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On Is Anaerobic Digestion The Ideal Sustainable Technology?

Willem

AD is more than just a technology that produces energy from a fuel or renewable source.

To quote from para 1.2.21 of the U K Goverment's recently published Strategy and Action Plan for AD [http://www.defra.gov.uk/publications/2011/06/14/pb13541-anaerobic-digestion-strategy/]:

"AD can play an important role as a means of dealing with organic waste and avoiding, by more efficient capture and treatment, the greenhouse gas emissions that are associated with its disposal to landfill. The technology also offers other benefits, such as recovering energy, producing valuable biofertilisers, and using the nutrients."

So it is a way of preventing emissions that would have happened by capturing the energy, thereby replacing other, fossil-based, fuels.

Its costs are initially high compared to, say, gas-fired power, but repay themselves if you factor in the the income from selling the fertiliser and the cost of waste disposal. (Here in the UK there is a Landfill Tax, because we're running out of places to put our waste and we are moving towards an eventual goal of a zero-waste, resource-efficient, closed-loop system.)

Energy efficiency should always come first, you are right - it is the cheapest option in most cases.

As for "When generating energy it should be done at the lowest cost and lowest CO2 per kWh and when creating jobs it should be done at the lowest cost per job for international competitive reasons", this is true sometimes but not always.

In order to become competitive in the future in emerging technologies, as many renewables are, support and investment is necessary to bring the prices down.

This is why some countries, like Germany and Denmark, are world leaders in wind energy for example.

The nuclear industry in the sixties also incurred huge losses in order to become cost-competitive because at the time it was far more expensive to produce electricity from nuclear than coal.

This is an independent source of info on AD: http://www.biogas-info.co.uk/

On Is Anaerobic Digestion The Ideal Sustainable Technology?

Not really - it's virtually carbon neutral.

If the same organic waste was left to rot outside or in landfill, it would contribute to global warming.

But AD stops that happening.

As the organic material is collected and burned for energy, it produces CO2, which is less of a greenhouse gas than methane. BUT - the growing of the crops absorbs the equivalent amount of CO2 from the air and so it is effectively almost carbon neutral, just as any form of biomass like wood or coppice is when used as a fuel - as long as the equivalent amount of biomass is grown again.

AD's feedstock is otherwise waste - whether slurry from intensive livestock farming, waste food from kitchens and catering, or waste crop residue and trimmings - rescued from the garbage tip.

And the other product of the process is soil fertiliser that can also be sold.

Plus, it creates jobs.

That's four wins!

On Is Anaerobic Digestion The Ideal Sustainable Technology?

yes Amelia, it's composting without oxygen, which produces smelly methane!

On IEA: Intermittency Of Wind And Solar Not A Problem

Willem, I think you might be surprised by what is actually happening to tackle this problem. Rationing is not on the table and such talk is merely scaremongering. Do not hide your head in the sand; instead, read on...

In Germany, an interesting [http://www.youtube.com/watch?v=aNZgjEDPe24] pilot project at Kassel University has shown how tackling intermittency will work in practice. Germany absolutely will lead the way on this as it is a crucial means to meet its twin targets of eliminating nuclear power while reducing carbon emissions.

The smart grid will be vital in balancing demand and supply, and an EPRI  report [http://my.epri.com/portal/server.pt/gateway/PTARGS_0_234325_317_205_776_43/http%3B/uspalecp604%3B7087/publishedcontent/publish/epri_analysis_estimates_costs_benefits_of_fully_developing_smart_grid_da_777189.html]  suggests that by enabling greater integration of renewable technologies, as well as reducing consumption, the smart grid could cut US 2030 carbon emissions by a staggering 58%, against a 2005 baseline. The benefits to society will far outweigh the costs - by up to $2,028 billion, EPRI says. In Britain, the savings to consumers are calculated at £7.3 billion.

Another crucial issue here is energy storage. Renewable energy generated for electricity (and of course all electricity) can be stored in a number of ways for use when needed:

    * landfill, sewage gas or biogas generated by anaerobic digestion and algae can be stored conventionally ready for use in a gas-fired power station that can be fired up at a moments notice
    * hydrogen can be generated to be stored ready for use in a similar way
    * pumped storage for hydroelectric generation, as in the North Wales Dinorwig plant, built in 1984
    * molten salts can store heat for up to 18 hours, which can then be used to drive turbines. This is being used in concentrated solar power stations in the US. Another system is described here: http://www.zeitnews.org/energy/another-cheap-way-to-store-solar-and-wind...
    * flywheels - being developed by, amongst others, America's Beacon Power, as an energy storage system on a grid-scale. Gene Hunt from Beacon Power gave a presentation recently which showed that that the system’s response time of four seconds is superior to fossil fuel plants taking up to five minutes, given that signals from energy operators can change every few seconds. He said market and regulatory reform present a central challenge, suggesting the creation of an energy storage regulatory category separate from energy generation. [http://2ndgreenrevolution.com/2011/03/08/world-future-energy-summit-wfes-2011-%e2%80%9ctechnology-forum%e2%80%9d-touches-on-all-major-green-technologies/#ixzz1O0dJqscE]
    
Another crucial point to understand is that because electricity has so far been tough to store and has had to be consumed as soon as it has generated, then this has dominated energy planning - forcing the construction of sufficient generation plant to meet peak demands.

But as soon as demand is managed better by the smart grid, and electricity can be stored, then this reduces the need for so much generation capacity.

So we save money and emissions by not needing so many polluting plants. Consumers benefit. Taxpayers benefit. The planet benefits. And no need for rationing. It's a triple-win pathway.

On IEA: Intermittency Of Wind And Solar Not A Problem

I refer you to the book, which has its own analysis of the figures, which do not match yours. This is the International Energy Agency we're talking about, an organisation normally highly conservative on renewables and projections of future energy needs.

On What Does A Melted Nuclear Core Look Like?

This is an inaccurate piece. You only have to read <a href="http://www.nytimes.com/2011/04/10/world/asia/10workers.html?_r=2">this New York Times article</a> to see a totally different picture, and how workers at the plant were exploited, mistreated and exposed to alarming levels of radioactivity.