Approximately half of the population of the United States lives in places where air pollution levels are high enough to harm public health and the environment. Nitrogen oxides, hydrocarbons, and particulate matter emissions from gasoline and diesel automobiles are a major cause of pollution. Hydrogen-powered fuel cell electric vehicles emit only water (H2O) and warm air and emit none of these hazardous chemicals.
Hydrogen produced from low- or zero-emission sources, such as solar, wind, and nuclear energy, as well as fossil fuels with enhanced emission controls and carbon sequestration, has environmental and health benefits. Because transportation emits nearly a third of all carbon dioxide in the United States, harnessing these sources to produce hydrogen for transportation can help reduce greenhouse gas emissions. More information on hydrogen emissions can be found here.
What are the benefits of using hydrogen as a source of energy?
What Benefits Do Hydrogen Fuel Cells Offer?
- Hydrogen is a clean and flexible energy source that can be used to help achieve zero-carbon energy goals.
Why might hydrogen be preferable to gasoline as a fuel?
The Energy Policy Act of 1992 classifies hydrogen as an alternative fuel. The ability to power fuel cells in zero-emission vehicles, as well as the fuel cell’s rapid filling time and high efficiency, have sparked interest in hydrogen as an alternative transportation fuel. In fact, a fuel cell with an electric motor is two to three times more efficient than a gasoline-powered internal combustion engine. Internal combustion engines can use hydrogen as a fuel. Unlike FCEVs, however, these emit tailpipe pollutants and are less efficient. More information on fuel cells can be found here.
1 gallon (6.2 pounds, 2.8 kilograms) of gasoline has about the same amount of energy as 2.2 pounds (1 kilogram) of hydrogen gas. Because hydrogen has a low volumetric energy density, it is compressed and stored aboard a vehicle to attain the same driving range as conventional automobiles. The majority of contemporary applications rely on high-pressure tanks that can store hydrogen at pressures of 5,000 to 10,000 pounds per square inch (psi). The FCEVs currently in production and available at dealerships, for example, have 10,000 psi tanks. These tanks can be filled in about 5 minutes using retail dispensers, which are mainly found at gas stations. Currently, fuel cell electric buses use 5,000 pressure tanks, which take 1015 minutes to fill. Other methods of storing hydrogen are being researched, such as chemically bonding hydrogen with a substance like metal hydride or using low-temperature sorbent materials. More information about hydrogen storage can be found here.
Is hydrogen a superior alternative to gasoline?
For hydrogen, flame velocity is also advantageous. Within the combustion cylinder, a higher flame velocity generates a better ratio of air that can be burned faster. Engineers love it when fuel is used to get the most job done. The Mercedes-AMG Formula One team can attest to this.
The automated ignition temperatures for hydrogen are likewise substantially greater than for gasoline, around 500 degrees Celsius against about 230 degrees Celsius. Because hydrogen has a higher octane rating, it can be used in engines with higher compression ratios.
Diffusivity refers to how quickly a fuel disperses, and in this situation, it’s a good thing hydrogen prefers to do so. It aids in a more effective combustion process once again. It also aids in the creation of a very consistent combination of air and fuel.
The quenching distance of hydrogenthe distance it travels away from the cylinder wall before the flame goes outworks in a similar way. It helps spread out that fuel for a better burn, but it could potentially backfire since hydrogen can fit through cracks more easily, such as between a valve and the combustion chamber.
Why is gasoline our default fuel if hydrogen is so good in many areas? For starters, gasoline is significantly more convenient to store. In terms of energy to volume, hydrogen is extremely dense. As a result, it takes up significantly more area in a combustion chamber (30% to 1-2%), lowering its power output as compared to gasoline, which is more power-dense. To do the same amount of work as gas, it takes more hydrogen. Because a hydrogen fuel tank takes up more space than a gas-powered automobile, it may take up important trunk and passenger space to travel the same distance.
Check out Jason’s whole explanation in the video above. It’s a 14-minute video with a lot of useful information.
What makes hydrogen fuel superior to fossil fuels?
The findings reveal that hydrogen is a far cheaper energy transporter than synthetic fossil fuels. Hydrogen conserves resources, saves money on transportation and capital expenditure, and lowers inflation, in addition to its environmental and efficiency benefits.
Is hydrogen more cost-effective than gasoline?
Safety is a problem since hydrogen, like gasoline and lithium-ion batteries, is combustible. The transfer of hydrogen for use at refueling stations adds to the dangers, as stations use sensors to detect leakage. In California, there have been no severe incidents, and the industrial sector has been carrying hydrogen for decades.
Alternative-fueled vehicles, which include hydrogen fuel cells and battery-powered electric vehicles, are not more dangerous than traditional internal combustion engines, according to the National Fire Protection Association. According to the NFPA, a car fire from an internal combustion engine vehicle occurs every three minutes in the United States.
In California, the average price for hydrogen fuel is around $16/kg gasoline is sold by the gallon (volume), while hydrogen is sold by the kilogram (weight). To put this into perspective, 1 gallon of gasoline contains roughly the same amount of energy as 1 kilogram of hydrogen. Most fuel cell electric cars carry roughly 5 kg to 6 kg of hydrogen yet travel twice as far as a modern internal combustion engine car with equal petrol in the tank, equating to $5 to $6 per gallon of gasoline.
According to the EPA, hydrogen fuel cell automobiles now have a range of between 312 and 380 miles. They’ll cost around $80 to refuel from empty (most drivers don’t let the tank run dry before refueling, so they end up paying $55 to $65). Automakers are presently covering this cost by providing lessees with prepaid cards for three years of fueling worth up to $15,000. Filling up a normal automobile with a huge petrol tank can cost $40 or more in California, which has the nation’s highest gas costs.
Annual fuel expenditures for the Toyota Mirai, Honda Clarity Fuel Cell, and Hyundai Nexo are estimated to be $4,495, which is three to four times the cost of gas-powered competitors, according to Kelley Blue Book.
“We recognize the automakers can’t keep paying for fuel, and we see the line of sight to get there,” said Shane Stephens, principal and chief development officer at FirstElement Fuel, which operates 19 of California’s 39 hydrogen refueling stations and is developing 12 of the state’s 25 additional stations. His company’s short-term goal is $10 per kilogram, or about $4 per gallon of gas. “In the next three to five years, that is a good near-term acceptable amount to hit and get people off automaker-subsidized fuel,” Stephens said.
The most serious issue is that automobiles remain prohibitively expensive. With a starting price of $59,345 (the brand’s comparable-sized Santa Fe starts at $24,250), the Nexo is the most expensive Hyundai on the market in the United States. The Toyota Mirai and Honda Clarity fuel cell vehicles both have a $59,000 starting price. Government subsidies are available for these car purchases; in California, a $5,000 tax credit is available.
Because the technology is new and early adopters don’t want to be locked onto a current model for a long time as the technology evolves and efficiency improves, leasing has become a popular consumer alternative for fuel cell and battery electric automobiles.
Fuel cell costs should fall as the market grows and obtains economies of scale in production and infrastructure, as with any new technology. “Honda has a long-term commitment to hydrogen,” Kumaratne added, “but you can’t sell cars without infrastructure.”
According to Stephens, if the market in California reaches “a few hundred thousand cars,” it will be cost-competitive with gasoline. This is a significant increase above the 6,000 cars sold thus far, but most new auto markets begin with small manufacturing runs. Toyota has stated that production of the Mirai will expand from 3,000 units per year to 30,000 units per year by 2021. “That’s a tenfold increase in magnitude.”
“In California, a couple hundred thousand cars isn’t that far away. That’s simply Toyota, by the way “Stephens remarked. “This isn’t about subsidizing infrastructure growth in its entirety; rather, it’s about assisting us in getting over the hump, which is on the horizon. We may begin to phase down government subsidies and become self-sufficient once we reach a few hundred thousand cars.”
What are the advantages and disadvantages of hydrogen fuel cells?
Pros: Vehicle emissions are limited to water vapor. Fuel economy is roughly double that of gasoline vehicles. Hydrogen is plentiful and may be produced using renewable energy sources.
The cost of this space-age technology is prohibitive. Acceptable range necessitates on-board hydrogen storage at extremely high pressures. There are few options for refueling. Transporting hydrogen is exceedingly expensive, and there is currently no infrastructure in place. Currently, hydrogen fuel is produced using nonrenewable natural gas, resulting in massive CO2 emissions.
Is it true that hydrogen automobiles are more environmentally friendly?
The fundamental benefit of hydrogen cars is that they emit no emissions at all at the exhaust, only water. This benefit is the same as with a regular electric car, putting both at the cutting edge of emission-reducing technology in the automotive sector.
The advantage of hydrogen cars over electric cars is that they can be filled at a gas station, which takes only a few minutes. You fill up, pay, and get on with your day, just as you would with a gasoline or diesel car, rather than having to wait hours for the same amount of range to be added to the battery pack.
Although hydrogen is environmentally friendly when used in a hydrogen car, getting the (liquid) hydrogen to the fuel pumps requires a lot of energy, and much of the current production is done with fossil fuels, so it contributes to global warming more than, say, an electric car charged with wind farm power.
As demand for hydrogen grows and more money is invested in developing better ways to produce it, it is believed that production will become totally sustainable.
Another disadvantage and currently the most significant is the infrastructure. There aren’t many hydrogen filling stations in the UK they’re not like they’re on every street corner.
In an electric vehicle, you’ll need to figure out where a nearby auto charging outlet is, but it’ll most likely be close by. With a hydrogen car, you may find yourself far from a fuel station. The majority of them are currently in London.
Hydrogen is also highly costly. While a full charge of an electric car from a home charger costs around 8, a full tank of a Toyota Mirai costs over 75.
However, these infrastructural issues and expenses will fade over time as more people purchase hydrogen cars, lowering costs and increasing the number of fuel stations available. For the time being, the vast majority of individuals believe that an electric car makes more sense.
Is hydrogen more efficient than natural gas in terms of energy efficiency?
Any gas must be compressed in order to be transported economically. And it turns out that this is the major issue with hydrogen distribution it’s why 85 percent of hydrogen generated in Europe, for example, travels a short distance to where it’s consumed because it’s produced on the same site or next door.
Natural gas has a density of around 8.5 times that of hydrogen, making it easier (and more energy efficient) to transport than less dense gases. Hydrogen compensates for this by having a higher energy density per unit mass nearly three times that of natural gas. Unfortunately, the amount of effort (mechanical energy) required to run a compressor is proportional to the number of moles of gas compressed, rather than their mass or volume. It also depends, albeit less strongly and in a more complicated way, on the ratio of the gas’s specific heats which, as it turns out, makes only a little difference (in favor of natural gas) and rises with increasing compression ratio. When the LHV of hydrogen per mole is compared to the LHV of natural gas per mole, natural gas is around 2.9 times as energy dense in molar units. Another way to say it is that compressing a MJ of heat energy as hydrogen needs around three times as much energy as compressing a MJ of heat energy as natural gas. And this, at least in part, explains why we don’t transport hydrogen by pipeline very often. Instead, we transport natural gas to the location where hydrogen is required and construct a hydrogen plant there. (The proof is at the end of the article.)
That threefold increase in compression effort costs not just energy, but also money for a gas utility, because every compressor in their network would need to be replaced with a new unit with three times the power and three times the suction displacement. And, because hydrogen is famously leaky, the volumetric flowrate of hydrogen is higher for a given heat flow in the pipeline, etc., the compressors would have to be completely different devices and much more expensive.
When starting and ending with electricity, hydrogen is already the best case scenario in terms of cycle efficiency. On a per unit energy basis, natural gas and electricity are nearly the same cost and efficiency to distribute, but hydrogen will cost around three times as much in wasted energy only to carry the gas. And, because downstream equipment is only 5060% efficient at creating electricity, you’ll have to transport nearly twice as much hydrogen energy to the destination to achieve the same result as if you moved electricity. That’s without considering the additional capital costs that would be incurred.
Pressure Drop in Piping A Wash
You’d expect that once you’d gotten hydrogen up to the correct pressure, you’d be penalized for moving it through piping – that was certainly my first impression. However, the answer to that question turns out to be fairly complex, and it depends on the conditions in which the calculations are performed. Natural gas is less dense, viscous, and energy dense per unit mass than hydrogen. When pressure drops are on the order of 5 psi per mile of pipe (rather than the 5 psi per 100 ft of pipe used in chemical plant piping), hydrogen and natural gas come out nearly even for a given rate of LHV heat delivered per hour through a pipe of given size.
This varies depending on where you are in the distribution system, but on average, an existing gas pipe can carry around 90% of the energy in the form of hydrogen that it could carry if fed the average natural gas it was intended for. The velocity will be about three times higher, but the density will be 1/8.5 as much, and the factors will nearly cancel each other out when combined with the slightly lower viscosity. However, because every kWh of energy lost due to pipeline friction must originate from a compressor, hydrogen still costs nearly three times as much per unit of energy to transport from source to destination through a pipeline.
“Line Pack What’s That? Another Problem…
I revise my articles when they teach me new things or point out my errors, like I promised my readers. And a competent source alerted me to a key issue that arises as a result of hydrogen’s decreased energy density per unit volume. “The amount of natural gas contained in the piping distribution system is referred to as a “line pack.” And we’ll lose that storage unless we increase the distribution system’s pressure which we can’t accomplish without new pipe. A normal gas system can withstand around 34 hours of average demand utilizing only stored gas in the lines, according to reports. Pure hydrogen, which has a density of energy per unit volume of 1/3 that of water, would cut the time in half. That might represent a huge difference in distribution system reliability, outage frequency and length, and the grid’s ability to handle demand changes like the massive spike when everyone arrives home, cranks up their furnaces or boilers, and turns on their cooktops.
I’m well aware that subdivisions can outgrow the rate at which gas providers can build additional lines to them. As a result, some utilities evaporate liquid natural gas from tanks and inject it into sites downstream of the pipeline “In order to keep the furnaces and cooktops running during peak hours, a “bottleneck” was created. Liquid hydrogen needs roughly 40% of the energy in the hydrogen only to liquefy it, boils at 24 Kelvin (24 degrees above absolute zero liquid methane boils at a balmy 112 Kelvin or -161C), and is still only 71 kg/m3 as a liquid methane is about 600 kg/m3 as a liquid.
Piping and Equipment
If you don’t overheat it, hydrogen is quite safe to transport in mild steel piping, even at high pressures. For soft mild steel or low alloy steel piping, such as that used in most chemical plant plumbing, the much-discussed “hydrogen embrittlement” isn’t an issue.
Natural gas pipelines, on the other hand, are not composed of mild steels, especially those that transmit natural gas over long distances or underwater. They’re made of harder, stronger steels, which are sensitive to hydrogen embrittlement or other hydrogen-related damage processes, notably in their welds and heat-affected zones, even at low pressures and temperatures, according to various reports.
Most of the high and medium pressure natural gas distribution system would need to be completely replaced to handle pure hydrogen, according to trustworthy publications produced by natural gas distribution companies themselves, such as this good one. (See p.12 of that reference for further details and these men, who own the pipes, should know!) That’s a colossal sum of money to spend on a fuel that might be better replaced with electricity anyway.
Note that hydrogen damage and embrittlement are complicated metallurgical subjects, and that nascent hydrogen (hydrogen atoms created by electrochemical action, such as during corrosion) causes damage that molecular hydrogen cannot unless a combination of high pressure and high temperature allows it. However, stories of H2 compatibility issues with natural gas pipes have been well documented by persons who are far more knowledgeable about this subject than I am.
The low-pressure distribution system is generally comprised of low-carbon steel and HDPE pipe, which can readily be used to transport hydrogen. Due to hydrogen’s low density and strong diffusivity, pipes designed to not leak natural gas can leak a lot of hydrogen. Unfortunately, stenching compounds used in natural gas to identify leaks, such as thiols (mercaptans), are incompatible with hydrogen, particularly hydrogen intended to feed PEM fuel cells used in cars. Sulphur compounds like that are particularly damaging to the catalysts of such fuel cells. Given the explosive range of hydrogen any mixture of 4 percent to 75 percent hydrogen in air is explosive the lack of a stenching agent to help detect leaks appears to be a difficult obstacle for distributing this fuel to homes and businesses.
Hydrogen/Natural Gas Mixtures
Instead of making the enormous jump to pure hydrogen, the earliest efforts all aim to smooth over these issues by mixing a little H2 into natural gas. And you’d think that “changing 20 percent of natural gas with hydrogen” would make a significant difference!
A 20% H2 combination in natural gas is a 20% mixture by volume. Because the mixture only has 86 percent the energy of a typical natural gas, you’d have to burn 14 percent more gas to get the same number of joules or BTUs of heat. The reduction in GHG emissions is nowhere near 20% – it’s closer to 6% if you simply look at the burning, and even less when you factor in the compression and pressure loss mentioned before. Users who are sensitive to heat content would scream at such a drop, thus forget about going to 30% H2! Because the gas has to flow quicker but isn’t sufficiently lower in density to compensate, a 20% combination of hydrogen in natural gas would take 13% more energy to compress and lose around 10% more pressure per unit length of pipe than if you stuck with natural gas. Some of your GHG emission reductions would be eaten up by those variables. While industrial users would be safeguarded because they pay per BTU or joule of LHV or HHV delivered by the gas utility, certain users may be underserved because they pay per unit volume.