HYDROGEN – PART OF OUR FUTURE

The World Hydrogen Energy Conference 2008 was held at South Bank, Brisbane mid June 2008 and Keith Sharp and myself attended to establish the status of this emerging industry and how it may impact on TfA’s business going forward.

The conference was attended by over 600 delegates from 44 countries. The conference appeared to be dominated by Germany which is as a result of their commitment to 1.4 billion € over a 10 year period by the Government and industry. The following summarises, in my opinion, where hydrogen is going.

Hydrogen Properties

Hydrogen is seen as the ultimate environmentally friendly energy carrier as when the energy is released from it, only water is produced.
Hydrogen can be stored as a gas or cryogenically as a liquid (very cold). Current gas technology is 35MPa and extensive R&D is extending this to 70MPa. By comparison, LPG is 2MPa. The storage pressure is testing the bounds of vessel design.
Hydrogen liquid occurs at -253ºC at 8kPa.
1kg of hydrogen (whether in the gas or liquid state) contains 3.75 times the energy available from 1 litre (or .75 kg) of petrol.
A Honda Clarity fuel cell car will travel 100km on 1.2 kg of hydrogen. (A fuel cell converts hydrogen into electric power with no moving parts and therefore much more efficiently.)
The BMW 7 hydrogen demonstration vehicle has an 8kg (110L) cryogenic fuel tank (i.e. liquid hydrogen), which provides a range of approx. 200km for the existing V12 internal combustion engine (ICE). This demonstration vehicle also has a traditional petrol tank, providing an additional 400km range.
Hydrogen energy is renewable, however hydrogen energy is only carbon neutral if it is produced from a renewable energy source such as solar, wind, wave action or geothermal.

Storage and Transport of Hydrogen

Storage of hydrogen as a liquid has significant boil off losses. Whilst the tank is extensively insulated, as heat transfers into the tank, hydrogen boils (vents) off to the extent that if the vehicle is parked unused for 2 weeks, the fuel tank would be emptied. BMW are working on a combined cryogenic/pressure storage tank to reduce boil off. A pressure storage tank does not have boil off losses.
Hydrogen storage tanks range from 35MPa progressing to 70MPa. These are exotic carbon fibre tanks with a polymer lining. This technology is becoming commercial at 70MPa.
Hydrogen stored within other metals is also progressing as well as cryogenic storage (less R&D on this), however the added weight is a disadvantage.
Hydrogen transported via truck is expensive compared to petroleum transport. The existing B-double transports 60,000L of petrol (or 1860GJ) of energy. The same volume of liquid hydrogen is 504GJ (4.2 tonne) which is 1/10th the weight of the petrol load but only 1/3 of the energy.
Transporting compressed hydrogen gas, even at 70MPa, is half as effective as liquefied hydrogen, although current technology only permits transporting at 20MPa. This is even less efficient.

Hydrogen Production

Currently there are no plants in Australia which produce liquefied hydrogen and only gaseous hydrogen is available (BOC, Air Liquide).

The hydrogen industry is developing in several streams for production and available technologies include:

Electrolysers – i.e. D.C. electricity to water to produce hydrogen and oxygen at the electrodes;
Reformation of natural gas – this is the current method of production at existing oil refineries;
Bio-production – i.e. solar energy through photosynthesis of algae produces hydrogen (as well as bio-diesel and ethanol).

An existing Heliocentric hydrogen electrolyser (produces hydrogen from electrolysis) can be purchased for 10,000 €, operating on 240 volt power. Its production capacity is only 60 standard litres per hour (or 1kg in 200 hours to travel almost 100kms). One of these units was on display as part of a technical tool and looks typically like a desktop PC.

Hydrogen Use

Australia has 3 hydrogen powered fuel cell buses operating in Perth, with hydrogen supplied by BP. It is a trial facility.
A hydrogen energy system was developed and implemented for trial at the Australian base Mawson in Antarctica and whilst the project has been discontinued, significant learning was achieved. The system included wind generation producing power to an electrolyser to produce hydrogen, which was subsequently to be used for quad bike fuel and cooking fuel and electrical power from a fuel cell.
Significant investigation into the direct conversion of hydrogen to electricity via a fuel cell or PEM (Poly Electrolyte Membrane) is occurring. Use of energy from a fuel cell is twice as efficient as that of an internal combustion engine. The Honda Clarity fuel cell car is becoming commercial and utilises fuel cell technology. It is typically 60-70% efficient.
Straight battery powered cars may be available for commuter type use with overnight recharging. The problems are current weight of batteries and the lengthy period to re-charge.

The hydrogen powered car such as the Honda Clarity has the following attributes:

Motors will be electric powered with onboard battery storage and onboard hydrogen fuel cell power.
The batteries will recover energy from regenerative breaking and iron out peak electrical power loadings.
Hydrogen storage for the fuel cell will enable rapid refuelling and efficient energy conversion.

In Summary

The energy system of the future appears to include hydrogen produced from a renewable source, such as solar, wind, geothermic or wave action.
As transportation of hydrogen is expensive, I believe production of hydrogen will be distributed around the areas where it is needed, although in-house refuelling from electrolysis is unlikely due to safety issues.

Power generation needs to be clean and renewable. Australian power generation at present is mostly based on coal. The continued use is very dependent on CO2 sequestration or clean coal technologies (CCT) where the gas is returned to an underground stable geological cavern. If we are to meet greenhouse gas targets, existing coal technology needs much development, if it is to be environmentally friendly in the future. Without CCT, Australia will have a major problem and needs to consider nuclear or others.
Whilst hydrogen is an ultimate answer, a carbon economy will still be a significant part of our future through chemicals and derived synthetics. There will be a transition to hydrogen as a carrier and source of renewably produced energy which will take over from existing carbon fuels, however this is utopia and a long way off. Synthetic fuels and biofuels will play an important part in the pathway.

After the 4 day conference, TfA, through the information available as a result of the conference and its continued research, are in a position to participate in this emerging industry at the cutting edge.

Tam Faragher
Managing Director