Obama appears to have pledged that America will get 20% of its electricity from non-hydro renewables by 2030. Long-term climate watchers will recognize the form. Targets must always end in zero and the target year must always end in zero. The only departure from the form here is that the target does not rhyme.
20% of electricity generation from non-hydro renewables only sounds impressive once you have either abandoned any hope of limiting increases in atmospheric temperature to 2 C or you have accepted that a transition to renewables is unlikely to unfold any faster than previous energy transitions.
Let me put this target into perspective.
Official statistics show that America got 281.6 GWh of electricity from non-hydro renewables in 2014. This was 6.9% of total net electricity generation. Here is the breakdown of non-hydro renewables by source:
Wind power dominates non-hydro renewables, with solar still contributing only a marginal amount. Wood-based fuels contribute a significant proportion.
American biomass energy is more or less exclusively derived from waste products from forestry. Furthermore, historical data indicates that the use of solid biomass in America has remained largely unchanged in the last 30 years. So, unless America changes course and acts like Europeans, wind and solar is likely to make up the vast majority of all new non-hydro renewable electricity.
This proposed level of non-hydro renewables in 2030 can be put in perspective by comparing it with the current absolute growth rates of wind and solar.
America has to go from 7% to 20% non-hydro renewable electricity in 16 years. This works out at around 4% every 5 years. And this can be achieved without a significant increase in the rate of addition of new wind and solar.
Between 2009 and 2014, combined wind and solar grew from 1.9% to 4.9% of net electricity generation. America can more or less meet its 2030 target by just deploying wind and solar at their current (if volatile) rates.
More starkly, we can put these proposed growth rates into further perspective by thinking about how long it would take to get to 100% renewable electricity. This target means that annual additions of wind and solar will represent just under 1% of the total generation of America. In other words, it would take a century for America to get to 100% wind and solar electricity. And that would ignore the emissions of carbon dioxide from driving cars, heating homes and industrial processes.
Clearly this target does not mean a renewables energy revolution is coming to America any time soon.