Science has a great set of articles on the problem of renewable energy production, a topic of great importance as we ponder not just global warming, but energy policy in general.
Fixing our energy generation, distribution and usage would be a critical problem even if the current system weren't making radical and potentially irreversible changes to our planet. As Roger Pielke, Jr. observed recently:
If mitigation can indeed be justified on factors other than climate change, which I think it can, then why not bring these factors more centrally into the debate?
As the figure above shows (from Whitesides and Crabtree's article), over half of the energy produced for our domestic market goes to waste. Fully two thirds of the energy produced by electrical generation and distribution goes to waste.
If we could get a handle on that waste, decreasing waste energy lost in the transmission grid, or improving efficiency of plants, the need to build massive new coal plants in Texas and in Kansas would be alleviated, at least for the time being. Couple increased transmission efficiency with increased customer efficiency, and we would not just save substantial amounts of money, and save the environment, but we'd buy ourselves time to lay the groundwork for a new energy economy.
The reasons why we aren't fixing those problems, and why businesses aren't trying to reap the financial benefits of increased energy efficiency, are complex. The Oil Drum has an interesting look at the psychology of "discount rates" - the degree to which we discount the value of future benefits versus current benefits. Our brains and the minds they house are not always trustworthy, and there is good evidence that we are biased towards short-term thinking. We discount the long-term financial benefits that come from compact fluorescent light bulbs, and keep buying incandescents. An incandescent bulb wastes 95% of the electricity passing through it, converting that energy to heat rather than light. They are cheaper to buy and more expensive to own.
There are all sorts of scams that run the same way - some offering you a small check if you will sign up for a service that charges a large monthly fee. A difference of a few percentage points in sticker price might attract someone to a gas guzzler over a hybrid, even if the differences in gas bills would erase that difference.
Part of the solution is to move those costs up front. Something as simple as printing the cost of a year's worth of gas for a new car might help.
The other part of the solution is to use the government's power to internalize some of these costs. We could lower gas taxes and put a tax on car sales that is indexed to fuel economy. The average consumer might pay the same amount in taxes over a reasonable time period, but when the consumer pays those costs would be shifted earlier.
Another component would be for the government to shoulder some of the short-term costs, for instance by paying to improve transmission efficiency of long-distance electric lines, perhaps recuperating those costs by raising taxes on those lines only. Improved efficiency in long-distance transmission coupled with local storage (pdf link) could substantially improve our energy economy by reducing inefficiency in generation, transmission and usage.
Science highlights a project in Europe called "Airtricity," which proposes to construct many offshore windfarms around Europe, linking them together so that wind power will always be flowing into the grid from somewhere, because the wind is always blowing someplace. The same argument would work for a widely distributed network of solar cells.
Re: "Fully two thirds of the energy produced by electrical generation and distribution goes to waste." A big part of the loss here is inescapable Carnot-cycle limited thermal losses -- The burned thermal energy consumed never even makes it through production into electricity to be wasted. Many of the efficiencies of turbines and other thermal engines are reported with respect to the thermodynamic limit of Carnot efficiency of *(T_h-T_c)/T_h * 100% Doing anything thermal is inefficient unless you can cool things to T_c = absolute zero. Try Carnot cycle
D: very true, and I don't know if that's accounted for in the figure. The paper is oddly silent on how that figure was prepared.
In any event, savings from improved energy efficiency alone based on existing technology could realistically reduce emissions by a substantial fraction according to many sources I've seen. 100% efficiency is impossible, but we can improve over what we have.
That graph up top is really just fantastically fascinating for a variety of reasons.
The biggest thing that interests me there is the big gray block saying "Energy Generation, Transmission & Distribution Losses". What is in there? And why exactly is it so big? I really would be very curious to see a breakdown of that-- it's easy to say, well, we need to improve electricity loss for long-range transmission, or we need to overthrow mathematics and repeal Carnot's Theorem, but it's hard to show that's really what is needed when it's unclear whether these are really the things that are causing this large energy loss in the first place.
(Though I may be about to say something naive: Along the lines of things that are easy to say but not demonstrated to be important, I keep wondering exactly how hydrogen technology for energy transportation and storage would fit into this graph-- particularly whether it could chop off part of that Generation, Transmission & Distribution Losses waste block, and whether it could chop off enough to be larger than the amount of energy waste that hydrogen technology would introduce by itself. (The Smalley paper is dismissive of hydrogen, but doesn't go into much detail there either.) For example, how much of that waste block is the result of energy overproduction, or other forms of energy loss that could be stored and reused instead of just lost if there were some kind of infrastructure for doing so? And for that part of the waste block due to transmission loss, exactly how badly does hydrogen do if you look at the energy costs in waste of transporting electricity to hydrogen and then transporting it somewhere, versus just transmitting that same electricity across power lines?)
Another thing that interests me about this graph is how small that certain things traditionally considered critical to the energy issue are when you look at them in perspective on this graph. For example, a mainstay of talking about energy conservation for thirty years has been somebody mentioning ways people can "save energy around the home", things like the incandescent bulbs you mention in this blog post. But the amount of residential energy waste here is really just an absolutely tiny sliver of the graph; that is of course assuming, very possibly erroneously, that things like waste from incandescent bulbs and thermostats left on are classified as "lost" and not "useful" energy on the graph, but even if we could somehow eliminate all residential energy use it would only be the amount of waste from "light-duty vehicles".
Simiarly, another interesting thing here is to be reminded, despite all the hype, exactly how little energy production is actually coming out of solar and wind power right now. I realize we're not doing as much with solar and wind as we could, but it seems difficult to imagine a set of circumstances where we could increase our solar and wind production enough for it to make a noticeable impact-- we'd have to do, what, four hundred times as much solar and wind production to get as much electricity out of it as we do from the sixty or seventy nuclear plants we have in the U.S. now?
One final thing I find interesting here: what on earth is going on with the fact that "light duty vehicles" and "freight" utilize almost exactly the same amount of "used" energy, yet the amount of energy waste from the light duty vehicles is two or three times as large? What are we seeing there?
I assume light duty vehicles are mainly passenger cars and light trucks/suv's, where as freight probably consists of rail and maybe heavy trucks. I suspect rail at least is much more efficient in terms of scale.
Wind only started getting extensively deployed in the '90s, and solar is still fairly expensive to deploy, so I'm not surprised at the low numbers for those. I am interested in the low residential inefficiencies, and I'm guessing that inefficiency from lightbulbs and losses from inefficient appliances, etc. are not factored in. But I'm not sure.
When looking for solutions to some of these issues, it helps, IMO, to see the synergy between various mechanisms.
For instance, the relatively simlpe solution of including solar energy in the construction of new housing increases the anmount of energy produced by solar energy, whcih is essentially free, and at the same time, reduces or eliminates a large part of waste from energy transmission since the power grid is integrated directly into the house.
Like Josh mentioned though, the long term thinking needed here just seems anathema to most Americans (in particular). The slight increase in up front cost and maintenance of solar panels would pay for itself in a matter of years for most homes (this would be more cost effective in parts of the southwest).
The utility companies don't want to see this happen though, as it cuts into their profits. (I know, I have watched the utility companies in Arizona fight mandating solar into building codes since the 70s.)
In other places (like here in Kansas) residential homes could do the same thing with a small wind generator for each home, or group of homes.
I know one home in Tucson, Az, where the owner built solar panels and a small wind generator for electricity, and a solar hot water heater with electric backup, who MAKES money every year from the excess power he generates that is routed back tot he electrical grid. (He had to sue the electric company to get them to put a two way meter/switch on his property.)
The vast majority of electric losses are in the conversion from fuel (entropy gains in combustion, inefficiencies of Rankine cycles) to electricity. Transmission and distribution losses average under 10%.
Here are some energy flow charts that aren't behind a pay wall.
Hot filter, turns the anchor into a style tool. Anyway, here's where the flow charts are from:
Very cool. Those charts aren't exactly the same, though. The one above includes wind power as a separate input, while those from LLNL don't.