Use of Renewable Energy: Challenges and Chances
Daily Mirror, Colombo
(The writer is Past President The Institution of Engineers, Sri Lanka and Consulting Engineer. The article to be continued is an extract of a presentation made at the Institution of Engineers Sri Lanka and at the British Scholars Association at the British Council recently).
When nuclear fission power was first becoming a commercial reality, the fossil fuel dominated the electricity generation industry and the budding nuclear power industries basked in the glow of numerous promises and said electricity would be almost free or at the very least, like water then was not worth metering. Water has since become an expensive commodity today, referred to as "White Gold" and is now widely metered. Today, the basic problem of nuclear power of ensuring reliable energy at reasonable cost, both in money and environmental terms, get progressively more difficult. Electricity is not free. It is most expensive and tapped resources are as scarce as they always were.
Climate change and global warning
Growing evidence has convinced most of the scientific community that some degree of climate change is taking place. There is no conclusive proof that indicates whether the cause of the climate change is a small glitch in the Sun's output of energy, or whether it is due to the activities of human kind or both. But the media and everyone slip easily into the use of phrases like "greenhouse gases" and "global warming". Greenhouse effect of carbon dioxide and other gases in the atmosphere has doomed the planet Venus to have the hottest planetary surface in the Solar System, which has resulted in a hellish atmosphere both physically and chemically. There are an increasing number of signs that the nature of the Earth's surface is beginning to change. At no time in modern history has energy played a more crucial role in the development and well being of nations than at present. The source and nature of energy, the security of supply and the equity of distribution, the environmental impacts of its supply and utilisation, are all matters which have to be addressed by suppliers, consumers, governments both rich and poor, industry academia and financial institutions. The discussions held in Kyoto and Johannesburg have increased the awareness of renewable energy. Much effort is still required to make an appreciable impact on the adoption of renewable energy as a major source of energy supply worldwide. Contributions made at various forums look optimistically at renewable energy technologies, both those well established and those that are still a long way from making a commercial impact. Wind power, passive and electronic solar energy and certain new methods in the use of biomass have moved into the normal commercial world. Technologies such as waves, ocean, thermal and tidal energy and the hydrogen economy have not, as yet; but the prospects are still good and the potential benefits are enormous.
Update on renewable energy
When considering global peace and posterity and the contribution renewable energy can make, the question that we are posed with is whether it is possible for renewable energy to meet all our energy demands globally? Given that four fifths of the world economies come under the designation of "Developing Country", and that they are found in the geographical areas which have an excess of 3000 sunshine hours per year, then by the year 2050 the answer could be Yes.
Presently Solar thermal applications such as water heating, processed heat, crop drying and thermal generation are all well established, and to a lesser extent ceramic making, metal melting and water desalination. Large hydro schemes are found in South America, Asia and Africa. Geothermal applications are well established not only in Europe but also in North and South America and to a degree in Africa.
Biomass usage for heat and electricity generation, energy crops and residues, liquid gaseous and solid fuels constitute 5% of total prime energy while the ratio increases to 15% in the developing world. It is worth mentioning that if we compare CO2 emissions from electrical power plants, we find that using coal or oil to generate produces 1110 gm of CO2/kwh; using Gas reduces the figure to 600 g/kwh but using biomass reduces dramatically to 16g/kwh (Ref. World Renewable Energy Congress VII Cologne 2002).
On the photovoltaic front which is perhaps the most publicised, use of renewable energy and thanks to space exploration, we find that cell and panel efficiency of both Monocrystalline and polycrystalline silicon has increased substantially. Monocrystalline average efficiency is 17.5% and Polycrystalline average efficiency is 15.5% while in the thin film technologies the stability and reliability of amorphous silicon has achieved an average efficiency of 11%.
It is possible to buy a PV system for US $5/Wp (Peak Watt). The UK government allocated US $15m to be spent on PV applications within buildings, while the Netherlands, Belgium, Denmark, Germany, USA, Spain and Japan have all created incentive schemes to provide PV usage.
The real success story in renewable energy lies in the Wind Energy industry. The cost of electricity produced from wind power has in some European Countries fallen as low as 4US cents/kWh which is cheaper than from gas. Europe remains the main market for wind power, followed by USA and India. Globally, the growth of wind power during 2001 was in excess of 30%. If this growth rate were maintained, Europe would have 22% of its electricity supplied from renewable sources by 2010, and globally by 2020 wind energy will produce 12% of electricity equivalent to 1200 GW. In order to achieve this, US $5.2bn must be invested immediately and rise to a peak investment of US $6.7bn by 2020. The present installed cost of wind energy, has been reduced to a value of US $675/Kw. Denmark represents one of the most successful suppliers of wind energy utilisation.
UK a representative of European Community (EC) Countries with its energy sources being shared by 38.9% from natural gas, 29.1% from Coal, 26.5% from nuclear power, 1.5% from oil, renewable and waste 2.8%, miscellaneous 1.2%. However EC has deemed that the percentage of electricity production from the renewables must increase to the proportions specified and achieve the targets by 2010.
Wind energy applications and economics
During the twelve years from 1990 to 2002, the World Wind Energy capacity has doubled every three years. Wind Energy capacity in 1990 which was 2000 MW has reached 25,000 MW in 2002. The growth rate accelerated in 2001 by 38%. The representative prices of windfarms and wind turbines and electricity generation costs depend on factors such as location, the size of the machines and size of the windfarm. The growth curve suggests that for every doubling of capacity that the prices fall by 15%. The steady decrease in costs is due to the move towards larger machines. In 1992 the cheapest machine was rated at 300 Kw. In 1996 it was about 500 Kw and now around 900 Kw. At present the prices of the largest turbines are dearer than those around the 1 MW mark. Large turbines means taller turbines which mean they intercept stronger winds, and this further enhances the attractions of large machines. The minimum price of wind turbines is about Î300/sqm. of rotor area. Most wind turbines have ratings around 450 W/sqm of rotor area with a benchmark price of around Î670/kW.
Operational Costs fall with the increase in turbine size. The data obtained from German wind installations show that the prices of insurance and guarantees both halve approximately as the ratings increase from 200 to 600 Kw. Total costs fall from around Î25/kW/year at 250 Kw size to around Î13/Kw/year at 1500 kW . On Shore "balance of plant" costs typically add 50% to turbine costs bringing the total aroundUS $900-1000/Kw.
At Off Shore however additional costs can almost double the turbine costs bringing the total to US $1100/Kw upwards.
There is a consensus that the installed costs for offshore wind is now in the region of US$1400 to US$1600/Kw. The advantages of off shore in many locations is that wind speeds are higher, leading to greater energy productivity. Estimates of installed costs range from US$50/Kw which roughly is the lowest cost for on shore, to US$1500/Kw in a typical offshore cost. For an on shore farm at US $1000/Kw, declining from around 9.5US c/kwh at 6.5 m/s to about US4.5 c/kwh at 9 m/sec.
As the capital costs dominate the calculations, off shore prices at same wind speeds, and US $1500/Kw are about 50% higher, and prices on shore, at US $750/Kw are about 25% lower. At the high wind speed end these latter prices come within the range of generation costs for a thermal plant.
The Wind industry has delivered impressive reductions in cost and productivity over the past twenty years. Energy generation prices are now almost on par with those of the fossil fuels. If wind energy capacity continues to double every three years or so, accompanied each time by a 15% reduction in wind turbine production costs, there will be a 30% reduction in prices by 2006.
Forecasting electricity prices from the thermal sources of generation is more difficult, but, at worst generation costs from gas will stay level at about 3 US c/kwh with gas prices offsetting gains from lower plant costs and higher efficiency. At best therefore, wind and gas prices might "Cross Over" around 2005 and at worst around 2009. Also new technological developments especially in power generation will have the potential to improve the efficiency of energy recovery.
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