WC Archive

An enormous amount of work on nuclear reactors that could burn thorium was done in the 1950s, most of it concentrated on fluid-fueled reactors that could take advantage of the unique properties of thorium while avoiding a great number of disadvantages. I've been collecting and compounding a number of these documents for years...you can download them from my website at:

http://web.utk.edu/~ksorense/MSR/pdfs/

Good luck!

Kirk Sorensen

I'm all for cogeneration, but the changes can't just stop there.  Any system which assumes that e.g. most heating plants also generate 20-30% electricity will have severe electric surpluses at times (strange but true!).  Any workable DG scheme will need substantial advances in management of the electric supply and demand.

We could build the cogenerators today, but AFAIK the grid managment isn't even close.  It's time to get cracking.

Could we perhaps compress some gas when there's a surplus? Desalinate water? Move water uphill? Do some boring tasks that don't mind being done at any time of day or night? Play Sisifo (you know, the greek guy who pushed a stone up a hill only to see it roll back down again)?

Lucas, look at the examples out there (you'll find more on that last if you google for "Sisyphus").  I believe you'll find that most are too geographically limited or expensive to store the quantities of energy required.

Demand-side management is another matter.  One of my favorite concepts is to use air conditioners to make ice when power is in surplus, then use the ice for cooling later.  Water is cheap and it is not difficult to make insulated tanks to hold ice for days or even months; the bigger they are, the cheaper they are per calorie.

I've argued against decentralization before - my main problem with it is that people think "the grid" is bad when in fact it's a pretty marvelous and extremely efficient energy distribution system as it is. Going "off grid" is a waste of resources, for the most part. Electricity generation is already widely "distributed" - we have thousands of generators in operation in the US, almost all within a few hundred miles of where the energy is used. Does cutting that few hundred miles to a mile or two really make much difference?

That said, generating electric power in places where heat is also needed for heating is a good idea. But it shouldn't be in homes, nor in most commercial buildings: converting electricity to heat through heat pumps (either in air or in the ground "geothermal") can be very efficient - up to three times as much heat out, as electric energy in. Rather the co-generators would best be located in industrial operations that are heavy heat users: petroleum refineries, steel mills, chemical plants, etc. These operate year-round and could be steady base-load power suppliers if the industries involved found it worthwhile.

Micro wind turbines are a dumb idea. The most efficient and cost-effective turbines are as big as possible, to catch fast high-altitude winds. Not only are small turbines going to be far more expensive per kW delivered, but doing lots of local installations of any such solution means lots of dollars wasted on variations from house to house. Why not send those dollars where they could make a real difference, building large off-shore wind turbines to make a major difference in energy supply?

Arthur:  you're proposing to violate Sutton's Law*.

Of course cogeneration should go to commercial buildings and even homes.  The amount of fuel consumed there for heating is huge; failing to make the most of that is throwing away enormous potential for gains in efficiency.  Besides, how are you going to power all those heat pumps from an industrial cogeneration base-load system which is already fully subscribed?  One source of electricity which is guaranteed to follow the demand for space heat is... cogenerating furnaces!

*Sutton's Law:  Go where the money is.  (Named after Willy Sutton, a noted bank robber.  When asked why he robbed banks, he answered "Because that's where the money is.")

"where the money is"? Whose money?

You can't force homeowners to do things that don't make economic sense to them, and I don't see that this does. Installation costs (and retail vs wholesale pricing) for small-scale stuff typically at least double the cost, vs. doing large-scale renewable or co-generation installations. For a few kilowatts of electricity generation it's probably tens of thousands of dollars. Plus:

* The electricity is only on when the furnace is running. You still need the grid for reliable service.
* The electronics to make switching between the sources smooth and reliable is pricey too, and what do homeowners do when this complex equipment breaks down and sends a power surge through half their appliances? (we just lost a microwave yesterday to flakiness in our local power company's supply).
* The greatest need for home electric power in most of the US is in mid-summer, with air-conditioning. That is precisely when you DO NOT want your furnace running.

Heat pumps are a much simpler solution to the home fuel-burning problem.

Oh, and the other point:

* fuel oil will eventually go away, as will propane etc. Rather than spending trillions of dollars on pricey co-generation systems that will be obsolete when the end comes for oil and gas, why not move straight to the passive (insulation) and electric-based heating - i.e. heat pumps that we'll eventually need anyway?

Arthur, without disagreeing with you on the co-generation vs. fuel pump question, I do want to emphasize that nobody here is talking about "off-the-grid" isolation. Every time we post about decentralized energy here, it's as part of a smarter "end to end" power grid. Not only does that buffer periods when building microgeneration is insufficient, it allows excess power from microgeneration to be put back onto the grid and into use elsewhere.

Considering the above comments. I think it is ok to chime in again and make a few observations. These are based on solid experience and are not mere vapor clouds of wishful thinking. In the near future we will have hardware that:

Runs on ANY fuel- gas, oil, logs, pellets, etc
has a very long life and needs only very simple mantenance
generates 1 kW of nice clean 60 hz 120VAC power
delivers whatever heat and hot water is needed
controls itself in a civilized manner without human care
makes almost no noise and does not shake
does not cost more than ordinary mortals would happily pay (in production, of course, not the one-off)
can live on or off the grid.
can be slammed on the grid without grief
will not fry domestic appliances under any circumstance

A prototype of this gadget is going into my house this winter, and I can tell you that unless it does all of the above my wife will shoot it without the slightest twinge of remorse.

Whose money?

For a few kilowatts of electricity generation it's probably tens of thousands of dollars.

Installation costs (and retail vs wholesale pricing) for small-scale stuff typically at least double the cost, vs. doing large-scale renewable or co-generation installations.

You can say that this isn't as attractive as a larger-scale system, and you'd be right.  But this is not an either/or proposition, and the amount of fuel consumed in homes makes it highly attractive regardless.

• The electricity is only on when the furnace is running. You still need the grid for reliable service.

  That is exactly the point; you trade power with other users and uses.  You could build the system with a starting battery and other capabilities to go stand-alone for grid outages, but most people wouldn't need them.

• The electronics to make switching between the sources smooth and reliable is pricey too...

  Grid-tie inverters are expensive mostly because they're low-volume items.  I'm not aware of any such units damaging equipment connected to them (not that I've looked, but victims of such mishaps tend to complain).  You can do without and just build a synchronous alternator if it pleases you; this would leave very little to be damaged or fail.

• The greatest need for home electric power in most of the US is in mid-summer, with air-conditioning.

  That's a different problem with a different solution, such as plastic PV awnings, solar-thermal vapor-cycle engines to drive A/C compressors, or absorption chillers.

Heat pumps are a much simpler solution to the home fuel-burning problem.

Who said it was a problem?  If you don't burn the fuel at home, you lose the ability to make productive use of the waste heat.  Suggesting that industrial cogeneration is the way to power domestic heat pumps begs the question:  what do you the rest of the time, idle your industry until there's a cold snap?

Rather than spending trillions of dollars on pricey co-generation systems that will be obsolete when the end comes for oil and gas, why not move straight to the passive (insulation) and electric-based heating - i.e. heat pumps that we'll eventually need anyway?

Because rebuilding or remodelling the housing stock will easily take 20 years, adding the extra generation to power your proposed heat pumps will take at least as long, and an extra $4000 per cogenerating furnace over 40 million houses is only $160 billion.

wimbi:  You da man.