New ideas to shrink our carbon footprint

It is now several months into the $10 million GE Ecomagination Challenge and with just two weeks left, there are now almost 50 ideas submitted across an array of options for lowering our carbon footprint. What's interesting is that few involve a new type of renewable energy power generator. Rather they tend to be a mix of ideas about how we might make better, more efficient use of energy, manage the variability of renewable energy sources, and employ information technology to make more efficient products, processes and services.

While a lot of the ideas are rough around the edges, and several I suspect simply won't work; as a group they represent quite a good synopsis of the kind of challenges we need to resolve if we're to dramatically lower carbon emissions.

Two areas that are attracting a noticeable number of ideas across the Australia and New Zealand-based competition are:

1) Improving energy efficiency and reducing waste; and

2) Storing energy to better manage the variability of demand and also variable supply from wind and solar.

Improve energy efficiency and reduce waste

Under this broad category we have ideas as straightforward as reusing car tyres as rubber material for playgrounds, underlay of synthetic playing fields and road-base material. 

In addition there is the well understood opportunity yet to be properly exploited in Australia, of using the organic material in our waste to produce methane via anaerobic digestion for power generation with a fertiliser by-product.

Then there are more sophisticated concepts like producing phase change materials out of waste plastics and oils which can be integrated into building materials to absorb energy from the sun during daylight hours cutting down heat gain and need for airconditioning. These can then release that heat once temperatures drop.

Another company is promoting its software, which can apparently analyse a building's energy use data and automatically diagnose where the customer could save energy.

Store energy to better match energy demand with supply

A number of ideas relate to how we might use energy storage to better align the available energy from the wind and sun to match that of demand and to also reduce peak demand. 

These include Australia's Redflow Energy's zinc-bromide flow battery which they intend to market as 5kW/10kWh modular units suited to applications needing 2-6 hour discharges and multi-hour charging.

Another company, Nano-Nouvelle touts the its use of nano-technology which it believes can create battery electrodes that will enable production of batteries that are lower cost, more efficient and powerful and last longer. 

Hydrogen inevitably pops up with one proponent suggesting they have an idea for a cheaper more efficient way for electrolysing water to make hydrogen via a graphite anode.

Another idea put forward is one many researchers are looking at, whereby solar and wind energy would be used to make liquid and gaseous fuels. The one profiled in the Ecomagination Challenge involves electricity from wind being used to for electrolysis of water to produce hydrogen which is then reacted with carbon dioxide to form methane. This can then piggy-back off the existing gas supply network and gas-fuelled equipment, which would present less technical challenges than employing hydrogen.

However others, including the ANU's Keith Lovegrove have looked at using solar and wind power to also produce syngas and liquid fuels such as methanol and Dimethyl ether or DME, which could more readily substitute for petroleum in transportation applications and be transported by ship without the need for energy-intensive liquefaction. 

Of course there are a range of other ideas put forward in other areas including biofuels, containerised transportable power stations, and even solar cells made of paint, all of which you can check out at the GE Ecomagination Challenge website.