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.

Wednesday, February 24, 2010

Renewable energy and hydrogen – what’s bringing them together?

From A CleanTech Insider's Perspective

I have been studying recently the hydrogen economy, and I’d like to share the insight I gained.

Taking a different look at energy, we should consider all forms of fuel as energy carriers and all forms of fuel production (whether mining, drilling, via nuclear reaction or solar/wind etc…) as primary energy sources.

Presently, most of our primary energy sources are non renewable, and most of our energy carriers deliver their energy while polluting the environment. What we want for tomorrow is renewable primary energy sources and non-polluting energy carriers, all at a consumer cost similar to the present.

Renewable primary energy sources are usually of a stationary nature – nuclear plants, wind turbines, solar farms or biogas plants. As long as we can directly produce electricity and transport it over wires to stationary consumers (such as households) we’re fine. However, much of the energy we consume is in a mobile setting – automotive and various devices. For these applications, as well as for isolated off-grid location, we need an easily transportable, non-polluting and renewable energy carrier. There is a broad consensus that Hydrogen can be such a carrier, provided we find ways to harness it.

Hydrogen (H2) can be cleanly produced from water with electricity generated by a renewable primary energy source, and when consumed it releases energy while producing clean water. In terms of energy content it is also very attractive: 1Kg of H2 contains the equivalent of 33kWh – compared to about 11kWh contained in the equivalent amount of Diesel fuel – and compared to 0.3kWh in 1Kg of a top battery.

I’ll expand on the practical aspects of hydrogen production, storage and transportation in a subsequent post.

In the meantime, I'm keen to learn about your view on the futur of energy.