In our recent special report issue on energy and global warming (“It’s Not Too Late,” July/August 2006), we argued that existing technologies have the potential to dramatically reduce our production of greenhouse gases–we need not wait for the advanced technologies of a “hydrogen economy” or exotic new types of alternative energy.

Now researchers at City College of New York are proposing very much the same thing in a policy discussion published in the journal Science. In the September 1 issue, they say the combined use of alternative energies for which we already have reliable technology “could replace all fossil fuel power plants.” These sources include concentrated solar thermal energy (in which heat from the sun creates steam to run generators), nuclear energy, geothermal and hydroelectric plants, wind energy, photovoltaic cells, and biomass.

They also claim that plug-in hybrid vehicles could replace 80 percent of the gasoline used in the United States. And they say the use of hydrogen for fuel is a bad idea in most cases–that using electricity directly in vehicles (stored in batteries) rather than to generate hydrogen is three times cheaper.

The catch? A huge price tag. Reducing total fossil-fuel use by 70 percent would cost $200 billion per year for 30 years, outlays the City College researchers hope could be collected through a tax on carbon-dioxide emissions of $50 per ton.

For example, that cost would come to more than a $300 tax per year on a Toyota Camry, based on figures from fueleconomy.gov.