That provides an incentive to retrofitting companies, while competition for customers, rather than for subsidies, will encourage the various providers to be efficient. (Many European governments currently have “cash-for-clunker” schemes that buy and destroy old cars; a cash-for-gas-engines scheme would make more sense by lowering costs and conserving the many car bodies that still work fine.)
如果政府足够有远见的话，他们不仅会对改装车进行补贴，而且会回收旧的汽油发动机。扶植那些从事汽车改装的工厂。随着改装厂的增多，竞争就会使得该行业越来越有效率。（现在许多欧洲国家政府正在实施一个名为“补贴以旧换新的购车政策”，如果再推出“汽油发动机换取现金”方案，就会降低发动机置换的成本，使得车主考虑用电动发动机来更换目前还运行良好的汽油发动机。）