State and federal legislators are pushing through renewable portfolio standards (RPS) bills that require energy producers to acquire a set percentage of their power from clean energy sources.

Congress is considering a law that would force utilities to buy at least 15 percent of their power from renewable sources, and while strong bi-partisan support is expected, Renewable Energy Access reports that Southern Company is on red alert in getting lobbyists to convince Republicans to kill the bill.

Similarly, Oregon is considering legislation backed by the governor that would require 5 percent of power from renewables by 2010.

An RPS should be based on an objective for reducing emissions. For example, if California wants to eliminate x tons of carbon dioxide from coal and natural gas power plants, figure out what percentage of carbon-free energy is needed.

Alternatives to mandating that all utilities meet an RPS, state and federal agencies could enact change on the demand side by instead saying that they will only purchase from utilities feature an RPS. This is less politically contentious and can meet the same objectives. Another option is through renewable tax credits that would function as a reverse carbon credit. Instead of the political risk of creating new taxes, cutting the tax bill of utilities that generate power from renewable sources has the same net effect.

RPS' will create domestic jobs since it will require the building of new wind farms and solar arrays. This job growth will expand the tax base, and can theoretically replace the revenue lost to tax credits.