Friday, August 15, 2008
Energy needs: India and the World
This post is mostly about non carbon alternatives for electricity generation, induced by an article in Nature. However, that article may not be available to people without a subscription and furthermore, in addition to a summary, I also include here some numbers specific to India which are not available in the article. The numbers quoted in the rest of this post are taken from either the Nature article or from sources which are linked in appropriate places. The world's total energy requirement is around 45,000 terawatt-hours of energy a year, of which about 18,000 terawatt-hours a year, or roughly 40% is for electricity alone. (At 9000 hours approximately to a year, this works out to a constant 2 TW generation capacity). Electricity generation alone produces 10 gigatonnes of carbon dioxide every year, the largest fraction of all the fossil fuel derived emissions. India's total energy consumption is around 4000 kilowatt-hour per year per capita. Of this around 10%, or more precisely 460 kWh per year per capita is for electricity alone. (Some comparative figures are 28,200 for Iceland, 13,300 for the USA, 1,600 for China). These are all 2005 numbers. (Aside: The energy debate is sufficiently complicated as it is; however matters are made worse by different agencies using different units, depending on whether they are in the US or UK or elsewhere in the world. To make sense of this mad profusion in units, here is a quick conversion: 1 Quad = 1 quadrillion btu, a quadrillion is ten to the power fifteen. 1 kWh = 3412.14 btu. May the devil take the non-metricians). Now let us look at the distribution of different types of electricity generation in India. (Here again, there is some disagreement in numbers -- the Nature article gives the total for India, as I stated above, at 460 kWh/year/capita whereas this quotes 587). Of this 25% is hydroelectric, around 2.5% is nuclear, 69% is conventional thermal and the rest (a little more than 3%) is a combination of what is commonly called non-conventional energy sources (geothermal/solar/wind/biomass but in fact, is mainly wind). Hydropower development in the Brahmaputra river basin in eastern India is expected to result, by 2012 in six large power plants, which will add nearly 30,000 megawatts of generating capacity. (At present the total installed electricity generation capacity is around 118 gigawatts though using the above numbers gives us about 50-60 gigawatts. Thus there are significant discrepancies in various numbers floating around). Now a look at the rest of the world for these non-carbon-polluting sources. The total hydroelectric generation capacity in the world is 800 gigawatts, about 10 times more than geothermal, solar and wind power combined. The Three Gorges dam in China will eventually generate 18 gigawatts. In the best of all possible worlds, the International Hydropower Association estimates that hydroelectric capacity could triple worldwide with sufficient investment, the growth being mostly in Asia and Africa. It is expected that up to a terawatt of capacity could be added. However, while a clean technology, hydropower causes, as we in India have seen over the last few decades, enormous disruption in human lives, and enormous costs involved in relocating people, along with significant ecological damage caused to ecosystms downstream and upstream. Nuclear power produces 370 gigawatts of energy, around 15% of energy generated worldwide. (The number for India is abysmally small - less than 3%). With improvements in design, using breeder reactors, and introduction of thorium as a fuel, nuclear capacity can grow by a factor of two or three and continue for a century or more. In principle the world could be 100% nuclear power based. However, apart from being capital intensive (offset partly by their long lifetime), there are issues of storage of nuclear waste, diversion of nuclear fuel for nuclear weapons, the dangers of the spread of radiation in case of an accident and so on. Various different studies both by he IAEA as well as by academic organisations predict a rise to around 1000 to 1200 gigawatts of energy by 2050. Biomass and geothermal account for about 40 to 50 gigawatts of energy generation and are easily surpassed by windpower. The total installed capacity for windpower is around 94 gigawatts (or around 5% of total electricity generation) and at the present rise of around 20% per year, could triple in the next six years. In this, India too is doing very well. Unfortunately, its intermittancy means only up to around 20% of a grid's capacity can be met with wind energy. Incidentally large wind farms can affect local and potentially global climate by altering wind patterns and reducing the cooling effect of the wind, as large turbines slow the wind down. Solar energy is plentiful, particularly in a country like India which has negligible solar energy generation. Unfortunately solar cells have an efficiency of around 12-18% going up to around 20%, which is much higher than photosynthesis (1%). Additionally solar cells are still expensive, though their price is falling. Even though installed capacity is 9 gigawatts, the actual energy produced is much less, due to nights and clouds. The Earth receives 100,000 TW of solar power at its surface - enough power it is said, per hour to supply humanity's needs for a year. I don't see though, how this number adds up. It is also said that the world's primary energy needs could be served by less than a tenth of the area of the Sahara. But I am yet to see a clear calculation that backs this up. However, there is clearly no question that the Sun does represent a virtually inexhaustible and non polluting source of energy for our needs, if only we knew how to harness it efficiently. Other than wind power, India lags behind very badly in developing non-carbon methods of generating energy, including electricity. Its success with hydroelectric power is marked by controversial and incomplete resettlement programs for people displaced by large dams (coupled with somewhat knee-jerk extreme reactions by environmental fundamentalists). Given our rising energy needs, there seems to be no option but to develop one or more of these energy sources. However, with the nascent state of research in solar energy and the almost complete exploitation of wind energy, nuclear power today appears to be the only option to pursue in the short term (10-20 years). This is contingent on two premises: that the Department of Atomic Energy improve its track record significantly, in adding substantial electricity generation capacity (it has over the years fallen behind hugely, its own predictions of capacity addition) and secondly that the world stop treating us as a pariah state and agree to do nuclear commerce with us, so that we can buy nuclear fuel in the open market.