Beyond Sustainable Economy: Renewable Energy Sources

Published: 27.08.2017

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Introduction

It is fashionable nowadays to promote renewable energy sources such as wind, solar, and biofuels as the answer to all energy and environmental problems. But it is not at all that simple. [A lot of notes have to be made with the several forms of alternative energy sources, and some will appear to be worse than the sources they are supposed to replace.] The low power density of these sources means that they require vast areas of land (or water). [An example is that local] residents and environmentalists often oppose 'green' energy sources: e.g. people living near proposed wind parks tend to oppose them because they disfigure the landscape, [are noisy] and kill birds; conservationists have opposed hydropower dams because they disrupt river ecosystems, kill spawning fish populations, and release large amounts of methane from decaying vegetation along riverbeds, etc.

[As we see in the below table, fossil] fuels and nuclear energy have power densities 10 to 10,000 times greater than those of renewable energy resources. David MacKay (2009, 112, 167, 367) gives the following figures:

Power source Power density (W/m2)
Nuclear
Solar PV panels
Hydroelectric
Onshore wind
Offshore wind
Tidal stream
Tidal pools
Biomass
Corn for bioethanol
Rainwater (highlands)
Geothermal
1000
5 to 20
11
2
3
6
3
0.5
0.002 to 0.05
0.24
0.017

In 2009 less than 8% of US energy consumption came from renewables: biomass 3.88%, hydro 2.68%, wind 0.70%, geothermal 0.37%, solar 0.11% (llnl.gov). [in 2014, about 9.8 percent of all energy consumed in the United States was from renewable sources[i], and they account for about 13.2 percent of the nation's total electricity production[ii]].[2] In January 2011 President Obama called for the US to generate 80% of its energy from 'clean' sources by 2035. This is more realistic because in 'clean energy' he includes nuclear energy, 'clean coal' (i.e. coal plants that use low-emission technology or carbon capture and storage), and natural gas, in addition to traditional renewables.

Before the industrial revolution everyone [in Europe] lived on renewables, but lifestyles and population densities were very different then. An average person consumed about 20 kWh of energy per day. Each person used 4 kg of wood per day, which required 1 hectare (10,000 m2) of forest per person. The area of land per person in Europe in the 1700s was 52,000 m2, falling to 17,500 m2 in regions with the highest population density. Today the area of Britain per person is only 4000 m2, so even if the country were completely reforested, a traditional lifestyle would no longer be possible (MacKay, 108).

The average energy consumption in the UK [today] is 125 kWh per day per person, excluding imports and solar energy acquired through food production. To provide this by means of renewable resources, would require covering an area the size of Wales with wind turbines, an area half the size of Wales with solar panels, and 75% of the UK (i.e. all its agricultural land) with energy crops, and also building wave farms along 500 km of coastline. [A comparable story would apply to all countries in the world.]

Wind

If we consider only the flux of the wind's kinetic energy moving through the area swept by wind-turbine blades, the power density is commonly above 400 W/m2 in the windiest regions. But because wind turbines have to be spaced 5 to 10 rotor diameters apart to minimize wake interference, the power density expressed as electricity generated per square metre of the area occupied by a large wind farm is a small fraction of that figure. We also have to take into account that a wind turbine's rated capacity (the power generated in optimal wind conditions) has to be reduced by the capacity factor (or load factor), i.e. the percentage of time that the wind allows turbines to work optimally. This figure is commonly put at 30% for the UK, 22% for the Netherlands, and 19% for Germany (MacKay, 267). This reduces year-round average power densities for large-scale wind generation to no more than 2 W/m2.

If 10% of the US electricity generated in 2009 (45 GW) were to be produced by large wind farms, they would have to cover at least 22,500 km2, roughly the size of New Hampshire (Smil, 2010b). If the windiest 10% of the UK were covered with wind turbines (delivering 2 W/m2), we would generate 20 kWh per day per person - or half the power used by driving an average fossil fuel car 50 km per day (MacKay, 33).

A recent study by Stuart Young Consulting, 2011, found that from November 2008 to December 2010 the average output of UK wind farms metered by the national grid was only 24% of rated capacity. During that period, wind generation was below 20% of capacity more than half the time, and below 10% of capacity over one third of the time. At each of the four highest peak demands of 2010, wind output was only 4.7%, 5.5%, 2.6% and 2.5% of capacity.

The variability of the wind means that wind power (like solar power) is not 'dispatchable' - meaning that you can't necessarily start installations up when you most need them. Wind turbines therefore have to be backed up by gas-fired plants or, in less wealthy nations such as China, coal-fired plants, thereby making wind power more expensive than conventional power generation. So adding wind (or solar) power to the grid does not replace an equivalent amount of fossil-fuel generating capacity. A survey of US utilities revealed that wind power reduces the installed power capacity at thermal power stations by 3 to 40% of rated wind capacity, with many falling in the 20 to 30% range (Cleveland, 2011).

A large wind farm reduces annual CO2 emissions by considerably less than the annual emissions of a single jumbo jet flying daily between Britain and America. Moreover, the construction of wind turbines generates enormous CO2 emissions as a result of the mining and smelting of the metals used, the carbon-intensive cement needed for their huge concrete foundations. (Booker, 2011). A typical megawatt of reliable wind power capacity requires about 32 times as much concrete and 139 times as much steel as a typical gas-fired power plant (Bryce, 90).

Nearly all the wind turbines now being produced depend on a rare-earth element called neodymium, whose supply is controlled by China.

In China itself, we find an 8-km-wide, 30-m-deep lake of toxic waste at Baotou. Seven billion kilograms of waste a year are discharged into the foul-smelling lake by the rare-earths processing plants in the background, with a devastating impact on local residents' health. The region has over 90% of the world's reserves of rare-earth metals, notably neodymium, which is used to make magnets for wind turbines and hybrid cars. (thegwpf.org)

Cattle can graze and crops can be grown beneath wind turbines but humans cannot live close to them because the low-level noise caused by the massive blades disturbs sleep patterns and can cause headaches, dizziness and other health problems. Wind turbines also cause other hazards. On the basis of available data (which are not comprehensive), there was an average of 103 accidents per year in the wind industry from 2005 to 2010, including 73 fatalities (Caithness Windfarm Information Forum, 2011). Most incidents were due to blade failure, in which whole blades or pieces of blade are thrown up to 1300 metres. Hence the proposal for a buffer zone of at least 2 km between turbines and residential areas. Fire is the second most common incident; because of the turbine height, the fire brigade can do little but stand and watch. Some incidents were due to ice being thrown from the blades for up to 140 m.

The worldwide mortality rate for wind power is about 0.15 deaths per trillion watt-hours (TWh). This is roughly the same as the figure for the mining, processing and burning of coal to generate electricity according to some researchers, or half that figure according to others, though this doesn't include increases in mortality from the air pollution resulting from burning coal (wind-works.org).

Another objection raised against wind power is bird kill, but this needs to be put in perspective. The American Bird Conservancy estimates that every year between 100,000 and 440,000 birds are killed by wind turbines in the US. But it also estimates that every year between 10 and 154 million [- how reliable are these estimates!?] - birds are killed by power lines, between 10.7 and 380 million by traffic, and between 100 and 1000 million by glass (abcbirds.org). In Denmark an estimated 30,000 birds per year are killed by wind turbines, and about a million by traffic. In Britain 55 million birds per year are killed by cats (MacKay, 63).

[So in a relative sense, the killing of birds by wind turbine blades is not high - but even one bird is a bird too much when seen within ahimsa philosophy.  All are victims of human activity (and cats) and can be avoided if energy is harvested from other sources.

It seems that we may conclude that, apart from local small scale applications in generally very windy areas of the earth, such as some specific (often very beautiful) mountain gorges or mountain tops - and I would already begin to protest before the ideas is born! - the only right place for wind parks or farms would be the open sea (or, occasionally but not preferably, large lakes), also known as off-shore wind power or energy. This is already done in, for example, the North sea between Britain and Holland, and along the coasts of 10 European contries. In 2014 80% of the world's off-shore wind energy was produced by Germany and Denmark. China has big plans, leading to a production of 30 GW  and it is expected that world-wide 70 gigawatts of wind energy will be produced

As of January 2014, German wind turbine manufacturer Siemens Wind Power and Danish wind turbine manufacturer Vestas together have installed 80% of the world's 6.6 GW offshore wind power capacity; Senvion-REpower comes third with 8% and Bard (6%).[3] Projections for 2020 calculate a wind farm capacity of 40 GW in European waters, which would provide 4% of the European Union's demand of electricity.[4] Even so, 4% is not very much. It could become more in the future - but just calculate what it would cost to provide the whole world with energy along this line! And so far you can not (yet) drive cars on electrical energy which answer the demands of average car drivers. The Chinese government has set ambitious targets of 5 GW of installed offshore wind capacity by 2015 and 30 GW by 2020 that would eclipse capacity in other countries. In May 2014 the capacity of offshore wind power in China was 565 MW.[5]

India is looking at the potential of off-shore wind power plants, with a 100 MW demonstration plant being planned off the coast of Gujarat (2014).[6] In 2013, a group of organizations, led by Global Wind Energy Council (GWEC) started project FOWIND (Facilitating Offshore Wind in India) to identify potential zones for development of off-shore wind power in India and to stimulate R & D activities in this area FOWIND. In 2014 FOWIND commissioned the Center for Study of Science, Technology and Policy (CSTEP) to undertake pre-feasibility studies in eight zones in Tamil Nadu which have been identified as having potential.[7]

 The winds at seas are more predictable and steady and usually stronger than the winds over land. It is not difficult to find out which seas are the windiest and the most constant over time. Unless there are uninhabited far off-coast islands are available, the windmills would have to be anchored (deep) below the surface, or be floating. If floating the mills should be stabilized (by heavy anchors below the surface, or by connecting them rigidly by horizontal bars or grids.) not to flatten down towards the sea. They would not have to be as high above sea level like the one's on land which have to rise above all obstacles. Still it would in many places be extremely costly both in building and maintenance, and the wind farms would have to cover large surfaces. An advantage would be however that the size of the seas are so enormous that, even when we were to provide the whole of humanity of energy in this way, the plants would take only a minute part of the available surface on earth. At this moment off-shore wind energy is more costly than fossil fuel energy, but it is estimated that this balance will change in the coming years. Still we would be dependent - politically and economically on particular countries providing certain rare materials as mentioned above. This problem again might be counteracted - if the available space for building them is no major issue, by building wind turbines that are less efficient, but independent or less dependent on these rare materials.

Bird killing (or any serious hazard or disturbance and 'decrease of happiness' of living beings - for example fish and seas mammals) poses an ethical brake on all big scale plans. Some dire side effects of any project may be prohibitive. But methods may be worked out by ornithologists so that birds may be magnetically and/or visually deceived in order to make them fly a slightly different route over sea. On land this would be more difficult, because there birds tend to orient themselves on basis of particular landmarks like coastlines and mountain ranges, but at sea  - perhaps: I am not aware that any research has been done in this direction - a sequence of artificial floating islands  parallel to and perhaps made attractive to birds, but just off the traditional flying route, might solve the problem. Another method might be to project images into the sky en route that birds naturally avoid - such as predator birds.

Windmills are often regarded as 'ugly' and as horizon pollution and unpleasantly noisy. All this would not apply if wind parks are situated far enough away from the coast. Advantages are that wind will never get exhausted, and that - apart from their one-time production, no air pollution or other chemical or radioactive pollution is brought forth. Wind is available everywhere, though in varying quantities. Using wind energy, like solar energy, is a form of 'accepting what is given by nature' and therefore always to be preferred above mining and drilling.]

Sun

Solar energy is the only essentially unlimited renewable resource. [It is a 'gift of nature' which goes to a large extend unused, while using it in itself can not be regarded as a form of parigraha.] It can be harvested and used in different ways:

- Trees, plants and vegetation absorb solar energy through photosynthesis and store it in chemical form. This energy is consumed directly when these materials are burned as fuel, or eaten by humans and animals, or it may be turned into bio-fuels, chemicals, or building materials. [Burning of vegetable materials, especially when wet, is highly inefficient and polluting. In fact biomass consumption for delivering heat, light and electricity is a renewable resource, and plant growth is a direct and fully natural way of capturing or accepting solar energy provide by nature. The pros and cons of biomass as source of energy are discussed in the appropriate section.]

- By means of solar thermal collectors (e.g. on roofs), sunlight can be used for direct heating of buildings or water. [This is widely done in poorer countries and increasingly elsewehere. Most or many houses in mountainous and rural regions now have simple, low-tech solar heaters: just blacked panels behind glass which collect enough heat to boil water. Disadvantage is that these provisions provide cold showers when the sun does not shine and it is cold and hot showers when it is warm. At night they don't work. An advantage is that cheap solar water heaters if needed can be repaired by the locals themselves.

In combination with a system of water storage tanks or tubes in floors and walls cold nights could become more comfortable and less fuel would be needed to heat the stove. If photovoltaic cells become affordable, solar energy may be used to produce storable energy. Other devices are parabolic water cookers, lamps that load through solar cells.]


- Photovoltaics (PV) converts solar radiation directly into electricity by means of solar panels composed of cells containing a photovoltaic material (e.g. silicon). The concentration of sunlight onto photovoltaic surfaces is known as concentrated photovoltaics (CPV). [It is more expensive and dependent on 'rare earths' - specific chemical elements which are not globally available.]
- Concentrated solar power (CSP) uses lenses or mirrors to concentrate a large area of sunlight onto a small area; the concentrated light is then converted into heat which drives a heat engine (usually a steam turbine) connected to an electrical power generator. [On a small scale the same system can be used for cooking food and heating water.]

Covering the south-facing roof of homes with photovoltaics may provide enough electricity to cover a large share of average electricity consumption, but roofs are not big enough to make huge dent in our total energy consumption (MacKay, 40). When the sun goes behind clouds photovoltaic production falls roughly 10-fold. Moreover, this method is less effective for two, three or more storey homes and high-rise buildings, where the percentage of the surface exposed to the sun is less.

Solar cells have a range of efficiencies, however the power densities of all types of solar power generation are well below those of conventional energy sources: The best cells have efficiencies surpassing 30% (for multi-junction concentrators) [Spectrolab (a subsidiary of Boeing) scientists also predict that concentrator solar cells could achieve efficiencies of more than 45% or even 50% in the future, with theoretical efficiencies being about 58% in cells with more than three junctions.] and about 15% for crystalline silicon and thin films, actual field efficiencies of photovoltaic cells that have been recently deployed in the largest commercial parks are around 12%, with the ranges of 6-7% for amorphous silicon and less than 4% for thin films, but the best applications can an average efficiency of 19% up to 21.5%]. A realistic assumption of 10% efficiency yields 17 W/m2 as the first estimate of average global PV generation power density, with densities reaching barely 10 W/m2 in cloudy Atlantic Europe and 20-25 W/m2 in subtropical deserts. (Smil, 2010b, 12). [Here we see how big is the difference between various climates.]

So although the largest solar PV parks generate electricity with power densities roughly 5 to 15 times higher than for wood-fired plants, this is at best 1/10 and at worst 1/100 of the power densities of coal-fired electricity generation. If only 10% of all electricity generated in the US in 2009 (45 GW) were to be produced by large PV plants, the area required (even with an average power density of 8 W/m2) would be about 5600 km2.

Environmental groups have criticized solar parks for taking up too much desert land, thereby displacing certain animal and reptile species. [Animal life should taken be seriously into account in decision taking and planning. As to human inhabitation, most deserts are thinly populated, but whatever human replacement this should, from an aparigrahic and any decent point of view, be done in full agreement with those concerned - and the people should always receive more in life quality than they lose. Another factor to be considered is the effect on the microclimate large surfaces of solar panels will induce.] The use of photovoltaic collectors is also challenged because they contain highly toxic heavy metals, explosive gases and carcinogenic solvents that present end-of-life disposal hazards (Bell, 2011). One million square kilometers would provide enough electrical energy for the present world population.

[If, theoretically, all these solar panels would be put together in one park, this would amount to 1000 x 1000 kilometer or 600 x 600 miles. This is very small compared to the total surface of the world's deserts. Not all deserts are as fit for this purpose as others - some are more just more dusty than others, so at such places more cleaning and maintenance would be required, which would reflect in the prize per energy unit. The surface of deserts - of which Antarctica is the biggest - in the world is 33 % of the land mass of the earth (http://www.universetoday.com/) (The land mass of the earth is 29 % against 71% water). As the earth's total surface is 509 million square kilometers, deserts cover about 50 million square kilometers. So if 2% of the deserts would be covered with solar panels, the world energy problem would, theoretically, be solved.

Of course in practice much smaller solar parks could be built in hundreds or thousands of places around the world. Some or the largest deserts are situated in what are now the oil-producing countries, and if they take quick initiatives the sale of electricity would partly substitute for their loss of oil revenues in the future. The Arabian countries could produce for large parts of Asia, and the North-African countries for Europe. Every continent has large deserts. At the same time the world at large could become largely independent on the present economic and political power structures connected with oil which haunt humanity at the moment. Such dependence to any specific political or economic power should at all cost be prevented for the future. Electricity can be much more easy and efficiently transported than oil.

The most efficient solar panels with photovoltaic units are dependent on rare materials found in only a few countries the world over - and this could rise to new economic and political dependence. Also the waste, produced on large scale when replacing old panels with new ones, if not recycled, is highly toxic. However, there are also simpler, though less efficient solar panels which depend merely on plates covered with black carbon (soot) and water. The soot absorbs heat and the heated water can drive turbines. This method of energy hoarding is just a more sophisticatd and efficient version of what is already done by millions of villagers in economically poorer regions everywhere on earth. At the side of this, such plates, in combination with sea water could be used for large scale desalination, and the water, if guided efficiently, could be directly used for very efficient agriculture in sunny countries. The use of solar energy is a from of 'receiving what is given by nature', involves minimum violence to the planet and to living beings. As the sun is there for everyone everywhere, tapping of solar energy is in harmony with aparigrahic philosophy.

The ahimsa factor

In an article titled Green deaths: The forgotten dangers of solar panels in Asian Correspondent (asiancorrespondent.com) of 17th May 2011 by Gavin Atkins, mainly based on the situation in Australia, we find that solar panels - especially when the construction of them is concerned, may not be as save as we might think, and actually shows bad compared to harvesting of nuclear power and even fossil fuels. "In recent years, thousands of solar panels have been placed on Australian roofs, and millions installed around the world. But how safe are they?

According to Safework Australia, each year about 30 Australians die in falls from a height, although the number of people involved in installing or maintaining solar panels is not broken down. Some falls involving people installing or maintaining solar panels are not reported as part of work-related statistics, and then there are people electrocuted when they come into contact with power lines. In California, where solar panels have been embraced enthusiastically, there has been a rash of deaths like this one, this one, and another three in quick succession. However, it is a worldwide phenomenon, so much so that statistics show roofing is more dangerous than coal mining. Because of our propensity to put panels on roofs, solar is in fact, far more dangerous than many forms of power generation, three times more dangerous than wind power and more than 10 times more dangerous than nuclear power, by comparison to the amount of power produced.

This study puts it in perspective, using figures from the United States:

"The fifty actual deaths from roof installation accidents for 1.5 million roof installations is equal to the actual deaths experienced so far from Chernobyl. If all 80 million residential roofs in the USA had solar power installed then one would expect 9 times the annual roofing deaths of 300 people or 2700 people (roofers to die). This would generate about 240 TWh of power each year. (30% of the power generated from nuclear power in the USA). 90 people per year over an optimistic life of 30 years for the panels not including maintenance or any electrical shock incidents."

But, of course, we could learn to be more carful - these are human mistakes rather than inherent consequences of the use of solar energy in general (Editor.]

Bio-energy

Biomass energy, or bio-energy, is energy from plants and plant-derived materials. Wood is still the largest biomass energy resource in use today, but other sources include food crops, grassy and woody plants, residues from agriculture or forestry, oil-rich algae, the organic component of municipal and industrial wastes, and the fumes (methane gas) from landfills. As well as being converted into electricity, biomass can be converted into liquid fuels, or biofuels, [which can then be used directly for cars, industry and house warming. Biofuels can economically replace diesel and petrol.] The two most common biofuels are ethanol (made from corn and sugarcane) [as 'petrol'] and biodiesel (made from vegetable oil, animal fat, or recycled cooking grease). All these produce carbon dioxide though.

[However, fuel production becomes part of larger-scale agriculturists' interests and put a burden on food production. This will lead to rising food process worldwide.] A World Bank policy research working paper concluded that up to 70-75% of the rise in food prices from 2002 to 2008 was due to 'large increases in biofuels production in the U.S. and EU' and 'the related consequences of low grain stocks, large land use shifts, speculative activity and export bans' (Mitchell, 2008, 17). An OECD (2008) report gave the following assessment:

The impact of current biofuel policies on world crop prices, largely through increased demand for cereals and vegetable oils, is significant but should not be overestimated. Current biofuel support measures alone are estimated to increase average wheat prices by about 5 percent, maize by around 7 percent and vegetable oil by about 19 percent over the next 10 years.

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Sources


Title: Beyond Sustainable Economy
Author: Dr. Rudi Jansma, Dr. Sushma Singhvi
Publisher: Prakrit Bharati Academy
Edition:
2016


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  1. Ahimsa
  2. Concentration
  3. Gujarat
  4. Parigraha
  5. Science
  6. Space
  7. Tamil
  8. Tamil Nadu
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