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Executive summary: Power from the Sun Solar thermal power is a relatively new technology which has already shown enormous promise. With few environmental impacts and a massive resource, it offers an opportunity to the sunniest countries of the world comparable to the breakthrough offshore wind farms are currently offering European nations with the windiest shorelines. Solar thermal power uses direct sunlight, so it must be sited in regions with high direct solar radiation. Among the most promising areas of the world are the South-Western United States, Central and South America, Africa, the Middle East, the Mediterranean countries of Europe, Iran, Pakistan and the desert regions of India, the former Soviet Union, China and Australia.In many regions of the world, one square kilometre of land is enough to generate as much as 100-200 Gigawatt hours (GWh) of electricity per year using solar thermal technology. This is equivalent to the annual production of a 50 MW conventional coal or gas-fired power plant. Worldwide, the exploitation of less than 1% of the total solar thermal potential would be enough to stabilise the world climate through massive CO 2 reductions.Tur ni ng Solar Heat into ElectricityProducing electricity from the energy in the sun’s rays is a relatively straightforward process. Direct solar radiation can be concentrated and collected by a range of Concentrating Solar Power (CSP) technologies to provide medium to high temperature heat. This heat is then used to operate a conventional power cycle, for example through a steam or gas turbine or a Stirling engine. Solar heat collected during the day can also be stored in liquid, solid or phase changing media like molten salts, ceramics, concrete, or in the future, phase changing salt mixtures. At night, it can be extracted from the storage medium to run the steam turbine. Solar thermal power plants can be designed for solar-only generation, ideally to satisfy demand during daylight hours, but with future storage systems their operation can be extended to almost base load requirements. Electricity from solar thermal power is also becoming cheaper to produce. Plants operating in California have already achieved impressive cost reductions, with generation costs ranging today between 10 and 13 US cents/kWh. However, costs are expected to fall closer to 5 US cents in the future. Advanced technologies, mass production, economies of scale and improved operation will together enable a reduction in the cost of solar electricity to a level competitive with fossil power plants within the next 10 to 15 years.Technology, Costs and BenefitsFour main elements are required to produce electricity from solar thermal power: a concentrator, a receiver, some form of a heat transport, storage and power conversion equipment much the same as for a fossil fuel-based plant. The three most promising solar thermal technologies are the parabolic trough, the central receiver or solar tower, and the parabolic dish.Parabolic trough systems use trough-shaped mirror reflectors to concentrate sunlight on to receiver tubes through which a thermal transfer fluid is heated to roughly 400°C and then used to produce superheated steam. They represent the most mature solar thermal power technology, with 354 MWe of plants connected to the Southern California grid since the 1980s and more than two square kilometres of parabolic trough collectors. These plants supply an annual 800 million kWh – enough for more than 200,000 households – at a generation cost of about 10-13 US cents/kWh.Further advances are now being made in the technology, with utility scale projects planned in Greece, Spain, Egypt, Mexico, India, Morocco, Iran, Israel, Italy, the United States and Algeria. Electricity from trough plants combined with gas-fired combined cycle plants – ISCC (Integrated Solar Combined Cycle) systems – is expected to cost 6 € cents/kWh today and 5 € cents in medium terms. Central receiver (solar tower) systems use a circular array of large individually-tracking mirrors (heliostats) to concentrate sunlight on to a central receiver mounted on top of a tower, with heat transferred for power generation through a choice of transfer media. After an intermediate scaling up to 30 MW capacity, solar tower developers now feel confident that grid-connected tower power plants can be built up to a capacity of 200 MWe solar-only units. Use of thermal storages will increase their flexibility.Although central receiver plants are considered to be further from commercialisation than parabolic trough systems, solar towers have good longer term prospects for high conversion efficiencies. Projects are in various stages of development (from assessment to implementation) in Spain, South Africa and the United States. In the future, central receiver plant projects will benefit from similar cost reductions to those expected from parabolic trough plants. The anticipated evolution of total electricity costs is that they will drop to 5 cents/kWh in the mid to long term. Parabolic dish systems are comparatively small units which use a dish-shaped reflector to concentrate sunlight, and heated gas or air to generate power in a small engine at the focal point of the reflector. Their potential lies primarily in decentralised power supply and remote, stand-alone power systems. Projects are currently planned in the United States, Australia and Europe. In terms of electricity costs, an attainable mid-term goal is a figure of less than 15 cents/kWh.Current trends show that two broad pathways have opened up for large scale delivery of electricity using solar thermal power. One is the ISCC-type hybrid operation of solar collection and heat transfer combined with a conventional state-of-art combined cycle gas-fired power plant. The other is solar-only operation, with a conventional steam turbine, increasing use of a storage medium such as molten salt. This enables solar energy collected during the day to be stored and then dispatched when demand requires.A major benefit of solar thermal power is that it has little environmental impact, with none of the polluting emissions or safety concerns associated with conventional generation technologies. There is no pollution in the form of exhaust gases during operation. Decommissioning a system is unproblematic.Each square metre of surface in a solar field is enough to avoid the annual production of 200 kilograms (kg) of carbon dioxide. Solar power can therefore make a substantial contribution towards international commitments to reduce emissions of greenhouse gases which contribute to climate change.The Global Solar Thermal MarketNew opportunities are opening up for solar thermal power as a result of the global search for clean energy solutions. Both national and international initiatives are supporting the technology, encouraging commercialisation of production. A number of countries have introduced legislation which forces power suppliers to source a rising percentage of their supply from renewable fuels. Bulk power high voltage transmission lines from high insulation sites, such as in northern Africa, could encourage European utilities to finance large solar plants whose power would be used in Europe.These and other factors have led to significant interest in constructing plants in the sunbelt regions. In addition, interest rates and capital costs have drastically fallen worldwide, increasing the viability of capital intensive renewable energy projects. Examples of specific large solar thermal projects currently planned around the world, evidence of the “race to be first”, include:· Algeria: 140 MW ISCC plant with 35 MWsolar capacity.· Australia: 35 MW CLFR-based array to pre-heat steam at a coal-fired 2,000 MW plant.· Egypt: 127 MW ISCC plant with 29 MW solar capacity.· Greece: 50 MW solar capacity using steam cycle.· India: 140 MW ISCC plant with 35 MWsolar capacity.· Israel: 100 MW solar hybrid operation.· Italy: 40 MW solar capacity using steam cycle.· Mexico: 300 MW ISCC plant with 29 MWsolar capacity.· Morocco: 230 MW ISCC plant with 35 MW solar capacity.· Spain: 2 x 50 MW solar capacity using steam cycle and storage.· USA: 50 MW Solar Electric GeneratingSystems.· USA: 1 MW parabolic trough using ORC engineThe Future for Solar Thermal PowerA scenario prepared by Greenpeace International and the European Solar Thermal Power Industry Association projects what could be achieved by the year 2020 given the right market conditions. It is based on expected advances in solar thermal technology coupled with the growing number of countries which are supporting projects in order to achieve both climate change and power supply objectives.SOLAR THERMAL POWER PLANTS 4.Over the period of the scenario, solar thermal technologywill have emerged from a relatively marginal position in the hierarchy of renewable energy sources to achieve a substantial status alongside the current market leaders such as hydro and wind power. From a current level of just 354 MW, by 2015 the total installed capacity of solar thermal power plants will have reached 5,000 MW. By 2020 additional capacity would be rising at a level of almost 4,500 MW each year.· By 2020, the total installed capacity of solar thermal power around the world will have reached 201,540 MW.· Solar thermal power will have achieved an annual output of more than 54,600,000 MWh (54.6 TWh) This is equivalent to the consumption of over one third of Australia’s electricity demand.· Capital investment in solar thermal plant will rise from US$ 375 million in 2005 to almost US$ 7.6 billion in 2020. The total investment over the scenario period would amount to US$ 41.8 bn.· Expansion in the solar thermal power industry will result in the creation of 200,000 jobs worldwide, even not counting those involved in production of the hardware.· The five most promising countries in terms of governmental targets or potentials according to the scenario, each with more than 1,000 MW of solar thermal projects expected by 2020, are Spain, the United States, Mexico, Australia and South Africa.· Over the period up to 2020 a total of 154 million tonnes of carbon dioxide would be saved from being emitted into the atmosphere, making an important contribution to international climate protection targets.A further projection is also made for the potential expansion of the solar thermal power market over another two decades up to 2040. This shows that by 2030 the world-wide capacity will have reached 106,000 MW, and by 2040 a level of almost 630,000 MW. Increased availability of plants because of the greater use of efficient storage technology will also increase the amount of electricity generated from a given installed capacity. The result if that by 2040 more than 5% of the world’s electricity demand could be satisfied by solar thermal power.KEY RESULTS FROM GREENPEACE-ESTIA SCENARIO 2002 TO 2020Capacity of Solar Thermal Power in 2020 21,540 MW Electricity Production in 2020 54,600,000 MWh (54.6 TWh)Cumulative Investment US$ 41.8 billionEmployment Generated 200,000 jobsCarbon Emissions Avoided 2002 – 2020 154 million tonnes CO 2Annual Carbon Emissions Avoided in 2020 32.7 million tonnes CO 2Projection 2021 to 2040Capacity of Solar Thermal Power in 2040 630,000 MWElectricity Production in 2040 1573 TWhPercentage of Global Demand 5%
Num. pages: 52
ISBN: 90-73361-82-6