DEAR EarthTalk: I've heard that cars can be modified to run on water. How is this possible?

There are kits that will convert your car to "run on water," but these should be viewed sceptically.

These kits, which attach to the car's engine, use electrolysis to split the water (H2O) into its component molecules – hydrogen and oxygen – and then inject the resulting hydrogen into the engine's combustion process to power the car along with the petrol. Doing this, they say, makes the petrol burn cleaner and more completely, thus making the engine more efficient.

Future mobility: The lightweight hydrogen-powered Riversimple car making its debut in London in June. Production of the two-seater may begin by 2013. Instead of selling the car, Riversimple intends to lease it, for £200 (RM1,160) a month.

But experts say the energy equation on this type of system is not, in reality, efficient at all. For one, the electrolysis process uses energy, such as electricity in the home or the onboard car battery, to operate. By the laws of nature, then, the system uses more energy making hydrogen than the resulting hydrogen itself can supply, according to Dr Fabio Chiara, research scientist in alternative combustion at the Centre for Automotive Research at Ohio State University.

Moreover, Chiara says, the amount of greenhouse gases produced by the vehicle "would be much larger, because two combustion processes (petrol and hydrogen) are involved."

Finally, there is a safety consideration for consumers who add these devices to their cars. "Hydrogen is a highly flammable and explosive gas," he says, and would require special care in installation and use.

The electrolysis process could be viable in saving energy if a renewable, non-polluting energy source such as solar or wind could be harnessed to power it, although capturing enough of that energy source on board the car would be another hurdle.

Researchers today put more focus on using hydrogen to power fuel cells, which can replace internal combustion engines to power cars and emit only water from the tailpipe. And though hydrogen is combustible and can power an internal combustion engine, to use hydrogen in that way would squander its best potential: to power a fuel cell.

Hydrogen fuel cell cars are gaining traction, but commercialisation of hydrogen fuel has not yet been accomplished.

Many companies are working on ways to produce, store and dispense hydrogen as well as develop hydrogen fuel cell technology.

Cars powered by fuel cells are in prototype stages now, nearing production.

While we all wait to see how that shakes out, the best choice today for high mileage and low emissions is still the petrol/electric hybrid car.

Mining boron leaves footprint

I'VE heard so much about using Borax for green house-cleaning. But if this mineral has to be mined, doesn't that negate some of its "green-ness?"       

Mining for minerals such as boron (the key ingredient in the Borax we use for cleaning, pest control and other household tasks) is an activity that typically leaves behind a big environmental footprint.

Mining degrades the local landscape and destroys wildlife habitat, while polluting both air and water.

It also usually consumes large amounts of water, which can be taxing in already arid regions, such as the Mojave Desert, one of two regions of the world (along with parts of Turkey) with large boron deposits.

Typically, boron is extracted in open-pit mines by drilling, blasting, crushing and hauling – all activities fuelled by petrochemicals.

The refining process then uses a significant amount of water.

Finally, the waste product – known in the industry as tailings – is deposited in man-made ponds where further refining is done before the water is then discharged into the local watershed.

The mining industry has long been criticised as an environmental baddie, but Jared Diamond in his 2005 book Collapse: How Societies Choose To Fail Or Succeed said that Rio Tinto's (the leading company that mines boron) mine in Death Valley, California, is now one of the most cleanly operated mines in the United States.

Boron, oxygen and sodium make up sodium tetraborate, which is sold as "20 Mule Team Borax" (the name comes from the teams of 18 mules and two horses that would haul large wagons of processed borax from mines in the late 1800s to the nearest railroad spur).

The powdered detergent is considered a least-toxic recipe as a natural disinfectant and household cleaner.

Beyond cleaning formulations, boron is also used in a wide variety of other products, including the manufacture of fibreglass and Pyrex.

Pest control is another use. One boron compound is used to treat wood to prevent fungal decay and repel carpenter ants, roaches and termites.

Boric acid is included on the national list of allowed substances for structural pest control in organic food production.

Emerging uses of boron, and new ways to recycle its waste, may make this mineral even more valuable.