Really depends how it's used doesn't it?

I've got a simple solution.

You can't sell the meat to power plans. Only donate it.

No profit = no increase in raising cattle.  It's just excesss.

Which is there point by the way.  They're afraid that either

A) Supermarkets will make money, or take less of a loss and therefore order more meat leading to a rise in factory farming.

B) Power Plants will start ordering meat directly from said factory farms.,, either because they're demand is greater then what they're getting in or they just avoid the uneven process of donation all together.

Seriously, just build a couple... and don't use them for baseline or mainline energy... perhaps have it work as "added" savings for the poor.  Such a plants likely would need to be government built though, with laws in place that allow the use of energy grids.  Not sure if the Uk has those laws or not.

You don't need to make the cost zero... The cost of the energy is much lower than the cost of the meat (that's guaranteed by simply the fact that much of the energy used to make and transport the meat is wasted, i.e. not stored in the final product).

This doesn't need any special solutions... the store can reduce its costs from wasted meat, but they'll still take a loss on it, and probably a rather big one.

BTW restaurants already sell their wasted grease (including oils, fats, etc) for making energy and maybe fertilizers too... this is just an expansion of that.

I should mention that one of the coolest up-and-coming technologies for extracting energy from waste is thermal depolymerization:

http://en.wikipedia.org/wiki/Thermal_depolymerization

It can process just about any organic-based feedstock and a pilot plant is turning a profit from processing turkey offal into high-grade crude oil. They're even paying money for the turkey offal.

That was one thing I thought about, a power plant has to keep up a certain consistency of power output. A rise in meat sales would mean that they would source their meat from elsewhere.

But I don't think that there is much of a chance of that happening as long as they have to adhere to regulation of spoiled meat only and take a role as only a secondary station.

That is fantastic. It's (somewhat) renewable, and doesn't pollute the air.

Anyone who objects can go generate their own power.

Honestly it depends.  There are two types of power plants.

Baseline Power Plants - These power plants provide a "baseline" amount of power.  As much as is estimated at minimium would be needed.

These are your bread and butter.  The type that are usually Coal or Nuclear... because they're cheap.

Peak Power Plants -  These kick in when power use rises past the baseline.  This is where this kind of plant would be perfect.  Peak Power Plants don't operate all day.  Sometimes they don't even operate every day. These are usually like natural gas... stuff like that.

Additionally you have a chance for a third kind of power plant.

A charitable one.  You get the government to build a couple.  Run them as non-profits, pick up donated spoiled meet and have them supply cheap energy to the grid.

Then with that cheap energy you give breaks to lower income families.  Charging "cost" for the energy provided.  This could really only be done in power grids where Peak power plants are used daily or weekly... but it'd work well if you have the kind of government that could do it efficently.

I think the cost of ordering meat directly from farms would be ridiculously prohibitive guys. This only works (economically) on waste because waste is free.

Rath,

You are absolutely correct.

Anaerobic digestion is not a very efficient method of power generation compared to even renewables if the material is needing purchased. However, if it is free, then I could only assume that it'd be worthwhile for use. This idea is all about efficiency - ensuring nothing goes to waste. It's the equivalent of recycling biodegradable materials.

http://en.wikipedia.org/wiki/Anaerobic_digestion#Power_Generation