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Posts Tagged ‘fuel’

The Flaw With Fusion

Fusion target implosion on NOVA laser

Fusion power is currently the undisputed ideal form of energy production. It is similar to the current widespread nuclear fission power, but instead of using enriched radioactive fuel, it works by focusing intense energy on a single point, causing several atoms to fuse into a single, larger atom. This is the same kind of energy that powers the sun. The easiest fuels to use are the isotopes of hydrogen: deuterium (²H) and tritium (³H), because they react at the lowest temperatures.

But you didn’t come here for a chemistry lesson. The fact of the matter is that fusion power has been marketed to the public as being able to use water as fuel and produce helium as a byproduct, which is true. But even though this form of production is incredibly efficient, we are still turning water into helium. I know what you’re saying, there’s a LOT of water on this planet, right? How much can we afford to lose? There is only so much water on this planet at one time, and we will never get that water back unless we invest the energy to turn the helium back into water.

These power plants are said to only need to consume one liter of water to produce the power we get from 500 liters of petroleum. But how much water do you think it will take to power the whole planet? In 2008, total worldwide energy consumption occurred at a rate of roughly 15 terawatts (source). If I did my math right, it would take 22,000 lbs. of water to power the Earth for one day on fusion power, that’s over 4 thousand tons per year!

That may not be very much water in relation to the amount on the planet right now, but we’re talking about permanently upsetting the balance. Once fusion power becomes economically and technologically feasible, and energy becomes more cheap and abundant, we will most likely start using more of it. That will result in a decrease in the amount of water in our ecosystem and an increase in the amount of helium.

That being said, fusion power will most likely be able to safely power our planet for at least a few thousand years, probably long enough to find a more reliable energy source, or a more abundant source of nuclear fuel. But people need to know what fusion power is all about before endorsing it. It’s not an end-all solution to the world’s energy problems, nor is it completely safe. It’s not even considered a renewable energy. I think that when fusion power becomes a reality, it should only be used to supplement renewable energy sources, not as the primary energy source. When you break it all down, the only true sources of renewable energy that we know of right now come from the heat of the Earth, or from the sun.

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Clean Energy Finally Gaining Steam

March 5, 2010 7 comments

Finally, somebody said what I’ve been waiting to hear, “… no member of the public has ever been injured by a nuclear power plant in the United States, nor has any nuclear worker died of a radiation-related incident…”, a statement made by Patrick Moore today in the LA Times. This is exactly what I’ve been talking about. People got all hyped up with the accident at Chernobyl (which happened under extremely rare circumstances, by the way) and decided never again to trust nuclear power. There is your proof that nuclear power is clean and safe, despite what people want to think about it. How many people have been killed in coal mines, or in natural gas or oil rig explosions?

We do have renewable energy sources right now: wind, solar, tidal, geothermal, etc. But they are not yet efficient or widespread enough that they can sustain our energy economy. Nuclear power is our next step to clean energy. People need to get over their preconceptions and accept that there is nothing wrong with nuclear power, it has been around for over 50 years now and the technology is well developed and widespread. They want to get rid of greenhouse gases, why not get rid of the big coal powerplants?

The extra money that we would save by getting rid of coal power could be put into research and development of nuclear fuel reprocessing technologies. I think that the big thing that people worry about is spent reactor fuel. Obviously, more reactors would mean more spent fuel. But it would also mean more funding for reprocessing research and storage facilities.

I believe that we are less than 50 years away from seeing reliable fusion power become a reality. When it does, we won’t need traditional nuclear fission reactors anymore, so you can do away with that waste. There is enough nuclear fuel on this planet to last us a long time, much longer than fossil fuels, which are running out fast. Our energy economy needs an overhaul, we’re not in the 1900’s anymore. Maybe coal and oil power was a bright future back then, but now, over 100 years down the road, supplies are running out and we’re seeing the repercussions of living this way. We can’t stay stuck in our ways just because we don’t want to change. The good times with fossil fuels are a thing of the past, now it’s time for us to grow up and move on to bigger and better things.

Nuclear Waste May End Up In Our Backyards

The Energy Department filed to withdraw an application for a nuclear waste repository at Yucca Mountain Wednesday in an attempt to reverse a policy set and invested in by the Bush administration (source: Wall Street Journal). A new panel was created by the Energy Department and the Obama administration hopes to develop a new plan for disposal of nuclear waste.

The Yucca Mountain facility, located in the Nellis Military Operations Area in Nevada, was intended to be the first national repository for spent nuclear waste, a one-of-a-kind facility designed for this sole purpose. The government has already rewarded at least $2.5 billion in contracts to maintain the facility.

If the Obama administration wants to go all-out on renewable energy sources, then by all means, let them. But taking away the infrastructure for our existing energy generation facilities is not the way to go about doing it. The fact of the matter is that we rely heavily on nuclear power at this point in time. As of November 2009, 20.2 percent of energy produced in the US was from Nuclear (source: USEIA), a 2.5 percent increase from 2008. Despite all of the skepticism and hype about nuclear energy, it is one of the cleanest non-renewable energy sources out there. There have been far fewer incidents and deaths related to nuclear energy in the US than there have with coal power plants. Coal power still accounts for almost 45 percent of our annual electricity production, would we rather have coal power or nuclear? I, for one, would rather live next-door to a nuclear reactor than a coal power plant. We can’t just jump right in to an absolute renewable energy economy and expect it to work, we first need to phase out the other forms of production: coal first, then natural gas and oil, then nuclear.

The nuclear reactors aren’t going to go away. It makes more sense for the waste from them to be stored in a dedicated facility than to rely on individual companies to do it their own way, because you know that they will cut corners. If the Obama administration has a better idea, they’d better get going, because it’s just a matter of time before there will be an accident involving spent nuclear fuel that was not disposed of properly.

The Two-Cylinder Club

Today, I’d like to discuss a technology used in some vehicles called cylinder deactivation, or variable displacement. It’s a system used in some reciprocating engines that selectively deactivates some of the cylinders to improve efficiency and save fuel. This is generally accomplished by incorporating actuators that hold the intake and exhaust valves open so as to create an “air spring”, which has an equalizing effect on the overall combustion cycle of the engine. A relatively old technology, the closest predecessor to use a design like this was the hit and miss engine, which accomplished the task by holding the exhaust valve open. Several automotive makers have experimented with variable displacement models, having little success. Today, the concept is regaining strength with rising fuel prices and increasing environmental awareness. Some newer engines that were previously deemed “guzzlers” are now being redesigned with selective cylinder deactivation technology as a less costly alternative to a hybrid power-train. One example of this is the newer Chrysler Hemi engine, though I understand from talking to the owners of these that the Fuel Saver mode only kicks in above 65 MPH.

In yesterday’s post I talked about hybrid vehicles. It was my understanding that the engines in hybrid vehicles were directly coupled to the electric motor and deactivated cylinders to “shut the engine off” while still running on the electric motor. I was under the impression that the engine still rotated with the transmission without firing when not in use. I guess I can’t give the auto makers quite as much credit now, as I realize that the engines in hybrids behave much like they do in non-hybrid vehicles with automatic transmissions, stopping the engine completely and restarting with a smaller motor when needed.

I don’t really understand why all vehicles don’t have variable displacement technology. I mean heck, a car or truck only needs one cylinder to idle, not eight. The goal is to use the full potential of each cylinder. At idle or partial throttle there is a vacuum inside the cylinders; in other words, an engine only uses as much air as it needs to. This becomes a problem with larger, multiple cylinder engines because you get pumping loss, inefficiency resulting in low pressure at top-dead-center of the compression stroke. Of course, lower pressure equals lower efficiency. So if at idle we take away 7 of the 8 cylinders in operation, that one cylinder left over has to use much more of it’s maximum power output to maintain operation of the engine. I would gladly take away three of the six cylinders in my car if it meant better mileage, not like I need all six anyway. Diesels could accomplish this even easier, simply by shutting off the fuel to the cylinders that you want to cut, now we’re talking mileage.

I think that all automakers should start designing their vehicles with variable displacement technology. The changes are easy to implement, and the rewards would be great to the consumers. If they just invest a little more time in getting the system right, it could be huge for a form of propulsion that is on it’s way out anyway.