Vehicle traffic can generate large amounts of energy on highways and streets that can be harvested using technology known as piezoelectric devices. Piezoelectric devices take advantage of the inherent ability of specific materials (known as piezoelectric materials) that can take applied mechanical stress – for example, the weight of passing vehicles – and convert it into electricity. Currently, however, there are no such materials that match the vibration caused by automobile traffic and thus are able to convert this energy to electricity in an efficient and cost-effective manner. This project aimed to address this gap in technology and develop piezoelectric devices – that is, regenerative pavement devices – that can efficiently harvest energy from vehicle traffic on roadways using piezoelectric materials at a price that would lower overall energy costs to California ratepayers. To enhance performance under realistic roadway conditions, the approach used state of the art equipment to augment the force applied from passing vehicles and maximize the efficiency and output of the regenerative pavement devices.
The system was tested using a subscale demonstration built on a flexible framework able to scale from hundreds of kilowatts to megawatts in output capacity. The project achieved power outputs greater than 300 watts per square foot and proved the technology worked with lightweight passenger cars as well as heavy-duty trucks. The regenerative pavement devices were demonstrated in a roadway environment and the results can help in assessing the economic merits of using these devices at a scale that can provide energy and other services to Californians.
