Tuesday, September 15, 2015

Benefits of electric vehicles, hybrid vehicles - now and down the line

hybrid vehicle combines energy from a gasoline engine and an electric motor to increase efficiency. Hybrid automobiles increase MPG compared to standard vehicles (50+ for the vehicles addressed in this article), while lowering CO2 and other greenhouse gas emissions. The benefits of hybrid cars include financial savings even above and beyond the $5000-$6000 in savings on gas (over 5 years) that the cars in this article average. For example, hybrids help to avoid road tolls such as London's congestion charge. Hybrids typically offer features with advantages over standard cars, such as regenerative braking, electric motor drive/ assist and automatic start/ shutoff.
Regenerative braking refers to energy produced from braking and coasting that’s normally wasted, which is stored in a battery until needed by the motor. During electric motor drive/ assist, the electric motor kicks into gear, providing additional torque for such things as hill climbing, passing or quickly accelerating.  For automatic start/ stop, energy is conserved while idling, as the engine is shut off when the vehicle comes to a stop, and is re-started when the accelerator is pressed.
Whereas a normal hybrid car simply combines an electric motor and a gas engine, a plug-in hybrid can run only on electric power, when charged, and can be recharged without using the gas engine. Plug-in hybrid electric vehicles (PHEV’s) have high capacity batteries, and charge by plugging into the grid, storing enough electricity to significantly reduce gas use.
There are two basic types of plug-in hybrids: extended range electric vehicles and blended plug-in hybrids. Extended range electric vehicles work by having only the electric motor turn the wheels, and can run only on electricity until the gasoline engine is needed to generate electricity to recharge the battery that powers the electric motor (or the gas engine can be eliminated entirely, on short rides). Blended plug-in hybrids work by still having both the gas engine and the electric motor connected to the wheels, both propelling the vehicle most of the time.
Electric vehicles (EV’s) drop the gas engine entirely, becoming much more environmentally friendly. The MPG goes way up, but the cost tends to go up as well, and the driving range goes down. These factors; the MPG, cost and range are tied to how efficient, how much capacity, the battery has. The higher the capacity of the battery, the higher the cost, MPG and range. Although EV’s emit no tailpipe pollutants, it remains important that the source for the energy from the grid that charges the vehicle’s battery remains green (i.e. renewable energy) as well.
Hybrid cars take numerous different forms, including the types mentioned above, and then compete against standard gas cars, flex-fuel vehicles, diesel vehicles, etc... European sales of standard hybrid vehicles have increased, but with roughly half the cars in the EU being more fuel efficient diesel engines, EV’s and plug-ins are the more popular choice. These cars can better compete in the global market, in terms of fuel efficiency.
The global hybrid market is still dominated by Toyota, in particular their Prius line, including the Prius Plug-in. The Prius remains California’s most popular car, as a testament to its global popularity. The Prius gets around 50 MPG, costs $25-30K and has a driving range of 540 miles on a full tank of gas. The plug-in model costs $30-35K and gets 95 MPG running on electricity only or 50 MPG running on both electricity and gas, with a driving range of about 600 miles.
The Tesla Model S and the Nissan Leaf are examples of successful electric vehicles. The Tesla Model S with a 60 kW-hr battery pack gets up to 102 MPG’s, costs around $70K and has a driving range of 208 miles on a fully charged battery. The Nissan Leaf costs $30-35K, can get 80 miles on a full charge and hits 128 MPG’s.
(*All figures are as of 2015.)

Tuesday, September 8, 2015

Nuclear energy is necessary to fight climate change

Nuclear energy is necessary to fight climate change and decrease fossil fuel use. Wind and solar are often distributed energy sources which are always intermittent and variableNuclear, however, is continuously available and represents a much more concentrated source of energy than renewables, with a much higher production capacity. Both nuclear and renewable energy's contribution to energy production on the planet must increase to a combined energy production level which is a little more than what coal alone currently provides.
In order to significantly cut down on the share of fossil fuels in the world energy mix, at least double the production of that which is illustrated in the chart above is needed by 2035. (A total of 40% of the world's energy mix for renewable and nuclear energies combined is needed to reach significant GHG targets. Only 20+% of renewable and nuclear combined is projected in 20 years - by 2035).
In order for the entire planet to achieve at least 25% greenhouse gas (GHG) reduction by 2025 compared to 2015 levels (a reasonable, yet challenging, GHG reduction goal for the planet), nuclear energy is going to have to augment truly clean, renewable energy in the effort to dramatically reduce fossil fuel use. Once it’s at the operational stage, carbon dioxide emissions from a nuclear reactor and the power plant’s site are minimal. Other than reduction of emissions, nuclear offers, by far, the most energy dense resource available.
Fossil fuels are more energy dense than renewable energy sources, but 1 kg of coal can only keep a light bulb lit for a few days, while the same quantity of a nuclear energy source will keep the same bulb lit for well over 100 years. Nuclear does this without any CO2, or most other GHG, emissions from the nuclear plant.
Current reactors, 1st and 2nd generation plants, rely on water and uranium. Therefore, these nuclear plants still deplete water supplies, create nuclear waste, use a fuel source that can be enriched to convert the material into a bomb, and represent a source of potential danger, as in the Fukushima disaster (although this risk is dramatically minimized in a 3rd generation plant).
A safer, cheaper, and still energy abundant and emissions-free design that uses relatively benign energy sources and relatively much less water than previous designs and operational plants, is being envisioned in 4th generation nuclear, and is currently available in 3rd generation designs.
Using a small fraction of the water as previous designs, the 4th generation nuclear plant designs are safe, cost-effective, environmentally-friendly and still offer tremendous potential for energy production. Molten salt reactors using depleted uranium, nuclear waste from other plants, or thorium, are being designed as 4th generation nuclear plants. 4th generation designs (and many 3rd generation plants, both planned and operational) are autonomous, smart plants that are even being designed to run on different fuel sources.
Thorium, instead of uranium, is being looked at as a fuel source, as it is abundant, much less radioactive than uranium, and also creates by-products from burning the fuel source, that can just be used again in the reactor. Thorium reactors are being designed with low up-front capital costs, and little manpower is needed to run and maintain 4th generation plants, due to the advanced computer technology set to be deployed in the plants.
Thorium, and depleted uranium, have a very low chance of being developed into a nuclear weapons, produce less radioactive waste, are abundant fuel sources, and are safer, cheaper and cleaner.
Thorium, in particular, is being looked at by developing nations like China and India because of the relatively low cost, increased safety, abundance of the material, and tremendous energy potential of this energy source. The U.S. has huge amounts of thorium, in places like Kentucky and Idaho, and there are large quantities in countries like India, Australia and Brazil.
The U.S., Europe and even some of the aforementioned developing countries also have large stockpiles of depleted uranium, with more being produced every day, which would work in many of the 4th generation designs. 3rd generation nuclear plants are already operating, and some 4th generation plants are projected to be developed and ready for operation by 2025. 4th generation nuclear promises to produce abundant, low-cost energy safely, and with little environmental impact.