Powering Public Transportation Agencies and Vehicles with Green Energy
- Date: June 22, 2022
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Fossil fuels have been relied on for decades to power our electrical grid and heat our buildings. However, combusting fossil fuels produces greenhouse gases, particulate matter, and other pollutants, which have been directly linked to climate change, health complications, and environmental and infrastructure degradation. That is why some public transportation agencies are choosing green energy to power their vehicles and facilities. Green energy is a zero-emissions alternative to fossil fuel combustion for energy production and is generated from natural resources that cannot be depleted. The green energy sources covered in this fact sheet include solar, geothermal, and wind.
Types of Green Energy
Solar energy is generated from the sun and can be captured by a solar panel to generate electricity or through a collector to generate heat. Panels need to be placed on surfaces that are exposed to the sun, such as a rooftop or the ground, as they generate electricity/heat when sunlight hits the panel or collector surface.
Geothermal energy is generated from the temperature differential between the earth and the air. In the summertime, the ground is generally cooler than the air, but in the wintertime, it is usually warmer. Geothermal energy can be used to heat and cool buildings through a heat pump that operates very similarly to a home’s air conditioning system or a refrigerator. Energy is exchanged in a heat pump between a space and the ground through a piping network that goes at least four feet below the surface.
Wind energy is captured by a turbine that operates similarly, but in reverse order to, a fan. Wind turbines generate electricity as air hits its blades and causes them to rotate. Many wind turbines serve as a power plant to the grid by being placed at locations with high wind speed, such as the turbines that are numerous stories high and commonly seen on drives through the countryside. For onsite generation at a building, small turbines can be placed on the building roof but have a limited capacity for power production.
EFFECTIVE LIFE/USEFUL LIFE OF EACH GREEN ENERGY
- Solar panels and collectors typically last between 15-20 years before needing to be replaced as they degrade roughly 0.5% generation capacity per year. The panels need to be routinely cleaned over the lifespan to ensure they function properly.
- Geothermal heat pumps have an average life of over 20 years, and the underground piping infrastructure can last up to 50 years before needing to be replaced.
- Turbines typically last 20 years with routine maintenance and operation.
ENVIRONMENTAL IMPACTS ON EACH GREEN ENERGY
Every green energy resource has minimal environmental impacts in comparison to fossil fuel energy resources. Outside of the regional electric grid emissions required to power a geothermal heat pump, green energy resources do not emit greenhouse gases or particulate matter during operation. Additionally, early life-cycle impacts (e.g., material mining, transport, and manufacturing) of solar panels, heat pumps, and wind turbines are significantly lower compared to the exploration, mining, and transportation needed acquire and combust fossil fuel resources.
Examples of Green Energy
Example 01. Solar
Martha’s Vineyard Transit Authority (VTA) in Massachusetts installed a 700kW onsite solar in combination with a battery energy storage system to power both their facility and transit vehicles. The system is designed to be capable of operating even when the grid electrical power goes down. Panels were installed on top of parking lot canopies which also provide shade for the vehicles.
Example 02. Geothermal
The John W. Olver Transit Center in Greenfield, MA was the nation’s first net-zero bus station. This includes geothermal pumps and 22 wells that provide all of the building’s AC and dehumidification.
Example 03. Wind
City Bus in Lafayette, IN installed three wind turbines in 2009 with an ARRA grant to offset power at its administration and maintenance facilities. The turbines provide direct power to the facility and are set up to put excess power back onto the grid.