On the eve of 2013, state officials are busy readying for tens of thousands of new laws that go into effect on the first day of the year. The nation’s most populous state, California, is  serving as a laboratory for several legislative measures, embarking on a number of policy experiments that were too controversial to be implemented on the national scale.

At the top of that list is California’s cap and trade program for greenhouse gases. Starting January 1, large power plants and industrial facilities in the state will have to either lower their emissions or be forced to buy credits at auction. The credits, called allowances, make the cost of polluting more expensive. Federal cap-and-trade legislation failed in Congress in 2009.