Last Updated: Oct 7, 2022
In 2019, the world purchased over two million electrical vehicles (EVs) - double the volume sold just two years before. Experts estimate that EVs will grow to about 245 million vehicles by the year 2030. The 2020 report, published by the International Energy Agency, states that the EV30@30 initiative aims for the global passenger car stock to consist of at least 30% electric cars by 2030. This target requires an annual growth rate of about 36% between 2019 and 2030.
As car manufacturers continue to increase their electric vehicle offerings, we need innovative strategies to provide sustainable electricity sources to power those vehicles. In addition, homeowners interested in switching to an electric car to reduce their carbon footprint should think seriously about installing a solar-powered charging station. This way, they will have a sustainable fuel source for their transportation needs, no matter what type of energy their grid relies on.
Let's look at the feasibility of independently and autonomously powering your vehicle with sunlight that shines on your roof. First, we will look at the power requirements and equipment needed to power your vehicle from the solar panels on your home. In addition, we will include a cost analysis to determine the potential savings over the long run compared to gas-powered vehicles and the extra utility costs of charging an EV from the municipal power grid.
The amount of power an electric vehicle requires depends on several variables, including:
Since electric cars don't rely on gasoline, the EPA has a different rating system from the traditional miles per gallon. Instead, the EPA rates EVs on the number of kilowatt-hours (kWh) it takes for the car to drive 100 miles. For example, the 2020 BMW i3 requires 30 kWh to drive 100 miles, while the 2020 Tesla Model 3 Long Range only requires 26 kWh to go an equal distance. The EPA converts this rating into "miles-per-gallon equivalent" (MPGe) to help consumers determine the most energy-efficient option on the market. When comparing the most energy-efficient EVs on the market, this government website offers complete information on the MPGe and kWh per 100 miles ratings.
The number of solar panels you will need will largely depend on how much you drive daily, weekly, or monthly. For example, if you have a 100-mile round trip commute to work, you will need a much larger solar panel installation. People living in dense urban areas with short commutes and limited mileage requirements will require fewer solar panels to power an EV.
To calculate the number of solar panels, you will need to figure out how much energy your electric vehicle will require per day. Consider the following equation:
The average American drives about 1,100 miles per month. No matter what type of car we drive, reducing our transportation needs should prioritize all people worried about their overall environmental impact. Let's imagine a family that drives less than the national average - about 600 miles per month, or 20 miles per day. The Tesla Model 3 mentioned above requires about 26 kWh for every 100 miles.
Based on the calculation mentioned above, this amounts to:
Assuming you receive around 5 hours of direct sunlight on your solar panels each day, a premium solar panel could produce about 1.5 kWh per day. So, you would need at least four 290 watt panels to give you the power you need to power your EV autonomously, without help from the grid. The more you drive, the more you need!
Remember that the solar panels needed to power your car are added to your home's energy requirements. So, for homeowners looking to achieve carbon zero status, you will need to slightly increase your solar PV array size to accommodate an EV's electricity requirements.
Besides a solar panel, you will need a way to store the energy produced by your panels. This storage is necessary because most families rely on charging their EV overnight when the sun is not shining. There are many home battery storage options on the market today. For example, the Tesla Powerwall 2 is one of the best batteries on the market for EVs as it stores up to 13.5 kWh of energy. This capacity should be enough to help you meet your daily mileage requirements.
In addition, you will need a charging station (usually located in your garage or driveway) where you can plug in your car. We recommend level 2 chargers, as they offer much faster charging times. There are many options available. Like the ChargePoint Home Flex EV Charger, some offer up to 37 miles for every hour of charging, thus radically reducing your overall charge time. This option is WiFi compatible, connecting to your smartphone to let you know how much time is left before your car reaches a full charge.
Finally, we come to the most important consideration: how much can you potentially save by switching from a gas-powered car to an EV, even after the extra expense of the equipment needed?
Let's say that you currently have a gas-powered car that gets 30 miles per gallon, and you drive an average of 30 miles per day. If the average cost of gas stays around $2.50 per gallon (and as oil becomes ever more scarce, it should only continue to rise in price), you will pay $2.50 per day or $912.50 each year in gas.
If you converted to an EV that gets an average of 3 miles per kWh, and the average cost of electricity is $0.13 per kWh, then it would cost you $1.30 per day or $474.50 in electricity costs, even if you were charging your EV from the municipal powered electrical grid.
Suppose you invest in a 1 kWh solar PV system, including a Tesla Powerwall battery and an efficient charger. In that case, the long-term savings begin to add up for your transportation needs. You can find a quality household EV charging station for under $600, and the Tesla Powerwall 2 currently is priced at $9,250, including all necessary hardware. The solar panel's cost stands at just under $3 per watt or $3,000 for a 1 kW system. Including installation costs, you might be looking at an investment of about $13,000 for a PV system that will autonomously power an electric vehicle for up to 25 years (the average lifespan of solar panels).
Even assuming that the price of gas remains steady over the next quarter of a century (which it surely will not), you could expect to save upwards of $12,000 over 25 years, even after factoring in the costs of installing a solar-powered EV charging system. Moreover, if you were to incorporate a solar power EV system into an already existing residential solar array, the prices would even be lower.
Switching our fleet of gas-powered vehicles to EV options is one of our society's most important sustainability challenges. Sustainably powering millions of EV vehicles, however, is not discussed enough. For homeowners looking to reduce their overall environmental impact, installing a solar PV system specifically designed to power an EV makes economic sense while drastically reducing your overall carbon emissions.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.