HYPERSOL
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Hydrogen Generation using Printed Electronics, Roll2Roll and Solar Energy

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Microsharp and Stored Solar’s renewable energy technology – HYPERSOL - splits water into hydrogen and oxygen, using solar energy. The subsequent use of the hydrogen to produce power does not contribute to CO2 emissions. Thus our “Solar Electrolysis” is a carbon free method of producing energy that can be stored directly as hydrogen gas. Storing energy chemically is significantly more efficient than storing electrical energy and indeed hydrogen has a similar energy density to petrol. Importantly, the Company’s method of making hydrogen will be cost competitive with today’s “dirty” alternatives and can be justified on an economic basis alone. This provides an attractive route to the “Hydrogen Economy”.

Whilst the market for hydrogen as an energy source is in its infancy, there is already a $125 billion market place for the gas in the chemical and petro-chemical industries. The non-fuel sector has an expected growth of over 8% during the next 10 years.The reformation of natural gas and hydrocarbons is not a sustainable solution to meet this growing demand, although it is how most hydrogen is produced today.

The Hypersol system is  a combined medium concentration PV system integrated using a wavelength splitting mirror system with a solar augmented water electrolysis system. The system includes pumps for the electrolyte and gases, solar tracking, a maximum power point tracker charger, a battery, a solar tracking system and inverters to enable output of AC power.

The system is able to dynamically change the bias voltage between zero and 2.5V to enable efficient response to the combinations of high or low direct electricity requirements, high or low solar illumination and the charge state of the battery.

The system can therefore operate to maximally produce electricity, hydrogen or both depending on the current requirements. The solar electrolysers can also be driven at low cost, pure electrolysers (for example at night) by raising the bias. In this way surplus electricity on the local grid can be stored as hydrogen gas.

The Technology Solution

Solar Electrolysis uses sunlight to activate a photo-sensitive layer to provide most of the energy required to split water into its constituent parts. The small amount of additional electrical energy required to bias the unit is supplied by solar photovoltaic (PV) cells). Microsharp’s and Stored Solar’s unique arrangement uses mid concentration solar energy to jointly power both the solar electrolysis and the solar PV by splitting the solar spectrum into short wavelengths which optimally promote electrolysis and longer wavelengths which are optimally absorbed by the PV system.

When fully commercialized, we estimate that ”Solar Electrolysis” will produce hydrogen at $3-5/Kg at both small scale (2Kg/day) and large scale (1,000kg/day).

Solar Hydrogen Production

A number of low cost surface materials are able to operate to wholly or partially convert solar energy to splitting water into hydrogen and oxygen. Only ultraviolet light is able to provide the amount of energy fully capable of splitting water, but longer wavelength light can be used in conjunction with a voltage bias to use solar energy to electrolyse water.

Stored Solar has been working in this area, based on the licensed IP originated by Professor Michael Grätzel at EPFL in Switzerland, in the use of modified, nanosurface structured metal oxides for solar electrolysis.

The photoanode generates Oxygen gas, whilst the counter electrode (cathode) generates Hydrogen gas

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The effect of sunlight can be demonstrated by the current through the solar augmented electrolysis unit in the light and in the dark.

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Concentrator Optics

A problem with any solar energy solution is the fact that the energy in sunlight is low per square metre (maximum intensity 1,000 watts per m2) and this results in large system areas. For solar hydrogen production, the electrolysis unit has to then fully cover the area of incident sunlight, and since this unit consists of multiple electrodes, sodium hydroxide electrolyte, case, electric and plumbing, the result is difficult to make low cost. However Stored Solar has produced systems and system designs for such an approach.
  

Concentrator optics offers the potential in solar energy system operating in high direct sunshine areas to replace costly large area solar receivers with large area low cost concentrating optics and compact receivers.

Medium concentration is appropriate for the solar augmented electrolyser (for example 10 times solar concentration) since we have demonstrated linear increases in solar hydrogen production up to these intensities and this can be readily provided by linear Fresnel lenses whose geometry matches the requirements (for e.g. gas extraction and electrolyte flow) of the electrolysis units.

          Initial Prototype Mid Concentration Systems                                                                   

 

 

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                                Second Generation Evaluation Unit        

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