“We looked at how large-scale adoption of electric vehicles would affect total energy use in a community, for buildings as well as transportation,” said chief author Markus Felgenhauer, he is a doctoral candidate at TUM and a former visiting scholar at the Stanford Global Climate and Energy Project. “We found that investing in all-electric battery vehicles is a more economical choice for reducing carbon dioxide emissions, primarily due to their lower cost and significantly higher energy efficiency.”
Fuel cells or Batteries
Electric vehicles commonly come in two configurations, Plug-in cars with batteries batteries and fuel cell vehicles that catalyze hydrogen gas into electricity with no harmful emissions.
Battery and fuel cell vehicles emit zero carbon when driven. But large scale transition to them will require an expensive and complex new infrastructure for producing and delivering electricity or hydrogen fuel.
A significant question for politicians is which transportation technology reduces total emissions the most, at the lowest cost. Could hydrogen technology also be used for heating and lighting buildings ? – Research indicate that this may be the case.
An in-depth study of both alternatives
The researchers used California which is a major player in innovative electric vehicle solutions. Across the state, battery driven electric cars are becoming more and more popular. As of now, only a few companies have started offering fuel cell vehicles.
To encourage the spread of fuel cell vehicles, California has has invested $92 million in a network of fifty hydrogen-fueling stations planned to be ready in 2017.
None of the energy source are totally emissions free at the moment. Charging battery electric cars requires plugging in to grid power, which is most often generated using some sort of carbon emitting technology.
Currently, most hydrogen fuel is extracted from natural gas using a process that emits carbon dioxide. An alternative method, electrolysis, can use solar or wind-generated electricity to extract hydrogen from water, at it’s current state, that technique is expensive but a lot of promising new research into membrane technology and better materials for electrolysis may change the equation in the future, something that is also considered in the study.
The study is based on hypothetical future scenarios for the Town of Los Altos Hills. Felgenhauer said “Los Altos Hills is distinguished by an unusually high solar-generation capacity in the county with the highest share of electric vehicles in the state,”
The scenarios looked ten to twenty years into the future, where fuel cell and battery vehicles are expected to be more common and where solar/wind power and electrolyzation is cost comparable with more conventional means of electricity generation.
In one scenario for 2035 the scientists assumed that electric vehicles would be 38 percent of the town’s fleet. They also made the assumption that locally produced hydrogen for the fuel cell vehicles would be available generated by some sort of emissions free technology like solar or wind.
Co-author of the study, Matthew Pellow, said “We provided data on the amount of energy Los Altos Hills needs throughout the day, as well as financial data on the cost of building new energy infrastructures,”, he continues, “We included our estimated cost of manufacturing electrolyzers, solar panels, batteries and other surrounding technologies. Then we asked the computer model to give us the most economical way to facilitate the total energy requirements of the community.”, the researchers also estimated CO2 emissions produced in each case.
The team also evaluated potential benefits of utilizing the hydrogen infrastructure to store excess energy produced during daylight-hours for use when needed.
The results were conclusive
Felgenhauer said that “In terms of overall costs, we found that battery electric vehicles are better than fuel cell vehicles for reducing emissions,”, “The analysis showed that to be cost competitive, fuel cell vehicles would have to be priced much lower than battery vehicles. However, fuel cell vehicles are likely to be significantly more expensive than battery vehicles for the foreseeable future. Another supposed benefit of hydrogen – storing surplus solar energy – didn’t pan out in our analysis either. We found that in 2035, only a small amount of solar hydrogen storage would be used for heating and lighting buildings.”
“Our goal is to provide objective, data-driven analysis to help inform policymakers in California and elsewhere about which technology pathway is likely to be more cost-effective in combating climate change,” Pellow said.
The results are only relevant for similar bedroom communities with a lot of sunlight in California. The scientists hope to expand the study to larger communities in the future and include other parameters that could influence consumers’ choices when deciding what kind of car to buy.