Global trends in the use of renewable energy

The use of renewable energy sources has been expanding rapidly in recent years and this trend is set to continue over the projection period. Investment in renewable energy sources for electricity, heating and in biofuels has increased considerably. However, if traditional biomass is excluded,1 renewable energy still accounts for a small share of the energy mix. In 2006 it met just 7% of global primary energy needs. The share was around 6% for heat demand (mostly from the direct combustion of biomass) and 1% for transport (biofuels derived from biomass). Renewables accounted for 18% of total electricity generation, the majority of it coming from hydropower plants (16% of total electricity generation). In the Reference Scenario, the share of renewables (including modern biomass) in the global primary energy mix increases from 7% in 2006 to around 10% in 2030.

In the electricity sector, the generating costs of coal- and gas-fired power plants remain high, because of both high fuel prices and high construction costs.2 Over the projection period, oil, gas and coal prices are assumed to remain high by historical standards (see Chapter 1). While the construction costs of some renewables have also increased recently, the costs of renewable energy systems are expected to fall in the coming decades, mainly as a result of advances in technology and declining capital costs as their use expands.

Demand for renewables for heating and cooling, and demand for biofuels are also expected to be boosted by high fossil-fuel prices. There is a good opportunity during the next decade or so for the renewables industry to prove it can become cost competitive without relying on subsidies and for the technologies to enter the mainstream. A carbon price on fossil fuels would make renewables even more competitive (see Part C).

Despite the improved environment for emerging renewables sources and technologies, many barriers to their deployment remain. These could hold back long-term growth of the sector. They include: the relatively high costs of some technologies in the absence of subsidies; relatively limited research and development until recently; growing concerns about the impact on food availability of the use of crops for energy; a lack of skilled labour and policymaking capacity; regulations that discourage variable and distributed powergenerating systems; inadequate investment in networks; and scepticism on the part of some major incumbent players in the energy sector about the viability of renewables.

Biomass (including traditional biomass) is expected to remain by far the single most important primary source of renewable energy for decades to come. In the Reference Scenario, total world demand for biomass rises from 1 186 Mtoe in 2006 to about 1 660 Mtoe by 2030, although its share of world primary energy demand falls slightly from 10.1% in 2006 to 9.8% in 2030. Biomass differs from other renewable energy resources in that it can be a substitute for all fossil-fuel based products, using a wide range of technologies to convert the range of resources into heat, electricity and liquid fuels (Figure 7.1). It can be used directly in traditional ways for heating and cooking, or indirectly using modern conversion technologies. An estimated 60% of current biomass use is in the form of traditional biomass such as scavenged fuelwood, dried animal dung and agricultural residues used on open fires and in crude, low-efficiency stoves to provide basic cooking and heating services.

1. The use of fuelwood, dung and agricultural residues in very inefficient stoves or on open fires for cooking r^ and heating.

2. See Chapter 6 for a discussion of recent increases in power plant construction costs. ยง

The quality of data on biomass use is often very poor, making future projections uncertain. Major uncertainties in projecting future demand for biomass for energy purposes include competition for land use (Box 7.1), the rate of improvement in crop yields, water availability for crop production, the effects of climate change and the development of advanced conversion technologies. Most of the biomass consumed in 2030 still comes from agricultural and forest residues, but a growing share comes from purpose-grown energy crops - mainly for making biofuels. A growing share is also projected to fuel combined heat and power (CHP) plants.

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