Big growth ahead for green technologies

Dramatic reductions have occurred in the cost of renewable energy in the past six years, and those reductions make US wind and solar energy competitive with coal and natural gas electricity generation, according to a new report from the Department of Energy.

Since 2009 the cost reductions for clean energy technologies range from 40% for land-based wind power to 90% for light-emitting diodes (LEDs). Distributed and utility-scale photovoltaics (PV) have fallen by 50% and 60% respectively, and advanced battery costs have plunged by around 70%, says the report Revolution Now: The Future Arrives for Five Clean Energy Technologies 2015 Update, released on 13 November. Land-based wind has led the surge, with more than 65 000 MW currently deployed in 39 states and another 13 600 MW under construction as of the first quarter of 2015. Wind now provides 4.4% of US electricity generation, enough to power more than 16 million households. Utilities’ purchase prices for wind have fallen from around 7 cents per kWh in 2009 to 2.4 cents per kWh in 2014.

Wind’s growth was spurred in part by a production tax credit, which was last set at 2.3 cents per kWh. Congress allowed the credit to expire at the end of 2014. In past years, new wind installations dropped precipitously when the credit was allowed to lapse. The American Wind Energy Association, however, reported that new wind installations through 30 September 2015 more than doubled from the same period in 2014.

A 3-MW wind turbine undergoes testing at the National Renewable Energy Laboratory’s testing facility in Boulder, Colorado. CREDIT: Dennis Schroeder, NREL

For utility-scale PV, the cost of installed systems dropped from $5.70 per watt to $2.34 per watt between 2008 and 2014, says the report. That reduction has fueled a surge in capacity from next to nothing in 2008 to 9.7 GW in 2014. The growth was spurred by the American Recovery and Reinvestment Act of 2009, which financed the first five US projects to produce more than 100 MW each. As of mid 2015, more than 27 000 MW of utility-scale solar projects were under development.

Costs for distributed PV systems, such as those installed on homes, have declined from nearly $9 per watt in 2008 to $4.17 per watt in 2014, according to the report. But although the cost of solar hardware has dropped, “soft” costs such as permitting, installation, interconnection and maintenance fees can account for two-thirds of total system costs, and they remain a barrier to greater US deployment. In Germany, for example, residential system pricing in 2014 was reported to be $2.13 per watt.

The development of lower-cost lithium-ion batteries, largely as the result of DOE-sponsored research, has enabled a doubling of US electric vehicle sales from 2012 to 2014 . Between 1992 and 2012, DOE spent $1 billion on battery R&D, which the report says advanced the state of the art significantly and created $3.5 billion in economic value. DOE models indicate that the modeled cost for electric vehicle batteries—the cost expected in high-volume manufacturing—has dropped 70% since 2008.