tony lopez on the unusual program that aims to make the roads safer for everyone. >> reporter: california'sof transportation will soon be looking for volunteers to light up a joint and get behind the wheel. >> it would be a little intimidating, but i would still do it. >> no. i would not volunteer to drive a car under the influence of weed. >> reporter: it's part of an upcoming study on the impacts smoking cannabis has on driving abilities. >> i would say no. i'm not brave enough to smoke in the joint and get in the car, but i do appreciate the process of it. >> reporter: those who take part will smoke marijuana or a placebo and drive around the chp academy racetrack in a car equipped with sensors regarding their actions and tracking their movements to within just two centimeters. >> they need to know how it is before they start giving people duis. >> reporter: recreational marijuana use has been legal in california since 2018, but unlike alcohol where the leaving driving limit is 0.08, currently there is no universal definition of illegal cannabis driving. >> folks under the influence of n

tony lopez shows us why. >> reporter: as california increases its reliance on solar and wind, there isa concern there may not be enough energy during certain seasons and times of the day to keep the lights on. >> the question is how do we deliver the reliability of the grid? >> reporter: the state is setting a major milestone in energy storage, california has the capacity to store 8600 megawatts of power using batteries, that is enough to supply or than 4 million homes. >> there such an important factor that battery energy storage place. >> reporter: the growth of battery storage capacity over the last 3 years has been exponential. >> in august of 2020, pg&e had 6.5 megawatts of battery storage, and today we have approximately 1200 megawatts. >> reporter: why is it needed in california? >> solar and wind, these are intermittent resources. >> reporter: batteries can provide power in the winter , or on summer evenings when it's still hot outside. >> between 4:00 and 8:00 p.m. when everybody is getting home, and the demand for energy release bikes. >> reporter: there is so much battery st