Sorry, but the question itself is making incorrect premise.
Republican party does not, in any way, shape, or form, oppose "alternative energy". This is, at best, an honest mistake stemming from not knowing the facts, or at worst, typical political lie by the media.
In fact, GOP's official platform's energy policy is officially called “All of the Above”
The United States and its neighbors to the North and South have been blessed with abundant energy resources, tapped and untapped, traditional and alternative, that are among the largest and most valuable on earth. Advancing technology has given us a more accurate understanding of the nation’s enormous reserves that are ours for the development. The role of public officials must be to encourage responsible development across the board. Unlike the current Administration, we will not pick winners and losers in the energy marketplace. Instead, we will let the free market and the public’s preferences determine the industry outcomes. In assessing the various sources of potential energy, Republicans advocate an all-of-the-above diversified approach, taking advantage of all our American God-given resources.
What they DO oppose are two things, each of them DIFFERENT from "alternative energy":
They oppose government support (especially, though not exclusively so, in the form of taxpayer dollars) to alternative energy industry to make it even remotely competitive for energy consumers.
In other words, if Google, on their own dime, does a bunch of things with energy conservation, alternative energy, and whatnot, Republican party as a whole couldn't care less and may even support that. Remember that oil independence from Middle East is a major GOP platform plank, and if Google invents some alternative energy technology which weans US off of ME oil, a vast majority of Republicans will be happy as clams.
If an alternative-energy tech startup (such as the now-defunct Solyndra), on the other hand, requires taxpayer-guaranteed (and taxpayer-subsidized) grants or loans, that's what is being opposed.
Attempts to hamper fossil fuel industry by government fiat. Now, this one is, indeed, somewhat rooted in anthropogenic global warming skepticism, specifically the cost-benefit analysis.
As a caveat, individual Republican party politicians DO oppose alternative energy vs. fossil fuels, because their own constituents are heavily involved with fossil fuel industry. But that's irrelevant to the spirit of the question, since (1) Democratic politicians in fossil fuel states pretty much do the same thing (See West Virginia's Democrat Manchin); and (2) Such behavior is really industry agnostic, and every politician of every party whose constituents are over-represented in a particular industry will of course behave the same way about competing disruptive industry; and (3) The main opposition is not on alternative energy per se, but on measures to tax/disrupt fossil fuel one.