Drilling advances

	Vol. 229 No.10
LES SKINNER, PE, CONTRIBUTING EDITOR, LSKINNER@SBCGLOBAL.NET

Drilling for hydrogen

The benefits of hydrogen for generating power from fuel cells are well-documented, whether for vehicles or commercial electricity production. Hydrogen combines with atmospheric oxygen in an oxidation/reduction reaction to produce electricity, with water and heat as the only byproducts. This presumably avoids such nasty waste products as sulfur dioxide, carbon monoxide and, the worst of them all (gasp), carbon dioxide. However, most folks don’t have a clear understanding of the sources of hydrogen.

Hydrogen, the most abundant of all elements, makes up more than 90% of all atoms. It is composed of one proton and one electron. Its atomic structure makes it attractive to electron-hungry molecules. So, free molecular hydrogen is not found in significant quantities in nature (less than 1 ppm in the atmosphere by volume). It is almost always atomically bound to something else, and to separate an appreciable volume of hydrogen gas these bonds must be severed. There’s plenty of it around, but not in a usable form.

Hydrogen contains no stored energy like wood, coal, oil or even uranium. Thus, it is not considered an energy source; rather, it is an energy carrier, akin to electricity. Like electricity, it requires a great deal of infrastructure to produce in commercial quantities, is difficult to store, and suffers from losses and added costs when transported. Also like electricity, when converting energy from a source (e.g., coal, gas, oil) to an energy carrier, inefficiencies occur, assuming the second law of thermodynamics still applies.

The most prevalent molecule containing hydrogen on the earth’s crust, of course, is water. Hydrogen (and oxygen) can be recovered from water through electrolysis, as every chemistry student has observed since the time of Cavendish in 1776. It can also be recovered by the surface action of steam on carbon. Hydrogen is liberated from water through its reaction with certain metals, like sodium. Dissociation of water by electrolysis is only about a 70% efficient process, assuming that none of the waste heat is recaptured or used, which is often the case in electricity production today.

The efficiencies involved in the production of electricity vary dramatically, from a low of about 30% to a high of about 90% (with recaptured heat), with the midpoint being about 40% or so today. Predicting what efficiency levels will be in the ensuing years, when hydrogen presumably would become a more widespread energy carrier (if ever) is a subject of great debate. Predicting the future always is.

At present, there exists a large and rapidly growing global hydrogen industry. Worldwide, about one-fifth as much volume of hydrogen is produced-about 21 Tcf-as there is natural gas produced each year. About 48% is steam-reformed from natural gas, 30% is derived from oil and 18% from coal. Only 4% comes from dissociating water with electricity. This is because generating hydrogen from electricity, especially from coal, makes no sense from an environmental or an economic perspective. If strictly wind or nuclear power were used, this would be a different story, but nuclear power still seems to be a politically risky subject with the “greenies.” Wind is growing at about 28% a year, and with T. Boone throwing his hat into the ring, its future seems assured.

But why use hydrogen at all? Hydrogen and electricity are both energy carriers, both cost about the same to transport, so, once electrical power is in the grid, it is the cleanest energy available. It doesn’t make any sense to use it just to generate another “clean” energy source. So, why convert, at all? Let’s just solve the remaining battery problems and go to battery-powered electric cars. (This may be a bit problematic in airplanes, however.) However, if natural gas continues to be the fuel of choice for new electricity generating capacity, we’ll need a lot more of it to power electric cars.

Suppose we stay on the hydrogen juggernaut; where would all this hydrogen come from? By far, the best source of hydrogen is methane, which, of course, comes from natural gas. Hot methane passed across a catalyst generates elemental carbon in one of its many forms plus large quantities of hydrogen. This requires less energy than electrolysis of water because of the weaker carbon-hydrogen bond. Of course, some natural gas must be burned to heat the feedstock, so additional CO₂ is released to generate hydrogen in commercial quantities.

Whatever the future marketplace decides is the best source of vehicle transportation fuel, as a bridge to a hydrogen future, natural gas is widely seen as the easiest fuel from which to derive hydrogen. Obviously, if hydrogen were used for transportation, soaring gas demand could only be met by considerable Arctic gas, which means large, long-term pipeline projects, or a much larger LNG supply. While there is enough natural gas in the world, it seems that competition for every LNG plant that might get built is increasing, with future supplies quickly spoken for.

So what does this mean to oil and gas producers? Quite simply (to paraphrase Marie Antoinette) “Let them have hydrogen!” In a hydrocarbon-based energy system like the one we now have, the only way to generate hydrogen is to produce more hydrocarbons. The nuclear alternative mentioned above has its own problems, because if the hydrogen is generated by high temperature, it must be done at the nuclear plant and then transported. If it’s done using electrolysis, after the electricity is transported, then efficiency becomes the problem that needs improvement.

The only thing that makes any sense at all, if hydrogen is the desired fuel for vehicles, is to go with the “plan” and provide the natural gas feedstock for all the hydrogen that we are going to need. Therefore, as an industry, we should support hydrogen-based fuel research.

Whether hydrogen or electric-powered cars win out, natural gas prices will doubtlessly increase due to shortages created by increased demand. This, in turn, will encourage exploration and development activities for even more natural gas.

In short, let’s go drill some “hydrogen feedstock” wells and supply the so-called “green” market with the fuel for which they so vehemently clamor. Think of it as our way of helping out.