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commercially – adv. related to the buying and selling of goods
solid-state – adj. of or relating to the use of the electric or magnetic properties of solid materials
density - n. amount of something in a particular space or area
sustainable – adj. able to be used without being completely used up or destroyed
convenient – adj. easy to use
grid – n. system of electrical wires and equipment to supply electricity to a large area
range – n. a distance
fossil fuels – n. a fuel (such as coal, oil, or natural gas) that is formed in the earth from dead plants or animals
intellectual property – n. something (such as an idea, invention, or process) that comes from a person's mind
breakthrough – n. a sudden development, especially one involving knowledge or a process
