Beyond the scope and scale of the issues involved, the challenge of moving to sustainable energy systems is complicated by several additional factors. First is the fact that different policy objectives can be in tension (or even at odds), especially if approached in isolation. For example, efforts to improve energy security—if they led to a massive expansion of coal use without concurrent carbon sequestration—could significantly exacerbate climate risks. Similarly, emulating historic patterns of industrialization in developing countries could, in a 21st century context, create substantial environmental and energy-security liabilities. Achieving sustainability almost certainly requires a holistic approach in which development needs, social inequities, environmental limits, and energy security are addressed—even if they cannot always be resolved at the same time. Priorities should be set, by region and by country.
Extending basic energy services to the billions of people who now lack access to electricity and clean cooking fuels, for example, could be accomplished in ways that would have only minimal impact on current levels of petroleum consumption and carbon dioxide emissions. Indeed, closer examination of the relationship between energy consumption and human well-being suggests that a more equitable distribution of access to energy services is entirely compatible with accelerated progress toward addressing energy-security and climate-change risks. Figure 1.6 compares per capita consumption of electricity in different countries in terms of their Human Development Index (HDI) — a composite measure of wellbeing that takes into account life expectancy, education, and GDP. The figure indicates that while a certain minimum level of electricity services is required to support human development, further consumption above that threshold is not necessarily linked to a higher HDI. Put another way, the figure indicates that a relatively high HDI (0.8 and above) has been achieved in countries where per capita levels of electricity consumption differ by as much as six-fold.
Box 1.2 A focus on cooking in the developing world
Clean, efficient stoves represent a major opportunity to extend energy and public health benefits to the billions of people who rely on traditional fuels for their household cooking needs.
Household energy ladder. Over 2.4 billion people in developing countries still rely on solid biomass fuels for their cooking needs. This number increases to 3 billion when the use of various types of coal for cooking is included. In fact, the use of solid biomass fuels for cooking accounts for as much as 30–90 percent of primary energy consumption in some developing countries. As incomes rise, people generally upgrade from dirtier fuels (animal dung, crop residues, wood, charcoal, and coal) to liquid fuels (kerosene) to gaseous fuels (liquid petroleum gas, natural gas, and biogas) and finally, sometimes, to electricity. Conversely, when prices of liquid and gaseous petroleum-based fuels rise, people tend to downgrade again to solid fuels—at least for certain tasks. As households move up the energy ladder, the fuels and stoves they use tend to become cleaner, more efficient, and easier to control—but also more costly. Because solid-fuel combustion for cooking is often inefficient and poorly controlled, the cost per meal prepared is generally not a simple function of the cost of the fuel or stove technology used.
Health and environmental impacts. The use of traditional fuels for cooking, often under poorly ventilated conditions, is a significant public health issue in many developing counties (Figure 1.5). Globally, exposure to smoke from household fuel combustion is estimated to be responsible for 1.6 million deaths annually, a death toll almost as high as that from malaria. Small children are disproportionately affected: they account for roughly 1 million of these deaths each year, usually from acute lower respiratory infections. Women are the next most affected group: they account for most of the remaining deaths, primarily from chronic pulmonary obstructive diseases (WHO, 2002).In addition to generating high levels of air pollution, extensive reliance on some traditional solid fuels—notably wood—can lead to unsustainable harvesting practices that in turn contribute to deforestation and generate other adverse impacts on local ecosystems. Moreover, some recent research suggests that biomass fuels used in cooking, even when they are harvested renewably (as crop residues and animal dung invariably are), can generate even higher overall greenhouse gas emissions than petroleum-fuel alternatives when emissions of non-carbon dioxide pollutants from incomplete combustion are accounted for (Smith and others, 2005).
Saving energy and saving lives. Several strategies have been tried in various places around the world to reduce the adverse impacts of cooking with solid fuels. Typically they combine simultaneous efforts to address three areas of opportunity: reducing exposure, reducing emissions, and using cleaner fuels. Options for reducing exposure include increasing ventilation, providing stoves with hoods or chimneys, and changing behavior. Options for reducing emissions include improving combustion efficiency, improving heat transfer efficiency, or preferably both. Fuel upgrades can involve switching to briquettes or charcoal (which creates problems of its own) and biogas. Several countries have subsidized shifts to kerosene and liquid petroleum gas in an effort to help poor households ‘leapfrog’ up the energy ladder. Smith (2002) has shown that if even a billion people switched from solid biomass cooking fuels to liquid petroleum gas, this would increase global emissions of carbon dioxide from fossil fuels by less than 1 percent. Emissions of greenhouse gases on an equivalent basis might actually decrease. Subsidizing cleaner fuels, however, suffers from several important drawbacks: it is expensive (India’s expenditures for liquid petroleum gas subsidies exceed all its expenditures for education); it is inefficient (government subsidies often end up benefiting households that do not need them); and it can actually increase household spending on energy as subsidized fuels get diverted to other uses (for example, kerosene and liquid petroleum gasare often diverted to transportation uses). Some countries, notably China, have implemented very successful programs to replace traditional cookstoves with cleaner models. Elsewhere, as in India, such programs have had mixed results.
In fact, U.S. citizens now consume electricity at a rate of roughly 14,000 kilowawtt hour per person per year while Europeans enjoy similar standards of living using, on average, only 7,000 kilowatt-hours per person per year.10 Improvements in energy efficiency represent one obvious opportunity to leverage multiple policy goals, but there are others — most notably, of course, changing the energy supply mix. To take an extreme example: if the resources used to meet energy needs were characterized by zero or near-zero greenhouse gas emissions, it would be possible to address climate-change risks without any reductions in consumption per se. In
Figure 1.5 The energy ladder: Relative pollutant emissions per mealNote: Health-damaging pollutants per unit energy delivered: ratio of emissions to liquid petroleum gas (LPG). Using a log scale in Figure 1.5, the values are shown as grams per megajoule (g/MJ-d) delivered to the cooking pot.Source: Smith and others, 2005.
Figure 1.6 Relationship between human development index (HDI) and per capita electricity consumption, 2003 – 2004Note: World average HDI equals 0.741. World average per capita annual electricity consumption, at 2,490 kWh per person.year, translates to approximately 9 gigajoules (GJ)/person.year [10,000 kilowatts (kWh) = 36 GJ]Source: UNDP, 2006.
reality, of course, some combination of demand reductions and changes in the supply mix will almost certainly be necessary to meet the sustainability challenges of the coming century. Meanwhile, deploying renewable and other advanced, decentralized energy technologies can improve environmental quality, reduce greenhouse gas emissions, stimulate local economic development, reduce outlays for fuel imports, and make it more feasible to extend energy services to poor households, especially in remote rural areas.
Other factors complicate the sustainable energy challenge and further underscore the need for holistic policy approaches. A high degree of inertia characterizes not only the Earth atmosphere climate system but also much of the energy infrastructure that drives energy-usage patterns, as well as the social and political institutions that shape market and regulatory conditions. Because the residence times of carbon dioxide and other greenhouse gases in the atmosphere are on the order of decades to centuries, atmospheric concentrations of greenhouse gases cannot be reduced quickly, even with dramatic cuts in emissions. Similarly, the momentum behind current energy consumption and emissions trends is enormous: the average automobile lasts more than ten years; power plants and buildings can last 50 years or longer; and major roads and railways can remain in place for centuries. The growth that has recently occurred in worldwide wind and solar energy capacity is heartening, but there are very few examples of new energy forms penetrating the market by indefinitely sustaining growth rates of more than 20 percent per year. Fundamental changes in the world’s energy systems will take time, especially when one considers that new risks and obstacles almost always arise with the scaling up the deployment of new technologies, even if these risks and obstacles are hardly present when the technologies are first introduced. As a result, the process of transition is bound to be iterative and shaped by future developments and scientific advances that cannot yet be foreseen.
Precisely because there are unlikely to be any ‘silver-bullet’ solutions to the world’s energy problems, it will be necessary to look beyond primary energy resources and production processes to the broader systems in which they are embedded. Improving the overall sustainability of these systems requires not only appropriate market signals—including prices that capture climate change impacts and other externalities associated with energy use—but may also demand higher levels of energy-related investment and new institutions. Most current estimates of energy sector investment go only so far as delivered energy, but investments in the devices and systems that use energy—including investments in buildings, cars or airplanes, boilers or air conditioners—will arguably matter as much, if not more.11 In all likelihood, much of the required investment can be taken up in normal capital replacement processes. With estimated world income in 2005 of US$60 trillion (based on purchasing power parity) and an average capital investment rate close to US$1 trillion per month, there should be substantial scope to accelerate the deployment of improved technologies.
