Wasted Energy: Alternative Fuel Solutions? Rubbish

The time has come for the human race to wean itself off fossil fuels, particularly oil.  Could your car be powered by the remains of last night’s dinner? I didn’t stuff two awkward metaphors into the title for nothing! Whether you believe in man made climate change or not (and why wouldn’t you?) there are many other reasons to kick our addiction to the ‘black gold’.  Wildly fluctuating oil prices and gas pipeline disputes show how untenable it is to rely so much, on a resource controlled by so few.  We are up to our necks in alternative energy sources for electricity generation (wind, tidal and solar power etc), but the future of transportation is less apparent.

What Are the Options?

The three main contenders, hydrogen, electric and bio-fuels, each have associated disadvantages and have yet to make a significant dent in the market.  Hydrogen fuel cells and electric cars would require an overhaul of the thousands of petrol stations to supply compressed/liquefied H₂ gas or electricity from the national grid.  Bio-fuel production, currently mostly from arable crops, takes up land that could be used for growing food, possibly leading to increased food prices.  There are other options though, including solar power or biodiesel produced from algae (see Algae As A Feedstock For Biodiesel Production).

Commercial entities, university lead research teams and governmental bodies are falling all over themselves to find the alternatives to oil.  There is fierce competition to see who can develop a fuel with both the ecological and economical advantages to take on the mighty clout of the oil industry. The prize is not just a greener earth, but also a massive financial windfall and personal acclaim.  The challenge is to develop a sustainable source of energy as well as the associated infrastructure required to support it. Each week there is a new idea proposed to be the solution to our energy woes, though I thought I might have already found it

They Said My Idea Was Rubbish, I Agreed

This Christmas I spent much of my time contacting potential PhD supervisors; one challenged me to propose a project.  While lying in bed one evening I looked around my bedroom filled with discarded packaging from presents and the remains of a half eaten turkey sandwich and it hit me.  We have too much waste and not enough energy.  Maybe we can get one from the other.

Household waste that cannot be recycled usually consists of biomass and certain plastics, both made of hydrocarbons.  Normally this would be sent to landfill, left to decompose into methane, a potent greenhouse gas.  The constituents of fossil fuels are also hydrocarbons, so how can the energy in rubbish be effectively utilized.  Incineration, complete combustion of waste, can be used to create heat and power, however this results in emissions of sulphur oxides and other pollutants.  Gasification offers an alternative.

Gasification involves heating the waste material in the absence of oxygen.  This produces a H₂ and CO gas mixture known as syngas; all other nasty materials are left as solid ash that is easily disposed of.  This syngas can be burnt to produce heat and power.  This is already being done by Energos.  Alternatively it can be reconstituted as methane or other hydrocarbons.  However, with the correct storage conditions (fuel cells, zeolites), could the syngas be used as an alternate fuel to replace oil?

No It Really Is Rubbish

I won’t lie to you.  I spend several days writing a proposal until I realised the potential pitfalls of my plan.  Many of the plastics would have derived from fossil fuels, thus still contributing to increasing CO₂ level.  Also The storage of a highly volatile gas like hydrogen and a highly poisonous gas like carbon monoxide would also be very tricky.  I got ahead of myself, but don’t be discouraged by this tale.  The world is full of inspiration and we will have to find an alternative to fossil fuels one day, even if it is rubbish.

Published - Mon 8th Feb 2010 20:31:38