The powered roadway for electric vehicles

In November 1980, LLNL researchers began work on a project that they hoped would change the face of the nation’s transportation system and help solve the ongoing energy crisis. LLNL engineers called the process they were working on inductive energy transfer for advanced electric vehicle propulsion. The concept involved burying electric cables into a “powered roadway” to provide energy to a moving vehicle and charge its batteries. A non-contact electrical pickup underneath the vehicle would collect energy from the energized cables by “induction,” and the onboard batteries would power it while traveling on unpowered roads. To test the concept, engineers poured a 220-meter strip of concrete roadway in the northeast corner of the Laboratory, along which they hoped to propel what was once a 1969 Volkswagen.

The concept of inductive energy transfer was not new. The first patents were issued in 1891 and 1895, around the time the electric vehicle itself was gaining popularity. Electric vehicles, invented in the early 1800s, had seen a rise in popularity at the turn of the 20th century, especially among urban populations. However, with the introduction of Henry Ford’s mass-produced gasoline-powered Model T in 1908, popularity of the electric car began to wane. Two decades later, with a better system of connected roadways and the discovery of cheap Texas crude oil, the electric vehicle had all but disappeared.

However, by the late 1960s and early 1970s, soaring oil prices and gasoline shortages, culminating in the 1973 Arab Oil Embargo, had created a crisis in the country and a call to lower its dependence on foreign oil. In 1976, the Congress passed the Electric and Hybrid Vehicle Research, Development, and Demonstration Act and authorized the Energy Research and Development Administration (the predecessor to the Department of Energy, created in 1977) to support research in electric and hybrid vehicle concepts. That year, the Lawrence Berkeley Laboratory (LBL) was tasked to conduct a feasibility study into inductive energy transfer as a means to extend the range of electric vehicles. Over the next two years, LBL was able to demonstrate the predictability and efficiency of inductive energy transfer, and the project was moved to Lawrence Livermore in 1979 so that dynamic tests could be conducted.

Livermore’s Roadway Powered Electric Vehicle (RPEV) test project, headed by Livermore engineer Carl Walter, consisted of a 220-meter roadway of which 50 meters was powered by an electrical steel trough containing several insulated cables—much like the system designed and patented in 1895. The trough was set into the roadway and electrified by a motor-generator providing 800 to 1,000 amps of alternating current along the loop. The test vehicle, a stripped-down, remolded 1969 Volkswagen Type 3, was equipped with an electric motor, eight 12-volt batteries and a power pickup, which could be raised or lowered to vary the gap between the car and the powered roadway.

In 1981, tests of the inductive energy transfer concept executed by Walter’s team were successful and the evaluative work that followed over the next couple of years yielded new insights into the RPEV performance. Walter had hoped that the 220-meter test strip would be the beginning of a much longer effort. He submitted a five-year plan to Washington calling for the construction of much longer roadways, as well as for extensive mass transit demonstration projects—suggesting, for example, that some of the roads at the Livermore site be powered, and that a number of vehicles, including the Laboratory’s taxis, be adapted to the system.

According to Walter, however, while the concept of inductive coupling was simple, electrifying a roadway was not cheap. In addition to regular roadway maintenance, he estimated that the cost (in 1980) to electrify a freeway could run an additional $350,000 to $600,000 per lane mile. Despite the high price tag, Walter believed the concept could work and that rising gasoline prices could push Americans back to the electric car they had turned away from decades ago. However, long-term funding for the project never materialized; and, within a few years, interest in electric vehicles in the country had receded, along with gas prices.

While research into the RPEV project halted with the testbed, Livermore’s work into alternatives continued over the following decades in a variety of areas, including research into refuelable aluminum-air batteries and work in hydrogen storage systems for vehicles. In addition, the Lab began efforts in the late 1990s to reduce onsite petroleum fuel consumption by identifying opportunities for using alternative fuels, such as ethanol, and increasing the number of alternative-fuel vehicles, hybrids, and electrics, in the Laboratory’s fleet of vehicles.

Pictured: LLNL Engineers Carl Walter (standing) and Doug Davis with the 1969 Volkswagen test vehicle on the powered roadway, 1980.