia, and China are relying on Lithium-Ion Rechargeable Batteries in two configurations, one is next to Solar Farms where batteries are stacked together as a power plant or part of a virtual power plant where each house with solar rooftops will install a Battery. This solution is still very expensive and are fully supported by the government.
We are still in the early stage of this expensive technology and we are not sure of the environmental challenges, that lies ahead, like the waste and the recycling efficiency of dealing with a hazardous material like Lithium. China is relying on different storage systems like pumped hydro storage systems. This technology will be like Hydro Power but in a recycling fashion between two reservoirs one in high altitude the other is lower. The excess electricity produced during the day will pump the water from lower reservoir back uphill to upper one. The turbine will be used as a pump and to produce electricity. This system is efficient when used on natural terrains where the mountain slope is steep with a high differential altitude and when the construction cost is the lowest. China has already many of these storage systems installed all over the country for a total of 30 GW capacity.
Energy Vault a startup has a good alternative, to the Hydro Power and Battery Storage, by using concrete blocks and cranes. It has been giving the name “LOW-TECH MAGIC” by Akshat Rathi who visited them in Switzerland and wrote an article on August 18, 2018:
“It seems that stacking concrete blocks might be an efficient way to store energy. The demo they have was built in 9 months with a cost of less than $2 million.”
“A nearly 400-foot (120-meter) tall, six-armed crane stands in the middle. In the discharged state, concrete cylinders weighing 35 metric tons each are neatly stacked around the crane far below the crane arms. When there is excess solar or wind power, a computer algorithm directs one or more crane arms to locate a concrete block, with the help of a camera attached to the crane arm’s trolley.”
“Once the crane arm locates and hooks onto a concrete block, a motor starts, powered by the excess electricity on the grid, and lifts the block off the ground. The system is “fully charged” when the crane has created a tower of concrete blocks around it. The total energy that can be stored in the tower is 20 megawatt-hours (MWh), enough to power 2,000 Swiss homes for a whole day.”
The world needs innovation like this, where there is no depletion of natural resources or environment recycling problems that will pass to our future generation. We should be smart enough not to do both.
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