In earlier articles we discussed the technical challenges of preventing massive economic and environmental dislocations because of climate change. Actually, the world has the capability to meet those challenges if it has the will.
For example, the United States transformed itself from an agricultural nation in the depths of an economic depression into an industrial giant able to manufacture the hardware needed to defeat the Axis powers in five years even with millions of its able-bodied men and women in military service. Compared with that, converting energy away from fossil fuels is easy.
The problems arise from attitude.
First there is the problem of skepticism about global warming. The evidence isn't just strong, it's conclusive. Yet people have made up their minds not to accept it. You can find them on the web even if you don't want to. Any criticism of the Intergovernmental Panel on Climate Change, justified or not, from any person, qualified or not, is touted to be the final "debunking" (a term much in fashion) of climate-change science.
Overcoming this obstinacy should be the easiest part of the problem to solve, but we can't even accomplish this much.
Next is the perverse refusal of nuclear opponents, all of whom claim the mantle of Defenders of the Environment, to acknowledge the clear necessity of nuclear energy for minimizing climate change. The same Defenders of the Environment deny both the environmental benefits of nuclear energy and the limitations of part-time energy sources.
We see some erosion of this monolithic inertia among more thoughtful members of the public, but the executives at the major international anti-nuclear political organizations aren't budging.
Then, assuming these problems can be overcome (or possibly ignored), we face the difficulty of implementing solutions.
Perhaps there will be local opposition to construction of nuclear power plants. But wind farms already are seeing fierce opposition. And the fights over solar panels haven't begun. When utility ratepayers realize how much they're paying to subsidize their neighbors' rooftop panels they'll do one of two things. Some of them will decide to cash in on the program. But if too many people do that the program will collapse from the expense. So all the people left out will see their rates go up dramatically. Before it's over you will hear people say they wish they'd never heard of solar energy.
What's left is conservation. And conservation is always the preferred nostrum; whenever energy and global warming come up, conservation is always our best and brightest hope.
But conservation means more than putting in compact-fluorescent lightbulbs and recycling wine bottles. It even means more than junking our SUVs and buying hybrid cars. It means smaller houses and no vacation homes. It means giving up motorhomes and cabin cruisers and recreational flying. No more flying vacation trips.
Sounds discouraging, no? It is discouraging if stubborn, misinformed people are allowed to dictate the world's energy future. But there is a way to solve this, and that will be the next articles's subject.
Showing posts with label energy conservation. Show all posts
Showing posts with label energy conservation. Show all posts
Monday, January 21, 2008
Wednesday, January 16, 2008
Solutions to Global Warming: Part 2
3) Renewable Energy Sources
In this article we'll look at alternative energy sources and appraise their effectiveness in minimizing global warming. The numbers apply to the US; nationals of other countries will have to figure this out for themselves.Residential Energy Sources
Some important savings can be made by making greater use of natural energy sources. Home heating and residential water heating could be switched almost entirely to solar and solar-heat-pump systems. Passive solar heating techniques can be built into homes. The remaining residential applications would mainly be cooking, which could almost entirely be converted to electricity. These changes would reduce CO2 emissions by 367 million metric tons, or 6.1% of the total.[source]
Wind Power
Wind power is already providing some electricity at a price which is only a little higher than electricity from fossil-fired power plants.[source] What limits wind power is the need for storage, since neither homes nor businesses can stop functioning when the wind power is unavailable. Currently, only one form of bulk storage is available for energy: existing hydroelectric dams, which account for 6.6% of total US electrical capacity.[source] There are limits to how much storage can be used, since dam operators have to maintain minimum water flows and also have commitments to irrigators, but it's conceivable that wind power could provide a few per cent of the country's energy.
If some sort of bulk energy storage could be developed, that could make wind energy practical. The storage method closest to practicality is pumped storage. In fact, there is a small amount of pumped storage in use now. A rough calculation shows, however, that there aren't enough places to install pumped storage for wind power to become the main electricity source.
A different strategy would be to have fossil-fired power plants standing by to back up wind power. Since wind turbines have a load factor of 25 to 35%, that would seriously hamper the effort to reduce greenhouse-gas emissions because the fossil-fired plants would have to operate a large portion of the time.[source] But the existing fossil-fired plants will be around for some decades while replacement capacity is built. In the meantime, they can be used as backup for wind turbines and other renewable sources. So, in the short term, wind power can be a major power source until replacement sources are constructed and the wind turbines wear out.
Solar Energy
Solar photovoltaic systems are presently too expensive to compete with other energy sources, but over the years can be expected to become cheaper.[source] They already are becoming popular in remote locations where connecting to the electrical grid is impractical. If costs continue to fall, solar energy can complement wind power but the unavailability of bulk storage will apply to solar energy as well.
Geothermal energy
Geothermal energy presently supplies 0.34% of the energy used in the US.[source] There are two types of geothermal energy: wet and dry. The wet type is being exploited about as much as it can be. There is a lot more available in dry form; unfortunately, there aren't any practical ways of extracting it.
Biofuels
Biofuels represent a possibility. To use them unblended as motor fuels would require new engine designs, but that will be unavoidable with any change from petroleum-based fuels. Currently, the best estimate is that it takes 0.75 gallons of fuel to produce the energy-equivalent of 1 gallon of conventional fuel. That's only true if credit is given for the value of the leftover material as animal feed; once the demand for animal feed is satisfied, the payoff ratio won't be as good. It is believed that the fuel input could be reduced to as little as 0.4 gallons with advanced technology that allows agricultural waste to be used as the raw material.[source] Agricultural waste is what gardeners call mulch; it hasn't been determined what would be the adverse consequences of diverting mulch away from fields. Research is being done on different biomass plants and chemical processes that could give better results.
The International Energy Agency estimates[source] fossil-fuel use at 388 exajoules per year worldwide, which may be expected to double or triple in this century. It also estimates that to supply 300 exajoules/year, a goal attainable with moderate effort, would require 7% of Earth's landmass, requiring forest clearing and insecticides and synthetic fertilizers. In comparison, 13.3% of the landmass is arable, including 4.7% already under cultivation.[source] The IEA concludes that biofuels can be an important means of reducing greenhouse-gas emissions on a global scale. For the US and Europe, though, given their limited free agricultural land and their high dependence on liquid fuels, the main effect would be switching from oil-rich suppliers to land-rich ones. Presumably, the benefit of reducing global warming would justify the higher cost.
Silver Bullets
Many other systems have been proposed: wave engines, tidal engines, and ocean-thermal-gradient engines, to mention only a few. People have suggested micro-hydroelectric power, installing small turbines on thousands of creeks and streams, but never have addressed the legal obstacles to extinguishing hundreds of species. Fusion research continues apace, but no projections are made regarding when it could become practical. Schemes have been suggested for energy storage, such as compressing air in caves, or building mammoth flywheels. All of these ideas are exactly where they were over thirty years ago: nowhere.
Hydrogen
But one idea has real potential: hydrogen. Presently, hydrogen use is hampered mainly by the low energy efficiency (around 30%) of converting water to hydrogen at ordinary temperatures.[source] There are more efficient processes, but they require high temperatures and are poorly suited to renewable energy sources. Alternatively, research is going on to improve the efficiency of photosynthetic production, currently around 2%.[source] If the efficiency could be improved, then there is a real future for hydrogen. Storage technology is ahead of production technology, and fuel cells are already proven. Hydrogen could be a fuel substitute and could well be the main element in future energy delivery.
However, there is a trap in something this attractive. For over thirty years, Americans have chosen to stay with fossil fuels based on the promise that something new and better was almost ready to displace the use of fossil fuels. The new and better something never materialized, with the result that fossil-fuel use now is threatening the planet's climate. Is it safe to continue this way, or should we look for other solutions that are available now?
Summary
There are two time-frames to consider. With present technology, renewable energy can displace a big part of fossil-fired electric power, but will lose that capability as the backup fossil-fired plants wear out. In the long run, the world must focus on non-fossil energy sources. Unless some form of bulk energy storage is invented, renewable sources will only be able to provide about ten per cent of the energy the US uses. Conservation, if pursued aggressively, could hold energy consumption to its current level.
The next few articles will take a look at nuclear energy.
Tuesday, January 15, 2008
Solutions to Global Warming: Part 1
In an earlier article we showed that CO2 from burning fossil fuels is causing global warming. So now we'll have a series of article on what to do about it. I'm going to present this from the perspective of the US. It's not my place to tell other people what to do about the problem, except insofar as we all will face the consequences so we all need to contribute to the solution.
The following information comes from the US Department of Energy, using data from 2005 for US emissions.[source]
The total emissions of CO2 for the US weighed in at 6009 million metric tons. The main contributors that are amenable to replacement are as follows:
The remaining 2291 MMT is spread over a large range of agricultural, residential, industrial, and transportation applications and miscellaneous applications such as road pavements. Some improvements can be sought here, but most of the users already are economically motivated to reduce energy consumption, so we should only count on modest improvements. Here's a plot that shows where all the greenhouse gases are coming from in the US:[source]
Out of all these, electricity generation is where the greatest savings can be made, accounting for 40% of the total CO2 emissions.Taking CO2 emissions as a whole, there are four options available: carbon sequestration, conservation, renewable energy, and nuclear energy. We'll cover the first two in this article.
1) Carbon Sequestration
It is possible that the CO2 could be captured and stored in some geological formation.
The problems with sequestration are that it's very expensive to pipe the CO2 from the power plant to the formation and pump it deep into the ground, and there's no way to be sure the CO2 will stay there. The scheme du jour is to bubble the gas into saline aquifers and hope the CO2 will form stable minerals there. No one knows what the capacity of the available aquifers is, or how to find out.
2) Conservation
Improving energy codes has gone a long way toward reducing greenhouse gases. Americans are using only as much energy per capita as they were ten years ago and twenty years ago. Meanwhile, energy consumption per dollar of domestic product has dropped about 40% since 1980. Of course, the US has shifted away from manufacturing toward importation in that same period, which accounts for some of the savings. Nonetheless, it's clear that energy codes can play a part in greenhouse-gas reduction.[source]
It can be stated with no fear of contradiction that people who live in affluent countries could reduce their energy consumption by large amounts. The problem with this solution is that there is a huge difference between can-do and will-do. People for the most part don't know how to quantify energy consumption. People drive motorhomes and put in compact fluorescent lights to balance their carbon footprints. People live in 8000-square-foot houses but recycle their wine bottles so it's all okay. An energy plan that depends on people giving up their big houses and their flying trips around the world and their motorhomes or boats or personal aircraft needs to be studied carefully.
What happened in the past was that alternative-energy advocates assured everyone that using fossil fuels was perfectly acceptable because new energy sources would meet the world's energy needs and switching over was only a matter of making some simple political decisions. But it turned out that the new energy sources weren't adequate for the task and continuing to use fossil fuels had tragic results.
In the next article we should look at some of those alternative energy sources and see what their limitations are.
The following information comes from the US Department of Energy, using data from 2005 for US emissions.[source]
The total emissions of CO2 for the US weighed in at 6009 million metric tons. The main contributors that are amenable to replacement are as follows:
| Electricity generation from fossil fuels | 2375 MMT | |
| Residential use of natural gas | 262 MMT | |
| Gasoline motor fuel | 1171 MMT |
The remaining 2291 MMT is spread over a large range of agricultural, residential, industrial, and transportation applications and miscellaneous applications such as road pavements. Some improvements can be sought here, but most of the users already are economically motivated to reduce energy consumption, so we should only count on modest improvements. Here's a plot that shows where all the greenhouse gases are coming from in the US:[source]
Out of all these, electricity generation is where the greatest savings can be made, accounting for 40% of the total CO2 emissions.Taking CO2 emissions as a whole, there are four options available: carbon sequestration, conservation, renewable energy, and nuclear energy. We'll cover the first two in this article.
1) Carbon Sequestration
It is possible that the CO2 could be captured and stored in some geological formation.
The problems with sequestration are that it's very expensive to pipe the CO2 from the power plant to the formation and pump it deep into the ground, and there's no way to be sure the CO2 will stay there. The scheme du jour is to bubble the gas into saline aquifers and hope the CO2 will form stable minerals there. No one knows what the capacity of the available aquifers is, or how to find out.
2) Conservation
Improving energy codes has gone a long way toward reducing greenhouse gases. Americans are using only as much energy per capita as they were ten years ago and twenty years ago. Meanwhile, energy consumption per dollar of domestic product has dropped about 40% since 1980. Of course, the US has shifted away from manufacturing toward importation in that same period, which accounts for some of the savings. Nonetheless, it's clear that energy codes can play a part in greenhouse-gas reduction.[source]
It can be stated with no fear of contradiction that people who live in affluent countries could reduce their energy consumption by large amounts. The problem with this solution is that there is a huge difference between can-do and will-do. People for the most part don't know how to quantify energy consumption. People drive motorhomes and put in compact fluorescent lights to balance their carbon footprints. People live in 8000-square-foot houses but recycle their wine bottles so it's all okay. An energy plan that depends on people giving up their big houses and their flying trips around the world and their motorhomes or boats or personal aircraft needs to be studied carefully.
What happened in the past was that alternative-energy advocates assured everyone that using fossil fuels was perfectly acceptable because new energy sources would meet the world's energy needs and switching over was only a matter of making some simple political decisions. But it turned out that the new energy sources weren't adequate for the task and continuing to use fossil fuels had tragic results.
In the next article we should look at some of those alternative energy sources and see what their limitations are.
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