According data from IEA 13.3% of the worlds total energy supply came from Renewable Energy (RE) in 2003. However, almost 80% of the RE supply was from biomass and in developing countries it is mostly converted by traditional open combustion, which is very inefficient. Because of its inefficient use, biomass resources presently supply only about 20% of what they could if converted by more efficient, already available technologies. As it stands, biomass provides only 11% of the world total primary energy, which is much less than its real potential. The total technologically sustainable biomass energy potential for the world is 3-4 TWe (UNDP), which is more than the entire present global electrical generating capacity of about 3 TWe.
In 2003, shares of biomass and hydropower in the total primary energy mix of the world were about 11% and 2% respectively. All of the other renewables, including solar thermal, solar PV, wind, geothermal and ocean combined, provided only about 0.5% of the total primary energy. During the same year, biomass combined with hydroelectric resources provided more than 50% of all the primary energy in Africa, 29.2% in Latin America and 32.7% in Asia (IEA). However, biomass is used very inefficiently for cooking in these countries. Such use also resulted in significant health problems, especially for women.
The total share of all renewables for electricity production in 2002 was about 17%, 89% of it being from hydroelectric power.
Wind-energy technology has progressed significantly over the last two decades. The technology has been vastly improved and capital costs have come down to as low as 1 Euro per Watt. At this level op capital costs wind power is already economical at locations with fairly good wind resources. Therefore, the average annual growth in worldwide wind energy capacity from 2000 to 2003 was over 30% and it continued to grow at that rate until 2007. The total worldwide installed wind power capacity was 39 GW in 2003, reached a level of 59 GW in 2005 (WWEA). The total theoretical potential for onshore wind power for the world is around 55 TW with a practical potential of at least 2 TW (UNDP), which is about 2/3 of the entire present worldwide generating capacity. The offshore wind energy potential is even larger.
On Global Wind Power a presentation can be found which illustrates the analysis above.
On Wind Turbine Types a presentation can be found on all modern windturbine types
On Wind Turbine Technology a presentation can be found on modern windturbine technology.
The amount of sunlight striking the Earths atmosphere continuously is 1.75×10^5 TW. Considering a 60% transmittance through the atmospheric cloud cover, 1.05×10^5 TW reaches the Earths surface continuously. If the irradiance on only 1% of the Earths surface could be converted into electric energy with a 10% efficiency, it would provide a resource base of 105 TW, whereas the total global energy needs for 2050 are projected to be about 25-30 TW. The present state of solar energy technologies is such that solar-cell efficiencies have reached over 20% and solar thermal systems provide efficiencies of 40%-60%. With the present rate of technological development, these solar technologies will continue improving, thus bringing the costs down, especially with the economies of scale.
Solar PV panels have come down in cost from about Euro 30/W to about Euro 3/W in the last 3 decades. At Euro 3/W panel cost, the overall system cost is around euro 6/W, which is still too high to compete with other resources for grid electricity. However, there are many off-grid applications where solar PV is already cost-effective. With net metering and governmental incentives, such as feed-in laws and other policies, even grid-connected applications such as building integrated PV have become cost-effective. As a result, the worldwide growth in PV production has averaged over 30% per year from 2000-2003, with Germany showing the maximum growth of over 51%.
Solar thermal power using concentrating solar connectors was the first solar technology that demonstrated its grid power potential. A 354 MWe solar thermal power plant has been operating continuously in California since 1988. Progress in solar thermal power stalled after that time because of poor policy and lack of R&D. However, the last 5 years have seen a resurgence of interest in this area and a number of solar thermal power plants around the world are under construction. The cost of power from these plants has the potential to go down to 4 Euro cents/kWh with scale-up and creation of a mass market. An advantage of solar thermal power is that thermal energy can be stored efficiently and fuels such as natural gas or biogas may be used as backup to ensure continuous operation. If this technology is combined with power plants operating on fossil fuels, it has the potential to extend the time frame of the existing non-renewable fuels.
Low temperature solar thermal systems and applications have been well developed for quite some time. They are being actively installed wherever policies favor their deployment.
On Global Solar Radiation a presentation can be found which illustrates this analysis.
Although theoretically harvestable biomass energy potential in on the order of 90TW, the technical potential on a sustainable basis is on the order of 8-13TW or 270-450 exajoules/year (UNDP). This potential is 3-4 times the present electrical generation capacity of the world. It is estimated that by 2025, even municipal solid waste alone could generate up to 6 exajoules/year (UNDP).
The biggest advantage of biomass as an energy source is its relatively straightforward transformation into transportation fuels. Biofuels have the potential to replace as much a 75% of the non-renewable fuels for transportation today (Worldwatch Institute). This is especially important in view of the declining non-renewable energy supplies worldwide. Biofuels will not require additional infrastructure development. Therefore, development of biofuels is being viewed very favorably by governments around the world. Biofuels, along with other transportation options such as electric cars and hydrogen, will help diversify the fuel base for future transportation. Global ethanol production more than doubled between 2000 and 2005. Biodiesel production grew almost fourfold, although it started from a much smaller base. In 2005, the world ethanol production had reached about 36 billion liters / year, whereas biodiesel production topped 3.5 billion liters during the same year.
The present cost of ethanol production ranges from about 25 euro cents to about 1 euro per gasoline equivalent liter, as compared to the wholesale price of gasoline that is between 40-60 euro cents per liter. Biodiesel costs, on the other hand, range between 20 Euro cents to 65 eurocents per liter of diesel equivalent.
An important consideration for biofuels is that the fuel not be produced at the expense of food while there are people going hungry in the world. This would not be of concern if biofuels were produced from municipal solid waste. According to the Worldwatch report, a city of 1 million people produces about 1800 tones of municipal solid waste and 1300 tones of organic waste every day that, using the present-day technology, could produce enough fuel to meet the needs of 58.000 persons in the US and 360.000 in France at current rates of per capita fuel use (Worldwatch Institute).
By definition, the term reserves does not apply to renewable energy resources. Therefore, we need to look at the annual potential of each resource. As in the case of other new technologies, it is expected that cost competitiveness of the RE technologies will be achieved with R&D, scale-up, commercial experience and mass production. The experience curves show industry-wide cost reductions in the range of 10%-20% for each cumulative doubling of production for wind power, PV, ethanol and gas turbines (UNDP). Similar declines can be expected in solar thermal power (CSP) and other renewable technologies. Wind energy technologies have already achieved market maturity and PV technologies are well on their way. A GEF report estimates that CSP will achieve the cost target of about euro 0.05 / kWh by the time it has an installed capacity of about 40 GW (GEF). As a reference point, wind power achieved that capacity milestone in 2003.
Simulation system examples for (Renewable) Power Systems can eg. be found on
General scenario simulation software can eg. be found on: