Na-adịbeghị anya, e nwere mgbasa ozi ga na-ekwu na ahịa na ire nke ọtụtụ electric ụgbọala, bụ ihe ọ bụla karịrị nanị izute California efu-anwuru iwu (na 1990s, iwu na-achọ ka onye ọ bụla efu-emission ugbo ala na-emepụta ọtụtụ puku emepụta ere ca .
