From Greenhouse gases we sigue into solar power. From Solar power we sigue into alternative power sources, and from there we end up back at one of my all time favorite writers ever, Steven Den Beste. Den Beste discusses conservation and alternative energy sources here , here and here.
Conservation is much overblown as a solution to the problem. For one thing, percentages don’t add up. That’s not how percentages work. If we save 2% on each form of energy usage we have, then the overall savings is 2%, and that won’t be enough.
This particular comment has stayed with me for the past five years:
But I have to disagree with the basic assumption that we actually could significantly reduce our energy usage through increases of efficiency if we just did enough research into it. What you have to understand is that for the last forty years we’ve already been increasing the efficiency of our physical plant, and in a lot of places we’re getting near the point of diminishing returns. We’ve already increased the use of insulation in our homes. Our cars and refrigerators are already a lot more efficient than they used to be. It’s not like conservation is a new idea; it’s been a policy of this nation since the oil crisis in the 1970’s. And we’ve already collected all the low hanging fruit, and a lot of the rest, too. (emph add)
Most of the electric cars around now use lead-acid batteries for storage. You plug your car into the wall at night and charge up your batteries, and then discharge them again while driving. Charging batteries is extremely inefficient; electricity is used to create a chemical potential in the battery, but most of the electricity is converted to heat. And when the battery discharges again, a lot of the energy stored in it also heats the battery.
If the original electricity was created by burning coal, then what this means is that a lot more CO2 is released per passenger mile by the battery-based electric car than by a gasoline car. You need to generate the energy actually consumed to move the vehicle, but also all the energy which was wasted in transmission and in charging and discharging the batteries, which means you need to burn more carbon at the power plant than a car would have needed.
On solar power being used to split hydrogen:
But here’s my best shot at one. Individual vehicles use hydrogen in fuel cells to create electricity which powers motors on the wheels. The hydrogen is shipped around in bulk, and you refuel your car with hydrogen at service stations, just as you buy gasoline now. The hydrogen is produced by large solar plants built in the desert, which use mirrors to focus the sun’s rays on a central generation plant which disassociates water into hydrogen and oxygen. The oxygen is captured and sold (it’s commercially valuable) and the hydrogen becomes the basis for the new fuel industry…
In 1998, the State of California consumed 13.496 billion gallons of gasoline. A gallon of gasoline yields about 130 million joules. So when you do all the math, you end up with about 1.755 * 1018 joules, which is an impressively large number.
One anti-solar-power advocacy site gives the “yearly average” solar power density in Albuquerque as 240 watts per m2. (That appears to be a 24-hour average; another site says that it’s 700 watts in daylight.) Then presuming that southern California is similar, each square meter of mirrors would be struck by 7.573 billion joules per year.
So if you assume 100% conversion, you’d need 231.7 million square meters of collection mirrors to make this work. 231 square kilometers.
But it isn’t going to be 100% efficient. That’s impossible, and it isn’t going to be remotely close to that. The mirrors won’t reflect perfectly and some of the sunlight will heat the metal instead of reflecting. The conversion process into hydrogen will be extremely inefficient. If you get 10%, you’ll be doing really well.
So we’re talking about paving 2300 square kilometers of California desert with mirrors. That’s a strip 13 kilometers wide stretching from San Diego to Los Angeles. It’s an area twice the size of San Francisco.
That’s a hell of a lot of metal! It ain’t gonna be cheap. The capital expense involved would be mammoth. Just clearing an area that large would cost a fortune; paving it with manufactured goods will cost a fortune. And something that big would take decades to build.
Figure each mirror at 10 square meters, and you’re talking about 23 million motor mounts. If you figure an average 5 year lifespan, then you’re going to replace more than 4 million of them per year.
That assumes conversion of the entire fleet. What about running it in parallel, to offset gasoline usage? There you run into other kinds of economic issues having to do with distribution. There needs to be a substantial level of usage of this in order for it to be commercially viable to create the distribution infrastructure. You’ve got tens of thousands of service stations which would have to install new facilities to refuel hydrogen cars in addition to gasoline and diesel. They won’t make that investment unless there are a lot of cars out there.
Conservatively, you have to assume at least 10% of the fleet converting over to make this work at all and be anything other than a really expensive toy for environmentalists. 230 square kilometers.
There are a lot of reasons to object to this, but the easiest is this: there’s no way this is going to happen by 2009. You’re talking about an engineering effort which might well take 30 years to even get going.
By the way, forget about photo-voltaics. They are also about 10% efficient, and they’re made of silicon. The idea of paving 2300 square kilometers of desert with solar cells is even more ludicrous; there isn’t any way that industry could approach that kind of volumes anytime soon. (If they’re producing a million square meters, one square kilometer, per year now I’d be very surprised. I bet they aren’t even producing ten thousand square meters.)
And what of the turtles? Just wait for the lawsuits to start.
The idea of writing an environmental impact statement for this boggles the mind. Making what amounts to a substantial lowering of the albedo of an area that large would have weather effects. It would change wind and rainfall patterns for the entire south-west US and large parts of Mexico. Remember, the whole point of this is to capture and move a substantial amount of the sun’s heat which now strikes those areas is released there. They’ll get colder as a result. How much? What other effects would it have? We can’t possibly know; we don’t have the ability to analyze it.
Many people seem to forget that the power one uses at any given time is generated for all intents and purposes at the very same time. Energy can’t be stored on the large scale necessary to power our society in any practical way.
Den Beste on Wind:
It isn’t where we need it, and it isn’t when we need it, and there ain’t enough of it. The power grid has to adjust its energy generation to match consumption, and we can’t turn the wind on when we need more energy. The source is diffuse and it requires a massive investment to make and install all the windmills. There are not all that many appropriate sites where the wind is regularly strong and a lot of the places where that’s true (e.g. the Columbia River Gorge) are protected areas. Windmill farms are an eyesore, and they kill a lot of birds. (A lot of birds.) The equipment is large, complicated and will require a lot of repair to keep working; the resulting energy will be inadequate and unreasonably expensive per unit energy yield. And I’m still not convinced that it won’t take years before any given windmill finally yields as much total energy as it took to make it, transport it and install it. Ireland is making a massive investment in wind power, but when they’re finished and have fully deployed all sites it’s only going to generate 520 megawatts, when the wind is blowing. That’s one eighth of the power generated by The Dalles Dam.
Hydrogen (as chemical energy):
The problem here is that hydrogen is a fuel but not an energy source. Gasoline is both. But there’s no substantial natural source of hydrogen which we can tap, so any hydrogen we use can only be created by utilizing energy from some other energy source. Hydrogen is like electricity, a way of moving energy from one place to another. That’s why discussion of conversion from internal combustion engines to fuel cells in vehicles may well be important when you’re concerned about air pollution or changes in industrial policy but isn’t when you’re talking about energy sources…
The biggest problem with hydrogen now as a fuel for vehicles is that it’s really hard to store an adequate number of joules in a small space with hydrogen without liquefying it. The best answer so far seems to be certain metals which spontaneously form hydrides and release the hydrogen equally readily, but the energy density doesn’t appear high enough yet to be practical, and no one will want a vehicle that has to be refueled every fifty miles or less.
Den Beste also discusses a topic I touched on yesterday – scale. The amount of energy the United States consumes at any given moment is staggering. According to Den Beste our electrical power consumption is 400 gigawatts non-peak, 1 terawatts peak. That’s 400 large coal or nuclear power plants nonpeak, 1000 of them peak – and unless you plan to have blackouts at any given time that means for all intents and purposes you are going to need even more of the puppies to account for units being down for maintenance.
If any proposed energy source can’t be scaled up to generate 10 gigawatts average (1% of that), it won’t be large enough to make any significant difference in the grand scheme of things even if it works and is really, really cool and clever and innovative and nifty.
Which is why windmills aren’t interesting, for example. The Irish windmill project will, once completed, utilize every reasonable site in Ireland and will generate 500 megawatts when the wind is blowing. For us to be interested within the context of this discussion, an American windmill effort would need to be at least 20 times larger, and that’s unlikely.
Things like biodiesel, or harvesting wave power with underwater flappers, or big floating devices in the ocean which utilize the temperature difference between the surface and the deep, just aren’t in the ballpark. They can generate energy, but not enough. If biodiesel ever exceeds ten megawatts, I’d be surprised, and that’s three orders of magnitude too small. While these things might well be practical ways to generate small amounts of energy, especially from waste products which are otherwise hard to dispose of, they’re still miniscule overall. (I think what I’m trying to say is, please stop sending me letters suggesting other ways. There are no other ways which can scale large enough to matter.)
Greens want to peg those of us who question their statements as being in the pockets of the coal/oil/nuclear industries. That’s a lot easier than recognizing us for what we are: people looking for practical solutions to problems.
So let’s assume Al Gore is right, Global Warming is happening and we have to do something to control it. Now consider the scope of the problem: 1 terrawatts of electricity plus another 3.3 tw used by transportation AT ANY GIVEN MOMENT IN TIME (these are NOT annual figures).
Given the above constraints (global warming, immense power usage), tell me a practical solution that meets these constraints and does not significantly damage our way of life or our economy.
(hattip: Blogmosis for remembering these posts in one place)