Tag Archives: Renewable Energy

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

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

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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.

Producing water from thin air – dream or reality?

I recently became acquainted with a new technology that is truely amazing – producing water from the air. I’d like to share more about that.

The extraction of air humidity as alternative water source is a solution that was primitively used since biblical times . In the last 15 years several attempts were invested using modern technologies for this process, but none was able to operate reliably over an extended period of time at acceptable costs.

The ideal solution is to affordably produce plenty of H2O (pure water). And voila – it should be now possible to get large amounts of drinking-grade water in places where water is limited or unavailable with minimal environmental impacts and at a reasonable price!  This goal is achieved using an innovative technology from the Israeli company EWA Technologies Ltd., to obtain atmospheric water in most climatic conditions, air quality, time and place.

The EWA technology aims to provide humanity with a new water source, which could easily answer necessities almost everywhere on the globe. The EWA technology can be considered as a rain substitute – without its erratic unavailability.

Some facts about water in the air
There is more than enough water in the air. The air volume of a big room (75-100 cubic meters) contains almost two liters of water. In atmospheric terms, a volume of 1 cubic km contains 10,000 to 40,000 cubic meter of water – enough to supply water for thousands of families.

The EWA 3rd generation technology
EWA-III incorporates a novel breakthrough and cost effective processes to supply remarkable quantities of water from the atmosphere. Leaving behind the traditional condensation concepts that were used so far to extract water from air, EWA-III utilizes a multi-stage, dry, chemically based concept that is unaffected by air pollution and suits most climatic conditions. EWA-III also breaks the cost barriers of equivalent technologies thanks to sophisticated heat exchange and energy management, to the point of generating carbon credits.
Practically, only the power consumed by the blowers and some incremental heat is needed, since EWA-III reuses 90% of the energy through heat transfers and innovative optimization. In biomass terms, the basic EWA-III/10 model consumes 5kg of biomass (or 5 litres of diesel fuel) to produce 1,000 litres of fresh water. The energetic efficiency increases upon scaling up to higher capacity models, reducing the cost to $0.50 per 1,000 litres of water at the efficient end.

The environmental impact
Water desalination technologies produce waste that negatively impact the environment, and generate carbon emission debits. The new technology requires moderate heat energy, can use natural and/or residual heat sources, and a little electricity. It does not use chemicals and does not produce any wastes or residues. Moreover, upon consuming heat energy from renewable energy sources, it actually produces carbon credits. Furthermore, this creates new fresh liquid water (transformation process) that is added to the water cycle.

In his paper about the combat against desertification , Professor Marc Bied-Charreton describes the causes and effects of desertification, and highlights the point that modifications of vegetation and land conditions have an impact on the climate; that soil denudation increases evaporation and reduces water storage; and that the increase of barren land areas has also an impact on the production/suspension of aerosols, contributing to climate mechanisms alterations. With enough water to develop vegetation in desert areas, desertification could be reversed and the effects of climate change mitigated.

The Rural Concept developed by EWA addresses the water – vegetation – waste – energy cycle, and makes use of agricultural wastes as an energy source for EWA’s water apparatus. EWA’s water apparatuses are able to utilize all types of energy, but mainly use moderate heat (a small amount of electricity is required to blow the air through the absorption chamber). Agricultural wastes are composed of organic matter that enables to produce heat without causing air pollution.

By using agriculture/municipal organic wastes to produce energy, it is possible to supply water for both domestic and agricultural purposes at a significantly lower cost than alternative water sources.