By EV World Editorial Team
The record-breaking responses to EV World's November ePOLL asking readers if they would buy a thorium-powered car if one were available, demonstrates an intense interest in the technology… if it exists.
Over one hundred years ago, steam-powered automobiles competed with battery-powered cars and the new fangled internal combustion engine for dominance in the early days of motoring. The best known steamer of the period was built by the Stanley brothers, whose original prototype was the first motor car to climb to the top of Mountain Washington in the state of New Hampshire, the highest peak on the U.S. East Coast.
In some respects, they proved more popular than either the hand-cranked ICE-age vehicles of the time and the electrics, offering superior range, certainly; that is once you got the boiler temperature up to produce steam. And it was that steam that gave buyers the confidence to invest in cars that often cost ten times the price of a Ford Model T of the period. They were, in effect, 'trains on wheels' and a technology with which everyone at the time was very familiar. They even sounded like a steam locomotive.
As was the case with electric cars, it was the invention of the electric starter and improvements in internal combustion engines that doomed the steam car, which apart from its cloud of steam, was nearly as clean as the electric cars of the time, if you took power plant emissions into account. While they burned kerosene, they were surprisingly smoke-free for the time.
Now jump forward a century and add a thorium laser instead of a kerosene burner and we might be looking at the rebirth of the steam-powered automobile, but with a couple interesting, as well as potentially controversial twists.
First reported some four years ago, a company called Laser Power Systems is said to be working on a way to marry the principle of the steam car and a thorium laser to create an electric car that could run for 300,000 miles on less than three-tenth of an ounce of thorium-232, a radioactive element with a half life of 14 billion years.
According to various reports in the online media, LPS, founded and run by Charles Stevens, is working on a thorium laser that, unlike other lasers that generate intense, coherent light, instead produces heat when excited. Presumably that heat, in turn, is used to turn a working fluid into steam, and that steam is used to spin a microturbine connected to an electrical generator. In effect, you'd have a zero emission series hybrid not unlike the Chevrolet Volt. In fact Cadillac debuted a Thorium concept car several years ago [above image].
Only, it wouldn't be entirely zero emission, no more so than an electric car or nuclear power plant, which is, in effect, what a future 'Stevens Steamer' would be.
The beauty of the thorium laser concept is that it takes such a tiny amount of 'fuel' to produce so much useable energy. According to Stevens, a single gram of thorium supposedly has an energy potential equivalent to something like 7,500 gallons of gasoline, a claim a lot of people have accepted at face value, though at least one commentator questions this assertion.
Of course, on closer examination, we have to ask where the energy comes from to initiate and then sustain the laser? If I understand their principle, conventional lasers use high voltage electrical current to stimulate photons within their crystals. Furiously bouncing between mirrors, more and more photons are excited and either released in short powerful pulses or as a continuous stream of intense, highly focused light, depending on the characteristics of the lasing element.
Since Stevens hasn't been all that forthcoming in explaining his technology, we have to make some assumptions - right or wrong - on what might be happening in that silvery canister of his. What we do know about thorium-232 is that while it is a relatively low level radionuclide that is found pretty much everywhere in the environment, including our own bodies, it isn't entirely benign either, as the EPA's website cautions.
Like the questions that earlier revolved around global lithium reserves being sufficient to meet future electric car battery production needs, similar questions are being asked about thorium. While it is found pretty much everywhere from plants to sea water, it needs to found in concentrations sufficient to justify the expense of mining it. The Thorium Forum has published estimates which how much may be accessible and where its located with India possibly possessing the highest potential reserves according to recent estimates.
A 2005 IAEA estimate places Australia in the top position at 489,000 tones, followed by the USA (400,000), Turkey (344,000), and India (319,000). Brazil (303,000) and Venezuela (300,000) round out the top six nations.
Once you've located it - and its usually found in association with rare earth monazite sands - you have to mill it and refine it, which isn't a benign process - again according to the U.S. Environmental Protection Agency. Facilities that used thorium to make kerosene light mantels and ceramic glazes are considered potential Superfund sites, with mill tailing sites being the leading candidates.
Before we get all excited about thorium laser technology powering your future Cadillac ELR - and according to this month's record-breaking ePOLL survey responses a lot of EV World readers seem pretty keen on the idea - we need to consider potential 'unexpected consequences,' like nuclear weapons proliferation. Despite claims that thorium can't lead to weapons grade material, that apparently isn't entirely the case.
At this point, we haven't even addressed the crash safety issues. If we think the media has overblown the trio of fires in Tesla Model S cars lately, imagine their reaction if they were thorium-powered.
Oh yes… and then there's the question of how much will the fuel cost and how do you pay for it?
So, while the idea of a car that can run for a 'century' on single fueling of thorium is certainly a titillating prospect, how realistic it is remains an open question.
And we thought introducing hydrogen cars was fraught with complications.
Originally published: 14 Nov 2013
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