 Costs . " Perhaps the most powerful force driving today ’ s clean @-@ tech growth is simple economics . As a general trend , clean @-@ energy costs are falling as the costs of fossil fuel energy are going up . The future of clean tech is going to be , in many ways , about scaling up manufacturing and driving down costs . " 
 Costs . " Perhaps the most powerful force driving today ’ <a href='null_genetive' title='1'><mark>s</mark></a>clean @-@ tech growth <a href='drop_aux' title='2'><mark>is</mark></a>simple economics . As a general trend , clean @-@ energy costs are falling as the costs of fossil fuel energy are going up . The future of clean tech is going to be , in many ways , about scaling up manufacturing and driving down costs . " 
Costs . " Perhaps the most powerful force drivin today ’  clean @-@ tech growth simple economics . As a general trend , clean @-@ energy costs are falling as da costs of fossil fuel energy are going up . The future of clean tech is goin to be , in many ways , abt scaling up manufacturing and driving down costs . "