Net Calorific Value of Fossil Fuel and Battery
Governments are exploring ways to reduce the dependency on fossil fuel and to lower emissions. They do this by promoting the electric car. This is done in good faith, but looking at Figure 5 we may be facing an impossible task. Many readers will agree that the success of personal transportation was only made possible with the abundance of oil at very low price in terms of net calorific value. The notion of driving a large vehicle for long distances may not be transferable with battery propulsion, even with government subsidies. Today’s batteries are weak contenders against petroleum, and the chart below demonstrates this. Li-ion, the battery choice for the electric vehicle, is hardly visible; the 90 percent efficiency of the electric motor does not make up for the low net calorific value.
Figure 5: Net calorific values of fuels with conversion efficiencies. The net calorific values of diesel and gasoline surpass hydrogen and Li-ion. The conversion efficiency refers to thermal output and does not include friction and drag.
* CNG (compressed natural gas) is 250 bars (3,625psi)
** Hydrogen is at 350 bar (5,000psi)
Hydrogen is also being dwarfed by petroleum. The slightly better efficiency of the PEM fuel cell in energy conversion compared to the IC engine has only a marginal benefit. In addition, hydrogen cannot be pumped from the earth as oil and needs energy to generate. Hydrogen can be seen as portable energy storage that needsenergyto produce, similar to charging a battery.
Let us conserve liquid fossil fuel because alternative energies will be more expensive. Daimler’s CEO, Dieter Zetsche, knows this and stressed at a 2010 meeting in Stuttgart, Germany, that major research and developments are needed now because, “in the long run there’s no alternative to the electric vehicle.” EV makers know that the investment is speculative and that the return will be moderate for some time to come. The success of the electric vehicle will ultimately lie on the battery. Performance, longevity and price will be the deciding factors.
1) What is your data source for the NCV -versus- fuel source graph?
2) What is” Wh/l” This is NOT explicitly mentioned in your graph.