There can be no progress without the use of energy, and no use of energy without the use of technology. Technology allows us to transform a raw energy source, such as coal, into a more usable form, such as electricity - which has underpinned the growth in living standards in the industrialised world. But man has become increasingly aware of the limits of his unchecked use of some energy sources. The threat of global warming might change long-term energy prospects entirely. A third of the earth’s 6 billion inhabitants still live without electricity. In their quest for growth, they will want to utilize their share of the Earth’s energy resources. A new course will have to be taken. It already has a name - “sustainable development”, which implies that progress must “meet the needs of the present without compromising the ability of future generations to meet their own needs” (Changing Course, 1992). But development relies on energy. And energy needs technology to make it available in an acceptable, sustainable way.
All energy here on Earth can be traced back to the output of the sun or the heat of the earth’s interior. It was not until the industrial revolution that man began to make significant use of stored solar energy in the form of coal. What took nature millions of years to conserve, man set about consuming within centuries. At first the supply seemed endless. But man ignored nature itself. In the same way that nature had provided the energy, nature now set a limit for the rate of its use.
According to today’s estimates, the supply of fossil fuels in the form of oil and gas will last only another half-century, and perhaps two and a half centuries in the form of coal.
The day will soon come when we have no more fossil fuel to burn. We might even be forced to leave some of it in the ground because of the threat of global warming caused by emissions of greenhouse gases. What alternatives do we have? First let us take a look at some of the global problems that have made us aware of the limits to growth.
Energy Technologies in a Greenhouse Gas (GHG) Constrained World
In December 1997 the United Nations global meeting on climate change took place in Kyoto in Japan. It was the third international conference convened after the Rio Summit in June 1992 to deal with the global environmental problems of the earth, of which global warming is the largest and most threatening. The Kyoto Protocol, agreed by 171 participating countries, saw the introduction of a set of legally binding limitations on emissions from the world’s 39 industrialized countries (including Central and East European countries). The limits vary between the countries concerned e.g. +10% for Iceland, +8% for Australia, -6% for Japan, -7% for the USA and -8% for the EU and Switzerland, but amount to an average reduction of 5.2% of their aggregate greenhouse gas emissions in the years 2008-2012 as compared to their 1990 emission levels.
The Kyoto conference underlines the very political nature of the world’s environmental problems. No longer are we dealing with localized national problems in our backyards. Greenhouse gas emissions create a global problem that can only be resolved through global cooperation and a common effort. GHG emissions in the future will come mainly not from the OECD or industrialized countries but instead from the developing countries, due to the rapid increase of their populations and to their rapid increase of energy use per capita. So the developing countries themselves will become increasingly involved in strategies to reduce global GHG emissions.
Today, mankind faces three major global climate problems, namely:-
-Global Warming or the man-made greenhouse effect caused mainly by emissions of CO2
-Depletion of Stratospheric Ozone caused mainly by emissions of CFCs
-Acid Rain caused mainly by emissions of NOx and SOx
Of these three problems, global warming is the most threatening and the one that most directly affects our daily lives. It is also the subject of this article.
The agreements reached at Kyoto are truly revolutionary and will have far-reaching consequences for the future development of energy technologies. Technologies will be preferred that emit less rather than more greenhouse gases, such as carbon dioxide, methane or nitrous oxide. The so-called ‘renewable’ energy technologies will seem more worth promoting in the long run. These use fuels that are replenishable and do not emit any appreciable net amounts of GHGs.
We have already seen a change in the energy technology landscape in Scandinavian countries, who have all introduced taxes on CO2 emissions. For example, the Norwegian oil company Statoil has built the world’s first major CO2 Sequestration Unit. About one million tons of CO2 p.a. are separated from natural gas from a North Sea well. Instead of venting the CO2 to atmosphere, as done previously, the CO2 is sequestered in a water-carrying aquifer about 800 m under the bottom of the sea bed. This is one company’s response to Norway’s self-imposed limitations on such venting and the deterrent of a $50 tax per ton of CO2 emitted. The sequestration unit has been operating successfully since October 1996 and further units are contemplated. Norsk Hydro, another large Norwegian oil and chemical company, recently announced a different strategy, namely to separate natural gas from some of their wells into hydrogen and carbon dioxide. They will consume the hydrogen in a combined-cycle gas turbine power plant to produce electricity and use the carbon dioxide by pumping it into oil wells to make them more productive and worth exploiting. These techniques show that technology develops by jumps and mutations. It takes certain circumstances, the right place, the right timing, to produce such developments. It also needs an industry that has the courage to meet the challenge and the financial resources to come up with workable solutions.
There is little doubt that global warming will be the most decisive force influencing the future development of new and improved energy technologies. But first let us look at what technologies we have today and which of these can contribute to reducing greenhouse gas emissions.
One would think that nuclear energy, being a concentrated source of power that emits virtually no greenhouse gas, would be ideally suited to solve mankind’s energy problems. Nuclear power has been developed during the last 50 years, provides about 20% of the world’s electricity requirements today and has reached a certain technological maturity. Yet nuclear power is no longer accepted in the USA and parts of Europe. Opponents point to the problem of the radioactive waste, but supporters cite countries who are close to a technical solution to this problem.
The public’s disaffection with nuclear energy is understandable - the association with nuclear weapons and the fear of accidents. But no technology is completely risk-free. There are risks associated with driving a car. Automobiles and their drivers cause the deaths of more than 100’000 people each year in the US and Europe alone. In the end, it will need a value judgment, politically directed, but with the support of public opinion, to decide how the dilemma of nuclear energy is to be resolved.
Not only nuclear energy but also hydro energy has come under attack in many parts of the world. Instead of recognizing the clean generation of emission-free power from a harnessed river, opponents only point to the negative effects of the man-made dams and reservoirs. Europe has fully utilized most of its hydro resources which have contributed substantially to the prosperity of the countries concerned. But the poorer regions of South America, Africa and Asia still have gigantic resources waiting to be exploited for the overall benefit of their people. Let us hope that a consensus may be found that enables us to harness such clean resources of renewable energy for the benefit of all without undue spoiling of nature’s wonderful world.
A further major field of energy technology which provides most of today’s global energy needs, is the field of fossil fuels. Because of their importance and the possibility for fossil fuels to obtain a second lease of life during the next century, we will treat them separately in the following section.
The Future Use of Fossil Fuels
The energy backbone of our modern societies - covering 80% of the world’s requirements - depends on fossil fuels, namely coal for power generation, oil for transportation fuels and chemical manufacture, and natural gas for power production and chemistry, and all three for heating purposes. The consumption of fossil fuels is responsible for about 75% of today’s levels of man-made greenhouse gas emissions, deforestation accounting for the rest. Fossil fuels provide such a concentrated, easy to use source of energy. Their ease of transport and storage gives them a particular advantage. It is hard to imagine how our dependence on these fuels can be quickly altered.
But times are changing. The environmental impact of sulphur oxide and nitrogen oxide emissions from fossil fuel combustion processes have been with us for a long time. Few power plants are built today without equipment to clean the emissions of these particular gases. But now the larger threat of global warming looms on the horizon. Global warming is caused mainly by emissions of carbon dioxide which has been an integral product of fossil fuel combustion. One could not be separated from the other - until now.
We are on the verge of entering a new age in fossil fuel technologies. In some laboratories around the world and in a few international research programs, energy experts have been working on new fossil fuel technologies which are free of GHG emissions. The IEA (International Energy Agency) R&D Program on Greenhouse Gas Emissions was started in 1991 by 13 countries to assess what could be done in this area. A particular focus of the program has been to explore ways of continuing to use fossil fuels. One idea is to separate the carbon dioxide from the fuel and then dispose of it. There are two paths to this solution which are both being pursued - to remove the carbon dioxide either before the combustion process, or afterwards from the flue gases. Norsk Hydro’s plan, mentioned earlier, to build a hydrogen-burning power plant is an example of pre-combustion separation. A coal power plant recently built by ABB at Shady Point in Oklahoma, USA, where 200 tons of CO2 per day are separated from the flue gases and used for food processing, is an example of the post-combustion method.
There are other ideas. Besides putting CO2 into under-sea aquifers, as Statoil has done, one can also dispose of it on land in empty oil or gas wells or in other natural cavities. One could also pump it deep into the ocean, far out of reach of animal or plant life. An international research effort is currently investigating this method. What else can one do? Recycle the CO2? Use the separated-out hydrogen as a source of energy? But hydrogen is difficult to store and transport. Convert CO2 and hydrogen into methanol, an easy to handle liquid which can be used as fuel for vehicles or gas turbines? Fine, but there is one catch - the hydrogen has to be produced in a CO2-free way.
Of the three fossil fuels, coal emits the most CO2. An oil-fired plant emits about 25% less than a coal plant, but a modern combined-cycle gas-fired plant emits only half. Gas is therefore a favored fossil fuel, especially for generating electricity, not only because of the limited emissions, but also because of the availability, low cost and high efficiency of such plants. These considerations have led to an increased demand for gas-fired plants world-wide.
But the coal technologists have not been idle. They have continuously improved traditional combustion processes and introduced new technologies such as fluidized combustion, where the coal comes into better contact with the oxidizing air. A further development is pulverized combustion where the coal is first ground to a fine powder for the same purpose. Beyond pulverized coal we have gasification of the coal itself, which can then be used as fuel for highly efficient gas turbines. Most of these advances have come from the developed world, influenced by stringent environmental considerations and the quest for higher operational power plant efficiencies. But global environmental problems can only be solved when the developed as well as the developing world combine their resources and commitment to achieve the same goal. A clean environment will be a necessity nobody in the world can ignore.
Fuel Cells, a non-combustion path to utilizing energy from fossil fuels, is a technology which is still under development. Fuel cells convert hydrogen, natural gas or methanol directly into electricity and heat. The major uses in the future will be for powering automobiles and for generating electricity and heat. Fuel cells are compact, modular and efficient and therefore very suitable for distributed power generation which does not rely on interconnected networks supplied by large-scale power plants.
Although technology advances may permit the continued use of fossil fuels for some time to come, the trend towards non-GHG emitting technologies such as solar and wind energy will relentlessly increase. The continued and unchecked use of fossil fuels, leading eventually to an immense loading of our atmosphere with greenhouse gases, is a scenario which as the years pass will become more and more untenable.
In the final chapter we will deal with the new renewable technologies, which although not yet viable for larger scale power production, may through changed circumstances gain new importance and market acceptance.
The Road to Renewables
The so-called ‘new renewables’, namely solar energy, wind, biomass, geothermal energy, small hydro plants and ocean wave energy, only account for 1.5% of the world’s total electric generating capacity of approximately 3.5 TW. Large hydro power plants, on the other hand, account for approximately 22% of the installed capacity. Apart from hydro, renewables have been too expensive to play a significant role in power generation (Renewable Energy, 1998). But if the Kyoto agreements come into force in the near future, the boundary conditions for renewables will change. If GHG-free emissions become the main criteria, renewables will have a head-start over the fossil fuel technologies.
What is the status of renewables today? Although expensive, they are being continuously developed and made more efficient and cheaper to build and install.
The Photovoltaics market is expanding at a rate of 30% per year, but from a small base. The total world market in 1999 was approximately 200 MW, the equivalent of one gas turbine. The price per kW installed is between ten to twenty times the price of a combined-cycle power plant - but the price is dropping. It is interesting that over half the market is in developing countries, in some of the poorest areas of the world. What seems like a paradox becomes credible when one realizes that these regions are often without any electrical power infrastructure. So a solitary solar power plant can make a lot of sense, despite its high price.
Wind energy seems to have gained a bigger foothold, costing only about twice as much as a combined-cycle plant. More than 3 GW of wind power was installed during 1999 and the total installed world-wide is around 15 GW. In some areas, wind power is believed to be competitive with fossil fuel power within certain limits. After initial development work in the US, the second generation of wind power plants are being produced in Europe, mainly in Denmark and Germany.
Biomass energy for power generation is only viable in certain countries, particularly Finland, Sweden, USA and China. This technology is certain to gain impetus from the Kyoto agreements. It is doubtful if biomass plants will ever be large and there is a clear tendency towards small plants - less than 10 MW.
Solar and wind power plants, in contrast to hydro and biomass, have no inherent energy storage facilities. They can only provide power when the sun shines or the wind blows. Up to now, the storage of solar and wind power has not been adequately solved. Another limitation is the low density of the sun’s radiation, usually less than 1 kW per m2. In the accompanying figure a comparison is given of the area requirements of various renewable technologies with nuclear and fossil technologies. Because of these limitations we cannot place complete reliance on the new renewables alone. Until we have an effective solution to the storage problem, auxiliary power supplies will still be necessary.
But despite these drawbacks, we believe that the use of renewable energies will continue to grow, and such plants will become cheaper and more readily accepted by the market. Demand will be boosted by the implementation of the Kyoto agreements. But at the same time, we must recognize that life as we know it today cannot be sustained on renewable energy alone, not now nor in the near future. We will have to rely on fossil energies for quite a while to come. If in the meantime we can keep greenhouse gas emissions low and dispose of the CO2, using advances such as those described in this article, then maybe it is a prospect we can come to accept.
Once implemented, there can be little doubt that the Kyoto Protocol will lead to an irreversible change over the longer term of the world’s energy technology market. As general awareness of the man-made global warming issue increases and the seriousness of the problems it causes becomes more evident, the demand for GHG-free technologies will increase. This challenge can be met either by fossil fuel technologies which include GHG sequestration or by further development and increased use of renewable energy technologies, which until now have played only a minor role in supplying our unsatiable energy demands.
However, we remain very optimistic that man with his ingenuity will deal with these problems so as to continue providing energy for the citizens of this world to use for their own betterment. After all, energy is the basis of our standard of living and will remain so for as long as we populate this planet.
-S. Schmidheiny, 1992. Changing Course. A Global Business Perspective on Development and the Environment, pp.5-6. The MIT Press, Cambridge, Massachusetts
-B. Eliasson, 1998. Renewable Energy. Status and Prospects, ABB Environmental Affairs, Växjo, Sweden