Saturday, February 27, 2010

Renewable energy and hydrogen – what's the effective cost of energy?

Bookmark Business Technology and People
We have seen in my previous post about hydrogen two main factors that can facilitate the supply and competitiveness of Hydrogen – H2 production, and H2 Storage and Transportation.

At present it takes about 1.5 times energy to produce H2 – meaning that we have to invest 1.5kW in order to obtain 1kW worth of H2. I suspect that the energy investment in obtaining 1kW of Coal or other fossil fuel is not less (in particular when you consider the cost of their being non-renwable). I did some research and found an interesting study by Prof Risto Tarjanne – Competitive Comparison of Electricity Production Alternatives - I copy here the relevant graphic.

What this implies is that Nuclear electricity cost is about 2.4€ç/kWh (3.6$ç), and that instead of wasting power during off-peak hours, we can cleanly produce large amounts of hydrogen from water using electrical energy. But given that the boiling point of hydrogen is cryogenic – at about minus 252.87 °C – it is very difficult and expensive to store it as is. One of the main challenges of the hydrogen economy is to find a way to store H2 in a similar density to that of fossil fuel.

Let’s conclude this post by stating that it should be possible to produce hydrogen without CO2 emissions at an energy cost of about 3.6€ç/kWh, or €1.2 per Kg of emission free hydrogen. In the next post, I’ll tackle the storage and transportation issue.

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