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With an incomprehensible quantity of concrete used in it, the world's largest dam proudly stands on China's Yangtze River. It is a hydroelectric dam situated in Yiling District, Yichang, Hubei province, China. The dam has increased the shipping capacity of Yangtze river in addition to power generation. Some facts are as follows,
Name: Three Gorges Dam, China (长江三峡水利枢纽工程)
Completion of dam body: 2006
Total capacity 39.3 km3
Time to build: 17 years
Cost to build: $22 billion
No. of main turbines: 32
Total power generation capacity: 22,500 MW

World's Largest Dam: Three Gorges Dam, China (长江三峡水利枢纽工程)
World's Largest Dam: Three Gorges Dam, China (长江三峡水利枢纽工程)
Image: PopularMechanics

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The Place of Micro Hydro
Micro hydro, defined as a plant between 10 kW and 200 kW, is perhaps the most mature of the modern small-scale decentralised energy supply technologies used in developing countries. 
There are thought to be tens of thousands of plants in the ‘micro’ range operating successfully in China, and significant numbers are operated in wide ranging countries such as Nepal, Sri Lanka, Pakistan, Vietnam and Peru. This experience shows that in certain circumstances micro hydro can be profitable in financial terms, while at others, unprofitable plants can exhibit such strong positive impacts on the lives of poor people and the environment that they may well justify subsidies.
A Micro Hydro Turbine in action
The evidence from this extensive experience shows such wide variation in terms of cost, profitability and impact, that it has often been difficult for investors and rural people to determine whether, and under what circumstances, this technology is viable and best meets their needs. Whilst supplying improved energy services to people for the first time is difficult, supplying such services profitably to very poor people who live far away from roads and the electricity grid poses a particularly difficult challenge. This report shows that micro hydro compares well with other energy supply technologies in these difficult markets. Despite this micro hydro appears to have been relatively neglected by donors, the private sector and governments in the allocation of resources and attention. In the past, rural electrification by means of grid extension was the option favoured by donors.
More recently the fashion has switched towards photovoltaics, probably because of its higher foreign content, and the higher added value returned to the metropolitan countries. The relative neglect of micro hydro has also been in part due to the fact that the circumstances under which it is financially profitable have not been systematically established, at least not in ways that investors find credible. In addition, while it is known that the growth and sustainability of the micro hydro sub-sector depends on certain types of infrastructure and institutional investments, it was often not clear which elements of this ‘enabling environment’ were essential, nor how they were best financed.
This study attempts to rectify these omissions by analysing and then synthesising the xperience of micro hydro over many years, across a broad range of developing countries. Primary evidence was obtained from Peru, Nepal, Sri Lanka, Zimbabwe and Mozambique. On the basis of this evidence an attempt has been made to establish ‘Best Practice’ in terms of the implementation and operation of sustainable installations. National teams, usually consisting of an independent consultant and a staff member of The Intermediate Technology Development Group, carried out the work using a common methodology developed at the start of the work. National reports were written separately and were subject to review at national workshops involving the key actors in the sector.
The microanalysis sought to examine a sample of specific installations. The sample was drawn from comprehensive databases of micro hydro plants in each of the five countries. It was selected using a typology which combined end-uses (productive uses, electricity for lighting, combined end-uses, etc.) with types of ownership (communityled projects, projects implemented by central bodies such as the utilities, and projects initiated by private entrepreneurs).
The Differing Objectives of Micro Hydro Development

One of the most important findings to emerge from the study of this experience is that micro hydro plants can achieve a wide range of quite different objectives. Much confusion and misunderstanding arises when all micro hydro plants are treated as a homogenous category. Analytically it is therefore important to judge the viability of each micro hydro investment in terms of a specific objective. Similarly in the formulation of government or donor policy, it is important not to expect micro hydro to achieve many, often conflicting, objectives. For instance, it is not possible to provide electricity to very poor people in remote locations through micro hydro and make a return on capital similar to that achieved in London capital markets.

Technology Demonstration,Social Infrastructure,or Small Enterprise? 

The field of micro hydro is ‘evolving’, particularly in relation to the motivation of project developers. Recently the majority of initial installations in each country might be said to be the result of a ‘technology push’. That is, plants were installed to test their technical viability and their acceptability. This experience has established the technical reliability of the micro hydro systems, reduced their cost, and has resulted in substantial technical improvement. Micro hydro is now a mature technology that has been greatly improved by electronic load controllers, low cost turbine designs, the use of electric motors as generators3, and the use of plastics in pipe work and penstocks.
The next group of projects is characterised by investments in micro hydro that were seen as part of the ‘social infrastructure’ more akin to the provision of health services, roads or schools. Due to their social objectives, these experiences have often generated little information on the capital and operating costs or cash flow returns of the investment, particularly of a form and quality that would be regarded as reliable by potential investors in conventional financial institutions. Indeed many of the promoters of this type of project justify their work solely in terms of contributions to social justice, the quality of life of marginalized people, and to the environment. In Sri Lanka, for instance, many micro hydro plants have been installed primarily to “improve the quality of life by providing electric light”. In Peru the key question for many project developers was “how long will the plant last”, rather than “how high is its rate of return”, or “how quickly the capital will be paid back”.More recently support programmes have returned to what might be called an older vision what might be considered an earlier approach, where micro hydro is seen primarily in terms of securing livelihoods and for the development of small profitmaking businesses. This can be seen in part as an admission that, like the previous attempts at rural electrification through grid extension, the sustainability of grant-based programmes is limited. Methods must be established to attract private capital if these programmes are to have anything but a marginal impact. Nepal has shown that small, almost subsistence businesses can survive using micro hydro power to mill grain. Over 900 micro hydro plants had been installed in Nepal by 1996, and over 80% of these were for grinding grain. In recent years there has been quite a rapid take-up of the small (1 kW) ‘peltric’ sets for generating small amounts of electricity. Introduced in the early 1990’s, there were said to be over 250 operating in the first five years.
Micro Hydro Mechanism
These very different starting points, along with the performance indicators used to evaluate projects, have important implications for what is regarded as a success. Micro hydro as ‘social infrastructure’ uses the approaches and indicators appropriate to schemes for the supply of drinking water, health clinics and schools. Micro hydro as ‘physical infrastructure’ uses the approaches applied to electric power generation more generally, and to such investments as the provision of roads and irrigation systems. Even more recently micro hydro has been seen in terms of small and medium enterprise development, and the role that such enterprises can play in ‘securing livelihoods’. There is little to be gained from arguing that one approach is superior to another, as in all probability each strand has a role to play. But failure to distinguish these very different motivations has lead to confusion and ineffective policy advice. Each approach is associated with very different mindsets of the people involved, and the differing objectives will result in quite different management, allocation of resources, approaches and even site selection.

Hard Choices Have To Be Made in the Allocation of Scarce Resources

Investments that are primarily intended to increase the adoption of micro hydro are likely to need to be financially viable and will therefore be located where there are concentrations of effective demand, or there are so-called ‘anchor customers’ who can pay for the bulk of the power supplied. This might include sales to the grid where possible and profitable. Programmes that are intended primarily to increase the ‘access’ of specific groups of people to improved energy supplies are likely to be located where poor live. This will frequently be in more remote areas that will not be reached by the central grid for some time, if ever, where all other options will also be expensive but where micro hydro is the least cost. Examples of the strategy to increase sales, regardless of their income or need, can be found in a number of renewable energy programmes, particularly in photovoltaics. Here it is argued that increased sales will reduce the cost of production, and more importantly, enable the overhead costs of providing technical support and supplying ‘retail’ credit to be spread over a larger number of unit sales. The danger is that some of the soft money that is intended for social investment is used to subsidise the costs of these supply options for those who can already afford to pay for it.
A key dimension of the trade-off is that the benefits and burdens of the choices made fall on different social groups. The people who can pay the full cost of energy supply often reside in different parts of the country from those with the greatest need. This means that if concepts of fairness are introduced to government policy or, more generally, into the allocation of resources, micro hydro is likely to have an important role in spreading access to electricity, even if the users cannot pay the full cost. The review of programmes in Nepal and Sri Lanka both suggest that they have both been explicitly motivated by ideas of social justice and fairness. Certainly rural people in many countries can be expected to ask why they should not they be entitled to the levels of subsidy provided to urban dwellers.
Micro hydro developers and the financial institutions that they work with have to make choices between these two extremes of profitability and social impact. There is likely to be a middle ground where social impacts can be achieved profitably, but its size is not yet known. What is clear, is that many rural people will remain without electricity unless there is some sort of redistribution of income from urban to rural areas.
There is a parallel here with arguments between the advocates of micro hydro and Ministries of Energy and their conventional utilities. Proponents of micro hydro are often disappointed that utilities will not take them seriously. Certainly micro hydro often faces unfair competition from a highly subsidised grid, and from subsidised fossil fuels. But, there is a genuine trade-off between maximising the access of people to ‘efficient and affordable energy’, and doing so in those places where micro hydro (and other renewable energy) is the least cost. The scarce resource is not energy, but the capital to make energy accessible. If the objective is to provide electricity to as many people as possible rather than to distribute electricity evenly across the country, the most effective way of doing it may well be through extensions of the grid, or more likely ‘intensification’ of the use to which the grid is put. Similarly where utilities have very severe limits on capital, the ‘opportunity cost’ of capital at the margin rises to very high levels, explaining perhaps why they then opt for diesel generators rather than hydro with its higher initial capital cost. 
Extending the Concept Of ‘Intermediation’

The case studies show that a wide range of actions have to be brought together to ensure the success of micro hydro investments. These actions take place a various levels: at the micro level of particular investment in a hydro plant at a particular location; at the macro level of policy formulation; and in the design and implementation of programmes of financial and other support mechanisms. In undertaking the case studies, it was found that the idea of ‘intermediation’ offered a convenient way to group the many hundreds of tasks that were identified as necessary. This provided considerable analytical insight about how policies might be developed to ensure that these tasks were indeed performed and integrated into the costings. The approach extends the idea of ‘financial intermediation’ and considers three additional forms of intermediation, namely technical intermediation, social intermediation and organisational intermediation.

Financial Intermediation involves putting in place all the elements of a financial package to build and operate a micro hydro plant. A process sometimes referred to as ‘financial engineering’. It covers:
  • the transaction costs of assembling the equity and securing loans;
  • obtaining subsidies;
  • the assessment and assurance of the financial viability of schemes;
  • assessment and assurance of the financial credibility of borrower;
  • the management of guarantees;
  • the establishment of collateral (‘financial conditioning’); and
  • the management of loan repayment and dividends to equity holders.
Financial Intermediation can also be used to cover whole schemes rather than just investment in an individual plant. In this way projects can be ‘bundled’ together to make them attractive to finance agencies, to establish the supply of finance on a ‘wholesale’ basis from aid agencies, governments, and development banks, and to create the mechanisms to convert it into a supply of retail finance (equity finance, and loan finance at the project level).

Technical Intermediation involves the ‘upstream’ work of improving the technical options by undertaking R and D and importing the technology and know-how, ‘down’ through the development of the capacities to supply the necessary goods and services. These goods and services include: site selection; system design; technology selection and acquisition; construction and installation of civil, electro-mechanical and electrical components; operation; maintenance; Trouble Shooting; overhaul; and refurbishment.

Organisational Intermediation involves not only the initiation and implementation of the programmes, but also the lobbying for the policy change required to construct an ‘environment’ of regulation and support in which micro hydro technology and the various players can thrive. This involves putting in place the necessary infrastructure, and getting the incentives right to encourage owners, contractors, and financiers. The case studies show that this organisational intermediation is also usefully distinguished from the Social Intermediation. Social Intermediation involves the dentification of owners and beneficiaries of projects and the ‘community development’ necessary to enable a group of people to acquire the capabilities to take on and run each individual investment project.

Turbine Manufacturing in Srilanka
The Importance of the Technology

While the rest of this is report focuses mainly on the ‘software’ of finance, management and social development, it would not be right to end this introduction without stressing the importance of the hardware and engineering skills in the success of micro hydro development. The experiences reviewed here repeatedly confront the need to get the technology right, and develop the technical skills necessary to build, install, operate and maintain the equipment and the associated civil works.
A study on the functional status of the state of existing micro hydro plants in Nepal emphasises the point. Despite much work on manuals, standards, training, and correcting faulty engineering and associated errors, the physical assets remain a substantial cause of failure. A study on the functional status of the state of existing
micro hydro plants in Nepal emphasises the point that despite much work on manuals, standards and training, faulty engineering and associated errors, the physical assets remain a substantial cause of failure. Some 30% of the installations were not operating, due in part to:
  • Poor site selection, inadequate/inaccurate surveys, wrong size, poor
  • Installation, faulty equipment;
  • Plants affected by floods and land slides;
  • Poor estimation of hydrology, in part due to surveys being conducted in the rainy season;
  • Uneconomic canal length, bad canal design;
  • Neglect of civil works;
  • Inability of owners to replace generators after breakdown;
  • Wrong estimation of raw materials, of demand, of end-use possibilities, oversized plants, over-estimation of tariff collection, inappropriate rates, ignorance of competition with diesel. 
Furthermore, there are still a number of unresolved technical issues. In particular there is a trade-off between the quality (and therefore the costs) of the civil works and the resulting costs of operation and maintenance. Low cost civil works tend to be swept away by the monsoon rains and have to be substantially repaired each year. It is not yet clear where the optimum balance lies between these two types of cost.

The successful design, construction, and operation of a reservoir project over the full range of loading require a comprehensive site characterization, a detailed design of each feature, construction supervision, measurement and monitoring of the performance, and the continuous evaluation of the project features during operation. The design and construction of earth and rock-fill dams are complex because of the nature of the varying foundation conditions and range of properties of the materials available for use in the embankment. The first step is to conduct detailed geological and subsurface explorations, which characterize the foundation, abutments, and potential borrow areas. The next step is to conduct a study of the type and physical properties of materials to be placed in the embankment. This study should include a determination of quantities and the sequence in which they will become available. The design should include all of the studies, testing, analyses, and evaluations to ensure that the embankment meets all technical criteria and the requirements of a dam as outlined in b below. Construction supervision, management, and monitoring of the embankment and appurtenant structures are a critical part of the overall project management plan. Once the project is placed into operation, observations, surveillance, inspections, and continuing evaluation are required to assure the satisfactory performance of the dam.
 
Basic requirements of an embankment dam

Dams are a critical and essential part of the Nation’s infrastructure for the storage and management of water in watersheds. To meet the dam safety requirements, the design, construction, operation, and modification of an embankment dam must comply with the following technical and administrative requirements:
(1) Technical requirements

• The dam, foundation, and abutments must be stable under all static and dynamic loading conditions.
• Seepage through the foundation, abutments, and embankment must be controlled and collected to ensure safe operation. The intent is to prevent excessive uplift pressures, piping of materials, sloughing removal of material by solution, or erosion of this material into cracks, joints, and cavities. In addition, the project purpose may impose a limitation on allowable quantity of seepage. The design should include seepage control measures such as foundation cutoffs, adequate and nonbrittle impervious zones, transition zones, drainage material and blankets, upstream impervious blankets, adequate core contact area, and relief wells.
• The freeboard must be sufficient to prevent overtopping by waves and include an allowance for settlement of the foundation and embankment.
• The spillway and outlet capacity must be sufficient to prevent over-topping of the embankment by the reservoir.
(2) Administrative requirements
 
• Environmental responsibility.
• Operation and maintenance manual.
• Monitoring and surveillance plan.
• Adequate instrumentation to monitor performance.
• Documentation of all the design, construction, and operational records.
• Emergency Action Plan: Identification, notification, and response subplan.
• Schedule for periodic inspections, comprehensive review, evaluation, and modifications as appropriate.

Embankment
 
Many different trial sections for the zoning of an embankment should be prepared to study utilization of fill materials; the influence of variations in types, quantities, or sequences of availability of various fill materials; and the relative merits of various sections and the influence of foundation condition. Although procedures for stability analyses afford a convenient means for comparing various trial sections and the influence of foundation conditions, final selection of the type of embankment and final design of the embankment are based, to a large extent, upon experience and judgment.
 
Features of design
 
Major features of design are required foundation treatment, abutment stability, seepage conditions, stability of slopes adjacent to control structure approach channels and stilling basins, stability of reservoir slopes, and ability of the reservoir to retain the water stored. These features should be studied with reference to field conditions and to various alternatives before initiating detailed stability or seepage analyses.
 
Other considerations
 
Other design considerations include the influence of climate, which governs the length of the construction season and affects decisions on the type of fill material to be used, the relationship of the width of the valley and its influence on river diversion and type of dam, the planned utilization of the project (for example, whether the embankment will have a permanent pool or be used for short-term storage), the influence of valley configuration and topographic features on wave action and required slope protection, the seismic activity of the area, and the effect of construction on the environment.

Micro hydro can be best benefited from by following the best practices extracted from the lessons learned.

The Critical Factors
  • Micro hydro programmes and projects need clear objectives. Is the project or programme:
o An investment in social infrastructure (that will be considered in the same way as a training scheme, a safe water supply, school, a health programme?);
o A programme to sell as many micro hydro schemes as possible (regardless on the users' needs); and
o To create small profit making enterprises that are financially self-sustaining.
  •  Financially self-sustaining projects have cash generating (usually day time) end-uses to produce cash flow and increase the use of the plant (load factor). Lighting-only systems will have the greatest difficulty in achieving financial sustainability.
  • Subsidies are likely to be necessary if micro hydro schemes are to substantially improve the access of poor people to electricity.
  • The cost of micro hydro plants is dependent on location and standards although effective management can contain this.
  • The form of ownership of micro hydro plant is probably less important to success than creating an effective business-like style of management.
  • Selecting and acquiring micro hydro technology that is appropriate to the location and task remains a necessary condition for success (wrongly sized plant and inappropriate standards remain a constant threat).
Best Practice and Profitable End-uses
  • It is easier to make a profitable micro hydro plant socially beneficial than to make a socially beneficial plant profitable
  • Profitable end-uses are difficult to develop because of the limited size of the local market and the general difficulty of small and micro enterprise development in remote locations.
  • Financial institutions willing to finance micro hydro should consider funding associated end-use investments in order to build profitable load.
  • It may well be that micro hydro should be promoted for its role in securing livelihoods, or developing small enterprises, rather than as an ‘energy programme’.
  • The choice of end-use can affect those who benefit from micro hydro and will therefore effect the poverty and gender impacts, even if not all the community has direct access to the energy.
Best practice and Tariff Setting
  • The financial performance of all micro hydro plant could be improved if the average tariff was kept in line with local inflation.
  • Life line tariffs under which the richer consumers cross subsidise households that cannot pay will spread the poverty reducing benefits of micro hydro - as long as the total revenue is adequate.
  • While there is clear evidence that demand is sensitive to the tariff charged (many potential users would be excluded by full cost covering tariffs in many locations), there is also evidence that the ability of some people to pay is higher than originally thought.
Best Practice for Governments
  • Governments need to assign clear responsibilities for micro hydro development and the development of the necessary ‘enabling environment’. Best Practice suggests that this would ideally be part of assigning more general responsibilities for the provision of decentralised energy services to rural (or marginalized).
  • Governments need to treat all energy supply options equally (‘offer the full menu of options’) and to favour what best meets the needs of the consumer in different locations.
  • Governments need to ensure fair competition between competing supply options and provide equal access to aid and other concessional funds, subsidies, tax breaks and support.
  • Plans for the expansion of the electricity grid should be rule based, and in the public domain to reduce the uncertainty about when the grid will reach a particular location. Clear rules should be published regarding the actions the grid supplier must make to compensate micro hydro owners when the grid arrives (either to buy out the plant at written down costs or to buy the hydro electricity produced).
  • While government finance tends to favour large scale energy investments (in say power or fossil fuels), micro hydro has the opportunity of utilising local capital (even the creation of capital through direct labour to build civil works) and it is part of the new trend towards ‘distributed’ power with much reduced costs of transmission.
Best Practice for Regulation
  • Regulation should aim to produce a structure of incentives that result in the needs of consumers being met most cost-effectively. It should be technologically neutral, and at costs that are in keeping with the scale of the investment and the ability of the various parties to pay.
  • Regulation should be transparent, stable and free from arbitrary political interference so as to foster competition between suppliers of technology, services and finance.
  • Regulation should set standards that are appropriate to the project cost and the ability of the various actors to pay.
  • Quality and safety standards should be enforced to prevent the users being exploited by shoddy equipment and installations.
  • Regulations should be designed so that they do not merely increase the opportunities for “rent seeking behaviour" of officials.
  • Regulations should be set so that: independent power producers can supply power to the grid at ‘realistic’ prices; and connection standards are appropriate for the power to be sold. Rules should be transparent and stable.
Best Practice in Financing
  • Best practice suggests that the expansion of micro hydro will continue to need both ‘soft funds’ and funds at commercial rates, particularly if micro hydro is to meet the needs of people with low money incomes.
  • Funding will be needed to cover capital costs, technical assistance and social/organisational ‘intermediation’.
  • Micro hydro development will need to leverage funds from many sources including those for small enterprise development, livelihood development, technical assistance social infrastructure, as well as the more usual energy and environment sources.
  • Micro hydro will need to widen the menu of financing options for acquiring both debt and equity, including leasing, novel forms of debt guarantee, and novel forms of collateral (e.g. in Peru the hypothecation of the cash flow from energy end-use, and municipal loans guaranteed by ‘intercept’ on revenues from Central government).
  • Loan conditions should be simplified, and collateral conditions modified to suit local conditions for asset (land, equipment) ownership.
  • Some financial institutions are likely to require training to understand the special needs and risks of micro hydro, or to build on analogous experience in other forms of rural investment.
Best Practice for Smarter Subsidies
  • Subsidies should be designed to achieve clearly stated objectives and should develop rather than destroy markets.
  • A particular problem with current subsidies provided by bilateral donors is that they have a tendency to ‘pollute the well’ – that is, they use their subsidies to spoil the market for others.
  • Smart subsidies should:
o follow pre-established rules that are clear, and transparent to all parties;
o focus on increasing access by lowering the initial costs (technical advice, capital investment) rather than lowering the operating costs;
o Provide strong cost minimisation incentives such as retaining the commercial orientation to reduce costs;
o remain technologically neutral;
o cover all aspects of the project including end-use investments, particularly to encourage pro-poor end-uses; and
o use ‘cross subsidies’ within the project to pay for life line tariffs and other ‘propoor’ recurrent cost subsidies (e.g. enable transfer from richer sections of the community, and commercial users to marginal connections).

Best Practice for Donors
  • Build programmes on a thorough understanding of what has already been tried before in the country and elsewhere.
  • Adopt funding strategies that enhance (rather than duplicate or destroy) local capabilities including organisations, regulatory frameworks, and technical capacities.
  • Maintain the ‘full menu’ of options, so as to give micro hydro the same chances for funding as other decentralised energy supply options.
  • Ensure funds build markets rather than destroy them - apply the principles of ‘smarter subsidies’.
  • Ensure funds are available for both micro hydro and associated end-uses. Give particular attention to the encouragement of pro-poor end-uses (and the views of women as major players in traditional energy systems).
  • Ensure funds are available for all aspects of project development.
  • Use soft funds to leverage access to large flows of more conventional loan and equity finance.
  • Be transparent to make others aware of what you are doing and try to harmonise activities with other donors, partners, equipment suppliers, contractors, and government programmes.
Best Practice for Project Developers
  • Project developers who have the skill and tenacity to put all the elements of a micro hydro plant together are crucial to the success of programmes, and are likely to be the main constraint to programme expansion, particularly if their costs cannot be covered by grants
  • Successful micro hydro programmes will need to be sufficiently large to produce sufficient work for the project developers and to achieve economies of scale in the supply of such services - such as where there are a number of plant in the same area allowing for costs of site visits to be shared by a number of installations.
  • Financial institutions and regulatory agencies need to strike a balance between their need for project developers they regard as credible (speaking English with formal qualifications in engineering and accountancy) and their cost. Best practice probably requires lower cost project developers with specific practical experience with micro hydro and the communities that use them.
  • The costs of ‘intermediation’ in project development should be recorded, and attempts made to cover them directly with grant funding.
  • Efforts should be made to estimate the realistic size of the market for micro hydro, taking into account, costs, alternatives, and the likely availability of finance, so as to determine whether the process of project development can be put on a more sustainable financial basis (including grants). Additionally the scale of project development capabilities should be increased sufficiently so as to reduce unit costs by capturing the economies of scale.
  • Technical assistance services should be separated from credit functions to ensure that sound judgements are made about the financial viability of each project (with or without subsidies) and credit worthiness of project owners.
  • Consideration should be given to productive end-uses from the outset, and treat micro hydro investment as a small enterprise (regardless of actual ownership structure).
  • Endeavour to create a business like management structure, even if co-operative or other forms of joint ownership are used.
  • Attempt to institute rules for tariff setting and for inflation adjustments that are technical and routine rather than arbitrary and politicised (e.g. link the price of electricity to some other freely traded commodity - such as a staple crop, kerosene, or candles).
  • Successful programmes include activities that stimulate demand for hydro and the financial and other support activities that are available.
  • Successful programmes include activities that lobby for changes in the ‘enabling environment’ created by government, financial institutions and donors. These are  probably most effective when operating as an ‘Energy Forum’ combining the interests of all people interested in rural, ‘alternative’, or decentralised energy options.
  • Project development would benefit from technical catalysts who can work in close proximity to villagers at relatively low cost.
Best Practice for Capacity Building
  • There would appear to be no short cuts in developing local capacities. The process takes a long time and is costly, but without such capacities micro hydro programmes cannot succeed.
  • Local capacities to build micro hydro plants locally appear to substantially reduce costs
  • Local capacities to manage, operate and maintain micro hydro plants are a necessary condition for success and resources will need to be devoted to building this capacity.
Best Practice for Management of Micro Hydro Plant

  • Regardless of ownership structure, it would appear that the successful management of micro hydro plants requires a ‘corporate structure’ that minimises political interference (e.g. from municipal authorities or powerful community members) by providing clear delegated authority to a management to achieve clearly stated objectives related to profitability, coverage, and the quality of the service to be provided.

Image courtesy http://www.cambridgeenergycentre.co.uk
Green energy includes natural energetic processes that can be harnessed with little pollution. Anaerobic digestion, geothermal power, wind power, small-scale hydropower, solar energy, biomass power, tidal power, and wave power fall under such a category. Some definitions may also include power derived from the incineration of waste.Some people, including George Monbiot and James Lovelock have specifically classified nuclear power as green energy. Others, including Greenpeace disagree, claiming that the problems associated with radioactive waste and the risk of nuclear accidents (such as the Chernobyl disaster) pose an unacceptable risk to the environment and to humanity.

No power source is entirely impact-free. All energy sources require energy and give rise to some degree of pollution from manufacture of the technology.In several countries with common carrier arrangements, electricity retailing arrangements make it possible for consumers to purchase green electricity (renewable electricity) from either their utility or a green power provider.

When energy is purchased from the electricity network, the power reaching the consumer will not necessarily be generated from green energy sources. The local utility company, electric company, or state power pool buys their electricity from electricity producers who may be generating from fossil fuel, nuclear or renewable energy sources. In many countries green energy currently provides a very small amount of electricity, generally contributing less than 2 to 5% to the overall pool. In some U.S. states, local governments have formed regional power purchasing pools using Community Choice Aggregation and Solar Bonds to achieve a 51% renewable mix or higher, such as in the City of San Francisco.

A Solar Trough System
By participating in a green energy program a consumer may be having an effect on the energy sources used and ultimately might be helping to promote and expand the use of green energy. They are also making a statement to policy makers that they are willing to pay a price premium to support renewable energy. Green energy consumers either obligate the utility companies to increase the amount of green energy that they purchase from the pool (so decreasing the amount of non-green energy they purchase), or directly fund the green energy through a green power provider. If insufficient green energy sources are available, the utility must develop new ones or contract with a third party energy supplier to provide green energy, causing more to be built. However, there is no way the consumer can check whether or not the electricity bought is "green" or otherwise.

In some countries such as the Netherlands, electricity companies guarantee to buy an equal amount of 'green power' as is being used by their green power customers. The Dutch government exempts green power from pollution taxes, which means green power is hardly any more expensive than other power.

In the United States, one of the main problems with purchasing green energy through the electrical grid is the current centralized infrastructure that supplies the consumer’s electricity. This infrastructure has led to increasingly frequent brown outs and black outs, high CO2 emissions, higher energy costs, and power quality issues. An additional $450 billion will be invested to expand this fledgling system over the next 20 years to meet increasing demand. In addition, this centralized system is now being further overtaxed with the incorporation of renewable energies such as wind, solar, and geothermal energies. Renewable resources, due to the amount of space they require, are often located in remote areas where there is a lower energy demand. The current infrastructure would make transporting this energy to high demand areas, such as urban centers, highly inefficient and in some cases impossible. In addition, despite the amount of renewable energy produced or the economic viability of such technologies only about 20 percent will be able to be incorporated into the grid. To have a more sustainable energy profile, the United States must move towards implementing changes to the electrical grid that will accommodate a mixed-fuel economy.

Turbine at a Micro Hydro Power Plant
Types of Green Energy Systems
However, several initiatives are being proposed to mitigate these distribution problems. First and foremost, the most effective way to reduce USA’s CO2 emissions and slow global warming is through conservation efforts. Opponents of the current US electrical grid have also advocated for decentralizing the grid. This system would increase efficiency by reducing the amount of energy lost in transmission. It would also be economically viable as it would reduce the amount of power lines that will need to be constructed in the future to keep up with demand. Merging heat and power in this system would create added benefits and help to increase its efficiency by up to 80-90%. This is a significant increase from the current fossil fuel plants which only have an efficiency of 34%.

A more recent concept for improving our electrical grid is to beam microwaves from Earth-orbiting satellites or the moon to directly when and where there is demand. The power would be generated from solar energy captured on the lunar surface In this system, the receivers would be “broad, translucent tent-like structures that would receive microwaves and convert them to electricity”. NASA said in 2000 that the technology was worth pursuing but it is still too soon to say if the technology will be cost-effective.

The World Wide Fund for Nature and several green electricity labelling organizations have created the Eugene Green Energy Standard under which the national green electricity certification schemes can be accredited to ensure that the purchase of green energy leads to the provision of additional new green energy resources.

Local green energy systems
 
Harnessing Wind Energy
Those not satisfied with the third-party grid approach to green energy via the power grid can install their own locally based renewable energy system. Renewable energy electrical systems from solar to wind to even local hydro-power in some cases, are some of the many types of renewable energy systems available locally. Additionally, for those interested in heating and cooling their dwelling via renewable energy, geothermal heat pump systems that tap the constant temperature of the earth, which is around 7 to 15 degrees Celsius a few feet underground, are an option and save money over conventional natural gas and petroleum-fueled heat approaches.

The advantage of this approach in the United States is that many states offer incentives to offset the cost of installation of a renewable energy system. In California, Massachusetts and several other U.S. states, a new approach to community energy supply called Community Choice Aggregation has provided communities with the means to solicit a competitive electricity supplier and use municipal revenue bonds to finance development of local green energy resources. Individuals are usually assured that the electricity they are using is actually produced from a green energy source that they control. Once the system is paid for, the owner of a renewable energy system will be producing their own renewable electricity for essentially no cost and can sell the excess to the local utility at a profit.

Using green energy

 
Renewable energy, after its generation, needs to be stored in a medium for use with autonomous devices as well as vehicles. Also, to provide household electricity in remote areas (that is areas which are not connected to the mains electricity grid), energy storage is required for use with renewable energy. Energy generation and consumption systems used in the latter case are usually stand-alone power systems.

Some examples are:
  • Energy carriers as hydrogen, liquid nitrogen, compressed air, oxyhydrogen, batteries, to power vehicles. 
  • Flywheel energy storage, pumped-storage hydroelectricity is more usable in stationary applications (eg to power homes and offices. In household power systems, conversion of energy can also be done to reduce smell. For example organic matter such as cow dung and spoilable organic matter can be converted to biochar. To eliminate emissions, carbon capture and storage is then used.
Tides-A form of Renewable Energy
Usually however, renewable energy is derived from the mains electricity grid. This means that energy storage is mostly not used, as the mains electricity grid is organised to produce the exact amount of energy being consumed at that particular moment. Energy production on the mains electricity grid is always set up as a combination of (large-scale) renewable energy plants, as well as other power plants as fossil-fuel power plants and nuclear power. This combination however, which is essential for this type of energy supply (as eg wind turbines, solar power plants etc.) can only produce when the wind blows and the sun shines. This is also one of the main drawbacks of the system as fossil fuel powerplants are polluting and are a main cause of global warming (nuclear power being an exception). Although fossil fuel power plants too can made emissionless (through carbon capture and storage), as well as renewable (if the plants are converted to e.g. biomass) the best solution is still to phase out the latter power plants over time. Nuclear power plants too can be more or less eliminated from their problem of nuclear waste through the use of nuclear reprocessing and newer plants as fast breeder and nuclear fusion plants.

Renewable energy power plants do provide a steady flow of energy. For example hydropower plants, ocean thermal plants, osmotic power plants all provide power at a regulated pace, and are thus available power sources at any given moment (even at night, windstill moments etc.). At present however, the number of steady-flow renewable energy plants alone is still too small to meet energy demands at the times of the day when the irregular producing renewable energy plants cannot produce power.

Besides the greening of fossil fuel and nuclear power plants, another option is the distribution and immediate use of power from solely renewable sources. In this set-up energy storage is again not necessary. For example, TREC has proposed to distribute solar power from the Sahara to Europe. Europe can distribute wind and ocean power to the Sahara and other countries. In this way, power is produced at any given time as at any point of the planet as the sun or the wind is up or ocean waves and currents are stirring. This option however is probably not possible in the short-term, as fossil fuel and nuclear power are still the main sources of energy on the mains electricity net and replacing them will not be possible overnight.

Several large-scale energy storage suggestions for the grid have been done. This improves efficiency and decreases energy losses but a conversion to a energy storing mains electricity grid is a very costly solution. Some costs could potentially be reduced by making use of energy storage equipment the consumer buys and not the state. An example is car batteries in personal vehicles that would double as an energy buffer for the electricity grid. However besides the cost, setting-up such a system would still be a very complicated and difficult procedure. Also, energy storage apparatus' as car batteries are also built with materials that pose a threat to the environment (eg sulphuric acid). The combined production of batteries for such a large part of the population would thus still not quite environmental. Besides car batteries however, other large-scale energy storage suggestions for the grid have been done which make use of less polluting energy carriers (eg compressed air tanks and flywheel energy storage).

Green Energy in United States

The United States Department of Energy (DOE), the Environmental Protection Agency (EPA), and the Center for Resource Solutions (CRS) recognizes the voluntary purchase of electricity from renewable energy sources (also called renewable electricity or green electricity) as green power.

The most popular way to purchase renewable energy as revealed by NREL data is through purchasing Renewable Energy Certificates (RECs). According to a Natural Marketing Institute (NMI) survey 55 percent of American consumers want companies to increase their use of renewable energy.

DOE selected six companies for its 2007 Green Power Supplier Awards, including Constellation NewEnergy; 3Degrees; Sterling Planet; SunEdison; Pacific Power and Rocky Mountain Power; and Silicon Valley Power. The combined green power provided by those six winners equals more than 5 billion kilowatt-hours per year, which is enough to power nearly 465,000 average U.S. households.

The U.S. Environmental Protection Agency‎ (USEPA) Green Power Partnership is a voluntary program that supports the organizational procurement of renewable electricity by offering expert advice, technical support, tools and resources. This can help organizations lower the transaction costs of buying renewable power, reduce carbon footprint, and communicate its leadership to key stakeholders.

Throughout the country, more than half of all U.S. electricity customers now have an option to purchase some type of green power product from a retail electricity provider. Roughly one-quarter of the nation's utilities offer green power programs to customers, and voluntary retail sales of renewable energy in the United States totaled more than 12 billion kilowatt-hours in 2006, a 40% increase over the previous year.



About the Author


Sardar Kashif ur Rehman He is B.Sc in Civil Engineering from "National University of Sciences and Technology Pakistan"

Renewable energy technologies are essential contributors to sustainable energy as they generally contribute to world energy security, reducing dependence on fossil fuel resources, and providing opportunities for mitigating greenhouse gases. The International Energy Agency states that:


Conceptually, one can define three generations of renewables technologies, reaching back more than 100 years.
First-generation technologies emerged from the industrial revolution at the end of the 19th century and include hydropower, biomass combustion, and geothermal power and heat. Some of these technologies are still in widespread use.


Second-generation technologies include solar heating and cooling, wind power, modern forms of bioenergy, and solar photovoltaics. These are now entering markets as a result of research, development and demonstration (RD&D) investments since the 1980s. The initial investment was prompted by energy security concerns linked to the oil crises (1973 and 1979) of the 1970s but the continuing appeal of these renewables is due, at least in part, to environmental benefits. Many of the technologies reflect significant advancements in materials.


Third-generation technologies are still under development and include advanced biomass gasification, biorefinery technologies, concentrating solar thermal power, hot dry rock geothermal energy, and ocean energy. Advances in nanotechnology may also play a major role.
International Energy Agency, RENEWABLES IN GLOBAL ENERGY SUPPLY, An IEA Fact Sheet


First- and second-generation technologies have entered the markets, and third-generation technologies heavily depend on long term research and development commitments, where the public sector has a role to play. A 2008 comprehensive cost-benefit analysis review of energy solutions in the context of global warming and other issues ranked wind power combined with battery electric vehicles (BEV) as the most efficient, followed by concentrated solar power, geothermal power, tidal power, photovoltaic, wave power, coal capture and storage, nuclear energy, and finally bio fuels. 


Nishidaira Dam
First-generation Technologies
One of many power plants at The Geysers, a geothermal power field in northern California, with a total output of over 750 MW.
First-generation technologies are most competitive in locations with abundant resources. Their future use depends on the exploration of the available resource potential, particularly in developing countries, and on overcoming challenges related to the environment and social acceptance.
International Energy Agency, RENEWABLES IN GLOBAL ENERGY SUPPLY, An IEA Fact Sheet

Geothermal Cooling Tower

Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived—many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean and have few emissions. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of significant amounts of carbon dioxide during construction and flooding of the reservoir.
Hydroelectric dams are one of the most widely deployed sources of sustainable energy.However, it has been found that high emissions are associated only with shallow reservoirs in warm (tropical) locales. Generally speaking, hydroelectric plants produce much lower life-cycle emissions than other types of generation. Hydroelectric power, which underwent extensive development during growth of electrification in the 19th and 20th centuries, is experiencing resurgence of development in the 21st century. The areas of greatest hydroelectric growth are the booming economies of Asia. China is the development leader; however, other Asian nations are installing hydropower at a rapid pace. This growth is driven by much increased energy costs—especially for imported energy—and widespread desires for more domestically produced, clean, renewable, and economical generation.

Cross section of a Hydroelectric Dam


Geothermal power plants can operate 24 hours per day, providing base-load capacity, and the world potential capacity for geothermal power generation is estimated at 85 GW over the next 30 years. However, geothermal power is accessible only in limited areas of the world, including the United States, Central America, Indonesia, East Africa and the Philippines. The costs of geothermal energy have dropped substantially from the systems built in the 1970s. Geothermal heat generation can be competitive in many countries producing geothermal power, or in other regions where the resource is of a lower temperature. Enhanced geothermal system (EGS) technology does not require natural convective hydrothermal resources, so it can be used in areas that were previously unsuitable for geothermal power, if the resource is very large. EGS is currently under research at the U.S. Department of Energy.
Biomass briquettes are increasingly being used in the developing world as an alternative to charcoal. The technique involves the conversion of almost any plant matter into compressed briquettes that typically have about 70% the calorific value of charcoal. There are relatively few examples of large scale briquette production. One exception is in North Kivu, in eastern Democratic Republic of Congo, where forest clearance for charcoal production is considered to be the biggest threat to Mountain Gorilla habitat. The staff of Virunga National Park have successfully trained and equipped over 3500 people to produce biomass briquettes, thereby replacing charcoal produced illegally inside the national park, and creating significant employment for people living in extreme poverty in conflict affected areas.


11 MW Solar Power Plant (Serpa,Portugal)
Second-generation Technologies

Markets for second-generation technologies are strong and growing, but only in a few countries. The challenge is to broaden the market base for continued growth worldwide. Strategic deployment in one country not only reduces technology costs for users there, but also for those in other countries, contributing to overall cost reductions and performance improvement.
International Energy Agency, RENEWABLES IN GLOBAL ENERGY SUPPLY, An IEA Fact Sheet

Solar heating systems are a well known second-generation technology and generally consist of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. The systems may be used to heat domestic hot water, swimming pool water, or for space heating. The heat can also be used for industrial applications or as an energy input for other uses such as cooling equipment. In many climates, a solar heating system can provide a very high percentage (50 to 75%) of domestic hot water energy. Energy received from the sun by the earth is that of electromagnetic radiation. Light ranges of visible, infrared, ultraviolet, x-rays, and radio waves received by the earth through solar energy. The highest power of radiation comes from visible light. Solar power is complicated due to changes in seasons and from day to night. Cloud cover can also add to complications of solar energy, and not all radiation from the sun reaches earth because it is absorbed and dispersed due to clouds and gases within the earth's atmospheres.
Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18 percent of the country's automotive fuel. As a result of this, together with the exploitation of domestic deep water oil sources, Brazil, which years ago had to import a large share of the petroleum needed for domestic consumption, recently reached complete self-sufficiency in oil. Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell “flexible-fuel” cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2006, there were approximately six million E85-compatible vehicles on U.S. roads.

Third-generation Technologies

Third-generation technologies are not yet widely demonstrated or commercialised. They are on the horizon and may have potential comparable to other renewable energy technologies, but still depend on attracting sufficient attention and RD&D funding. These newest technologies include advanced biomass gasification, biorefinery technologies, solar thermal power stations, hot dry rock geothermal energy, and ocean energy.
International Energy AgencyRENEWABLES IN GLOBAL ENERGY SUPPLY, An IEA Fact Sheet


Tidal Stream Generator — SeaGen
According to the International Energy Agency, new bioenergy (biofuel) technologies being developed today, notably cellulosic ethanol biorefineries, could allow biofuels to play a much bigger role in the future than previously thought.Cellulosic ethanol can be made from plant matter composed primarily of inedible cellulose fibers that form the stems and branches of most plants. Crop residues (such as corn stalks, wheat straw and rice straw), wood waste, and municipal solid waste are potential sources of cellulosic biomass. Dedicated energy crops, such as switchgrass, are also promising cellulose sources that can be sustainably produced in many regions of the United States.

In 2007, the world's first turbine to create commercial amounts of energy using tidal power was installed in the narrows of Strangford Lough in Ireland. The 1.2 MW underwater tidal electricity generator takes advantage of the fast tidal flow in the lough which can be up to 4m/s. Although the generator is powerful enough to power up to a thousand homes, the turbine has a minimal environmental impact, as it is almost entirely submerged, and the rotors turn slowly enough that they pose no danger to wildlife
Solar power panels that use nanotechnology, which can create circuits out of individual silicon molecules, may cost half as much as traditional photovoltaic cells, according to executives and investors involved in developing the products. Nanosolar has secured more than $100 million from investors to build a factory for nanotechnology thin-film solar panels. The company's plant has a planned production capacity of 430 megawatts peak power of solar cells per year. Commercial production started and first panels have been shipped to customers in late 2007.
Most current solar power plants are made from an array of similar units where each unit is continuously adjusted, e.g., with some step motors, so that the light converter stays in focus of the sun light. The cost of focusing light on converters such as high-power solar panels, Stirling engine, etc. can be dramatically decreased with a simple and efficient rope mechanics.In this technique many units are connected with a network of ropes so that pulling two or three ropes is sufficient to keep all light converters simultaneously in focus as the direction of the sun changes.




About the Author

Sardar Kashif ur Rehman He is B.Sc in Civil Engineering from "National University of Sciences and Technology Pakistan"

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