A recent article discusses the differences in energy use in households between the developed and developing world both in terms of usage and sources of energy. It states that average global per capita household energy use in developed countries is about nine times higher than developing countries. In India, where 50% of its commercial energy demand is met through coal, there are high energy deficits due to growth in demand for electricity primarily from industries, agriculture, and urban households. However, it is also due to inefficient distribution at stages between electricity generation and end-use. In trying to make energy consumption more efficient, a number of decentralized supply systems for renewable energy are being tested such as those for solar power, wind energy, and biomass. It is suggested that besides being environmentally friendly, these systems may be the best option for long-term energy use and greater electrification rates.
Domestic energy consumption pattern varies from country to country depending upon their requirement for various activities. According to one estimate, per capita energy consumption ranges between 0.201 to 0.902 ToE (Tons of oil Equivalent)* respectively for India and USA (1 ToE = 42 GJ = 11 630 kWhr.). If China and India adopt Western Lifestyles, an extra 500 MToE/yr will be consumed. India, in particular would therefore need more and more power plants to match even the per capita of the world which stands at 0.348 ToE.
In view of the recent developments primarily focusing on ‘Energy Efficiency’, there has been a lot of awareness in India on the conservative approach by the end-users. An attempt therefore is made here to look at prospects of domestic sector focusing mainly on renewable options for households.
Background
Primary energy use of the household sector accounts for 15-25% in developed countries which could be higher in developing countries. Energy-based living standards and more efficient energy use are indeed opposing trends in developing countries that affect household energy consumption. Energy use in developing countries unlike western counterparts is primarily required for lighting, entertainment, water lifting and to a little extent air condition during peak summer months.
Work Program of the Commission on Sustainable Development on changing consumption and production patterns included “identifying the policy implications of projected trends in consumption and consumption patterns”.
In fact, review of 1992 (Earth Summit) progress report in 1997 provided the basis for policy recommendations of the above commission. The progressive evaluation provided substantial annual / five year statistics contributing broadly on the trends in each sector – selected minerals, private transportation, land resources and agriculture and energy and transport. While the household energy consumption pattern at the global and regional levels are most indicative of movement towards or away from sustainability, the same at the national level examines the impact of policies on trends.
Global Household Energy Use
The average global per capita household energy use in developed countries is about nine times higher than developing countries. Non-commercial fuels provide a large share of household energy in developing countries. North America presented decline in per capita household energy consumption as a result of many factors including increased energy efficiency and saturation with domestic electrical appliances. In contrast, this was higher in Africa owing to a higher share of fuel wood and other biomass as energy source. Such differences are extremely apparent between rural and urban populations; high and low income groups not only within the country but even among countries.
While climatic and cultural differences are important, urbanization and economic development are factors which account for these differences. Traditionally, fuel wood, charcoal and agricultural wastes constitute major sources of household energy consumption. Efficiency of liquefied Petroleum Gas (LPG) however is almost 4 times of traditional fuel wood. Savings from efficient technologies for cooking, heating and lighting combined with building insulation provides substantial savings. However, diffusion of such options in developing countries is rather slow mainly because of the inability to afford initial high cost directly related to low income. Shortage of particular fuel, distribution network and failure of distribution system further add to immediate adoption.
What is the Alternate?
India, the 6th largest energy consumer supplies 3.4% of global energy consumption to 17% of the global population. More than 50% of India’s commercial energy demand is met through coal. While the investment in recent years on renewable has been substantial, a massive commitment towards various nuclear reactors has been made.
A report published by Citigroup Global Markets, India is expected to add 113 GW of installed capacity by 2017. Renewable share might increase to 36 GW.
The current installed capacity as on April, 2011 is 1, 74,361 MW — 1, 13,559 MW Thermal; 37,567 MW Hydro; 4780 MW Nuclear; 18455 MW Renewable Energy Sources and 19509 MW Captive.
Power sector problems seem quite unique despite huge investment since independence and increase in generating capacity. Moreover, social, economic and environmental implications of late clubbed with huge extension of grid based electricity supply attract careful review from not only the point of sustainability but, more importantly global warming perspective as well.
Grid based centralized generation in India coupled with long transmission lines, complex distribution network associated with transformers, reduced reliability and increased capital & operational costs invite efficient huge organizational structure. Human induced error will however be inevitable. Such a system could be economical with large size power plants and concentrated loads which are unfortunately a mismatch with Indian villages spread apart.
Between 1996 and 2009 the peak power deficit has touched a maximum of 18% and annual energy deficit has gone up to 11.5%. The deficits experienced during the last two decades can be attributed to two main reasons. One reason is the huge growth in demand for electricity, mostly from industries and agriculture. Urban residential load also has seen considerable growth largely because of the penchant for energy guzzling gadgets like air conditioners, refrigerators, water heaters, computers and many types of entertainment tools. The other reason is the unbelievable level of inefficiencies at all stages between electricity generation and its end use.
The other limitations of the industry are: the unscientifically targeted subsidies which have become unsustainable; huge losses incurred by the electricity supply companies, which alone is reported to be about Rs. 25,000 crores a year; Urgent measures such as improving the generating plant performance; reducing the T&D losses; minimizing the wastage in end usage; optimize the demand side management (DSM); and maximizing energy conservation will be able not only to eliminate the existing deficits, but also will be able to meet a good portion of the future electricity demand.
A number of pilot projects across the country have indicated that decentralized supply systems based on renewable energy sources such as solar; wind, bio mass etc. are the best supply options to most of the rural areas of our country. Many of these renewable energy sources such as solar water heaters have already become established as good sources of renewable energy in urban areas like Bangalore, while solar photovoltaic panels are getting widely used in rural areas. Adequate support by the state and central government in the form of well-targeted subsidies and/or suitable tariff policies to encourage feed-in-tariff mechanism has the potential not only to drastically reduce the pressure on the existing grid but also to reduce the future load on the grid.
The decentralized supply systems based on renewable energy sources appear to be the only way of achieving 100% electrification in the near future.
Renewable Potential for Households
Recent publication — ‘BP Energy Outlook 2030’ — outlines forward-looking analysis of long-term energy trends with educated guesses about the course of economic growth, policy and technology. The report indeed is a distillation of what ‘today’s elite’ expect in the next two decades which is unsurprisingly, disturbing.
How do we meet the growing power demand and with what kind? The report indicates that the renewables and natural gas are likely to grow faster while oil and coal to substantially slow. However, there will be more oil and coal burnt in 2030 than 2011. This fossil fuel growth will undoubtedly promote GHG build up thus complicating the task on their reduction. We of course know where we are in our current GHG issue, — still struggling with solutions.
Let me quote from one of the recent publications, “According to the best judgment of our intellectual elites, our current path leads to catastrophe. Yet those elites cannot even envision a scenario in which that catastrophe is avoided. We’re headed for suffering and we have no idea how to avoid it”.
Resources constraints seeking technological breakthrough coupled with serious effort on global policy could perhaps be the solution.
However, it is indeed time that we as individuals start thinking hard on solutions on our own without being silent spectators on the developments in the electricity sector, WHICH may not happen at all considering the current priorities.
Looking at the global developments on the renewables and the recent findings, renewables could save us (households) from our current dependence on electricity boards for our meager power requirement. Everyone is of course aware the renewable’s journey so far. Although they apparently seem cost-prohibitive at this juncture, the rapid efforts of the global scientific community seem to make it reasonably affordable and perhaps could make it more competitive with fossil fuel generation pretty soon.
Solar, wind and to a little extent hydro could be the solution to make the individual households independent in their power requirement. An attempt is made here to outline the ‘action plan’ on these options to enable those interested to incorporate them and set a model not only for themselves but to the community at large.
1. Solar:
The amount of solar energy reaching the surface of the planet in a year is so vast that it would be twice obtained from all non-renewable sources. Solar, wind or biomass could supply our energy needs. However, being intermittent resources, there are other limitations for these resources. Solar power is conversion of sunlight into electricity either using photovoltaic (PV) or Concentrated Solar Power (CSP).
The intensity of sunshine has also been applied to generate clean ‘Green Energy’ from roof top panels. Clean path Ventures have in fact extended this benefit in the form of ‘Solar Farms’ and offering ‘garden plots’ to homeowners who own the electricity generated by their photovoltaic panels. Apartment dwellers and other residents (where, rooftop solar arrays are not suitable) are offered to own a piece of the power plant.
Similar to solar farms, solar shares program provides customers the option of buying power from a half-kilowatt or one-kilowatt portion of the solar farms. A household using 2,158 kilowatt-hours annually, one-kilowatt solar system would account for 81% of their electricity consumption.
In fact, rooftops are indeed an ideal solution to households in India consuming one kilowatt or less than one kilowatt. Since modern energy systems assume continuous power and to account for seasonal variations, energy storage is an important issue as solar energy is not available during cloudy days and at night.
Thermal mass systems can store solar energy at domestically useful temperatures for daily or seasonal variations. Well-designed systems can lower peak demand, shift time-use to off-peak hours and reduce overall heating and cooling requirements. Phase change materials – paraffin wax and Glauber’s salt which are inexpensive and readily available are capable of delivering domestically useful temperatures, are other thermal storage media. Solar energy can be stored using molten salts – Solar Two is estimated to store 1.44 TJ in 68 m3storage tank with an efficiency of about 99%. Rechargeable batteries serve excess electricity storage for off-grid PV systems.
The new constructions therefore, can plan such options right in the beginning as it is worth becoming electricity independent. In a few cases where the power generation is in excess of the requirement, it could either be stored or fed to the grid after appropriate follow up of guidelines.
Despite huge potential, high installation cost and inability to produce energy at night were great limitations of solar power. However, these two seem to have been adequately addressed over the last few years which should encourage consumers to go for it with least reservations.
-Keahole Solar Power’s new Holaniku Solar Farm (2 MW) on Hawaii’s Big Island has set up thousands of micro-scale solar power concentrators to generate energy efficiently even in the dark.
-17 MW Spanish solar project : The flagship project from Torresol Energy Investment uses molten heat systems to store heat during the day so that electricity can also be produced during the night.
It is estimated that in a day, a well-located PV panel will typically generate between 2.5 and 5 times its rated power output. Therefore, a 1kWp (kilowatt peak) PV panel could produce between 2.5kWh (kilowatt hours) and 5kWh per day, or between 880kWh and 1750kWh per year.
Continued decline in the cost of building solar plants is allowing developers to compete with fossil energies in certain markets.
Here’s another important statistic: When SunPower built the 14-megawatt Nellis Air Force Base system in 2007, it cost $7 per watt. Today, commercial and utility systems are getting installed at around $3 per watt. In 2010 alone, the average installed cost of installing solar PV dropped 20 percent. It would appear that solar PV is also cheaper than new nuclear:
2. Wind:
Tropical country like India is also blessed with wind energy potential. Although the option was cost prohibitive a couple of years back, thanks to the recent scientific and technological improvisations which prompt them as one of the options, at lease for households requiring power in the range of 1 kilowatt hour. We can’t however think of a wind farm on our roof tops. As hybrids are experimented even commercially, wind could supplement solar on roof tops.
In addition, there is indeed a possibility of storage here. North Carolina power giant along with Xtreme Power propose world’s largest wind battery storage project which could best guide storage of smaller capacities to meet household power requirement.
Wind turbines generate DC current for battery charging. Wind turbines suitable for residential or village scale wind power range from 500 Watts to 50 kilowatts.
Hybrid options aren’t any more distant dreams. While combinations of renewable were experimented, GE has come up with a new hybrid plant soon to be commissioned in Turkey using Natural Gas, Solar Power and Wind energy to produce 530 MW, first of its kind to go live in 2015.
3. Hydro:
Conventionally, the household daily water requirement is pumped into overhead tanks and used at convenient outlets in the house. They do experience adequate pressure through some of these outlets. Since the basic principle of hydro generation is through water falling from a height, there is scope to tap this option into electricity generation for the households. The amount of electricity that could be generated can be calculated by the simple formula: Q x H / 300 = kWh where Q is flow of water (m/sec) H is the height from the overhead tank.
Water flow is measure in gallons per minute (gpm) cubic feet per second (cfs) or liters per second (l/s). More head uses less water and the equipment could be smaller and the turbine runs at higher speed. Since power is the product of head and flow, more flow is required at lower heads.
While 20 ft at 100 gal/min generates 200 Watts, 100 feet head at 20 gal/min generates the same output. Micro turbines could facilitate this power generation. We need to identify suitable capacity and enhance the same depending upon the potential over a period of time. Micro portable hydel sets with no maintenance cost can provide electricity to small cluster of villages in hilly regions of India.
Basic principle could be similar to Hydro Electric Power generation as Overhead tank would act as Forebay tank and gravitational flow of water will have enough pressure to turn the turbine or water motor to generate electricity.
A recent communication hints at five of the top methods for integrating renewable energy into the grid — proving that intermittency isn’t the showstopper that critics make it out to be.
The combinations of solar, wind and hydro as proposed above could free households from their dependence on electricity boards for their power requirement.
Since the recent emphasis on ‘Energy Efficiency’ has provided quite many simple options to minimize our energy requirements, the net energy requirement could perhaps be much less than what could have been initially worked out. Some of the energy efficiency options are : Turn off lights, TV or other appliances when not in use; Replace incandescent with fluorescent bulbs; use low-watt bulbs where lighting is not critical; reduce hot water usage to the extent possible; sensors wherever possible to minimize water usage.
There are in fact, other developments which could be add on to the above scheme at an appropriate time. Scientists have attempted electricity out of water more efficiently than conventional solar cells where one and half bottles of wastewater could power the entire house for a day. The estimate could be mind blowing — ” Nocera estimates that the world consumes 14 terrwatts (TW) of power today. By 2050, it will need 16 TW. If this solution works, said Nocera, it would need a swimming pool full of water every day to meet the world’s electricity needs.
Scientists at Massachusetts Institute of Technology (MIT) have created what may be the first practical artificial leaf — a device about the size of a playing card capable of splitting water into hydrogen and oxygen and storing the energy in a fuel cell. Placing the leaf it in a single gallon of water in sunlight could produce enough electricity to supply a house in developing countries with its daily electricity requirement, according to researchers.
More importantly, effective policy can work miracles.
http://www.energypulse.net/centers/article/article_display.cfm?a_id=2461