UNDERSTANDING HYBRID ELECTRIC VEHICLES (HEVs)


Recently I discovered that some subscribers to this newsletter don’t seem to appreciate the vital role that HEVs and plug-in hybrids (or PHEVs) can have on the future of this country. Therefore, I have devoted this page to explanations that might be helpful.

First of all, the notion that nickel metal hydride or lithium ion batteries are so bad for the environment that they negate the benefits of electric power for small vehicle transportation is WRONG, as is the myth that a rescue worker would be electrocuted if he or she dared to use the ‘jaws of life’ on anyone pinned in an HEV. Such silly stories have been tossed around on the internet to give negativists an excuse for staying in their ruts.

The electric car has been around for over 100 years. Even though it was quieter, cleaner and much easier to start, it lost out to the gasoline-powered car because of its limited range and speed. Gasoline is the most efficient hydrocarbon for an engine, and it was abundant 100 years ago. Although we haven’t run out of it yet, we now know that its supply is limited, and worse, it’s damaging our environment in many ways. T. Boone Pickens urges us to switch to natural gas (methane), because it’s cheaper and cleaner. Like octane, however, it’s in limited supply, and it also pollutes our air, just not as rapidly. So Pickens is right about using more wind power, but wrong about switching cars to methane.



 The HEV allows small batteries to assist a small gas engine (as in the 2010 Honda Insight above) or the reverse (in the case of the Toyota Prius). The batteries are recharged by the kinetic energy of the car during coasting or braking. The best hybrid cars are light in weight, and they use ‘auto-stop’, which shuts off the engine at red lights to save even more fuel.

But HEVs are really just a niche along the evolution of the modern car to the PHEV. PHEVs are similar to HEVs except for two things. First, they have a larger battery pack so they can operate in all-electric mode for local trips of 10 to 20 miles. Second, they can be plugged into a standard 110V home outlet for recharging without the engine running. Many are now delivering 100 MPG.

At today’s battery and gasoline costs, driving a PHEV costs a quarter to half that of a conventional gasoline-powered car. As for reducing carbon emissions, that depends upon where you live, but for the USA as a nation, it comes out to 42% per mile driven on electric power. Owners who plug in their cars at night will be more motivated than ever to install solar panels at home and harness the sun’s clean energy rather than depend on a coal-fired power-plant. You might find this hard to imagine right now, but some forward-thinking engineers are predicting that one day, vast numbers of PHEV-owners will sell energy from their car batteries to help support the electric grid after sunset or when the wind dies.