Can Electric School Buses Help Solve Our Grid Problems?

An all-electric school bus. (Credit: Barry Sloan)

Renewable energy is America’s future. Climate change makes that inevitable. But America’s electricity grid will face tough new challenges as we transition away from dirty fossil fuels, and move toward clean technologies like wind and solar.

For the electricity grid to operate properly, supply must always be in balance with demand. Wind and solar are variable resources, although we are getting better at predicting their availability a day or more in advance. Utilities understand that incorporating renewables to the grid has its benefits, but in order to get the most out of these energy sources, technological innovation is needed.

Electric School Buses As Grid Storage

Energy storage can allow supply at certain hours of the day to be held in reserve, and tapped to meet demand later. This makes it a unique complement to variable renewable resources like solar and wind. Utilities already use energy storage in the form of pumped hydropower, which pumps water uphill when energy supply is high, then allows the water to flow back down and generate electricity when it is needed. However, according to Scott Baker of PJM Interconnection, this process is expensive and is running out of room to grow in a renewable future. Enter an idea backed by National Strategies (NSI), PJM Interconnection, and Clinton Global Initiative with a creative solution: use electric school bus fleets as a big renewable energy storage battery.

When school buses are not picking up eager school children and dropping them off at school, what are they doing? What about during the summer? They are sitting in lots just waiting to be put to use. Why not take these diesel engine buses, convert them to an all-electric fleet, and allow them to store power from the grid for when it is needed?

“School buses are a really good opportunity for electric storage,” says Baker, “They have larger batteries with more energy capacity, they charge at night, and [they] are idle during the summertime.” He explains that PJM could really use the extra storage during the summer months when their system is at peak capacity.

The project will produce eight electric (EV) school buses to be placed evenly in two school districts. Once the buses are placed in the school system, the team will run a “project demonstration”. Kevin Matthews of National Strategies describes the demonstration’s main components. The first component will have the EV buses operating within the fleet, shadowing an existing diesel bus so the team can quantify the cost savings from reduced fuel and downtime. The second component will have the EV buses plug in while not in operation to see how much revenue is generated from storage. Afterwards, once the hard data has been gathered, the team will run an economic model to see how the EV buses stack up with current diesel school buses.

“We believe we will be able to show that the total cost of ownership will be close to or a little more than diesel,” Matthews says, “but the additional health impacts should push EVs over the hedge.”

While the economic benefits of the program have yet to be determined, the health benefits are undeniable. Exhaust from diesel school buses not only pollutes the surrounding environment, but also seeps onto the buses — posing serious health risks to our children. In a 2003 study, the California EPA Air Resources Board determined that “self-pollution” is a significant source of pollutant exposure, especially when the windows are up. The board also found that the increased pollutant exposure from riding diesel school buses increases a child’s risk of cancer (approximately 4 percent), lower respiratory symptoms (approximately 6 percent), and daily hospitalizations for asthma (approximately 1 percent).

There are other benefits to replacing diesel buses with EV technology apart from health benefits and renewable energy storage capacity. “[Electric buses are] quieter, cost less to operate, require less maintenance, and the fuel cost is one third the cost of equivalent diesel,” says Baker. School districts could certainly benefit from extra reliability and lower fuel costs — allowing them to divert money and resources away from getting kids to school and focus on keeping them there.

The project has its share of challenges as well. Baker explains that the biggest issue is that there are very few companies that produce electric school buses, making these buses relatively expensive. High up-front capital costs could be a significant barrier for adoption. However, the group is steadfast in their efforts, and believes their demonstration will prove that EV buses are a worthwhile investment for both school districts and utilities.

“We are trying to change a really old industry,” Baker says, “That takes a lot of time and education. Educating the youth is a really good way to educate everyone else.” Similar to the recycling campaign of the 90’s — where kids went home and told their parents what they had learned about recycling — Baker hopes children will return home and spread the good news of clean energy from electric buses. Getting parents involved will be key to expanding the project in the future.

“This is about getting kids off of diesel school buses,” said Matthews, noting that Frito Lay now produces goods in a near zero emission environment, “If Frito Lay can make an economic argument for potato chips then we can do the same for our students.”


7 Responses to Can Electric School Buses Help Solve Our Grid Problems?

  1. Turboblocke says:

    How about mandating that taxis be EVs as well? Mass production of electric cars is already available and cities/towns are the ideal habitat for EVs: many short trips, high concentration of charge stations, reduced pollution.

  2. Paul Magnus says:

    Good idea. However, I dont think that an electric store is going to be cheap than a water battery.

  3. rollin says:

    Using the bus to provide nighttime or mid-day power will deplete it’s battery during it’s normal charge cycle and reduce it’s range for it’s intended purpose. Using them during the summer when they are idle might work, but that reduces the life of the battery and the owners will want compensation.

    Since school buses do a lot of stop and go, they are prime candidates for being hydraulic hybrids.

  4. Martin V says:

    The health aspect can’t be overemphasized. Cities like Mexico City suffer immensely from the exhausts of their huge bus fleets. It got so bad that there was no escape even for the rich: killer air was affecting everyone. Caused the city to research retrofitting cat filters, using cleaner fuel etc.

  5. MorinMoss says:

    Using EVs as energy storage / power backup will have only a marginal effect on battery life as the power flow in either direction is typically small compared to moving at moderate to high speed.

  6. J4Zonian says:

    What if the buses are owned by the city or county, the people of which should also, of course, own the utility? They’d be leased, loaned or rented to the schools or school district and used as the utility chooses, prioritizing school use.

    And I must have missed the part of the article that said OF COURSE every bus roof would be covered with solar panels. Wouldn’t come close to fully charging the bus but could be useful in emergencies and as an adjunct/top-off. And/or the buses could be parked in lots, covered–as all lots and many roads should be–with solar panels (and maybe studded with wind generators, maybe vertical axis).

    The road surface itself can be a solar collector. Slight paradox between wanting to use this on well-traveled roads on the one hand and nearly empty roads on the other, but trolley-bus use of such a power source would help as well, I think. The possibilities are endless if one gets creative and metaphorically kills all the naysaying delayalists in one’s mind.

  7. J4Zonian says:

    How horrible! No escape even for the rich? That just doesn’t seem fair, does it?