PowerSwitch

Not a recent article, but worth posting...
http://www.eaem.co.uk/opinions/can-alga ... -source-uk

The technology and the economics are coming good, but what about the ecological impact of algae-based fuels?

There has been considerable interest surrounding the use of algae for fuels and energy uses in the past few years and while there has been a large amount of research focusing on improving the economic sustainability of algal fuels production, environmental sustainability has received considerably less attention. Dr. Claire Smith of the NNFCC, the UK’s National Centre for Biorenewable Materials, Fuels and Chemicals, describes the current state of algae production sector in the UK and identifies what is needed to develop a sustainable fuels and energy industry in the UK.

Although regarded as a nuisance by many, algae forms the basis of a large and expanding global industry. Globally, in 2010, around 10,000 dry tonnes of microalgae (worth £5.2bn) and 1.6m dry tonnes of macroalgae (worth £4.6bn) were produced. Algae are used in an astonishing range of products: from anti-oxidants and flavour ingredients for use in cosmetics, personal care and food ingredient markets, to proteins and the polyunsaturated fatty acids such as omega oils, which can be used in functional foods or for aquaculture. The extraordinary diversity of algal species has the potential to provide new or improved performance in a wide range of future products.

More recently, there has been an increased focus on the potential for developing fuels, energy and commodity chemicals from algae. The potential for using microalgae as an oil feedstock for biodiesel production has received significant attention, especially in the USA where there has been considerable investment. However, there are a wide range of other fuel and energy products which can be obtained from algae.

Many algae species contain high levels of carbohydrates and these can be fermented to produce a range of different fuel, energy and chemical products including ethanol, butanol, succinic acid and lactic acid. Ambitious projects are underway in Chile, South Korea and the USA to investigate the potential use of macroalgae for the production of ethanol and butanol. Algae may be used as an anaerobic digestion feedstock to produce a biogas for use in transport, electricity or for heat, and in the longer term, hydrothermal processing could be used to produce an oil-like product enabling the substitution of a wide range of products currently produced from fossil fuels, such as plastics, fuels and commodity chemicals.

Fuels and energy are low value products. But a biorefinery approach could allow sufficient scale of operations to enable economic production of energy and fuel from algae with any high value co-products being sold separately. The scale of operation would however need to be carefully considered to ensure that higher value chemical markets do not become saturated.

Continues.....

At a guess, but only a guess, solar PV would be better at getting sunlight into electricity than Algae.

As I understand, the focus is more on using it for liquid fuels, chemical feed-stocks etc., rather than to generate electricity.

Those could work. It is really an issue as to any system of photosynthesis. Growing trees is one way. I suppose you could have a steam powered vehicle that was powered with burnt wood rather than coal.

From what I have read previously the problem is that in order to avoid contamination from dominant wild algae the species used have to be contained in a closed environment. This adds considerably to the costs as massive structures are required to produce the quantities needed to replace our current fossil fuel use. There were experiments carried out in open ponds in the US which failed because of contamination.

The fuel produced by algae and PV for battery charging for EVs would have to be subjected to an EROEI analysis to decide which was best. If the EROEI was close both could be used to diversify fuel production. Both energy production methods benefit from high levels of sunlight though so current fossil fuel producing countries, North Africa, Arabia and the US, would be in line to benefit once again.

johnhemming2 wrote:Those could work. It is really an issue as to any system of photosynthesis. Growing trees is one way. I suppose you could have a steam powered vehicle that was powered with burnt wood rather than coal.

It would probably be better to pyrolyse the wood and produce a liquid bio fuel from the wood gas. The resulting biochar could then be used a a soil improver and carbon sink.

kenneal - lagger wrote:It would probably be better to pyrolyse the wood and produce a liquid bio fuel from the wood gas. The resulting biochar could then be used a a soil improver and carbon sink.

You may be right, but that is an issue to be solved through experimentation and mathematics.