Environmental Benefits of Electrified Vehicles

Full BEVs are considered "zero emission" because they don't release greenhouse gases or other pollutants during use. But that term can be misleading. Operating an electric vehicle can cause emissions, but the location of the emissions is shifted from the vehicle to the power plant. Electric vehicles do reduce pollutants generated by burning petroleum fuel in the vehicle in proportion to the reduction in vehicle fuel consumption. However, replacing gasoline with electricity generated from coal, for example, could result in emissions at the power plant, including carbon dioxide, nitrous oxides, sulfur dioxide, volatile organic compounds, carbon monoxide and particulate matter. As a result, the environmental benefits of PHEVs and BEVs depend largely on the fuels used to power the electrical grid. Operating a PHEV or BEV on the current average U.S. electrical grid, which relies heavily on coal power, has only a small emissions advantage over an HEV.

Plug-in vehicles could help reduce overall CO₂ and other emissions if the electricity used to charge them was generated from cleaner fuels, and ideally renewable resources, which produce significantly fewer emissions than the coal or natural gas that are often used for power generation. In addition, "smart grids" that include grid-to-vehicle communications would enable utilities to make more efficient use of electricity supplies, thereby potentially reducing emissions and electricity costs.

Using renewable energy: Recharging using electricity generated by renewable energy sources (such as solar, wind, hydropower or biomass) can cut CO₂ emissions dramatically, but production from these sources can be variable and unpredictable. Smart vehicle-to-grid communication can help utilities better use renewable energy sources. For example, it can allow vehicles to recharge at times that wind power is most available (usually at night) or during the day from solar arrays, depending on the renewable source available and its output. As the power-generation sector continues to improve its fuel mix and explore technologies such as carbon sequestration (i.e., collecting CO₂ emissions from power generation and storing them), the environmental impact of driving a plug-in vehicle will diminish substantially – perhaps even toward zero.

"Smart grids:" The development of "smart grid" technologies, which can provide utilities and customers with real-time information on energy use and energy prices, is a key enabler of efficient integration of electric vehicles and grids.

Smart charging would allow utilities to control the current going into the vehicle battery and thereby help to ensure that electric vehicles generate as little incremental CO₂ as possible. Armed with the knowledge of how much energy is needed and by when, a smart grid would be able to use the batteries in electric vehicles to store excess electricity or to shut off the current when there is a sudden demand elsewhere. This control would help to smooth the peaks and valleys of supply and demand at both the micro and macro level. Vehicles could also be taken off the grid completely, by charging with electricity from small individual generation units, such as household solar electric and wind power systems.

Smart grids will also help make the electrical grid and electrical vehicle charging more efficient by channelling vehicle recharging to times when electrical grid resources are currently underutilized. Since demand for electricity fluctuates (generally peaking in the afternoon and dropping off at night), utilities typically use a mix of fuels and power plant types to meet demand. That means that the environmental impacts of electric vehicle use will vary depending on where and when the vehicles are charged. During certain seasons and particularly at night, utilities generally have excess generation capacity – unused resources that create financial inefficiency. Charging PHEVs and BEVs during these off-peak hours, when this excess capacity is available, can increase the overall efficiency of the electric grid – potentially reducing CO₂ emissions, as well as the cost of electricity. But if PHEVs and BEVs are charged at peak times, that could create increased CO₂ emissions from power generation and also create demand for additional power plants. Utilities have a role to play in educating electrified-vehicle users and providing them with incentives to charge their vehicles at the most beneficial time.

With all these variables, utilities will be key partners in defining and developing electricity supply systems for electric vehicles that are efficient, affordable and environmentally sound. That's why Ford has partnered with several utilities throughout the United States and Canada, as well as the U.S. Department of Energy for its PHEV pilot program.