DOE Revolution Now – the state of clean energy technology


kuang By Jennee Kuang, Fall 2016 Fellow

When I was in high school, two representatives from a solar company knocked on the door of my parent’s California home, telling us that we had a beautiful southern-facing roof – perfect for solar panels. Three years ago, I worked for an energy efficiency program and started introducing communities to LED light bulbs at farmers markets and local festivals. In May 2015, I drove by a remarkable field of hundreds upon hundreds of wind turbines dotting an otherwise bare, hilly landscape. In the past several months, I have seen many Washington, D.C. taxis proudly displaying green electric vehicle decals.

A clean energy revolution is occurring, and these technologies have become a familiar part of our daily lives. But what does this all mean? Just how much of our power is now generated by wind and solar, how widely adopted are LED lights, how many electric vehicles are on the road, and more importantly, why does any of this matter?

The U.S. Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy produces an annual Revolution Now report that answers those questions. The latest update, released in September 2016, discusses both established and emerging technologies.

Revolution Now

The report highlights the technological innovation that has made clean energy become familiar in our daily lives. These include wind energy technology, solar panels, LEDs, and electric vehicles.


According to the National Renewable Energy Laboratory (NREL), wind turbines are mounted on a tower to capture wind energy with propeller-like blades. For utility-scale energy generation, a large number of wind turbines are typically built in close proximity to form a wind plant, or wind farm. Stand-alone turbines can be used for water pumping, communications, or household-level electricity.

Wind capacity in 2015 grew by 12% since 2014, represented 41% of all new capacity installed in the U.S. in 2015, and provides nearly 5% of total U.S. electricity generation. In 2015, wind power reduced annual U.S. carbon dioxide emissions by more than 132 million metric tons and decreased water consumption by more than 73 billion gallons – critical reductions in a warming and more drought-prone world.


Solar cells convert sunlight to electricity (NREL). They are also known as PV cells, which gets its name from the process of converting light (photons) to electricity (voltage). According to DOE, individual cells are connected together in chains to form larger units known as modules or panels, which is what most of us recognize solar panels as today. One or more of these arrays is then connected to the electrical grid.

Solar PV: Utility-Scale

Enough solar energy and land area is available in the United States for utility-scale solar PV to generate ten times the energy needed to power the entire nation. The installation cost of utility-scale PV has fallen over 64% since 2008, and there has been a 43% increase over 2014 capacity. The total capacity installed in 2015 represents 15% of all utility-scale domestic electric capacity installed that year. In 2014, solar power saved 17 million metric tons of CO2, worth approximately $700 million in benefits. It resulted in an additional $890 million worth of benefits from improved air quality due to the reduction of air pollution. Solar deployment reduced water consumption by 7.6 billion gallons, with the majority occurring in drought-stricken areas in California.

Distributed PV

Distributed PV systems use the same basic technology as utility-scale projects, but they can be sized to fit a household’s rooftop. Distributed PV generated about 12 billion kWh in 2015, providing enough electricity to power over 1.1 million homes.



According to Energy Star, LEDs are light-emitting diodes, semiconductor devices that produce visible light when an electrical current passes through them. If designed well, LED lighting can be more efficient, durable, versatile, and longer lasting than incandescent and compact fluorescent lighting (CFL). LEDs are able to use light and energy more efficiently than incandescent and CFL bulbs because LEDs emit light in a specific direction, while incandescent and CFL bulbs emit light and heat in all directions.  

The best-performing LED bulbs now consume 85% less energy than incandescent bulbs. LEDs present vast energy savings potential and improved performance. In one year (2014-2015), total installations of home LED bulbs increased from 77 million to 202 million. In 2015, LED light bulbs prevented 13.8 million metric tons of CO2 emissions and saved $2.8 billion in energy costs. With additional research and development, LED technology can make it far more affordable and practical to construct zero-energy buildings. Additionally, conversion of street lighting to LEDs may allow municipalities to dramatically reduce their energy and maintenance costs. LEDs are projected to comprise over 85% of the nation’s lighting installations by 2035.

Electric Vehicles

I recently learned that electric cars were actually first introduced over a century ago. A series of technological breakthroughs in the 1800s, from the battery to the electric motor, led to the first electrical vehicles. In fact, electric vehicles rose in popularity over time until Henry Ford’s Model T made gasoline-powered cars widely available and more affordable. Electric vehicles disappeared by 1935. In more recent history, the 1990 Clean Air Act Amendment and 1992 Energy Policy Act, in addition to new transportation emissions regulations issued by the California Air Resources Board, helped create a renewed interest in electric vehicles in the U.S. (DOE).

In 2015, Americans purchased more than 115,000 electric vehicles, bringing the total number of electric vehicles to over 400,000 at the end of 2015. Electric vehicles result in little to no tailpipe emissions, reducing local air pollution. Electric vehicles also increased the nation’s energy security by reducing oil use, while simultaneously cutting carbon emissions. Electric vehicles are also boosting the economy – lithium ion battery manufacturing added about $400 million in value to the economy in 2014. The cost and performance of these batteries are key to continue lowering the costs of electric vehicles.

Clean energy is important for so many reasons – reducing emissions, strengthening energy security, and increasing cost savings. DOE’s Revolution Now report also includes a section that discusses emerging technologies that could transform the energy sector in the future, including super trucks, smart buildings, and big area additive manufacturing. With the recent rate of clean energy innovation, perhaps these developing technologies will soon become as commonplace as the solar panels that are now being installed across my hometown’s public schools and government buildings.

Jennee Kuang is a Fellow with the Clean Energy Leadership Institute and an Innovation Support Specialist, U.S. Environmental Protection Agency.