Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems

Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems Volume 1 photovoltaic solar energy 1 35 – very large scale photovoltaic systems

1.35 Very Large-Scale Photovoltaic Systems T Ehara and K Komoto, Mizuho Information & Research Institute, Tokyo, Japan P van der Vleuten, Free Energy Consulting, Eindhoven, The Netherlands © 2012 Elsevier Ltd All rights reserved 1.35.1 1.35.1.1 1.35.1.2 1.35.1.3 1.35.2 1.35.2.1 1.35.2.2 1.35.2.2.1 1.35.2.2.2 1.35.2.3 1.35.2.4 1.35.2.4.1 1.35.2.4.2 1.35.3 1.35.3.1 1.35.3.2 1.35.3.3 1.35.4 1.35.4.1 1.35.4.2 1.35.5 References What is Very Large-Scale Photovoltaic System? Definition of Very Large-Scale Photovoltaic Multibenefit Approach Deployment Strategies Evaluation of the VLS-PV from Various Aspects Energy Potential Economics of VLS-PV Generation cost of VLS-PV Impact of capital costs Technologies for VLS-PV Environmental Aspects Lifecycle Analysis Ecological impacts Progress in VLS-PV VLS-PV as a Dream Dream to Reality Emerging New Initiatives in MENA Regions Future for the VLS-PV Sustainability Issues VLS-PV Visions and Roadmap Conclusion 733 733 733 734 734 734 736 736 737 737 737 737 738 739 739 739 739 741 741 743 743 744 1.35.1 What is Very Large-Scale Photovoltaic System? 1.35.1.1 Definition of Very Large-Scale Photovoltaic The concept of ‘A very large-scale photovoltaic (VLS-PV)’ system was first presented by the International Energy Agency Photovoltaic Power Systems Programme (IEA-PVPS) Task working group in 1999 [1] According to the group, VLS-PV is defined as “a PV system ranging from 10 MW up to several gigawatts (0.1–20 km2 total area) consisting of one plant or an aggregation of multiple units operating in harmony and distributed in the same district” [2] The features of the concept are not only the scale of the PV plant The basic idea is to install a VLS-PV system in a desert region where solar irradiation is abundant Since the output from PV from a unit of system is dependent on solar energy radiated on the PV surface, application in the most solar resource-rich regions would improve the economy of the project substantially In addition, it is worth noting that most of the desert areas are hard to utilize effectively for other purposes; hence, it will not compete with other land use objectives such as agriculture and grazing Figure shows a conceptual VLS-PV system 1.35.1.2 Multibenefit Approach A VLS-PV project is also expected to foster the community development of the region where the plant is constructed VLS-PV development would create a sustainable market for solar electricity as well as PV system components and installations It will generate new jobs in this field and hence create a very unique community Desalination of the water using the generated electricity from VLS-PV is also within the scope of the VLS-PV concept Desalinated water could be used for agricultural, industrial, and municipal purposes In arid areas, production of water that can be used for drinking or irrigation would be greatly appreciated Agriculture is often the largest economic sector in developing regions where the population continues to increase; therefore, VLS-PV could be an attractive option for those regions Salt accumulation and associated desertification in the arid and semiarid region is a serious problem With the VLS-PV, agricultural water can be obtained from ground sources through solar pumps, or from seawater through a desalination plant driven by the solar energy A reverse osmosis (RO) system may be the promising technology for desalination It would also be possible to recycle treated water from municipal sewage As is discussed above, VLS-PV concept pursues multibenefits from the various perspectives The expected benefits presented by the IEA-PVPS Task group are summarized in Table Comprehensive Renewable Energy, Volume doi:10.1016/B978-0-08-087872-0.00149-9 733 734 Applications Figure Conceptual image of a VLS-PV system in the desert area [2] Table Various benefits of VLS-PV [2] Economic benefits Social benefits Security of energy supply Environmental issues Peace/poverty alleviation International recognition 1.35.1.3 Introducing a solid strategy for the introduction of VLS-PV solar electricity generation will create a large and sustainable local market for solar panels and other system components and materials, including installation and maintenance In addition, Clean Development Mechanism (CDM) credits will be generated The generated electricity can be distributed in the local market as well as in the export market and the CDM credits can be sold in the international market The sustainable local market that will be created by the adoption of a solid long-term strategy for solar electricity generation allows for national and international investments in local production of solar panels, solar cells, silicon materials, and other basic materials such as glass, metals, and concrete This will create significant additional employment in desert regions For the introduction of state-of-the-art technology, international cooperation and technology transfer will be needed Because a lot of sunshine is and will always be available in desert regions, this is the most secure source of energy and sunshine is basically available to everybody Because the components and systems for converting sunshine into electricity will become cheaper with technology evolution, very large as well as very small systems will become cost-effective in the near future For reducing the effects of climate change, international agreements for reducing greenhouse gas emissions have been and will be concluded By generating solar electricity instead of conventional electricity, greenhouse gas emissions will be significantly reduced The abundant availability of solar energy (sunshine) in desert regions provides fair access by everybody to affordable and sustainable energy solutions This is an important condition for preventing wars over energy Moreover, the availability of solar electricity will stimulate economic development in desert regions By the introduction of a sustainable energy strategy based on solar electricity, an example will be created that will generate international recognition and this example will be followed by many other countries Deployment Strategies As for the deployment strategies, the IEA-PVPS Task group has proposed a very unique approach Figure illustrates the proposed deployment steps for the sustainable growth of VLS-PV: the Solar Pyramid As an initial stage, start-up VLS-PV plants as well as PV module manufacturing facilities are constructed After installing the start-up VLS-PV plant, a part of the solar-generated power supply is supplied to the PV module factory The PV module produced in the facilities will be used to enlarge the VLS-PV capacity This ‘step-by-step’ approach has many advantages not only from an environment but also from an economic point of view For example, the PV owner may be able to enjoy the benefits of ‘experience curve’ developments The cost of PV would be reduced as the manufacturing process improves and scales up Another advantage is risk management Starting from relatively smaller capacity would reduce the risk of the project Since there are no PV systems operating more than 20 years in the desert area, preliminary operation and the careful monitoring of the system performance in the start-up stage would enhance the system reliability 1.35.2 Evaluation of the VLS-PV from Various Aspects 1.35.2.1 Energy Potential One of the characteristics of solar energy is its relatively low energy density In order to have multi-megawatt or gigawatt scale of VLS-PV, naturally, the land requirement associated with the plants would be considerable However, fortunately, the dry desert area Very Large-Scale Photovoltaic Systems 735 Covered by η = 15% PV modules (0.5 space factor, assuming 0.7 system performance ratio) (= 114 PWh/y = 114 × 1012kWh/y) Gobi 300 000 km2 Sahara 600 000 km2 Total land surface 412 EJ /yr−1 PV Electricity (1EJ = 1018J) Total earth surface World primary energy supply in 2009 = 509 EJ /yr −1 Figure Solar pyramid Negev 2,5 Gobi 64 Thar 18 Sonora 7,4 Great Sandy 34 Sahara 626 n.a Low Crop Suitability Steppe High Desert 0,55 0,45 0,35 0,25 0,15 NDVIymax Figure Annual generation of the world’s arid areas by PV resource analysis (PWh yr−1) [3] on earth is abundant It covers approximately one-third of the total land surface of the earth According to the simplified calculation in the IEA-PVPS study, 4% of those desert areas would be sufficient to provide global energy needs [2] In reality, however, not all desert areas are suitable for the VLS-PV application Specifically, geometry and hardness of the ground are important from the point of view of stable installation From these perspectives, a gravel desert is preferred over a sand dune desert for the VLS-PV application Figure shows the evaluation of suitability of desert areas by using satellite image analysis The analyzed deserts include the Gobi, Sahara, Great Sandy, Thar, Sonora, and Negev deserts The total areas for these deserts represent half of the global desert area and 10% of the global land surface The gray areas of the map in Figure represent the unsuitable areas for VLS-PV application, while colored areas stand for suitable areas The red color indicates that the land is arid with less vegetation (preferable for VLS-PV application); on the other hand, green color illustrates relatively higher vegetation (less-suitable for VLS-PV application) According to the analysis, the potential PV power generation from all suitable areas is estimated to be 752 petawatt hours (PWh) or 2707 EJ, which is equivalent to approximately times the world’s annual energy consumption in 2010 The results indicate that the Sahara desert has the highest potential with 626 PWh, which is more than 80% of overall potential in the desert The analysis above strongly justifies the VLS-PV concept at least from energy resource point of view [3] 736 Applications 1.35.2.2 1.35.2.2.1 Economics of VLS-PV Generation cost of VLS-PV Another interesting issue for people involved would be the economics and related financial aspects of VLS-PV Although there are many aspects in this regard, one of the parameters commonly used to evaluate the economics of power plants is the so-called generation cost Generation cost comprises the overall costs during the whole lifetime, both initial cost and running cost, divided by the total generated power Figure illustrates the generation costs in eight different desert regions, namely, Gobi Sainshand, Gobi Huhhot, Negev, Sonoran, Sahara-Ouarzazate, Great Sandy, and Sahara-Nema The economics of VLS-PV in each desert area varies since those are strongly influenced by regional specific conditions such as material costs, transportation, and labor cost as well as annual solar irradiation The other parameters or assumptions underlying the calculation include the exchange rate (¥120 = US$1), the interest rate (3%), the salvage value rate (10%), the property tax rate (1.4% per year), the overhead expense rate (5% per year), and the lifetime of the system (PV: 30 years, inverters: 15 years) Clearly, the generation cost is heavily influenced by the module price of the system As indicated in Figure 4, the generation cost of the VLS-PV system is approximately 18–22 ¢ kWh−1 at a PV module price of US$ W−1, while the generation cost can be reduced to the range of 7–9 ¢ kWh−1 if the module price goes down to US$ W−1 Figure shows the historical change in average PV module price in Europe As presented in the figure, the average price reaches 1.2 € W−1 in 2011 from 4.2 € W−1 in 2000 due to the continuous effort of the PV industry and drastic market expansion This dramatic module cost reduction has strengthened the competitiveness of VLS-PV substantially Taken into consideration the current trends of increasing cost of fossil fuels, the analysis clearly indicates that VLS-PV is becoming one of the promising technologies for utility-scale power generation even from an economic perspective Gobi Sainshand Generation cost (US cents kWh−1) 30 Negev Gobi Huhhot Sahara-Ouarzazate Thar Great Sandy Sahara-Nema Sonoran Module price US W$−1 25 US W$−1 US W$−1 20 US W$−1 15 10 1500 2000 2500 Annual global horizontal 3000 irradiation (kWh−1 m2 yr −1) Figure Generation cost of VLS-PV (1 GW) in various desert areas [3] Polysilicon shortage 100 ±4.2 W−1 80 % 60 40 Figure Change in average PV module price in Europe [4] 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 (July) 2011 ±1.2 W−1 20 Very Large-Scale Photovoltaic Systems 1.35.2.2.2 737 Impact of capital costs VLS-PV projects are highly capital-intensive in general; therefore, access to the financial sector will be the key to success in this business It should be kept in mind that the economics of the VLS-PV projects would also be strongly influenced by the capital cost and hence availability of an appropriate financial scheme As for the financing scheme, there are mainly three factors that affect the economics of the project A first factor is the ownership of the project The financial structure would be completely different if the plant is owned by utility as its own asset or by private entity within a portfolio of assets Public–private partnership (PPP) is also an alternative for the ownership that would have a completely different structure The second factor is the market value of the power generated from VLS-PV The value of the electricity can be regarded as electricity alone, but there is an opportunity that the environmental value is also added to the electricity market price, say the emission reduction credit A third factor is the support mechanism from central or local government There are several supporting mechanisms already put in place in the market such as tax incentives, feed-in tariffs, and market-based incentives Taking the capital costs into account, the cost analysis presented in Figure would be changed to some extent According to the IEA-PVPS Task group analysis, the generation cost of VLS-PV would increase to around 30 ¢ kWh−1 in the case of US$ W−1 as PV module price and to 12 ¢ kWh−1 if the module cost is reduced to 1US$ W−1, if the capital cost were included (0.75% of total investment costs was assumed [3]) As such, development of a favorable financial scheme is essential for accelerating further VLS-PV developments 1.35.2.3 Technologies for VLS-PV There are several PV cell and module technologies available for VLS-PV application at present Crystalline silicon wafer-based technologies are the major technologies widely used in the current market The efficiency of the silicon cells have reached more than 20%, meaning that 20% of total solar energy radiated on the PV panel is converted into electric energy The cost of the crystalline silicon cell has been diminished as the thickness of the cells becomes thinner and the efficiencies improve Another technology is thin-film modules The production cost of thin-film cells is lower compared to crystalline silicon cells There are several types of commercially available thin-film modules, namely, amorphous silicon (a-Si), copper indium selenide (CIS), copper indium gallium selenide (CIGS), and cadmium telluride (CdTe) It should be noted that the lower production cost of thin-film modules will not necessarily improve the economics of the overall project since lower efficiencies of the modules would lead to higher balance-of-system (BOS) cost The III–V compound semiconductors (multijunction gallium arsenide types) are also an option mainly for the concentrator type of application The concentrator application uses an optical concentrator to focus light onto the cells A tracking system is required to direct the cells precisely toward the Sun The efficiency is approximately 30%, while 40% has been reached in laboratories Those are well-proven technologies and widely available in the current market However, one of the uncertainties of VLS-PV is the long-term reliability of the systems Since there are no VLS-PV systems operating more than 20 years in the desert, the reliability of the system might be a concern especially for the financial sectors The investors must wait at least 20–30 years to see the actual performance of the project throughout its lifetime; however, the risk can be minimized through applying careful design in the initial stage Regarding the detailed technological design specially designed for more reliable systems in the desert, technical guidelines for the VLS-PV system will be published in 2012 by the IEA-PVPS Task group 1.35.2.4 1.35.2.4.1 Environmental Aspects Lifecycle Analysis PV in general emits no greenhouse gas during its operation This environmental feature is one of the strong reasons why PV attracts public attention today Nevertheless, energy is certainly consumed and associated greenhouse gas emission occurs during produc­ tion or transportation of the system The concept of lifecycle analysis (LCA) is applied to evaluate the environmental burden of all processes from production of PV to decommission and disposal of the system Figure illustrates the energy payback time (EPBT) of VLS-PV with various types of PV module The EPBT represents years required for VLS-PV to generate the same amount of energy consumed in its lifecycle process The assumptions underlying the analysis include the following: • • • • • • • • • System capacity: GW Location of the site: Hohhot in the Gobi desert in Inner Mongolia, China Horizontal global irradiation: 1702 kWh m−2 yr−1 Tilted angle (30°) annual irradiation: 2017 kWh m−2 yr−1 Annual ambient temperature: 5.8 °C Electrical equipment: manufactured in Japan and transported to the site by cargo ship Foundation and steel structure: manufactured in China Lifetime of the system: 30 years (inverters 15 years) Decommission: Transported to a wrecking yard and transported for reclamation 738 Applications Energy payback time (year) 3.0 2.5 2.8 2.6 2.5 2.4 2.2 2.1 2.0 1.5 1.0 0.5 CdTe CIS Thin- film Si a-Si/scSi sc-Si mc-Si 0.0 80 71.0 70 60 61.6 66.5 58.8 52.8 51.5 50 40 30 20 10 CdTe CIS Thinfilm Si a-Si/scSi sc-Si mc-Si CO2 emission rate (g-CO2 kWh−1) Figure EPBT (year) of VLS-PV systems [3] made using different PV technologies Figure CO2-equivalent emission (g kWh−1) associated with VLS-PV systems [3] As is shown in the figure, the EPBTs are in the range of 2.1–2.8 years That is to say that VLS-PV can produce more than 10 times the amount of energy that is consumed during its 20–30 years of lifecycle As such, it is obvious that VLS-PV can contribute to reduction in energy consumption as well as greenhouse gas emission considerably Figure indicates the CO2-equivalent emission per unit of electricity output (g kWh−1) of the VLS-PV systems Although the result is not comparable with other studies because of the difference in base assumptions, a similar LCA study for conventional fossil fuel power plant indicates that the CO2 emission per unit of electricity output is at the magnitude 500 g kWh−1 for liquid natural gas (LNG)-based power plants to 1000 g kWh−1 for coal-fired power plants in Japan 1.35.2.4.2 Ecological impacts Another measure to evaluate the environmental impact introduced in this chapter is an ecological footprint (EF) According to the Global Footprint Network, the EF is defined as “a resource accounting tool used by governments, businesses, educational institutions and NGOs to answer a specific resource question: How much of the biological capacity of the planet is required by a given human activity or population?” [5] The EF is measured in units of global hectares (gha) and is normalized to the area-weighted average productivity of biologically productive area The criteria of the ecological footprint analysis (EFA) is called biological capacity (BC) The BC is the ability of an ecosystem to produce useful biological materials and to absorb carbon dioxide emissions; therefore, by definition, EF should be kept lower than BC so as to be sustainable According to the latest analysis, the world’s EF today is almost 1.5 times higher than BC Then, to what extent VLS-PV can contribute to reduce global and regional EF? In order to answer the question, the impact of VLS-PV on the ecological footprint was analyzed It is expected that VLS-PV would have positive effects on both EF and BC since VLS-PV can • reduce the CO2 emissions by substituting existing electricity power generation, thus reducing the EF in the area of question, and • increase BC through a regional development of the project area As shown in Figure 8, a 100 GW VLS-PV development could reduce the EF per capita from 12.5 to 11.9 gha per capita, while a 1000 GW of VLS-PV project can achieve 6.4 gha per capita, well below the BC in China From the global point of view, 10 000 GW VLS-PV is required to keep the EF within the BC Very Large-Scale Photovoltaic Systems 739 China Without VLS-PV VLS-PV: 100 GW VLS-PV: 500 GW VLS-PV: 690 GW Biocapacity VLS-PV: 1000 GW China, Mongolia, and Korea Without VLS-PV VLS-PV: 1000 GW World Without VLS-PV VLS-PV: 10 000 GW 10 15 20 25 Ecological footprint and biocapacity (ghaita capper) Cropland Pasture Forest Fisheries Built space Energy Figure The possible ecological impact of the VLS-PV project on the Gobi desert [3] 1.35.3 Progress in VLS-PV 1.35.3.1 VLS-PV as a Dream When the VLS-PV concept was presented in 1999, it was regarded as a ‘dream’ of scientists, although the concept attracted much public interest The cost of PV was too high for massive applications compared with conventional power plants at that time Additionally, there were no manufacturers that could produce such a large number of PV panels Considering the fact that the cumulative PV capacity installed in the global market in 1999 was less than 500 MW in total, the reaction from the public may be reasonable 1.35.3.2 Dream to Reality As the PV market expands, the cost of PV system starts decreasing (Figure 5) The cost reduction curve is known as the ‘experience curve’ or ‘learning curve’ As the cost of PV modules decreases, the concept of VLS-PV attains more reality Furthermore, introduction of renewable energy policies such as the ‘feed-in-tariff’ (FIT) enhances the competitiveness of VLS-PV considerably FIT is a policy measure to foster grid-connected renewable energy power generations including PV by offering a relatively high tariff for electricity generated from greener energy sources As a result, a number of megawatt-scale PV systems were planned and constructed especially in Germany and Spain, where innovative FIT schemes were introduced The number of megawatt-scale PV systems has increased drastically from around 10 at the beginning of the twenty-first century to more than 1000 today The capacity of the plants also expands, with the maximum capacity becoming closer to 100 MW in 2010 (Figure 9) Table shows a list of examples of megawatt-scale PV systems currently installed or operated around the world 1.35.3.3 Emerging New Initiatives in MENA Regions In 2009, 10 years after the initial VLS-PV concepts, a new nonprofit foundation dedicated to renewable energy utilization in the EU-MENA regions (Europe, the Middle East, and North Africa) called ‘DESERTEC’ was founded The DESERTEC initiative was founded by the German Association of the Club of Rome and other committed scientists or individuals [7] The initial DESERTEC concept was designed during 2003–07 according to the DESERTEC foundation Figure 10 shows the conceptual image of the infrastructure development plan of DESERTEC The red squares in the map represent ‘concentrated solar thermal power (CSP)’ plants Although CSP and VLS-PV concepts assume different technologies, the 740 Applications Capacity of VLS-PV system (MW per system) 120 Megawatt-scale PV system installation in each year 100 80 60 40 20 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Figure Trends in megawatt-scale PV systems installation [6] Table Examples of megawatt-scale PV systems around the world [6] Name Country Location Sarnia PV power plant Montalto di Castro PV power plant Solarpark Finsterwalde I, II, III Solarpark Senftenberg II, III Lobpuri Solarpark Lieberose San Bellino PV power plant Parque Fotovoltaico Olmedilla de Alarcón Copper Mountain Solar Facility Avenal Solar Facility Solarpark Straßkirchen Solarpark Tutow I, II Canada Italy Italy Portugal Sarnia (Ontario) Montalto di Castro (Lazio) Finsterwalde Senftenberg Lobpuri Turnow-Preilack San Bellino Olmedilla (Castilla-La Mancha) Boulder City, NV Kettleman Hills Straßkirchen Tutow (MecklenburgVorpommern) Puertollano (Castilla-La Mancha) Canaro Moura (Alentejo) Germany Kothen Parque Fotovoltaico Puertollano Serenissima PV power plant Moura photovoltaic power plant Solarpark Kothen Germany Germany Thailand Germany Italy Spain USA USA Germany Germany Spain PV capacity (MW) Fixed/tracking Installed operated 97 84.2 Fixed Fixed 2010 2010 80.245 78 73 71 70.556 60 Fixed Fixed Fixed Fixed Fixed Fixed 2010 2011 2011 2011 2010 2008 60 57 54 52 Fixed Fixed Fixed Fixed 2010 2011 2009 2011 47.6 Fixed 2008 48 46 Fixed Tracking 2011 2008 45 Fixed 2011 overall missions and objectives are quite similar Since CSP and VLS-PV have different technological features, those two technol­ ogies should be regarded as complementary rather than competitive Similarly, the French government proposed the Mediterranean Solar Plan (MSP) in 2008 MSP is one of the six flagship projects of the ‘Union for the Mediterranean (UfM)’ The goal of the MSP was to achieve 20 GW of renewable energy projects by 2020, and the expected investment needed to achieve the goal was approximately €80 billion In response to those initiatives, northern African countries have developed their own strategies for renewable energy For example, Morocco sets a renewable target of 4000 MW by 2020, with 2000 MW from solar energy (PV and CSP) A number of companies, research institutes, and governments join these projects The private companies involved in the framework include manufacturers, construction companies, trade companies, system integrators as well as banks As such, the concept of solar energy in the desert is no longer a dream It is now a commercially attractive option for business sectors Very Large-Scale Photovoltaic Systems 741 Figure 10 Conceptual image of DESERTEC infrastructure development [7] 1.35.4 Future for the VLS-PV Although VLS-PV is now in the business process, the present share of renewable energies in the global energy mix is still marginal Taking into account today’s sustainability issues, the role of VLS-PV is far from its final goal In other words, VLS PV has unlimited potential to contribute to the world’s sustainability issues 1.35.4.1 Sustainability Issues Sustainability of our society has been threatened by various issues, namely, climate change, energy depletion, water resource shortage, food shortage, and ecosystems These issues are not independent and closely influence each other in a very complicated manner Figure 11 is a simplified diagram of interrelations between various sustainability issues Fossil fuel use Increase in CO2 emission Increase in fossil fuel consumption Increase in nonconventional energy use Climate change Energy depletion Increase in extreme events (floods, droughts, fires) Change in ecosystem structure and diversity Reduced carbon sequestration in soil and woods Decreased plant and soil organisms species diversity Biodiversity loss Land degradation (desertification, deforestation) Soil erosion (loss of nutrients and soil moisture) Figure 11 Vicious circle of environmental issues [3] Decrease in biomass resources Increase in biomass use 742 Applications Increase in energy demand associated with economic expansion and population increase is regarded as one of the major issues for sustainability Clearly, fossil fuels are finite energy resources and, sooner or later, these resources would be depleted As fossil fuel use decreases, the costs of energy will increase because of the imbalance between demand and supply It is needless to say that the increase in energy cost could damage global economy considerably Since the current economy is heavily dependent on secured energy supply, energy depletion or associated cost, increase may damage most of the sectors all over the world Climate change associated with greenhouse gas emission from fossil fuel combustion is another serious issue to be overcome The regional impacts of climate change would vary depending on the local conditions; however, the Intergovernmental Panel on Climate Change (IPCC) report indicates that most of the regions will experience economic losses if the global temperature rise is greater than 2–3 °C above 1990 levels [8] To make matters worse, if energy depletion issues become serious and nonconventional fossil fuel energy sources are utilized, the greenhouse gas emissions per unit of energy consumption are expected to increase, thus accelerating climate change even further One of the threats of climate change is the increasing risk of natural disasters including flood, drought, forest fire, and desertification Those natural disasters often lead to degradation or erosion of land There are also possibilities of land degradation caused by deforestation mainly led by the increase in biomass use for energy or material use The increase in energy cost would enhance the pressure for more biomass use especially in developing countries Naturally, land degradation and deforestation would have negative impacts on the ecosystems in the local and global communities It is noteworthy that there are many regions where the economy relied mainly on rain-fed agricultures The impacts on those regions could be significant if appropriate adaptation measures are not in place (a) 1974 2000 2010 2030 2100 2050 PV module technology 1G 133 TW 2G 4,5 TW yr −1 3G 4,5 TW yr −1 Recycle SHS (cumulative) Developing region scenario + storage Global energy mix Mini-Grid Community-Scale grid scenario (Micro-Grid) Rooftop PV + storage community-grid VLS-PV to Global Grid Large-scale to very large-scale PV + storage International to global grid (b) Net Stock 800 GW 10 TW 75 TW 133 TW 100 GW TW 30 TW 133 TW in 2100 67 TW 140 000 VLS-PV Cumulative installation (GW) 120 000 Cumulative PV installation 100 000 50% VLS-PV 80 000 60 000 Rural and mini-grid 30% 40 000 Urban and community grid 20 000 Figure 12 PV roadmap for various applications (a) and cumulative PV installation (b) [3] 2100 2090 2080 2070 2060 2050 2040 2030 2020 2010 20% Very Large-Scale Photovoltaic Systems 743 Diffusion of VLS-PV Decrease in fossil fuel consumption Reduction in CO2 emission Energy conservation Climate change mitigation Stable ecosystem structure and diversity Decrease in extreme events (floods, droughts, fires) Increased carbon sequestration in soil and woods Biodiversity conservation Increased plant and soil organisms species diversity Stable supply of biomass resources Land conservation (desertification, deforestation) Soil conservation (nutrients and soil moisture) Figure 13 Virtuous circle of environmental issues [3] 1.35.4.2 VLS-PV Visions and Roadmap In order to be a major source of energy in the global energy mix and contribute to sustainable energy development, VLS-PV should overcome a number of barriers Such barriers include further system cost reduction, development of replacement or recycling scheme for decommissioned PV systems, and grid stability control In order to address those issues, a technological development and market penetration roadmap is developed as part of the IEA-PVPS Task studies (Figure 12) The roadmap indicates that the replacement/waste issue would be an issue after 2015–20 and calls for development of recycling technologies As for VLS-PV, the market continues to grow with the development of global grid and storage technologies The overall capacity of PV systems reaches 133 TW in 2100, and 50% of the capacity is from VLS-PV Although the cost of PV systems continues to decrease, the PV market is expanded to US$5.1 billion yr−1, US$214 billion yr−1, and US$1.7 trillion yr−1 for 2020, 2050, and 2100, respectively If this vision is achieved in reality, PV is expected to supply approximately a third of global energy assumed in IPCC SRES A1 Scenario [8] In such a world, various uses of VLS-PV output may become available such as solar hydrogen or solar methane production As already discussed above, VLS-PV has great potential to contribute to overcoming these global issues Especially, after the nuclear accident in Fukushima, Japan, expectations for renewable energy including VLS-PV become higher The future dream for VLS-PV is to contribute to the global sustainable energy supply and to turn the vicious circle of the environmental issues into a virtuous circle as presented in Figure 13 1.35.5 Conclusion VLS-PV is a very unique idea originally presented in 1999 by the IEA-PVPS Task group The concept has been studied for more than 10 years and the feasibilities are widely evaluated With the cost reduction of PV modules as well as favorable governmental support, such as the FIT, VLS-PV has become a commercially attractive option today Currently, more than 1000 megawatt-scale plants are operating or constructed around the world If the effort of technology and market development continues, VLS-PV would be a powerful solution for current sustainability issues It is reasonably concluded that VLS-PV has a great potential to turn the vicious circle of environmental issues into a virtuous circle and to solve these problems at the same time 744 Applications References [1] IEA-PVPS Task http://www.iea-pvps.org/index.php?id=35 (accessed 27 October 2011) [2] Kurokawa K (ed.) (2003) Energy from the Desert – Feasibility of Very Large Scale Photovoltaic Power Generation (VLS-PV) Systems London, UK: James & James (Science Publishers) [3] Kurokawa K, Komoto K, van der Vleuten P, and Faiman D (eds.) (2007) Energy from the Desert – Practical Proposals for Very Large Scale Photovoltaic Systems London, UK: Earthscan [4] European Photovoltaic Industry Association (2011) Solar Photovoltaics Competing in the Energy Sector (available at: http://www.epia.org/index.php? elD=tx_nawsecuredl&u=0&file=fileadmin/EPIA_docs/publications/epia/Competing_Full_Report.pdf&t=1325939055&hash=964a868c9b3c7c432528399ef17ca57e) [5] Global Footprint Network http://www.footprintnetwork.org/en/index.php/GFN/page/frequently_asked_questions/#gen1 (accessed 27 October 2011) [6] Data Source: Resources Total System Co., Ltd http://www.pvresources.com [7] DESERTEC Foundation http://www.desertec.org (accessed 27 October 2011) [8] IPCC (2007) Climate Change 2007 – Impacts, Adaptation and Vulnerability Contribution of Working Group II to the Fourth Assessment Report of the IPCC Cambridge: Cambridge University Press  ... 2 010 80.245 78 73 71 70.556 60 Fixed Fixed Fixed Fixed Fixed Fixed 2 010 2 011 2 011 2 011 2 010 2008 60 57 54 52 Fixed Fixed Fixed Fixed 2 010 2 011 2009 2 011 47.6 Fixed 2008 48 46 Fixed Tracking 2 011 ... in Europe [4] 2 010 2009 2008 2007 2006 2005 2004 2003 2002 20 01 2000 (July) 2 011 1. 2 W 1 20 Very Large-Scale Photovoltaic Systems 1. 35.2.2.2 737 Impact of capital costs VLS-PV projects are highly... the dry desert area Very Large-Scale Photovoltaic Systems 735 Covered by η = 15 % PV modules (0.5 space factor, assuming 0.7 system performance ratio) (= 11 4 PWh/y = 11 4 × 10 12kWh/y) Gobi 300 000