Cons The largest problem with diesel, especially biodiesel, is increased emissions. "Diesel-powered vehicles and equipment account for nearly half of all
nitrogen oxides (NOx) and more than two-thirds of all particulate
matter (PM) emissions from US transportation sources" ("Diesel Engines and Public Health."). To add to the problem, biodiesel has been proven to be even worse at one of the most damaging emissions: NOx. As stated in the table below, in a diesel that is 20% biodiesel, there is a 2.4% increase in NOx. In a 100% biodiesel fuel, there is an incredible 13.2% increase in NOx emissions (The State of California). |  |
Pros
One of the largest factors in the favor of algal biodiesel is that it can be used in any diesel engine without any modification. This means that any diesel vehicle today could run on it. This is extremely important because it means that we would not have to alter our current infrastructure.
Although biodiesel produces higher NOx emissions than the already high emissions of regular diesel, biodiesel from algae has been shown to produce lower levels of NOx than biodiesels from other sources. The oil produced by the algae that later becomes biodiesel is of higher quality than oils used in most other type of biodiesel and therefore has reduced particulate matter. The final thing that could be done is to change engine emission standards, which California is leading the nation in. "Installing available retrofit technology both on new and in-use trucks
and trailers could reduce global warming pollution emissions by 17
million metric tons (MMT) of CO2eq (carbon dioxide equivalent) by
2020—the same effect as taking 2.5 million cars off the road" ("Delivering the Green: Reducing Trucks' Climate Impact While Saving at the Pump (2008)."). As shown in the table and graph above, NOx levels are higher, but Particulate Matter, Carbon Monoxide, and Volatile Organic Compounds are all down by about or more than 50%. And, Sulfur Dioxide, a cause of smog and ground-level ozone, is reduced by 100%. Developers are currently working on ways to reduce NOx release while still keeping the other benefits of biodiesel (The State of California).
