I'd love to see an energy budget for heating with pollard wood.

I was taken aback some years while playing with various ideas for heating my house ago to realize that natural gas was significantly cheaper than wood.  Here is a table that illustrates that.

• Coal – Powder River Basin1 – $0.56
• Coal – Northern Appalachia1 – $2.08
• Natural gas2 – $5.69
• Ethanol tax credit3 – $5.92
• Propane4 – $13.28
• Petroleum5 – $13.43
• #2 Heating oil4 – $14.74
• Jet fuel4 – $15.48
• Diesel4 – $15.59
• Wood pellets6 – $17.33
• Gasoline4 – $17.81
• Corn ethanol7 – $23.46
• Electricity8 – $26.31
• Cellulosic ethanol from corn cobs9 – $30.92

I also spent a bit of time looking at coal as an alternative.  As a child I lived for a period in Pittsburgh and the house had an unused coal bin in the basement.  But we heated that house with natural gas. It turns out we have burnt all the good coal. What is left is harder to burn and it stinks.  You need to have a lot of scale to handle it well.

That natural gas is so dominate says something about housing density.  Quarter acre plots are probably the upper limit of when it’s worth running the pipes.  Of course that distribution infrastructure is a tempting target for monopolists.

Those numbers are US based.  Natural gas is less reliable and more expensive in Europe.  I mention monopolists didn’t I?  Ben recently did an wrote something similar, looking at biomass, for rural Britain and he too make the point the author of that table makes, that “there just isn’t enough biomass to meet present energy demands.”   While that point is right on, I don’t think we are going to find the one solution; or at least not for quite a while.

At night cool outside air is used to solidify the wax, and during the day inside air is cooled by melting the wax.   This is analogous to how I cool my house; cooling it at night and sealing it up during the day.  I let the building provide the thermal mass.

They claim you can use it to store heat over night, but I assume that’s only going to work if you warm the house over 72F during the day.  But maybe the slurry is a mixture of wax for different temps.

They can store about 4kWh of energy the slurry.  That’s not a lot as air conditioning loads go (a medium sized room?); but they claim the capital cost per cubic meter and much lower operating costs.

The manufacture is currently testing units around London.  The box looks like a clunky old steam radiator.

So, interesting that a daily cycle, room sized, phase change scheme might show up in the market soon.   There are daily cycle, office building, phase change schemes where in a block of ice is frozen each night.  I’ve thought it would be a hoot to build something similar that was yearly cycle, and house sized.  More here.

Thousand BTU/Passenger Mile
4.2 Public Transit Buses
3.9 Personal trucks
3.4 Cars
3.3 Commercial Air
3.0 Rail - commuter
2.8 Rail - transit
2.6 Rail - intercity
2.2 Motorcylces
1.3 Vanpool

My motorcycle/scooter riding friends may continue to gloat. And no this is not an excuse to to drive rather than take the bus, since adding you to a bus costs about zero btu/mile; and of course motorcyclists who ride in packs should get a car.

My model of using hydrogen as an energy storage system was that it became inconvenient in other parts of the system.  Hydrogen is a pain to store; transport, etc.  The conversion of hydrogen back to energy required over engineered devices; like fuel cells.  I’d presumed that making hydrogen wasn’t a problem.

In any case they formed a thin film of cobalt and phosphate on a conductive glass.  When they slip the water, using electricity, they get oxygen.  I gather that what’s good is that they get the oxygen directly and not thru some inconvient intermediary?  Apparently their is a second step that helps to assure they get the hydrogen more directly as well, and I’m not following that either.  This second step while straight forward typically is done using platinum as a catalyst; so there is some separate story about how to work around that cost – but that’s not part of this invention.

Apparently it’s very nice that this all happens at room temperature and neutral PH.  I guess that’s good, presuming that the existing efficient processes are far from that.

There is apparently a subplot about how the water isn’t pure; but has a dose of phospate in it so the thinfilm is self repairing.

I guess these are my questions.  First how much does this simplify existing practice.  Second is this actually significanlty more efficent than existing practice.  And finally, and I think this is outside the scope of the press release, what is the round trip efficency and complexity of an energy storage scheme based on this?

Update: This posting over at The Oil Drum is quite snarky and dismissive of this “breakthru.”  It is a refresing counter point to the ripple of republished MIT PR.  Presuming it is correct then what’s different is that existing high efficency electrolisis schemes are more complex than this.  How much that effects the capital costs isn’t clear to me, but not much looks likely.

Update: This video is pretty nice and reasonably clear.

Those are US Department of Energy forecast numbers.  They are published annually, for example here are the recently released 2008 numbers.  That link is a good place to get a sense of what the numbers mean.  I drew the numbers for the other years from this page.  Even amateur economists are right some of the time.  I can’t believe that’s stable.  Maybe I should be trying to lock in my natural gas fuel price for next winter.

In related news Martin brings my attention to a company EnerNoc that sells negative energy, i.e. load shedding, to the utilities. They use telecom and widgets to shift power consumption from high demand time periods into low demand time periods. Martian’s example is the fridge. You chill when power is plentiful and let it coast when others are paying higher prices.

I assume that EnerNoc’s role in all this is to aggregate small power users into a large enough pool to be worthy of selling to the utilities. It’s a interesting example of a coordination problem. There are of course other ways to approach the problem; ones that are less dependent on a thicket of contracts and ongoing coordination signals controlled by a middleman and enabled, as Martian, points out by the telecom infrastructure.

The obvious alternative is to just broadcast signal; and let the demand side react to the signal by selling some simple technology that responds to the signal in reasonably simple ways. That alone would enable substantial contributions from the demand side. But you can improve the incentive structure either thru regulation or by using statistical sampling to tell which customers have gotten with program; and then reduce their tariffs.

The amount of signal that needs to flow from the grid operators to the consumers is small, in the sense that you can broadcast it. A signal only needs to flow back the other way sufficient to assure that the incentives play out right. It is stupid to presume that the only incentives that are available are monetary or that they need to be executed with fastidious accounting. Most social systems have very fuzzy accounting and they work just fine, thank you!

The puzzle to be solved here is how to draw more of the peripheral demand into a load balancing system. Reading about EnerNoc’s approach isn’t the first time I’ve seen discussion of this. For example Bruce Schneier mentioned a regulatory attempt at something similar. I liked that one a lot, it provided a way to signal household thermostats. He was concerned that the resulting system would attract hackers. I presume he’d be just as sanguine about the security of the EnerNoc system; probably more so since it’s a closed system.

Such concerns are appropriate, but for heaven sakes I wish smart people like Bruce would stop pretending that these cases are somehow unique. It is the very rare large scale system that doesn’t have vunerable choke points. Hubs who’s failure can bring the entire system to it’s knees. Telling designers not to build large systems because of those risks is lame. Helping them know how to build them so they are safe and robust is hard, yes. But these systems get built because they generate mind boggling amounts of value. So it’s better to do the hard job and forgo the short term pleasure of a bit of hysteria.

Speaking of load shedding: turning your car’s engine off when you stop is more efficient than you thought.

Solar collectors need to point at the sun. So there is a lot of mechanism to rotate them through out the day. These clever guys decided to mount a huge number of mirrors on a turntable and rotate the whole thing. This can work by arranging the mirrors in strips, each strip runs in a line toward the sun. This is easy to understand by watching this little video.

They are building one in the desert; it’s not too big. The unit costs goes down the larger you make them; particularly the power plant. You can get a sense of it’s scale because, I assume, those are your typical big trunks scattered around the site.

They have two additional tricks. The rim of the turntable floats in a channel. Then a membrane is stretched over it and air pressure under it supports the mirrors and the pipes.

Now if they would just hook these up to a fireless steam engine, and or a solar lime kiln I’d be even happier.

The these are scattered over two metrics. How much power the tech can supply and how much total the tech can store. It’s a shame that there aren’t points in all four corners. I guess the sun kind-a-sort-a goes up above the upper left corner. I assume the dots show existing systems and there large practical areas around those points.

One of the metrics not shown is the maturity of the technology and the market. SMES looks like it’s close or just past solving the major tech-maturity questions. I enjoyed, for example, a fun essay about using the magnets pulled from old medical scanners for energy storage. CAES is ready to build out large market share; but as of yet there aren’t a lot of existing systems. Flywheels are even further along and look like they have lots of potential for sales in the next few years. PH is probably tapped out – i.e. fully built out, at least in the industrialized countries.

Regions of the chart are delimited and labeled to show what applications fall into that region. As the entire system comes under increasing stress power quality applications are going to get a lot of capital. Load management is quite a range of problems: balancing daily load, weekly to monthy variations in solar and wind sources, and seasonal variations from demand or distribution bottlenecks.

In any case the horizontal axis is showing how large various things are.  There isn’t really anything surprising along that axis.  Hydro systems are large, solar panels are small.  Cities are bigger than houses!  The red regions are demand energy, the blue regions are ways of supply in.  The vertical axis shows how concentrated the flux of energy flowing in or out is.  Oil fields and power plants have very dense energy flows; while plants and hydro-electric impoundment areas don’t.

This suggests that one big change that will come if we step back from fossil fuels is a change in which side of the energy distribution system consumes the most real estate.  Right now 10 to 100 times more real estate is used on the demand side, and afterwards it might be 10 times more on the supply side.  That is quite a flip.
I love this kind of chart, i.e. big broad overviews.