MABUK-DONG, South Korea – “Stepping on the gas” takes on a whole new meaning behind the wheel of Hyundai’s third-generation fuel-cell electric vehicle, the ix35.

Powered exclusively by hydrogen, the zero-emission cross/utility vehicle was completed late last year by some 200 engineers at the Korean auto maker’s fuel-cell development center here.

Next year, Hyundai will begin small-scale production of the FCV in Ulsan at the same plant that makes conventional gasoline-powered versions of the vehicle, known in the U.S. as the Tucson, says Jae Young Shim, senior research engineer working with Fuel Cell Vehicle Team 1 at the tech center here.

Between 2012 and 2014, the auto maker plans to manufacture 1,000 FCVs for lease only. An undetermined amount will come to the U.S.

In the meantime, a small number of prototypes has been parceled out globally to government organizations hoping to wean their economies off petroleum.

In 2015, Hyundai expects to begin mass production of FCVs, with a first-year target of 10,000 units. The goal is to sell the vehicles for $50,000 apiece.

At least that’s the gameplan. Political, economic, technical and environmental challenges are sure to surface during this timeframe, but one thing is certain: Fossil fuels will not last forever. What’s surprising is that there are few surprises when test driving the ix35 FCV. It all looks and feels completely ordinary, like a conventional car.

The driver notes a gentle whirring of the 100 kW (134-hp) electric motor that turns the two front wheels, much like that of plug-in EVs such as the Nissan Leaf, Chevrolet Volt or Mitsubishi i.

But the accelerator and brake pedals feel familiar – a far cry from the grabby regenerative brakes and surge-prone thrust of the first-generation hybrid-electric vehicles.

Stepping on the accelerator propels the vehicle forward like any of the newer EVs on the market. Acceleration is linear, coming in precise amounts commensurate to the pedal input. The heavier the boot, the greater the torque.

This feeling of a conventional interface is crucial to consumer acceptance of these new vehicles. People might be willing to pay for advanced technology, but don’t expect them to recalibrate their thinking about driving. Familiar is good.

Within 20 years, people will be consuming new types of energy as carbon-based sources thin out, Hyundai says.

Today, about 90% of the world’s energy comes from nuclear reaction and fossil fuels such as oil, coal and natural gas. By 2015, these combined sources should peak at about 95% and then trail off to 76% in 2030, 50% in 2050 and 17% in the year 2100, according to German energy consultants Ludwig-Bolkow Systemtechnik.

Meanwhile, 64% of energy in 2100 is expected to come from renewable sources such as photovoltaics, wind, hydropower and solar thermal power plants, the researchers say. Picking up the slack with the remaining 19% is expected to be biomass and other renewable sources such as geothermal energy and solar heat collectors.

This means the gasoline-fueled internal-combustion engine, which has powered about a billion cars and logged trillions of miles over more than a century, will have to be replaced, if people want to maintain a sense of independent mobility, the Ludwig-Bolkow research suggests.

Another motivating factor: The European Union and the “G8” countries agreed in 2009 to reduce carbon-dioxide emissions 80% by 2050, which will require 95% of vehicles to be carbon-free by then.

Based on current technology, only battery- and fuel-cell electric vehicles are up to the challenge, auto makers say.

When using pure hydrogen, fuel cells emit only heat and water, alleviating concerns about greenhouse gases.

Auto makers say battery-electric vehicles are well suited for short-range transportation – in big cities, for instance – while hydrogen, the most abundant element in the universe, is a renewable energy source and an attractive media for storing large amounts of electricity so vehicles can drive long distances.

A cross-country road trip would be no problem, provided the refueling infrastructure is in place. The hydrogen tank perched below the cargo hold of the ix35/Tucson FCV can hold 12.3 lbs. (5.6 kg) of the gas, stored under high pressure at 10,153 psi (700 bar).

Based on the European driving cycle, the range is 321 miles (517 km) although other estimates suggest 400 miles (644 km). Maximum speed is 100 mph (160 km/h), and the vehicle can reach 62 mph (100 km/h) in 14 seconds.

The car actually feels faster than that. The short test drive stays on the grounds of the tech center here, so we never get it up to highway speeds. But a series of short straightaways and undulating turns demonstrate the FCV’s sure-footed nature. Underpowered it is not.

The fuel-cell stack, produced internally by Hyundai and placed under the hood, constitutes about a third of the vehicle cost and can produce 100 kW of power.

Currently, Hyundai builds the stacks at the research center and has capacity for 500 units a year. A secondary lithium-polymer battery pack, positioned under the front seats and rated at 24 kW, is the same as in the Hyundai Sonata/Kia Optima hybrid.

Hyundai and other auto makers have proven the viability of FCVs, but the biggest hurdle is providing the refueling infrastructure.

In the U.S., California leads the way with 20 stations, but availability is spotty elsewhere. Plans are under way to add hydrogen stations in the Northeast, and Michigan got its first publicly accessible station this past summer, near Flint.

Hyundai engineers drove the Tucson FCV from San Francisco to New York in September to promote awareness of childhood cancer, as well as the need for a hydrogen refueling infrastructure.

Here on the Korean peninsula, 10 stations provide decent coverage, most of them near Seoul, home to about 25 million people.

Europe is investing heavily in a hydrogen infrastructure. Denmark, Norway, Sweden, Belgium, Germany, the U.K. and France are among the nations adding fueling stations, and Hyundai is delivering its latest FCV to many of the countries for testing.

“We think by 2020, there may be more of a hydrogen infrastructure to the point we can market our fuel-cell vehicles,” says Cho Kwon Tae, a senior research engineer with Hyundai’s Fuel Cell Vehicle Team 2.

The cost at the pump is competitive and becoming more so. Currently priced in many areas at $10 per kilogram, the ix35 FCV can be filled up for $56, about what it costs to top off a fullsize pickup, with similar driving range.

Tae says the industry expects the cost of hydrogen to fall dramatically to about $5 per kilogram by 2015. “But in the U.S., they are targeting around $2 to $3 per kilogram by 2015,” he adds.

Hydrogen fuel currently is derived from petroleum and natural-gas reforming, but future potential renewable sources include wind, solar, biomass and nuclear energy.

Hyundai’s research suggests the total cost of ownership will plummet for FCVs. In 2010, the cost in Euros was about E0.9 per kilometer driven, compared with E0.5 per kilometer for a BEV, E0.3 per kilometer for a PHEV and E0.2 per kilometer for a gasoline-powered vehicle, the auto maker says.

By 2015, all four of these vehicle classes is expected to be below E0.4 per kilometer, and by 2020 the total cost of ownership will be the same for all four, about E0.3 per kilometer, according to Hyundai research.

“Eco-friendly vehicle cost is much higher than an internal-combustion engine right now, but after 2020 it will be much closer,” Shim says.

Since Hyundai began its fuel-cell program in 1998, costs have come down dramatically. The first prototype a decade ago cost 1.1 billion won ($1 million) to build. This latest version cost 168 million won ($150,000).

Kiho Yoo, director of Fuel Cell Vehicle Team 2, says the new vehicle handles more confidently than the first iteration. “The weight balance is much better than it was 10 years ago,” Yoo tells WardsAuto.

Although the research program has been extremely expensive, Yoo says he is sure the payoff will come.

“We believe the fuel cell is the ultimate future,” he says. “And we are prepared for this future.”