1. We could upgrade the nation's rail infrastructure with electrified rail replacing diesel engines and with the addition of double-track lines to minimize traffic congestion that can slow trains to an average of 2mph on some routes.
weatherize every home in America. (Heating, ventilation, and cooling puts paid to about a third of all the electricity used by US homes.)
Another issue is funding for fuel reduction. Funding and acres treated rose (roughly doubling) between FY2000 and FY2003, and have stabilized since. Currently about 3 million acres are treated annually. However, 75 million acres of federal land are at high risk, and another 156 million acres are at moderate risk, of ecological damage from catastrophic wildfire. Since many ecosystems need to be treated on a 10-35 year cycle (depending on the ecosystem), current treatment rates are insufficient to address the problem.UPDATE: A recent study found fuels management increases greenhouse emissions. So while it might or might not be worth it, it's off my list of green jobs.
4. We could construct a backbone of HVDC lines connecting the regional power authorities across the United States, an "interstate highway" system for the power grid. This would cut transmission losses, today approximately 6.5% of all electricity generated. (Cutting those losses in half would be the equivalent of bringing 45,000MW of clean energy onto the grid -- and reliably linking the US power grid from coast to coast would greatly reduce the indeterminacy problem of high levels of wind and solar -- while the wind does not blow nor the sun shine all the time, if a thousand wind and solar plants are contributing to the grid, the law of averages will inevitably push their contribution towards a steady state.)
Incentives to develop wind, or solar, or geothermal energy are all very well and good, but it is difficult to pick an industry and make it successful, especially if an important part of your motivation is to create jobs. Even successful industries may not create very many jobs, and there is nothing to stop the successful, once established, from taking those jobs elsewhere.
What we can and should do is radically upgrade our national infrastructure and our management of public lands. Those tasks cannot be left to the private sector. The private sector cannot set a new standard for rail lines, cannot protect federal lands from wildfires, cannot improve disaster response capabilities. True, a hefty carbon tax would advance many of these goals, including weatherization. But not only are the politics of such a tax difficult right now, but it would fail to provide the short-term stimulus and job creation which our economy needs.