Dark money and solar Industry opponents used by power companies is aimed at reducing expansion of solar in Arizona | Democracy, elections and voting

From Wikipedia:

In the politics of the United States, dark money is a term that describe funds given to nonprofit organizations—primarily 501(c)(4) (social welfare) and 501(c)(6) (trade association) groups—that can receive unlimited donations from corporations, individuals, and unions, and spend funds to influence elections, but are not required to disclose their donors.

According to the Center for Responsive Politics, “spending by organizations that do not disclose their donors has increased from less than $5.2 million in 2006 to well over $300 million in the 2012 presidential cycle and more than $174 million in the 2014 midterms.”