Does a kWh of electricity result in the same environmental impact regardless of where we generate it?
In a previous article, we explained how an inventory of all inputs and outputs is necessary to conduct a Life Cycle Assessment (LCA). In addition, we explained that the benefit of an LCA is to understand environmental impact. We also demonstrated that for corporations with facilities throughout the world, it’s essential to specify the location. Similarly, when inputs or outputs have various processing options, it’s essential to use the appropriate process option in the LCA model to get a valid and accurate result. For example, electricity is a typical input to most facilities, while waste water is a typical output to most facilities. In this article, we’ll look at two examples using electricity production and waste water disposal.
Electricity Production Considerations
First, let’s look at an example that demonstrates why it’s crucial to consider where we produce a kWh of electricity. In this example, we’ll use two of the commonly known midpoint impact categories of
- Global Warming (Climate Change); and
- Particulate Matter (Human Health – Lung Function).
The scenario modeled below is a factory with 470K sq ft of manufacturing floor space and 150K sq ft of office space. We are assuming that the factory uses 100kWh/sq ft, and the office uses 20kWh/sq ft annually. Therefore, the total annual consumption of electricity is approximately 50 million kWh.
Environmental Impact from a Global Warming Perspective
The point of the chart below is not that this hypothetical factory is using 50 million kWh of electricity. Instead, the illustration shows the environmental impact differing significantly depending on the location of this facility.
The chart above shows the midpoint impact category of Global Warming Air in kg CO2 equivalent. In this example, we see that India’s electricity production releases more than twice the CO2 equivalent compared to the United States’ electricity production.
The chart below shows the kg of 2.5 micron-sized particulate matter released in the air as a result of this amount of electricity production.
- China’s electricity production releases more than 25 times the amount of particulate matter air pollution compared to the United States’ production.
- India’s electricity production releases nearly 40 times the air pollution than the United States’ production.
Waste Water Processing Considerations
Next, let’s look at an example that demonstrates why it’s crucial to consider process details of inputs and outputs. In this hypothetical example, the factory is located in the US and produces 10,000 gallons of wastewater per weekday. The critical consideration here is whether the sewage treatment plant that processes their wastewater sends their sludge output to be
- applied for agricultural benefit;
- landfilled; or
- lastly, incinerated for energy recovery.
- the best solution is incinerating sludge for energy recovery;
- the second best solution is agricultural land application; and
- lastly, the least favorable approach is placing sludge in a landfill.
In conclusion, these two examples of electricity production and wastewater disposal highlight the importance of specifying location and process details for accurately modeling midpoint impacts and performing Life Cycle Assessment modeling.