Russell's Blog

The contractors installed the last row of panels this morning and switched on our solar array. Our house now produces about 15% more electricity than it uses!

The array produces between one and three kilowatt-hours for every hour of sunlight, so for today's half-day of production, we've generated 13 kwh.

Here's the read-out on the inverter :

Sadly, I don't have a way of getting the data out of the inverter yet. Once I add the RS-232 module, I'll have have more interesting things to say about our system. I'll post some pictures of the array itself once we've passed inspection.

The Sunny Boy inverter has an interesting user interface. There aren't any buttons -- you interact with the display by knocking on the front panel with your knuckle.

Our contractor, EE Solar, is about halfway finished with the solar installation at our house. Here is what they are installing :

• 14 SunPower 230 watt panels
• One SMA Sunny Boy 3000 inverter
• A second digital utility meter
• AC and DC disconnects with lockout-tagout switches.

The 14 panels will be arranged into two arrays with south-facing exposures producing 3220 watts of DC power. The inverter is about 95% efficient, so the nameplate capacity will be 2854 watts. The USGS indicates that we should get about seven to eight hours of usable sunlight per day on average. The array should produce an average of 17 to 20 kilowatt hours a day. This should easily cancel out our usage, and maybe a little beyond. I'm hoping for slightly better production, since Pasadena is higher and dryer than most of the LA basin.

Here is the equipment after delivery and upacking :

We were supposed to get a Sunny Beam monitoring station, but evidently there are some issues with buggy firmware, so they won't be available until September (more about that later).

So far, roof has been preped, the mounting rails are installed, the conduits are bolted in place, the DC wires are pulled, and the inverter has been bolted down. All that's left is to hang the panels, do the AC wiring, and get the inspection.

The installer crew was supposed to finish that on Friday, but evidently they decided to take the day off. The project manager at EE Solar pitched a fit. Nick, the crew boss, called on Friday to say he was really sorry. I told him that his schedule is his business, but if he can't come when he promised, he ought to let us know. On Moday, I'll ask him to run some extra conduit for ethernet to make amends.

I was looking for something to do while Mimi was taking a nap today, and I remembered that the Energy Information Administration has tons and tons of cool data on their web site. It's more fun than video games.

So, I decided to play a little game: Let's pretend that America has just ratified a treaty that obligates us to cut our CO2 emissions by, say, 50%. How do we do it?

First, let's see how our emissions break down by economic sector :

Since about 1978, emissions from the industrial sector have been fairly flat. Meanwhile, transportation has been exploding, and overtook industrial emissions right around the end of the Clinton administration. Commercial and residential emissions have been growing at a steady clip, with residential emissions leading the way.

First, let's look at the biggest, fastest growing culprit, the transport sector.

No surprises here. Petroleum, mostly gasoline, makes up the overwhelming majority of emissions, with natural gas just barely registering. The single most effective measure we can take to cut emissions, then, is to cut petroleum consumption in the transportation sector.

This is going to be difficult. The trend has been an inexorable rise for more than half a century, and probably longer. Even the oil shocks of the 1970s don't look very impressive on the 50-year scale. In fact, in the decade prior to the shocks, there was a rise in the rate of emissions (and thus consumption), and the shock resulted in a regression to the previous trend. So, we're going to need more than just improved fuel economy. We're going to need new technology. Most importantly, we're going to have to get people to stop driving so much.

This is a tall order; if we want people to drive less, we need to uproot the automobile fetish that our country has developed. This will require a big mobilization of cultural assets. Right now, people will sacrifice a great deal of money, time, space, convenience and health to own a car. This preference has to be reversed. Culturally, we need to find a way to make car divestiture a desirable achievement. It has to be cool not to have a car. Here is an area where entertainment can play a positive role. For three generations, it's been the opposite, with movies and television fetishizing car culture from the very beginning.

We need movies and TV shows that exploit the coolness of riding the train, or walking to work, or riding a bicycle. This shouldn't be difficult. Good entertainment is all about human interaction, but the automobile is the most isolating mode of transportation possible. If you want to write about people, then trains, buses and bicycles are fertile venues, while cars are not. If we've got TV shows that revolve around crimelab investigations and people with magic and superpoweres, why not a TV show about bus drivers? There are a hundred angles you could take on that idea; it could be a noir drama, or it could have a supernatural element, or it could be a crime show. You could set it during the Montgomery Bus Boycott and make it a historical drama. You could set it during and after 1929, and make it a period piece.

Here are three policy initiatives that could get things moving in the right direction. First, all cities with public transportation have registered trademarks for their systems. The federal government could create a fund that would pay for product placement of these public transport "brands" in movies and TV. The more positive the circumstances of the placement, the larger the bonus.

Second, attack consumption directly. Raise fleetwide fuel economy standards. Raise taxes on gasoline and diesel. Go after really conspicuous consumption with direct measures; refuse to certify new Hummers, Ferraris, and Vipers as road-worthy. Give people tickets for driving aggressively.

Third, fix Amtrak. Create an endowment to support its operation and expansion so that it won't be at the whim of Congressional funding. Fund the endowment with fuel taxes, tolls on interstate freeways, and fines levied on the airlines for violating the Passenger Bill of Rights. The Atlantic and Pacific coastal cities should have rail service like France's TGV -- 200 mile per hour express trains with reasonably priced coach tickets.

Next, let's have a look at the industrial sector.

The clearest trends are volatile but stagnant conditions in petroleum and natural gas emissions while coal emissions crash and electrical emissions soar. Looking at the beautifully anticorrelated trends in coal and electricity emissions, I suspect something fishy is going on here. Let's have a look at electricity generation.

Ah ha! The industrial sector is outsourcing its coal burning to the electricity generators, who are burning coal like there's no tomorrow, if you'll pardon the gallows humor. Emissions from electricity generation are actually somewhat higher than for transportation, though they are on the same order. However, the trend in emissions from coal is actually significantly steeper than for petroleum use in the transport sector.

The coal explosion in the electricity generating sector is responsible for the rise in emissions in other sectors as well. For example, the commercial sector :

The emissions due to electricity in the commercial sector notch almost perfectly into the trend for emissions from coal. The residential sector doesn't notch in quite as clearly, but the trend holds.

It's the same trend across all non-transport sectors. We see the stagnation of petroleum and natural gas emissions while coal vanishes and emissions due to electricity explode, following the trend of coal in the electricity sector.

This makes it very clear. The absolute emissions and the growth of emissions in all non-transport sectors of the economy are due to burning coal for electricity. You'd expect coal to make up most of our electric generating capacity, wouldn't you?

Nope. Coal is responsible for most of the emissions from electricity generation, but only about a third of the electricity. We get about twice as much electricity from natural gas, but it's responsible for a relatively small fraction of our emissions.

Of course, this should be fairly obvious from the chemistry of coal and methane: Coal is more than 90% unsaturated carbon, consisting of long chains of double and triple bonded carbon atoms and aromatic cyclic structures, mixed with amorphous graphite and some volatile hydrocarbons, while disassociated methane is four-fifths hydrogen by volume. Coal is mostly carbon, and natural gas is mostly hydrogen.

The upshot is this; if we can wring about 30% worth of efficiency improvements from the non-transport sectors of the economy, we can do away with our coal plants altogether. This will cut the emissions of the industrial sector by about 40%, and 65% and 75% for the residential and commercial sectors, respectively.

Alternatively, we could aim for about a 15% efficiency savings, and double our nuclear capacity, or increase our renewable capacity by about fivefold. Whatever policy is chosen, it is abundantly clear that it must result in the eradication of coal from our electric generating portfolio. Even petroleum and natural gas are better.

Our prospects in the non-transport sectors are actually pretty good compared to the transport sector. We have a mix of different technologies, none of which make up a plurality of our portfolio, and most of the emissions can be attributed to the second-largest minority component. We have 1,493 coal plants which have an aggregate capacity of 335 gigawatts. That is an equivalent capacity to about 55,833 wind turbines. That many turbines would cost about $446 billion to procure and install. For comparison, the direct cost of the Iraq war has been about $478 billion, as of today.

Technically speaking, a 50% reduction in CO2 emissions is not far-fetched. It's well within our ability to build and to finance. A 20% reduction could probably happen without any noticeable drag on our economy whatsoever -- we just need to provide good incentives for saving electricity, and preferentially shut down coal plants.

Don't be afraid of mandatory carbon caps, even aggressive ones. If we can blow half a trillion dollars on a pointless war that gains us no advantage whatsoever, we can afford to fix our emissions problem. Maybe not both at the same time, but we'll be leaving Iraq soon anyway.

My mom has been interested in energy conservation for a long time. She's managed to take a pretty considerable bite out of her electricity and gas usage by taking some very simple steps. Below, I've plotted her energy use over the last couple of years. I was only able to find a handful of bills, but it's enough to see the trend. The first big reduction is just from minor adjustments in habits -- turning the lights off when she leaves the room, and opening the blinds to use natural light in the daytime. The second big reduction is from installing compact florescent bulbs. That doesn't sound very exciting, but it cut her electricity use by 50-70%. If you've been doubting that those sorts of changes make a difference, seeing is believing. This is, by the way, without any new appliances. She's still got a washing machine and dryer that are almost as old as me, a non-EnergyStar dishwasher, and a massive professional refrigerator that predates EnergyStar altogether.

The most obvious place to start, of course, is the refrigerator, which I estimate to be sucking down between 2.5 and 5 kwh per day. Or, at least, that's what it would have used when it was new, so it could be as much as 20% more than that. To maintain that nice downward trend, I've advised her to trade up to a Sun Frost RF16, which absolutely crushes the competition, using less than half a kwh per day. The most efficient models from big brands use about three times as much. Also, they're built right here in the USA, in Arcata, California.

The cost-benefit analysis for washer, drier and dishwasher isn't quite as stark. The main reason for swapping those out are to save water and gas. For gas, the easiest savings can be had by replacing the water heater, and she's already got an awesome tankless water heater. For water, toilets and outdoor watering are the main culprits. She has a couple of dual-flush toilets on order, and a there are a bunch of rain barrels staked in the driveway. They will be hooked up when the new rain gutters are installed.

When that's all done, she'll be ready to push the trend line the rest of the way down to the axes. Ultimately, solar is the way to go in southern California, but as long as panels cost a couple of dollars per watt, you'd be crazy not to do the easy stuff first. In any event, she wants to have some excess capacity in her photovoltaic system. Someday, she swears, she's going to have an electric car.

As we all know, dust kills computers. It clogs up the fans and mucks up their bearings. Eventually they begin to emit an annoying grinding or mooing noise. Even if the racket is tolerated, eventually the computer will stop working.

But even a relatively clean computer suffers from dust. You don't need giant dust bunnies clogging your CPU fan to see a significant impact on its cooling effectiveness. The thin, translucent coating of dust that settles onto anything after a few weeks is actually a pretty good insulator. It's like wrapping your heat sync in thermal underwear.

Here is what happens when you clean off that thin little layer of dust:

I have the polling rate for the temperature set at 1/20 Hz, so this is actually a significant length of time. I mention this to demonstrate that the temperature drop wasn't caused by the compressed air.

It's also worth noting that the hotter a semiconductor (or, in most cases, an ordinary conductor) gets, the higher its resistance. The increased overall resistance will cause larger voltage drops within the gate logic. Semiconductors require a minimum voltage to work reliably. So, you have two options; raise the supply voltage, thus dissipating more power, or run the risk of the voltage dropping too low somewhere in the gate logic, thus causing a logic fault. Either way, it's bad.

If the machine adjusts the supply voltage to avoid a logic fault, the part will get hotter, causing its resistance to go up even more, which requires another increase in supply voltage. One hopes that the cycle damps out before it runs away and the part explodes. So, even a relatively small improvement in heat dissipation can lower the temperature significantly due to this compounding effect.

So, boys and girls, remember to keep your computer clean. It will run cooler, last longer, and use less electricity.