Damn the dams?

Floodwaters from the Xiol

Are dams good, or is coal better or is nuclear the best option? You are sure to hear proponents of each espousing the respective energy option. What is the truth? Does it as always lie somewhere in between?

To reduce its carbon intensity by 40 percent by 2020, China has undertaken a five year plan with grandiose plans, among which are big dams. As part of its low-carbon diet, the Chinese government plans to approve new hydropower plants with a capacity of 140 gigawatts over the next five years. For comparison, Brazil, the United States and Canada have each built between 75 and 85 gigawatts of hydropower capacity in their entire history. Achieving the new plan's target would require building cascades of dams on several rivers in China's south-west and on the Tibetan plateau.

Experts believe this would spell disaster for its rivers and biodiversity hotspots. Because of dam building and other factors, freshwater species have on average lost half their populations between 1970 and 2000, and more than a third of all freshwater fishes are at risk of extinction.

International pressure to limit greenhouse gas emissions is the single most important factor behind the huge push for hydropower in China. But, in the process is it set to create new crises? Should emissions reductions come at the cost of biodiversity and loss of rivers?

New small-scale hydro plant

In a number of newly industrialized nations, huge dams are being discussed that would flood settled landscapes and destroy ecosystems. In many underdeveloped countries, the funds and engineering know-how that would be necessary to bring hydroelectric power on line are not available. Smaller power stations entail considerable financial input and are also not without negative environmental impact. Until now, the use of hydroelectric power in connection with a relatively low dam height meant that part of the water had to be guided past the dam by way of a so-called bay-type power plant -- a design with inherent disadvantages.

Researchers at Technische Universitaet Muenchen (TUM) have developed a small-scale hydroelectric power plant that solves a number of problems at the same time: The construction is so simple, and thereby cost-efficient, that the power generation system is capable of operating profitably in connection with even modest dam heights.

Moreover, the system is concealed in a shaft, minimizing the impact on the landscape and waterways. Their approach incurs very little impact on the landscape. Only a small transformer station is visible on the banks of the river. In place of a large power station building on the riverside, a shaft dug into the riverbed in front of the dam conceals most of the power generation system. The water flows into a box-shaped construction, drives the turbine, and is guided back into the river underneath the dam. The core of the concept is not optimizing efficiency, however, but optimizing cost.

Shaft power plants could play a significant role in developing countries. Distributed, local power generation by lower-cost, easy-to-operate, low-maintenance power plants is the only solution. If turbines are not financially feasible, it is possible to use a cheap submersible pump and run it in reverse -- something that also works in the new power plant.

Any thoughts on the new technique?

Big vs Strong

The Chinese government has ordered the closure of 2,087 aging steel and cement mills and other factories in an aggressive push to improve the country’s energy efficiency. The closings — which target “backward” facilities that produce steel, coke, paper, and other products — are part of a drive to reduce energy consumption per unit of economic output by 20 percent this year compared to 2005.

Chinese leaders have become increasingly concerned about reliance on imported oil and gas and growing air and water pollution. According to the Ministry of Industry and Information Technology, the factory closings are intended to “realize a transformation of industry from being big to being strong.”

Whether that is also a recognition of the mistake behind Three Gorges dam cannot be decided! The dam, which is an engineering marvel, has been in the midst of problems and controversies since it was completed in 2009. Thousands of tons of garbage washed down by recent torrential rain has been threatening to jam the locks of the Dam. More than 3,000 tons of trash was being collected at the dam every day, but there was still not enough manpower to clean it all up. The trash is around two feet deep, and in some parts so compacted people can walk on it.

The Three Gorges Dam is the world's largest hydropower project, and was built partly to tame flooding along the Yangtze, which killed over 4,000 people in 1998 and countless more over the centuries. Enormously expensive and disruptive, the dam has cost over 254 billion yuan ($37.5 billion) and forced the relocation of 1.3 million people to make way for the reservoir. Towns, fields and historical and archaeological sites have been submerged.

Coupling the dam's 32 main generators with 2 smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam will eventually reach 22.5 GW. From completion through September 2009 the dam has generated 348.4 TWh of electricity, covering more than one third of its cost. Not only the power considerations make it attractive, but at full power, Three Gorges reduces coal consumption by 31 million tonnes per year, avoiding 100 million tonnes of greenhouse gas emissions.

Is Big the way to be, or Strong? Is it better to go for massive projects that in one go deliver big chunks of power and carbon benefits, or opt for many, small projects that do not affect the environment or people?

River turbine powers a town

In a remote town of Eagle, Alaska, a river turbine is turning kinetic energy to electricity without building dams. The 25 kilowatt turbine, made by New Energy Corp., is attached to a barge in the Yukon River, requires no dam on the river at all and rotates at slow enough speeds that aquatic life is not placed at risk.

AP&T claims the project will make Eagle Village the first town in the United States to be entirely powered by a hydrokinetic river turbine. Pilot and small-scale projects like this are plenty but scaling them to supply bigger areas is the challenge.

What exactly are the challenges of scaling up? Do share your thoughts. Why cannot this model be adopted instead of opting for huge, multi-million dollar projects that displaces people and forests?

To dam or not to dam!

The 17th Electric Power Survey projections show that by 2012, peak energy demand in India will double from that of base year 2003/04. From 362,799 million units, the country’s annual energy consumption will be 755,847 million units. This is based on the assumption that government is able to deliver its power to all by 2012, and that utilities are able to contain their T&D losses.

The earlier survey had envisaged an addition of 1 lakh MW by 2012. It had called for a 60:40 ratio of thermal to hydel, as against the present 75:25, for optimum utilization of installed capacity. Of the additional requirement, some 16,553 MW is expected from hydro.

There is identified potential of over a lakh MW of hydro power in the country. So where is the problem?

Environment concerns stalk hydropower in India, as also anywhere else. This is because most of these are in fragile, mountainous regions where the potential for eco-damage is most. There is worry about what damming could do to the natural flow of rivers which keep large tracts of land fertile besides supplying water. Submergence and rehabilitation is a big worry. Tectonic considerations add to the woes.

It is the environmental clearances that deter potential investors from hydro sector. Often these take a long time. The technical due diligence studies calls for data like rainfall, water, etc from the last 20 years which is often unavailable. The flow data of rivers is often very old and leads to storage capacities never getting filled. Silt accumulation in reservoirs is another problem that deprives land downstream of nutrients.

It is to address this lack of enthusiasm that government policy has been drafted to make life easy for investors. The power generator has to invest only 30 percent of capital as equity while the rest comes as loan for which government pays interest! The investor gets annual fixed charge if the generation goes beyond a certain capacity index. Here, experts feel that capacity is not gauged properly beyond machinery availability and can boast a big number even when generation is very low.

While there are 55 hydro projects in different phases of construction and planning, many face opposition from environment groups. EIAs are done without sufficient attention to facts. In many difficult terrains, getting the data for EIAs is a laborious and complex step. Inefficient projects based on outdated data have meant profits for investors without any significant energy generation.

In such a scenario, more power generators are going in for run-of-the-river projects. These are projects that seek not to dam the river but to merely divert water to fall at a gradient, generate power, and return the water to the river downstream.

However, some amount of storage is required to generate sufficient flow and pressure. This water is sent down a tunnel, ranging in kilometers, before it falls on the turbines. The fact that there is no limit for storage to be defined as run of the river has meant that certain liberties are taken.

Also, there is no submergence of land in r-o-r projects.

But such projects could end up with rivers drying up in the patches where diverted. And also cause disturbances in the fragile eco-system around, by way of constructions, roads, etc.

The Pathrakadavu dam being pursued by Kerala in the Silent Valley periphery is being touted as a r-o-r project with minimal damage to the river or the forests. But viewed as a whole it lies very much in the once-envisaged wider boundary of the national park and has potential to cause considerable eco-damage. This is for a few hundred MW which can be had by addressing T&D losses, say activists.

What is the solution? Everyone wants power. With ‘dirty’ coal still being the dominant source for a few more decades at least, hydro power would seem a better option. It is clean and renewable and does not incur recurring costs, even if initial costs are high at about Rs 6 crore for one MW, and gestation period long. It has a long lifetime. True, the IPCC has raised doubts about how clean this source is by pointing that reservoirs are sources of methane, a greenhouse gas. But not many are willing to accept that.

Should we dam our rivers? Are big hydels the answer or smaller ones that do not have large storage capacity? Reservoir-induced seismicity and landslides has been evidenced at Idukki project which also caused drying of river Periyar downstream. But we need to acknowledge that dams with storage reservoirs do facilitate irrigation in many places.

Going for big or huge dams do have negative fallouts. Already there are concerns over China’s Three Gorges project which promises to deliver 84.7 bn KWh when completed next year.

Taking 17 years to build, costing $24 bn the dam is 185 mt high, 2309 m long and has 26 turbines. It has already displaced 1.3 million.

Evidences of landslides triggered by the damming construction activities, caving in of shores along the reservoir, pollution of the Yangtze river, etc are some of the concerns that predict major catastrophes ahead.

The project was meant to tame the river, increase river shipping and power generation.

Obviously, big means bigger risks even if it promises big power. Still, can we rule them out when the need for power is acute?

The prudent choice would be to look holistically at each project in terms of the need, economic feasibility, ecological damage and sustainability.