Introduction

For most developing countries, interest in renewable energy technologies was originally a response to the energy shortages and price increases of the early and late 1970s. But by mid-1990, international oil prices were back to levels as low, in real terms, as they were in the late 1960s. In this context, it is instructive to reflect on why there is still interest in renewable energy technologies, what the contribution of renewable energies to developing countries has so far been, and what is likely to be their future contribution.

The increasing demand for energy

In almost all developing countries the demand for energy is growing as populations increase and as economic development takes place; a process which is often conventionally associated with increasing per capita consumption of energy.

But in most of these countries, it is all too clear that there are limits on the ability of existing energy resources and delivery systems to meet this increasing energy demand, especially in the energy forms needed by low-income groups and at prices they can afford. The situation varies both between and within countries, but some broadly valid observations on why this happens can still be made. In doing so it is useful to distinguish between two categories of energy resource and delivery systems – the traditional and the modern/conventional.

Traditional energy systems

The traditional energy resource base in developing countries is biomass (over 80 of total energy use in some of the poorest countries) in the form of wood, wood and crop residues, and animal residues. This biomass provides mainly heat for domestic cooking, space heating, and commercial and industrial heat processes, especially for processing agricultural and forestry products. Direct solar energy provides further heat for drying crops and animal products.

Energy in the form of draught power is also provided by biomass, although indirectly, in the form of food and fodder for animals and humans. Biomass as a source of power is also often supplemented by traditional water and wind technologies.

Over the past few decades, many developing countries have suffered rapid reductions in the capacity of traditional energy systems to supply the energy needs of their growing populations at existing levels of per capita consumption, let alone those associated with economic growth. There are many reasons for this, often inter-related, and combinations of the following are usually important:

* Land clearances for agriculture, large-scale cash-cropping and monocultures, urban and industrial developments, hydro-electric, drainage and other infrastructural development, and the wind and water erosion and salination that so often follow them, can and often do reduce the biomass available as a direct energy resource.

* Rapid urbanization, population increases and overgrazing all increase demand on biomass resources. In many cases demand goes beyond the capacity of the land to replace the biomass removed, leading to reductions in biomass stocks and production.

* Armed conflict can have the same effect by forcing populations to move to areas unable to sustain them.

* Restricted access to or ownership of land forces poor people to exploit biomass resources on what land to which they do have access to, unsustainably.

* Some experts argue that climatic change also contributes to reductions in biomass cover in some parts of the world, especially in areas vulnerable to the expansion of existing deserts.

Conventional modern energy systems

For many years, the modern/conventional sector has gradually supplemented and replaced traditional energy resources. Liquid fossil fuels are used for static power (e.g. irrigation pumping, milling) and mobile power (e.g. for tractors and related machinery, and for transport); kerosene is used for lighting and for domestic cooking, and oil or gas for process heat. Finally, rural electrification, usually from fossil fuels or large scale hydro, has brought electricity for power, lighting, entertainment and refrigeration.

However, the ability of the conventional modern sector to meet all the energy demands of both increasing populations and increasing economic activity, especially in the rural areas, is also limited. In the case of domestic heat energy, although kerosene is usually available in urban areas, and often in rural areas, supplies are frequently interrupted. In rural areas, its costs are usually high relative to those of biomass fuels, so although it is used for lighting by most people, its use as a cooking fuel tends to be restricted to high-income groups. Cooking by liquid petroleum gas (LPG) or electricity is, in most rural areas, confined to very small minorities.

The purchasing power of industry allows it to overcome biomass fuel shortages more readily than households. Even so, in many countries rural and even urban industries who had switched to oil for heat have then been forced back onto wood because of rising fossil fuel costs.

In the case of power, diesel generators, engines and pumps are very common. But again, supplies of low-cost fuels are not necessarily secure, while operating costs can be very high. Many rural villages are electrified in the sense that the grid has reached them. But the proportion of households within the village which is actually connected is, in many areas, very low. This is largely because of connection costs; but it is also because low-income levels, and the lack of industrial customers mean that load factors on rural electrification schemes are very low, and tariffs are, unless subsidized, too high to be afforded by poor people.

Meanwhile, the costs of providing further rural electrification schemes increase, while the ability of many developing countries to afford the necessary foreign exchange is also limited. Large hydro-electric schemes run into increasing opposition on the grounds of population removal, deforestation and environmental considerations. Environmental and cost pressures also work against fossil and nuclear installations, and are likely to do so even more in the future.

In this context it is likely that scarce capital resources and foreign exchange will tend to be devoted to large-scale conventional schemes which serve urban areas and major industrial plant. Although conventional rural electrification in the form of grid extensions will continue, it is unlikely to meet more than a small fraction of the unmet power demand of many rural populations, especially those in isolated and/or mountainous areas.

The role of renewables

It is clear that there is a gap, both now and in the future, between the energy needs of economic development, especially in rural areas, and the ability of both the traditional and the conventional modern energy sectors to meet this need. In seeking means of bridging this gap, consumers, rural energy planners and decision-makers need to bear in mind what energy technologies will contribute to sustainable development. Here are five criteria for sustainable development, together with brief comments on the extent to which renewable energy technologies meet them:

* They should be appropriate in ownership terms to local needs and resources. (Most renewable energy systems, apart from large and mini-hydro, are small-scale, stand-alone systems, amenable to local ownership and control.)

* They should, as far as possible, generate income and employment in rural areas, and use minimal foreign exchange. (Some renewable technologies – e.g. micro-hydro, biogas – can be manufactured locally, at least in part, and thus reduce dependence on imported parts and fuels.)

* They should have minimal negative impact on the productive capacity of the land: this means at worst avoiding, and at best reducing soil erosion from wind, water or salination. (Biomass-based and hydro systems can be environmentally harmful or beneficial, depending on, for example, the design of the overall production system – other renewable energy technologies are usually environmentally neutral or beneficial.)

* They must take into account the fact that there is likely to be increasing pressure in future years for energy systems, even rural energy systems, in developing countries, to conform to stricter emission standards, such as that of CO2. (Provided biomass systems are self-sustaining, all renewables meet this criterion.)

* They should provide a secure supply of energy, which will not be interrupted by international crises. (Except insofar as imported spares are needed, all renewables meet this criterion.)

Clearly, renewable energy technologies have the potential to meet many of the criteria outlined above, and many commentators suggest that they should be promoted on a large scale in developing countries. The following section discusses some of the possibilities and problems in more detail.

What are the 'renewables'?

Renewable energy technologies are extremely varied in both type and scale, in the problems and opportunities that they present, and in the uses to which they can effectively be put. They can be categorized in different ways, which have different implications for their end uses and dissemination. One set of categories distinguishes between the new and unfamiliar, and the relatively familiar. At one extreme, solar photovoltaic (solar PV) is a completely new technology, which so far has had little impact in the industrialized countries, let alone in the developing world. Solar thermal and the production of liquid fuels from biomass (the latter is not covered in this book because it is a large-scale technology with limited relevance in the developing world at present) also fall in this category.

At the other extreme, many of the technologies are concerned with the combustion and consumption by humans and animals of biomass, which already provides the vast majority of the energy needed in many poor countries. These technologies – improved biomass kilns, stoves, ovens and furnaces; biogas and producer gas; steam and Stirling engines – together with micro-hydro and wind, consist of modernized versions of technologies from the nineteenth centry or even earlier, which provide cost and/or performance-related improvements over the traditional versions, and which, in many cases, make the technology much more widely available than was possible before.

In the first case, an emphasis on renewables implies the introduction of a completely new concept; in the latter, improvements in existing biomass production or conversion systems.

Another basic difference between the various renewable technologies is their product, the two categories being power and heat. The power technologies covered in this book are solar PV, micro-hydro, hydrams and wind, together with the four biomass power technologies – biogas, producer gas for power, and steam and Stirling engines. The heat technologies are solar thermal, solar distillation, solar drying, charcoal, producer gas for heat, stoves and industrial combustion.

The power categories can be divided further according to the scale of power produced in a typical installation, and to costs. Solar PV systems cost (although it is possible that in the future costs will fall) upwards of US$6000/kWe installed, and installed systems are rarely more than 1 to 2 kWpe. This contrasts with micro-hydro, and with producer gas as the main existing example of a biomass-fuelled power system. Their capital costs are in the region of US$1500 and US$350 to $1000/kWe installed, respectively. All these should be taken in the context of the capital costs of small diesel generators, which can be as low as US$150/kWe in countries such as Bangladesh and India.

Obviously, diesel and producer gas systems (and other biomass-fuelled power systems) have much higher operation and maintenance costs, and, above all, fuel costs. On a lifetime cost basis, these running costs must be added to their capital costs, countering at least some of their capital cost advantages with respect to technologies with higher per kW installed costs such as solar PV.

The impact of renewables

If we now look at the role of renewables in the developing countries so far, two basic points must be emphasised.

First, with the exception of ethanol in Brazil, Malawi and Zimbabwe, the renewable technologies have had no impact on liquid-fuelled transport systems, and are unlikely to do so in the near future. Second, the contribution of the improved and new renewable energy technologies described in this book (excluding large hydro systems) to static power or to improvements in fuel efficiency in heat systems is, so far, negligible. There are certainly a number of success stories – for example household stoves in Sri Lanka, micro-hydro in Nepal, biogas in Orissa and solar PV for household lighting in the Dominican Republic. These successes only serve however to highlight the many failures in the twenty years since support for the use of renewable energy technologies gained ground in the early 1970s.

There are many complex and inter-related reasons for this lack of impact, and it is important that they should be made clear if greater success in the dissemination of renewable energy technologies is to be achieved during the next decade. Four of the most important reasons are:

* Very few of the renewable energy technologies so far promoted in developing countries are in widespread use in industrialized countries. This means that production volumes are low, costs tend to be high, and support systems (information, training, spares, maintenance) are not available, even in urban areas. In rural areas, where most of these technologies tend to be located, support systems may be even more difficult to establish.

* In many cases, the technologies put into the field are unreliable prototypes produced by technical research organizations, with little understanding of the real needs of potential users and beneficiaries.

* Although maintenance and the supply of fuel can be difficult problems in certain areas at different times, the small diesel engine is a remarkably cost-effective, long-life, well-supported, convenient, familiar and flexible means of providing power. This makes it extremely hard for competing power technologies to be established in the market.

* Biomass power systems need to be integrated with the agriculture/ forestry sector. While this can provide very great economic and environmental benefits, it is difficult to establish the necessarily complex management and organizational systems.

* Despite reductions in biomass availability, biomass fuel costs are still relatively low in most countries, and improving fuel efficiency may not be a high priority amongst fuel users. This makes the introduction of new combustion technologies more difficult; other potential benefits have however to be considered in the dissemination of these technologies, such as speed of cooking and reduction in smoke levels (improved domestic stoves), changes in the product quality (improved brick kilns).

Renewable power systems

The renewable technology that has probably received the greatest attention and promotion in developing countries from external sources and development agencies, is solar PV. In developing countries, solar PV has been promoted to provide very small amounts of high-value power for lighting, health clinics, pumping, vaccine refrigeration, communications, etc. Most solar PV projects provide less than lkW of electricity, and in quantitative terms, the impact of solar PV has been minimal. Global PV sales are about 40MW/year, most of which is for items such as watches and calculators. The developing countries' share of larger systems for power is not known, but is certainly not more than a few MW per year.

In contrast to the commercial status of solar PV, research on and dissemination of small-scale biomass power technologies – mainly producer gas – has taken place in the developing countries, without commercial backup or stimulus. The results have been piecemeal; although several hundred small systems have been installed, especially in Asia, technical viability is not yet assured, while the problems of support systems, especially on the fuel supply side and its integration with agricultural and forestry production, have hardly been addressed. Steam plant is limited to very small numbers of traditional large systems, and although over 100 small Stirling engines have been installed in the field in India, evaluation has not been made public, and it is not known whether or not the programme will continue.

Plant output for all these technologies is usually very much larger than that of PV systems – in the range of 5 to 50kWe for producer gas, suitable either for one specific power use such as milling, or for a village grid system. These higher outputs and the capital cost differences noted above, have important implications for energy technology choice, which will be discussed below.