Ten "Rules-of-Thumb" to Select Better Hydroelectricity Projects

Perilous Power? Considering Options

Ten “Rules-of-Thumb” to select better hydroelectricity projects

Guest post by Dr. Robert Goodland

Comments and corrections to: RbtGoodland@gmail.com

1.  Adopt Best Practice

Follow “Best Practice” to the fullest extent possible.  This includes utilizing best technology, as per rule 10 below.  All dam proponents and financiers need an environmental and social policy. Much best practice for hydro selection, planning, construction, monitoring (starting with adequate pre-project surveys which are required if progress is to be measured), including panels of social and environmental experts, is well codified by the World Commission on Dams (2000).  Follow best practice throughout the Environmental and Social Impact Assessment (ESIA) process -- beginning with adequate pre-project demographic, environmental, health, and socio-economic baseline surveys – and then throughout construction, operations, and decommissioning. Teams who have worked in any one country should uphold or strengthen standards when working on dams in foreign countries; avoid double standards.

2.     Perform regional planning 

Reduce environmental impacts by cramming many dams on the fewest rivers in a country or region.  Often, the first dam imposes most of the impact of a cascade of dams.  But scrutinize social risks beforehand. Interpolating one more dam to a cascade generally is lower impact.  The highest impacts would be to site a single dam on each of the nation’s rivers. Interpolation of a dam between two existing dams or shortly upstream of an existing dam greatly reduces the impact of the new dam.  The first dam on a river normally has the biggest impact, compared with the impacts of subsequent dams on the same river.

3.  Rehab existing projects before new projects   

Rehabilitate, refurbish, renovate or upgrade existing hydros before going ahead with new hydros.  Adding new turbines or replacing old turbines with more efficient or bigger ones are almost always much lower impact than building new dams.  Rehabs should normally be well in hand before a new dam is contemplated, just as energy conservation and demand management should be well in hand before new generation is permitted. For example, it has been calculated that 70,000 MW could be developed in the USA by rehab alone, with no new dams. Now that Venezuela’s Guri hydro complex, Nigeria’s Kainji and the Zambia/Zimbabwe Kariba hydros, for example, are several decades old, they are being usefully upgraded with low impacts.

5.     Dam tributaries before the mainstem  

Develop dams on tributaries before dams on the mainstem. If a mainstream dam is necessary based on comprehensive options assessment, it should be sited as far upstream as feasible. That will often impose less impact.  Outstream diversions may be high impact.

6.     Uphold Human Rights, especially Free Prior Informed Consent  

Seek free prior informed consent from stakeholders, as well as meaningful consultation.  Reject any use of force, and reject any measure that would be involuntary.  Choose sites with little or no need for resettlement.  All resettlement must be strictly voluntary (UN FPIC). As soon as oustees consent to their move, it should proceed expeditiously. Oustees must promptly become better off project beneficiaries as soon after their move as possible. If the dam is built and owned by Indigenous People or ethnic minorities (e.g., Canada’s Minashtuk Hydro) other rules will apply.

Avoid conflict zones and militarized areas. Ensure effective grievance mechanisms and respect for human rights.  All potentially impacted stakeholders (upstream, reservoir basin, downstream, and other (including those living along transmission lines and project roads) must be consulted and participate in decisions affecting them from the options assessment stage, to get away from a project-centered perspective, thru pre-feasibility and construction and afterwards. 

7.  Promote irrigation before electricity

Many dams are labeled ‘multipurpose’ nowadays, suggesting that the purpose of the dam in question includes more than one purpose, such as generation of electricity, flood control, water supply, fisheries, navigation and irrigation.  This can be misleading because in operating the dam, power generation is almost always the topmost priority, as compared to secondary uses such as irrigation. Electricity generation earns by far the most revenue.  Some of this revenue is best allocated to promoting other uses, such as irrigation. Most so-called ‘multipurpose’ dams indeed have more than a single purpose, but the other purposes are subsidiary to power generation.

In many poor rural areas, water to grow food is much more important than electricity. Irrigation often depends on water storage during the wet season for release during the lean season. While it is possible for irrigation to be combined with hydro in multi-purpose schemes, there are often inherent incompatibilities between generation of electricity and provision of irrigation water when water is scarce but most needed during the dry season. When dam operators must choose one over the other, electricity generation almost always trumps irrigation. This is important in several ways, especially when in contrast to hydro electricity generation, there are few alternatives to irrigation dams, and agricultural intensification is much needed as world population may exceed 9 bn by 2050.  

8.     Manage both climate mitigation and climate adaptation

All new dam designs nowadays need a thorough greenhouse gas (GHG) emissions assessment. Choose low emissions designs.  Dams likely to emit as much GHG as a coal-fired equivalent should not be developed.  Conversely, dams likely to emit less GHG than a gas-fired equivalent should be promoted.  Reduce the amount of biomass in the reservoir before filling. More than 27 European nations and Australia, and many jurisdictions (e.g., Vancouver) now mandate a charge for GHG emissions.  Hydro must internalize its GHG emissions in project design and cost/benefit analysis.

The best hydros will be designed to take climate change into account. Hydros are designed based on the best historic river discharge data obtainable. Now climate change has arrived, the best hydros will be designed using the most reliable predictions of climate change on the future of river flows.  Extreme events (heavy rains, storms, droughts) may become more frequent. Appropriate adaptation strategies will include diversified and decentralized investments, to avoid putting all eggs into one basket in a time of increasing hydrological uncertainty.

9.      Conserve Biodiversity   

Choose sites with little or no valuable biodiversity habitat (such as tropical forest).  Lower the dam height or move the dam to minimize forest loss. If some forest loss cannot be avoided, finance compensatory offsets that provide better benefits than the area inundated. Conservation units (e.g. National Parks, UN World Biosphere Reserves, UN World Heritage sites, protected forests) should normally always be avoided.

10.   Reduce reservoir size and minimize hydraulic head 

Optimize the potential of hydrokinetic turbines or non-dam hydro. Select no-head, ultra-low head (c.3 m), and micro-hydro – all before higher-head hydros.  Hydros in which the reservoir fills the riverbed up to the annual wet season level are usually low impact.  In the paramount tradeoff between reservoir area and impacts, reduce reservoir area by optimizing flow (by tube turbines), and reducing head, preferably to zero. Select engineering (e.g., by kinetic turbines) to reduce the size of the reservoir area.

Caveat  

Pithy “Rules-of-Thumb” suffer from simplification and these are no exception. Although these Rules-of-Thumb apply only to hydroelectricity dams, and not to irrigation dams, they would also all apply with minor revisions to most development projects (except # 10, which is entirely hydro-specific). These Rules-of-Thumb apply only to hydroelectricity dams which supply about 20% of world electricity, and for which there are many alternate sources of electricity, particularly renewables (e.g., solar, wind, wave). They apply mainly to big dams, rather than to microhydro, which impose lower impacts. The “Rules-of-Thumb” are offered mainly to hydro designers, hydro financiers and those seeking to reduce the impacts of big hydro.  Renewable energy is fast becoming more feasible as climate change, democracy and biodiversity are accorded more importance. 

The author, Robert Goodland, served the World Bank Group as environmental adviser for 23 years, where he drafted and persuaded the Bank to adopt its current mandatory social and environmental “Safeguard” policies. He helped set up the World Commission on Dams in Cape Town.  After retirement, he was the Technical Director of the independent Extractive Industry Review of the World Bank’s oil, gas and mining portfolio (EIR.org). He was elected chair of the Ecological Society of America (Metropolitan), and President of the International Association for Impact Assessment. Last year he was awarded IUCN’s Coolidge Medal for outstanding lifetime achievement in environmental conservation.