Hydrogen Energy

Hydrogen is not a source of energy; it is only a carrier of energy. Thus, technically it is not a renewable energy source; however, it still merits discussion here owing to its potential as a medium for generating clean power. 

Hydrogen carries high energy per unit mass (one kg of hydrogen has approximately the energy content of one gallon of gasoline – about 2.7 kg), potentially facilitating energy portability. In addition, pure hydrogen is a non‐polluting fuel, producing only water vapor at its point of use, so that pollutants will not be dispersed throughout a hydrogen energy economy but will primarily be localized where hydrogen and other elements of the energy system are produced. 

To a significant extent, the use of hydrogen to produce energy is by its use in fuel cells. In these cells, hydrogen is combusted with oxygen to result in electricity and pure water. This is the precise advantage of hydrogen (and hydrogen fuel cells) – the only exhaust from the system other than energy is non-polluting, pure water. 

One area where hydrogen can be used to produce energy through fuel cells is transportation. While there are a number of challenges for hydrogen based transportation (the chief among them being storage of hydrogen), this domain presents exciting possibilities, especially for research-minded entrepreneurs. 

Production of hydrogen

One of the advantages of hydrogen as an energy carrier is that it can be produced from a wide variety of primary energy sources and different production technologies.

Market growth

  • Global investments in building the hydrogen economy cost over $1.3 billion in 2006 and are expected to rise to nearly $1.7 billion in 2007 and $5.5 billion in 2012. These figures represent a CAGR of 27.0% over the next 5 years.
  • Technologies for converting hydrogen to energy, particularly fuel cells but also hydrogen internal combustion engines and turbines in the out-years, account for the bulk of the market: 78% in 2006 to 2007, declining somewhat to 76% in 2012.
  • Hydrogen storage and distribution technologies are also expected to lose market share (i.e., from 5.5% in 2006 to 3.9% in 2012). Hydrogen production technologies should increase their market share from 10.6% in 2006 to 14.3% in 2012, while other technologies' (mainly hydrogen sensors) share should remain steady at 5.9% of the market.

BUILDING THE HYDROGEN ECONOMY: PROJECTED GLOBAL INVESTMENTS IN PLANT AND EQUIPMENT, THROUGH 2012 ($ MILLION)

 

2006

2007

2012

CAGR*   2007-2012

Hydrogen Production

143.3

160.1

786.4

37.5

Storage and distribution

74.7

106.7

214.8

15.0

Energy conversion

1,055.0

1,305.0

4,185.4

26.2

Other

80.9

98.8

323.8

26.8

Total*

1,353.9

1,670.6

5,510.4

27.0

Hydrogen energy potential and issues in commercialization 

Hydrogen has potential to be a clean, sustainable fuel. It does not occur naturally, so it needs to be created and then stored as a fuel, which can be converted to energy via hydrogen fuel cells. It is possible to create hydrogen from renewable resources, and the environmental impact is low to negligible. However, a variety of obstacles must be overcome for this to be realized. 

Current technologies seek to generate hydrogen in fuel cells via electrolysis of a renewable material such as water or biomaterial. Nonetheless, the electrode design, catalysts and electrolyte materials used in fuel cells pose technical problems that limit power and longevity. 

Electrolysis currently is used to split water into oxygen and hydrogen for fuel cells. However, this is an expensive process, and because it is powered by diffuse solar energy, large tracks of land need to be covered with solar panels to produce sufficient quantities of hydrogen. 

Photoelectrolysis is the direct splitting of water into hydrogen and oxygen using light. Such "artificial photosynthesis" could reduce capital costs and increase the efficiency of hydrogen production. Sunlight is the only energy input, and hydrogen is evolved without external current flow. Development of a new catalytic film has made the process viable, which is a step toward efficiently generating hydrogen for fuel at low cost and with negligible environmental impact. However, substantial development remains necessary. 

Logistical issues are associated with implementation of hydrogen as a widely used fuel source. Storage of hydrogen in porous materials in part would provide a solution. However, the ultimate goal is to carry hydrogen as a liquid, as cars running on fuel cells could use stations employing roughly the same liquid-fuel infrastructure as already exists. 

Some 14% of global greenhouse emissions come from the transport sector. In the developing world, this proportion is growing rapidly. Hydrogen fuel could allow transport growth to have minimal effect on the atmosphere. Furthermore, the volatile price of oil has helped ensure that the push for alternative transportation technologies is well funded and has international support. 

Leading countries 

Initiatives launched in the U.S., Japan and the E .U. suggest a promising future for the hydrogen energy industry. A spike in interest and projected research investments has begun to create career opportunities in academia and industry for chemists, physicists and engineers. 

While the E.U. has lagged behind Japan and the U.S., investment now is forthcoming. Pilot schemes already are underway. Large corporations also are investing huge amounts of capital into hydrogen fuel technologies. 

How far from commercialisation 

The transition to a hydrogen economy will require large investments in capital equipment and durable goods at every stage of the hydrogen chain, from production of hydrogen through its distribution and storage to the conversion of the hydrogen to useful work or energy. These investments are both an economic challenge, to the extent that they require the mobilization of sufficient financial resources, and a business opportunity for providers of related goods and services 

Fuel cells are a fairly old concept, but are still not economical. The timeframe for fuel cell commercialization is not entirely clear, but some experts expect fuel cells to play a major role in the renewable energy equation by about 2020. 

Benefits 

  • One the cleanest forms of energy for power, as the only by product is water
  • Fuel cells per se are quite a well understood domain, hence scalability should not be difficult 

Challenges 

  • There are few, if any, scale systems available for hydrogen-based power.
  • Industry experts do not expect a hydrogen energy to bloom for at least another 25 years

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