Alternative energy sources

The outlook on energy alternatives to fossil fuels is looking a little bleak.

There have been several recent studies or reports casting significant doubt on the economic and/or environmental viability, at least for the near and intermediate future, of some of the leading contenders to supplant fossil fuels.

First up: nuclear power. Of course, environmentalists and others have had grave doubts about nuclear for decades, because of problems with safe disposal of spent nuclear fuel and the dangers of diversion of enriched uranium to manufacture of weapons. On top of that, there is the argument that replacing generation of power from burning fossil fuels with generation from nuclear sources may well contribute more to release of CO2 into the atmosphere than continuing to use fossil fuels. This comes about because so much power (generated from burning of fossil fuels) will need to be expended simply to build from scratch many new nuclear power plants and sharply increase the mining and purification of uranium:
Nuclear Power Not Efficient Enough To Replace Fossil Fuels, Study Finds

                                               Nuclear energy production must increase by more than 10 percent each year from 2010 to 2050 to meet all future energy demands and replace fossil fuels, but this is an unsustainable prospect. According to a report published in Inderscience's International Journal of Nuclear Governance, Economy and Ecology such a large growth rate will require a major improvement in nuclear power efficiency otherwise each new power plant will simply cannibalize the energy produced by earlier nuclear power plants.

Here's another way to look at this. If you consider just the marginal costs of producing a kW of energy from nuclear fuel vs. fossil fuel – counting (if you can) both direct economic costs and costs due to release of CO2 into the atmosphere – nuclear energy might be superior. However, if you also consider the capital expense (both direct and indirect) required to build enough new nuclear facilities to replace existing conventional facilities and also meet increased demand, then (according to the study) nuclear loses.

So what about using other energy sources as alternatives to fossil fuels, in order to significantly reduce dependency on fossil fuels and release of CO2? Like hydrogen, for example. Of course, this depends on further developing a lot of technology that's either not cost-competitive yet (fuel cells) or not even available yet (practical and safe means of storing and transporting hydrogen). To say nothing of the capital costs (as above) needed to build hydrogen infrastructure if and when the technology is available.

Even if technology can solve the difficult problems of storing and transporting hydrogen, there's another fundamental problem. Hydrogen itself is more of a form of energy suitable for transport and storage than it is a readily available source of energy (like sunlight or fossil fuels) that can be acquired or extracted (relatively) cheaply. There's no hydrogen just sitting around (like natural gas) waiting to be mined and distributed. Energy has to be consumed in order to separate hydrogen from oxygen, which together make up H2O. This energy has to come from some other source, as input to the electrical/chemical process that separates out hydrogen (or recombines it to make another fuel such as methane). This energy is regained later – but always with some percentage loss – when hydrogen is chemically recombined with oxygen (as in a fuel cell).

There really isn't any energy advantage to hydrogen at all, except for the (presumed) advantage over batteries in storage and transport. Of course, energy in a storable form is required for use in vehicles like cars and airplanes, in spite of the unavoidable losses along the way. The following essay goes into all of this in more detail.
The Hydrogen Economy

                                          Skeptics scoff at perpetual motion, free energy, and cold fusion, but what about energy from hydrogen? Before we invest trillions of dollars in a hydrogen economy, we should examine the science and pseudoscience behind the hydrogen hype.

There are some problems with the essay. First, one does not "make" hydrogen. It is extracted from chemical compounds like water, hydrocarbons (fossil fuels except coal), or biomass (carbohydrates, cellulose, etc.). Energy has to be input to the process in order to break the chemical bonds between hydrogen and other elements (carbon or oxygen). You get the energy back out when hydrogen recombines with oxygen or carbon (in a fuel cell, combustion chamber, etc.) – but always at some loss.

Second, the essay mostly assumes hydrogen will be stored and transported in liquid form, which is difficult and expensive, since liquid hydrogen boils at an ultracold -253°C. There is some hope that technology can be developed to store gaseous hydrogen in exotic solid materials at reasonable temperatures and pressures. However, at this point that's still conjectural. The larger point is that a practical "hydrogen economy" is still, at best, not in the near future.

Saturday, March 15, 2008
Alternative energy sources
The outlook on energy alternatives to fossil fuels is looking a little bleak.

There have been several recent studies or reports casting significant doubt on the economic and/or environmental viability, at least for the near and intermediate future, of some of the leading contenders to supplant fossil fuels.

First up: nuclear power. Of course, environmentalists and others have had grave doubts about nuclear for decades, because of problems with safe disposal of spent nuclear fuel and the dangers of diversion of enriched uranium to manufacture of weapons. On top of that, there is the argument that replacing generation of power from burning fossil fuels with generation from nuclear sources may well contribute more to release of CO2 into the atmosphere than continuing to use fossil fuels. This comes about because so much power (generated from burning of fossil fuels) will need to be expended simply to build from scratch many new nuclear power plants and sharply increase the mining and purification of uranium:

Nuclear Power Not Efficient Enough To Replace Fossil Fuels, Study Finds

Nuclear energy production must increase by more than 10 percent each year from 2010 to 2050 to meet all future energy demands and replace fossil fuels, but this is an unsustainable prospect. According to a report published in Inderscience's International Journal of Nuclear Governance, Economy and Ecology such a large growth rate will require a major improvement in nuclear power efficiency otherwise each new power plant will simply cannibalize the energy produced by earlier nuclear power plants.

Here's another way to look at this. If you consider just the marginal costs of producing a kW of energy from nuclear fuel vs. fossil fuel – counting (if you can) both direct economic costs and costs due to release of CO2 into the atmosphere – nuclear energy might be superior. However, if you also consider the capital expense (both direct and indirect) required to build enough new nuclear facilities to replace existing conventional facilities and also meet increased demand, then (according to the study) nuclear loses.

So what about using other energy sources as alternatives to fossil fuels, in order to significantly reduce dependency on fossil fuels and release of CO2? Like hydrogen, for example. Of course, this depends on further developing a lot of technology that's either not cost-competitive yet (fuel cells) or not even available yet (practical and safe means of storing and transporting hydrogen). To say nothing of the capital costs (as above) needed to build hydrogen infrastructure if and when the technology is available.

Even if technology can solve the difficult problems of storing and transporting hydrogen, there's another fundamental problem. Hydrogen itself is more of a form of energy suitable for transport and storage than it is a readily available source of energy (like sunlight or fossil fuels) that can be acquired or extracted (relatively) cheaply. There's no hydrogen just sitting around (like natural gas) waiting to be mined and distributed. Energy has to be consumed in order to separate hydrogen from oxygen, which together make up H2O. This energy has to come from some other source, as input to the electrical/chemical process that separates out hydrogen (or recombines it to make another fuel such as methane). This energy is regained later – but always with some percentage loss – when hydrogen is chemically recombined with oxygen (as in a fuel cell).

There really isn't any energy advantage to hydrogen at all, except for the (presumed) advantage over batteries in storage and transport. Of course, energy in a storable form is required for use in vehicles like cars and airplanes, in spite of the unavoidable losses along the way. The following essay goes into all of this in more detail.

The Hydrogen Economy

Skeptics scoff at perpetual motion, free energy, and cold fusion, but what about energy from hydrogen? Before we invest trillions of dollars in a hydrogen economy, we should examine the science and pseudoscience behind the hydrogen hype.

There are some problems with the essay. First, one does not "make" hydrogen. It is extracted from chemical compounds like water, hydrocarbons (fossil fuels except coal), or biomass (carbohydrates, cellulose, etc.). Energy has to be input to the process in order to break the chemical bonds between hydrogen and other elements (carbon or oxygen). You get the energy back out when hydrogen recombines with oxygen or carbon (in a fuel cell, combustion chamber, etc.) – but always at some loss.

Second, the essay mostly assumes hydrogen will be stored and transported in liquid form, which is difficult and expensive, since liquid hydrogen boils at an ultracold -253°C. There is some hope that technology can be developed to store gaseous hydrogen in exotic solid materials at reasonable temperatures and pressures. (Recent examples: here, here.) However, at this point that's still conjectural. The larger point is that a practical "hydrogen economy" is still, at best, not in the near future.

So hydrogen is not an energy source, and it is even very problematical as a way to store energy in a portable form for use in cars and airplanes. Fortunately, there are other ways to make energy portable, such as batteries. A Toyota Prius uses nickel metal hydride batteries to store energy from the regenerative braking system, and it seems to be an economically successful product. Lithium ion batteries, such as are used in laptop computers, have a higher energy density than the nickel metal hydride type. They have problems of their own, but significant improvements are being made. (See here, here, here.)

That still leaves the problem of developing additional actual sources of energy, that are alternatives to fossil fuels. Ethanol (grain alcohol) is getting a lot of publicity these days. It's politically popular with the agricultural industry, for obvious reasons. Ethanol partially solves one problem with fossil hydrocarbon fuels – by removing some dependence on politically unstable areas as a fuel source. But ethanol does nothing for the problem of CO2 emissions.

And it creates serious problems of its own, such as driving up the cost of agricultural products needed to feed people. Further, as with hydrogen, it takes a lot of energy to extract ethanol (or other energy carriers such as other biofuels or methane) from agricultural crops or biomass. Critiques of ethanol and other biofuels are not new, though they don't seem to get the attention they deserve.

               Other alternatives? There's always solar (photovoltaic) energy. Of all new but currently available alternative energy sources to fossil fuels (whether oil, natural gas, or coal), solar seems to be the most economical, especially taking reduced CO2 emissions into account.

But of course, solar also has its problems too. These include capital costs for building infrastructure to capture solar energy and to store it (for peak or nighttime use) or transmit it from the sunniest areas with low land prices. It's these capital costs (initial construction and eventual replacement) that hurt, since the marginal cost of each kWh is almost nil.

However, making detailed economic comparisons with traditional energy sources is rather difficult, as this study argues: Cloudy Outlook For Solar Panels: Costs Substantially Eclipse Benefits.

It would seem that the real difficulty of economic analysis lies in predicting the future costs of conventional energy sources – fossil fuels, especially oil. Some of the problems:

•How to estimate costs associated with CO2 emissions, given that the idea of global warming itself is so controversial (especially in the minds of economists and political officials, if not atmospheric scientists). To say nothing of estimating social costs of conjectural side effects, such as sea level rise, serious water shortages, detrimental impact on human and animal health, impact on agricultural production, etc.

•How to estimate the foreseeable rise in price of fossil fuels (especially oil) due to political instability, rising extraction costs (deep ocean sources), depletion of supplies, and rapid increase in demand from developing parts of the world. (There are large uncertainties in all of these factors, and some cost has to be allocated to this uncertainty itself.)

•How to handle the issue of proper pricing for energy at times of peak demand, as opposed to off-hours. (The report just mentioned discusses this.)

At present, the cost of solar energy, taking into account such things as installation costs, depreciation, etc., might well be two to four times the cost of energy from fossil fuels. But at least the cost of solar is pretty certain to decline, while the cost of energy from fossil fuels can only increase – and at a worrisomely unpredictable rate, in view of the uncertainties just listed.

 

More about alternative energy

About a month ago, I wrote about the shortcomings of various alternative energy sources. That was mainly about a variety of problems with nuclear energy, solar energy (photovoltaics), and hydrogen.

I didn't even get into the subject of biofuels, but I should have, because the problems in that area are becoming painfully obvious.

Ordinarily I would not expect to find much significant reporting on a scientific/technical subject in Time magazine, especially something that challenges "conventional wisdom". But via DarkSyde at Kos I see there's an interesting article on the problems of "biofuel": The Clean Energy Scam

Several new studies show the biofuel boom is doing exactly the opposite of what its proponents intended: it's dramatically accelerating global warming, imperiling the planet in the name of saving it. Corn ethanol, always environmentally suspect, turns out to be environmentally disastrous. Even cellulosic ethanol made from switchgrass, which has been promoted by eco-activists and eco-investors as well as by President Bush as the fuel of the future, looks less green than oil-derived gasoline.

Meanwhile, by diverting grain and oilseed crops from dinner plates to fuel tanks, biofuels are jacking up world food prices and endangering the hungry.

The Time article focuses on the loss of rainforest, and consequently the loss of its ability to soak up and sequester CO2. When the forest is gone, CO2 will still be incorporated in biomass (crops of some sort). But then that is converted to biofuel, and released back into the atmosphere when it's burned. (To say nothing of the energy that's just wasted along with release of CO2 when the forest biomass is burned to clear it away.) Given all the energy that has to be expended to grow and harvest biofuel crops, with resulting additional release of CO2, we are worse off in terms of greenhouse gas emissions than if we just burned oil (or even coal).

But that's not the only serious problem. Crops that are grown to make fuel (from sugar cane, corn, switchgrass, or whatever) use land where food crops (for people and animals) could be grown instead. Driving up the cost of food for everyone on the planet. (Have you checked the price of bread or eggs at the market recently?)

Economists have spoken out about this problem for several years, when the hype for biofuels and ethanol was just beginning to build. For instance, we have from Howard Simons in early 2006: Making Our Food Fuel Isn't the Answer

If high prices strengthen energy's claim on food supplies, governments everywhere will intervene on behalf of their hungry citizens. If low prices torpedo biofuels' economics, governments everywhere will respond with subsidies for these industries. Only an elimination of current mandates and subsidies today will avoid these problems tomorrow, but the likelihood of this happening is near zero. Somehow I believe we will rue the day when we decided to make food and fuel substitutes at the margin.

In early 2007 Paul Krugman picked up the story: The Sum of All Ears

There is a place for ethanol in the world’s energy future — but that place is in the tropics. Brazil has managed to replace a lot of its gasoline consumption with ethanol. But Brazil’s ethanol comes from sugar cane.

In the United States, ethanol comes overwhelmingly from corn, a much less suitable raw material. In fact, corn is such a poor source of ethanol that researchers at the University of Minnesota estimate that converting the entire U.S. corn crop — the sum of all our ears — into ethanol would replace only 12 percent of our gasoline consumption.

So ethanol doesn't even help the U. S. all that much in terms of dependence on foreign oil. And this February Krugman returned to the subject here, linking to this: Ethanol Demand in U.S. Adds to Food, Fertilizer Costs

About 33 percent of U.S. corn will be used for fuel during the next decade, up from 11 percent in 2002, the Agriculture Department estimates. Corn rose 20 percent to a record on the Chicago Board of Trade since Dec. 19, the day President George W. Bush signed a law requiring a fivefold jump in renewable fuels by 2022.

Increased demand for the grain helped boost food prices by 4.9 percent last year, the most since 1990, and will reduce global inventories of corn to the lowest in 24 years, government data show. While advocates say ethanol is cleaner than gasoline, a Princeton University study this month said it causes more environmental harm than fossil fuels.

And then last week Krugman had even more: Grains Gone Wild

The subsidized conversion of crops into fuel was supposed to promote energy independence and help limit global warming. But this promise was, as Time magazine bluntly put it, a “scam.”

This is especially true of corn ethanol: even on optimistic estimates, producing a gallon of ethanol from corn uses most of the energy the gallon contains. But it turns out that even seemingly “good” biofuel policies, like Brazil’s use of ethanol from sugar cane, accelerate the pace of climate change by promoting deforestation.

And meanwhile, land used to grow biofuel feedstock is land not available to grow food, so subsidies to biofuels are a major factor in the food crisis. You might put it this way: people are starving in Africa so that American politicians can court votes in farm states.

Here's a report of a scientific study on the issue: Some Biofuels Risk Biodiversity And Could End Up Harming Environment

Corn-based ethanol is currently the most widely used biofuel in the United States, but it is also the most environmentally damaging among crop-based energy sources.

Finally, to bring this back to a solid scientific foundation, Sean at Cosmic Variance reminds us that Energy Doesn’t Grow on Trees

In particular, biofuels (such as ethanol) and hydrogen are not actually sources of energy — given the vagaries of thermodynamics, it costs more energy to create them than we can get by actually using them, as there will inevitably be some waste heat and entropy produced
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Although all this bad news about just about every prospective near-term form of alternative energy is discouraging, there are a few other options that may become available in the slightly more distant future. There's the old perennial, controlled nuclear fusion. Even though work on that is even more active than ever, it's still at least several decades away.

But there's another significant option that's often overlooked: solar power satellites. This technology uses very large arrays of photovoltaic panels high in orbit around the earth. The energy is beamed back to the ground in the form of microwaves. (So this should not be confused with simply using mirrors to redirect additional sunlight, which presents serious problems of its own.)

Solar power satellites also have many uncertainties and potential problems, but the largest is simply boosting enough of them into orbit, and maintaining them. A possible approach to those problems involves space elevators. But those, again, present a whole additional set of challenges.

For now, here are a couple of articles from last fall with more details: