A critical view on the eco-friendliness of small hydroelectric installations

Highlights

• It is believed that a complete shift to renewables will mitigate global warming.

• We show how that belief is questionable, with the example of hydropower.

• Large hydropower, once considered totally clean, is now known not to be so.

• The paper brings out that small hydro, too, is no more clean/green than large hydro.

• There is no basis in the belief of eco-friendliness of small hydro.

Abstract

Renewable energy sources are widely perceived as ‘clean’, ‘green’, and ‘inexhaustible’. In recent years the spectre of global warming and ocean acidification, which has been primarily attributed to fossil fuel burning, has brought renewable energy at the forefront of most climate change mitigation strategies. There is strong advocacy for large-scale substitution of conventional energy sources with the renewables on the premise that such a move would substantially reduce environmental degradation and global warming. These sentiments are being echoed by scientists and policy makers as well as environmental activists all over the world.

‘Small hydro’, which generally represents hydroelectric power projects of capacities 25 MW or lower, is one of the renewable energy options which is believed to be clean and sustainable even as its bigger version, large hydro, is known to cause several strongly adverse environmental impacts.

This paper brings out that the prevailing perception of ‘eco-friendliness’ of small hydro is mainly due to the fact that it has only been used to a very small extent so far. But once it is deployed at a scale comparable to fossil fuel use, the resulting impacts would be quite substantially adverse.

The purpose is not to denegrade small hydro, less so to advocate use of fossil fuels. It, rather, is to bring home the point that a much more realistic and elaborate assessment of the likely direct as well as indirect impacts of extensive utilization of this energy source than has been done hitherto is necessary.

Introduction

All hydroelectric power projects are sources of renewable energy but the larger versions of such projects are not counted among renewable energy sources because, in the general perception, large hydropower projects (LHPs) are not ‘clean’ while other renewables are. Small hydropower projects (SHPs), which include minihydel, microhydel and picahydel units, are considered sources of renewable energy because they are perceived as the ‘clean’ and ‘green’ alternatives to LHPs. Driven by this perception, governments of several countries provide subsidies and other incentives for the promotion of small hydro, even as large hydro is denied that kind of patronage and is subjected to much more intense pre-licence scrutiny.

Interestingly, till as recently as in mid 20th century, LHPs had a much more favourable image than is commanded by SHPs at present. LHPs had appeared to be the cleanest of all energy sources, as ‘totally clean’ as the sunlight is when it is used directly for obtaining heat or light. Hydropower appeared even more virtuous than sunlight for the crucial reason that whereas sunlight is intermittent, hydropower is continuous. Hydropower had yet another distinguishing feature: its use seemed to provide numerous benefits over and above energy production. The very long roaster of the virtuesof cleanliness, dependability, and versatility of hydropower as were perceived thenincluded the following:

• It revolves round the use of one of the world's most benign, inexpensive, and abundant fluids: water.

• It utilizes water in a totally non-destructive fashion. After hydropower generation, the water remains intact and reutilizable with hardly any deterioration in its quantity or quality.

• It utilizes two basic forms of energysolar heat and force of gravitywhich both are ‘carbon free’, perpetual, and inexhaustible (in foreseeable geological time).

• It transforms these carbon-free forms of energy to electricity which, again, is carbon free and ‘clean’ in that sense.

• It is linked to creation of reservoirs by damming rivers at suitable sites. At one time, the reservoirs themselves had appeared to be a great boon. They promised to utilize the river flow to the maximum. They stored water when it was available in excess, for use in times when the flow in the stream was too lean or totally stopped. Additionally, reservoirs promised to control floods, promote fisheries, facilitate irrigation, recharge underground aquifers, and ensure uninterrupted public water supply.

• Unlike thermal power plants no gaseous or flyash emissions were seen coming out during the production of hydropower. And, unlike nuclear power plants, there were no radioactive wastes to contend with.

• The reservoirs had an additional virtue no other type of power plants possessed: they made an aesthetically pleasing sight. Wast spans of clean water always have great recreational value: reservoirs provided it. Indeed very many large reservoirs continue to be highly sought-after tourist spots.

During the middle of the 20th century, when only a few LHPs existed in the world outside North America and a few West European countries (WCD, 2000), and before anything was known about their downside, LHPs appeared paragons of virtue; the ultimate gift of technology. Everything about LHPs appeared unquestionably good, and more, while nothing negative came to mind. There was such a euphoria about LHPs that Jawaharlal Nehru, the then Prime Minister of India and a major global personality associated with the Non Aligned Movement, was moved deeply enough by the sheer appeal‒then felt‒of LHPs to call them the ‘temples of modern India’ (Chari et al., 2005a, Chari et al., 2005b, Abbasi and Abbasi, 2012).

Riding on such faith and euphoria, developing courtiers committed large chunks of precious public money in LHPs in particular and dams in general. There was such a spurt in dam building that by the end of the 20th century the world had over 45,000 large dams, recording an staggering 9-fold increase over the figure that had existed in 1949 (WCD, 2000). The world did not just build more and more dams, it built bigger and bigger dams, too.

As the number and the size of LHPs increased, there was also an increase in the reports of their adverse impacts. By the late 1970s LHPs had begun to lose their pre-1949 sheen, a process which became quicker with each passing year as public opposition to new LHPs became more and more strident. All over the world more and more environmental activists began going up in arms whenever a hydroelectric power project was planned. In India, several persons even offered to lay down their lives through the Gandhian means of fast-unto-death in protest against hydel projects (Chari et al., 2005a). By now the tide has turned so completely that efforts are on to even dismantle some of the existing hydroelectric dams, especially in the USA (Huesemann, 2006, Hoffert-Hay, 2008) where there is little dam-building since 1976 after an exponential growth in this sector between 1916 and 1976 (Kosnik, 2008).