A day before his visit to Chandigarh on Tuesday, Kejriwal had said his party, if voted to power in Punjab, will provide free electricity. Have you read these stories? China's President Xi Jinping and U. President Joe Biden will hold a virtual summit on Tuesday morning, the Chinese foreign ministry Afghanistan could face big food crisis in winter Case filed against Salman Khurshid in Jaipur Bihar: 38,72, litres of illicit liquor confiscated Hinduism different from Hindutva: Rahul Gandhi.
ET NOW. Brand Solutions. Video series featuring innovators. ET Financial Inclusion Summit. Malaria Mukt Bharat. Wealth Wise Series How they can help in wealth creation. Honouring Exemplary Boards. Deep Dive Into Cryptocurrency. ET Markets Conclave — Cryptocurrency. Reshape Tomorrow Tomorrow is different. Let's reshape it today. Corning Gorilla Glass TougherTogether. ET India Inc. ET Engage. ET Secure IT. How to keep your electric car, two-wheeler trouble-free Electric vehicles including cars and two-wheelers need less maintenance, but some components of e-vehicles still require special care.
Ather Energy logs fold increase October sales "The festive season has been very encouraging for us as Ather Energy recorded a 12 fold growth in sales in the month of October, when compared to last year," Ather Energy CEO and Co-founder Tarun Mehta said in a statement. Please do not remove the pixel counter. All Rights Reserved. Singularity University is not a degree granting institution.
Sign in. Forgot your password? Get help. Password recovery. Singularity Hub. Topics Experts Events Videos. Singularity Group Singularity Community. Because, free stuff! Attention again turned to the huge sources of energy surging around us in nature — sun, wind, and seas in particular. There was never any doubt about the magnitude of these, the challenge was always in harnessing them so as to meet demand for reliable and affordable electricity.
Today many countries are well advanced in meeting that challenge, while also testing the practical limits of doing so from wind and solar variable renewable energy, VRE. The relatively dilute nature of wind and solar mean that harnessing them is very materials-intensive — many times that from energy-dense sources. Wind turbines have developed greatly in recent decades, solar photovoltaic technology is much more efficient, and there are improved prospects of harnessing the energy in tides and waves.
Solar thermal technologies in particular with some heat storage have great potential in sunny climates. With government encouragement to utilize wind and solar technologies, their costs have come down and are now in the same league per kilowatt-hour dispatched from the plant as the costs of fossil fuel technologies, especially where there are carbon emissions charges on electricity generation from them.
However, the variability of wind and solar power does not correspond with most demand, and as substantial capacity has been built in several countries in response to government incentives, occasional massive output — as well as occasional zero output — from these sources creates major problems in maintaining the reliability and economic viability of the whole system.
There is a new focus on system costs related to achieving reliable supply to meet demand. In the following text, the levelised cost of electricity LCOE is used to indicate the average cost per unit of electricity generated at the actual plant, allowing for the recovery of all costs over the lifetime of the plant. It includes capital, financing, operation and maintenance, fuel if any , and decommissioning.
Another relevant metric is energy return on energy invested EROI. This is not quoted for particular projects, but is the subject of more general studies. EROI is the ratio of the energy delivered by a process to the energy used directly and indirectly in that process, and is part of lifecycle analysis LCA. An EROI of about 7 is considered break-even economically for developed countries. First, their maximum output fluctuates according to the real-time availability of wind and sunlight.
Second, such fluctuations can be predicted accurately only a few hours to days in advance. Third, they are non-synchronous and use devices known as power converters in order to connect to the grid this can be relevant in terms of how to ensure the stability of power systems. Fourth, they are more modular and can be deployed in a much more distributed fashion.
Fifth, unlike fossil or nuclear fuels, wind and sunlight cannot be transported, and while renewable energy resources are available in many areas, the best resources are frequently located at a distance from load centres thus, in some cases, increasing connection costs. All the modelling is within a 50g CO 2 per kWh emission constraint, and quantifies the system costs due to different levels of VRE input, despite declining LCOE costs and zero marginal costs for those.
System effects are often divided into the following four broadly defined categories:. The NEA study states: "Profile costs or utilisation costs refer to the increase in the generation cost of the overall electricity system in response to the variablity of VRE output. They are thus at the heart of the notion of system effects.
They capture, in particular, the fact that in most of the cases it is more expensive to provide the residual load in a system with VRE than in an equivalent system where VRE are replaced by dispatchable plants. High levels of VRE require significant enhancement of system integration measures. These measures include flexible power sources such as hydro and open cycle gas turbines, demand-side measures, electricity storage, strong and smart transmission and distribution grids.
The costs of all these, over and above the generation costs, comprise the system costs. See later section on System integration costs of intermittent renewable power generation. A further aspect of considering sources such as wind and solar in the context of grid supply is that their true capacity is discounted to allow for intermittency. In the UK this is by a factor of 0. This novel convention is not followed in this information paper. There is a fundamental attractiveness about harnessing such forces in an age which is very conscious of the environmental effects of burning fossil fuels, and where sustainability is an ethical norm.
So today the focus is on both adequacy of energy supply long-term and also the environmental implications of particular sources. In that regard, the costs being imposed on CO 2 emissions in developed countries at least have profoundly changed the economic outlook of clean energy sources. A market-determined carbon price creates incentives for energy sources that are cleaner than current fossil fuel sources without distinguishing among different technologies. This puts the onus on the generating utility to employ technologies which efficiently supply power to the consumer at a competitive price.
Wind, solar and nuclear are the main contenders. Sun, wind, waves, rivers, tides and the heat from radioactive decay in the earth's mantle as well as biomass are all abundant and ongoing, hence the term "renewables". Solar energy's main human application has been in agriculture and forestry, via photosynthesis, and increasingly it is harnessed for heat.
Until recently electricity has been a niche application for solar. Biomass e. The others are little used as yet. Turning to the use of abundant renewable energy sources other than large-scale hydro for electricity, there are challenges in actually harnessing them.
Apart from solar photovoltaic PV systems which produce electricity directly, the question is how to make them turn dynamos to generate the electricity. If it is heat which is harnessed, this is via a steam generating system.
This means either that there must be reliable duplicate sources of electricity beyond the normal system reserve, or some means of large-scale electricity storage see later section. Policies which favour renewables over other sources may also be required.
Such policies, now in place in about 50 countries, include priority dispatch for electricity from renewable sources and special feed-in tariffs, quota obligations and energy tax exemptions.
This load curve diagram shows that much of the electricity demand is in fact for continuous supply base-load , while some is for a lesser amount of predictable supply for about three-quarters of the day, and less still for variable peak demand up to half of the time; some of the overnight demand is for domestic hot water systems on cheap tariffs. With overnight charging of electric vehicles it is easy to see how the base-load proportion would grow, increasing the scope for nuclear and other plants which produce it.
Source: Vencorp. Most electricity demand is for continuous, reliable supply that has traditionally been provided by base-load electricity generation. Some is for shorter-term e. Hence if renewable sources are linked to a grid, the question of back-up capacity arises; for a stand-alone system, energy storage is the main issue.
Apart from pumped-storage hydro systems see later section , no such means exist at present on any large scale. However, a distinct advantage of solar and to some extent other renewable systems is that they are distributed and may be near the points of demand, thereby reducing power transmission losses if traditional generating plants are distant.
Of course, this same feature more often counts against wind in that the best sites for harnessing it are sometimes remote from populations, and the main back-up for lack of wind in one place is wind blowing hard in another, hence requiring a wide network with flexible operation. Hydroelectric power, using the potential energy of rivers, is by far the best-established means of electricity generation from renewable sources. It may also be large-scale — nine of the ten largest power plants in the world are hydro, using dams on rivers.
In contrast to wind and solar generation, hydro plants have considerable mechanical inertia and are synchronous, helping with grid stability. Apart from those five countries with a relative abundance of it Norway, Canada, Switzerland, New Zealand and Sweden , hydro capacity is normally applied to peak-load demand, because it is so readily stopped and started.
The individual turbines of a hydro plant can be run up from zero to full power in about ten minutes. This also means that it is an ideal complement to wind power in a grid system, and is used thus most effectively by Denmark see case study below.
Hydropower using large storage reservoirs on rivers is not a major option for the future in the developed countries because most major sites in these countries having potential for harnessing gravity in this way are either being exploited already or are unavailable for other reasons such as environmental considerations.
Growth to is expected mostly in China and Latin America. Brazil is planning to have 25 GWe of new hydro capacity by , involving considerable environmental impact. The chief advantage of hydro systems is their capacity to handle seasonal as well as daily high peak loads. In practice the utilisation of stored water is sometimes complicated by demands for irrigation which may occur out of phase with peak electrical demands.
Hydroelectric power plants can constrain the water flow through each turbine to vary output, though with fixed-blade turbines this reduces generating efficiency. More sophisticated and expensive Kaplan turbines have variable pitch and are efficient at a range of flow rates. With multiple fixed-blade turbines e.
Francis turbine , they can individually be run at full power or shut down. Run-of-river hydro systems are usually much smaller than dammed ones but have potentially wider application. Some short-term pondage can help them adapt to daily load profiles, but generally they produce continuously, apart from seasonal variation in river flows. Pumped storage is discussed below under Renewables in relation to base-load demand.
Wind turbines of up to 6 MWe are now functioning in many countries. A prototype 8 MWe unit built by Siemens Gamesa with a metre rotor diameter was commissioned in Denmark early in The average size of new turbines installed in was 5. The turbine will be metres tall from base to blade tip with a rotor diameter of metres. The power output is a function of the cube of the wind speed, so doubling the wind speed gives eight times the energy potential.
Larger ones are on taller pylons and tend to have higher capacity factors. Where there is an economic back-up which can be called upon at very short notice e. There is a distinct difference between onshore and offshore sites, though the latter are more expensive to set up and run.
In Germany, with high dependence on wind, there is corresponding high uncertainty of supply. Stage 1 is 2. It is auctioning MWe per year to With increased scale and numbers of units, generation costs and levelised cost of energy LCOE is now often competitive with coal and nuclear, without allowing for backup capacity and grid connection complexities which affect their value in a system.
Wind is intermittent, and when it does not blow, backup capacity such as hydro or quick-start gas is needed. When it does blow, and displaces power from other sources, it may reduce the profitability of those sources and may increase delivered prices. With any significant input from intermittent renewables sources, system cost not the LCOE to meet actual demand becomes the relevant metric.
One approach to mitigate intermittency is to make hydrogen by electrolysis and feed this into the gas grid, the power-to-gas strategy.
It has been suggested that all electricity from wind might be used thus, greatly simplifying electrical grid management. Vattenfall at Prenzlau in Germany is also experimenting with hydrogen production and storage from wind power via electrolysis. Also in Germany, near Neubrandenburg in the northeast, WIND-projekt is using surplus electricity from a MWe wind farm to make hydrogen, storing it, and then burning it in a CHP unit to make electricity when demand is high.
In the Netherlands, Gasunie plans a 20 MW unit. BNetzA forecasts a 3 GW potential for power-to-gas by Wind turbines have a high steel tower to mount the generator nacelle, and typically have rotors with three blades. Foundations require a substantial mass of reinforced concrete.
Hence the energy inputs to manufacture are not insignificant. Also siting is important in getting a net gain from them. Bird kills, especially of raptor species, are an environmental impact of wind farms. In the USA half a million birds are killed each year, including 83, raptors hawks, eagles, falcons etc. According to Environment Canada, wind turbines kill approximately 8. Migratory bats are also killed in large numbers. New wind farms are increasingly offshore, in shallow seas. The UK had MWe wind capacity offshore at the end of , over two-thirds of the world's total.
The London Array, 20 km offshore Kent, has turbines of 3. Replacing old turbines is becoming an issue — repowering the wind capacity.
Approximately half of European capacity will be retired by , and needs to be replaced mostly with larger turbines, likely without subsidies. The repowering priority is at the best sites. Full decommissioning involves removal of old towers and foundations, not simply turbines.
According to lobby group WindEurope, some 22 GWe of wind turbines over 20 years old in Europe will be decommissioned by , and 40 GWe by At least one-fifth of these will involve full decommissioning. A Renewable Energy Foundation study in showed that the performance of onshore wind turbines in the UK and Denmark declined significantly with age, and offshore Danish ones declined more. Solar energy is readily harnessed for low temperature heat, and in many places domestic hot water units with storage routinely utilise it.
It is also used simply by sensible design of buildings and in many ways that are taken for granted. Industrially, probably the main use is in solar salt production — some PJ per year in Australia alone equivalent to two-thirds of the nation's oil use.
It is increasingly used in utility-scale plants, mostly photovoltaic PV. Domestic-scale PV is widespread. Three methods of converting the Sun's radiant energy to electricity are the focus of attention. The best-known method utilises light, ideally sunlight, acting on photovoltaic cells to produce electricity. Flat plate versions of these can readily be mounted on buildings without any aesthetic intrusion or requiring special support structures. Solar photovoltaic PV has for some years had application for certain signaling and communication equipment, such as remote area telecommunications equipment in Australia or simply where mains connection is inconvenient.
Sales of solar PV modules are increasing strongly as their efficiency increases and price falls, coupled with financial subsidies and incentives. Small-scale solar PV installations for domestic or onsite industrial use are commonly 'behind the meter', and may feed surplus power into the grid. In recent years there has been high investment in solar PV, due to favourable subsidies and incentives. More efficiency can be gained using concentrating solar PV CPV , where some kind of parabolic mirror tracks the sun and increases the intensity of the solar radiation up to fold.
Modules are typically kW. The HCPV cells in achieved a world record for terrestrial concentrator solar cell efficiency, at CPV can also be used with heliostat configuration, with a tower among a field of mirrors. In several Californian plants planned for solar thermal changed plans to solar PV — see mention of Blythe, Imperial Valley and Calico below.
In China commissioned a 2. Storage capacity of MWh is claimed. The Indian government announced the 4 GWe Sambhar project in Rajasthan in , expected to produce 6. The 2. There is a 97 MWe Sarnia plant in Canada. Research continues into ways to make the actual solar collecting cells less expensive and more efficient.
In some systems there is provision for feeding surplus PV power from domestic systems into the grid as contra to normal supply from it, which enhances the economics.
A feed-in tariff regime will support this. The particular battery system required is designed specifically to control the rate of ramp up and ramp down. System life is ten years, compared with twice that for most renewable sources. The manufacturing and recycling of PV modules raises a number of questions regarding both scarce commodities, and health and environmental issues.
Copper indium gallium selenide CIGS solar cells are a particular concern, both for manufacturing and recycling. Silicon-based PV modules require high energy input in manufacture, though the silicon itself is abundant. Recycling solar PV panels is generally not economic, and there is concern about cadmium leaching from discarded panels.
Some recycling is undertaken. Solar thermal systems need sunlight rather than the more diffuse light which can be harnessed by solar PV. They are not viable in high latitudes. A solar thermal power plant has a system of mirrors to concentrate the sunlight on to an absorber, the energy then being used to drive steam turbines — concentrating solar thermal power CSP.
Many systems have some heat storage capacity in molten salt to enable generation after sundown, and possibly overnight. In there was about 6. World capacity was 5. The concentrator may be a parabolic mirror trough oriented north-south, which tracks the sun's path through the day. The fluid transfers heat to a secondary circuit producing steam to drive a conventional turbine and generator.
Several such installations in modules of up to 80 MW are now operating. Each module requires about 50 hectares of land and needs very precise engineering and control. These plants are supplemented by a gas-fired boiler which generates about a quarter of the overall power output and keeps them warm overnight, especially if molten salt heat storage is used, as in many CSP power tower plants.
A simpler CSP concept is the linear Fresnel collector using rows of long narrow flat or slightly curved mirrors tracking the sun and reflecting on to one or more fixed linear receivers positioned above them. The receivers may generate steam directly. The plant was projected to produce GWh per year and covers about hectares with mirrored troughs that concentrate the heat from the desert sun onto pipes that contain a heat transfer fluid.
Andasol, Manchasol and Valle have 7. It has a ha solar field and started operation in Abengoa's MWe Mojave Solar Project near Barstow in California also uses parabolic troughs in a ha solar field and came online in It has no heat storage. However, this became a solar PV project, apparently due to difficulty in raising finance.
Solucar also has three parabolic trough plants of 50 MW each. Power production in the evening can be extended fairly readily using gas combustion for heat. The steam cycle uses air-cooled condensers. There is a back-up gas turbine, and natural gas is used to pre-heat water in the towers. BrightSource estimates that annual bird kill is about from incineration, federal biologists have higher estimates — the plant is on a migratory route.
Another MWe Ashalim plant developed by Negev Energy uses parabolic troughs and was also commissioned in Further phases of the project will involve solar PV. Using molten salt in the CSP system as the transfer fluid which also stores heat, enables operation into the evening, thus approximating to much of the daily load demand profile.
It also uses diphenol oxide or oil for heat transfer and molten salt for heat storage. Spain's Gemasolar employs tonnes of salt for both heat transfer and storage. SolarReserve filed for bankruptcy in It will have heat storage using molten salt. Majority ownership is by Huanghe. The project will apply to NDRC for feed-in tariff.
0コメント