Rain Water Harvesting - an imminent necessity

My mother remembers being able to feel the water in a well by just lowering her arm into it. This was the situation decades back in a water-well in my cousins’ place, right beside our house in Cuttack. Today, the well has water a few feet below; this being in a city surrounded by two rivers. Ground water depletion is not alien if you are living in bigger cities like Chennai, Bangalore, Delhi, etc. In Bangalore, 800-1000 feet depth is the norm of new bore wells in most areas. 20 years back, a 150 feet bore well was sufficient to get water in that area. Rampant usage and removal of rain water harvesting sites like lakes and ponds are the causes of this. Ponds being replaced with high rises are a common sight in every developing city. 

more than 200 days of free swach water considering Kejriwal’s 700 litre per day use. Imagine the amount of rainwater wasted every year.

What is ground water? 

Ground water is the rain water percolated in the earth’s porous surface. Consider the surface below us a huge water storage. The top soil layers (sand, silt, gravel) are porous. Rain water gets absorbed through these and moves down by gravity till it reaches an impermeable surface rock or cracks in such rocks. The rain water saturated in this region can be extracted for use by drilling a well. These water bearing rocks or unconsolidated materials (sand, silt, gravel) are referred to as an aquifer. The depth at which aquifers are found depends on the geology of the place and amount of rainfall it receives. In rocky high altitude Bangalore, the water table lies much lower than the riverbed city of Cuttack where bore wells of 100 feet can suffice. Bhubaneswar, the twin city of Cuttack, has a lower water table too owing to its slightly higher altitude and distance from big rivers. Apart from that, rampant construction has lead to ground water shrinkage in the capital city. New bore wells have average depths of more than 200 feet here. Well it is undeniable that dry aquifers can lead to catastrophic effects on human civilization; storm water off buildings and roads causing flash floods, or dry wells aiding water tanker mafias. 

The percolation pit and recharge well are functionally similar to a soak pit.

What can be done to recharge the ground water? 

Ground water has depleted because rain water has not been allowed to enter the aquifers. In urban areas, there are a few ways to recharge the ground water. One of the simplest ways is rain water harvesting off the surface of buildings instead of letting it run off in the storm water drains. Storing the rain water in underground tanks/sumps or drums is very effective. Rain water is one of the purest sources of water. However, the roof surface must be clean enough to ensure that this water is potable. A simple mesh filter is often enough to use this water for most purposes like cleaning, washing, bathing, etc. This directly reduces your water consumption. Rain water is water filtered to perfection by nature. When this water reaches polluted rivers or streams via storm water drains, it gets contaminated. Pumping and treating this water back to houses is wastage of huge amounts of energy. Soak-pits are another simple way of recharging ground aquifers. A soak-pit is essentially a small dug out pit lined and layered with permeable materials like sand, coal, gravel, etc where rain water is allowed to flow, get absorbed and filter into the aquifers. A small soak-pit of 4x4x4 (feet) dimension can do wonders to increasing your ground water level. Larger the soak-pit, greater is the water absorbed. 

Aquifer

Another important way is recharging your bore well directly with the rain water. This process involves adding filters to the rooftop storm water discharge pipe. Every defunct bore well should be fitted so. Alternatively, one can dig up a soak-pit near the bore well. This would filter the water better and prevent clogging but a lot of water would have to be diverted away as its capacity & filtration rates are low. 

How much water can be collected? 

Rain water collected = Area of catchment (roof) X Total rainfall in a year. For Bhubaneswar, which receives around 1500 mm of rain every year, the rain water that can be collected from 100 square meters roof is 150000 litres. This means more than 200 days of free swach water considering Kejriwal’s 700 litre per day use. Imagine the amount of rainwater wasted every year. 

Rain water harvesting needs to be implemented both on the individual and organizational level. The government needs to introduce laws which mandate rain water harvesting in every building and plot of land. Some states in India have laws for bigger buildings. Apart from that, community and public rain water harvesting projects can be undertaken to improve ground water levels. Soak-pits or recharge pits by the side of roads can immediately reduce chances of flash floods while recharging dried aquifers below. High rise buildings, where consumption is high per unit area, can greatly benefit from rain water to bore-well recharges. According to a recent report, 80% of surface water in India is contaminated. Water is extremely precious; we have to start caring immediately. 

Maruti Suzuki to launch Swift Hybrid - can 48.2 kmpl be real?

Maruti Suzuki is expected to launch the Swift/DZire Hybrid car in India this year. The car is ready and was driven around on World Environment Day (5^th June) in Delhi. This announcement comes after the introduction of FAME (Faster Adoption and Manufacturing of Electric Vehicles) by the NaMo Government. Under this scheme, four wheelers will get incentives ranging from Rs.13,000 to Rs.1.38 lakh from the Government of India. The Swift Hybrid will be a Range Extending Hybrid, that is it will have a 5kWh lithium battery, with a 55 kW(expected) permanent magnet synchronous electric motor and a 658cc, 3-cylinder petrol engine. The net power output will be 73bhp. Maruti claims an impressive fuel economy of 48.2kmpl which we will cover later. This car has an all-electric range of 25.5km. By plugging in to the mains(200 V), this car can be recharged in 90 minutes. The car weighs 1600 kg, which is substantially heavier compared to the petrol (965 kg) and diesel (1060kg) variants. 

The Maruti Suzuki Swift Range Extender Hybrid will have 3 modes - Series Hybrid, Parallel Hybrid and all-electric. In series hybrid mode, the 658 cc petrol engine charges the lithium-ion battery which then powers the electric motor. In parallel hybrid mode, both the petrol engine and the electric motor drive the car. In all-electric mode, it is battery power alone. 

The running cost can be assumed to vary between Rs.1.3 to Rs.4 per km

How efficient will it be?

48.2 kmpl seems like a tall claim and this is probably under ideal conditions(or all-electric mode only). The thing with hybrids is that the cost of running is very different when it runs on battery alone (all-electric mode) and when it runs on petrol mostly(series mode). The parallel mode will deliver an efficiency figure in between the other 2 modes. This engine used is the one powering the new Japanese Alto and Wagon R Kei cars. It is extremely fuel efficient, having a rating of 36kmpl for the Japanese Alto. Mind you, that Alto weighs weighs less than half of this Swift Hybrid. And more the weight, less the fuel efficiency. We assume 48.2 kmpl is the equivalent cost of running in all-electric mode. The 5kWh battery would need slightly more than 5 units of electricity to charge. Considering unit cost of 5 rupees, and the range of 25.5km, the running cost in all-electric mode would be around Rs.1.3/km which corresponds to the 48.2kmpl figure (Rs.67/48.2kmpl = Rs.1.39/km). The fuel efficiency in the series mode, that is after the battery charge from mains has depleted, will determine the real running cost of the car. If the car delivers 18kmpl (half of Alto Kei), then it will be as economical (around Rs.4/km) as a normal small car. Hence the running cost can be assumed to vary between Rs.1.3 to Rs.4 per km. 

Yes, it will definitely be more efficient than a normal small car because of regenerative braking. Regenerative braking is the process of recovering energy that would have otherwise been lost during braking. The electric motor runs as a generator when the accelerator is let off, thereby gradually slowing down the car and charging the batteries. This is extremely useful in busy roads. Regenerative braking also increases the life of brake pads. Thus, the hybrid is extremely efficient in a stop-start traffic situation. A petrol/diesel car wastes a lot of fuel idling. In hybrids, generally there is no idling as the electric motor and battery take care of the drive in choc-a-block traffic conditions. Energy is also recovered during braking. 

How well does it drive? 

The Swift petrol and diesel have been a hoot to drive. How the Maruti Suzuki Swift Range Extender Hybrid will drive is a big question. The extra weight due to the battery and electric motor, is a concern. The battery on the base will aid handling by lowering the center of gravity. Torque figures have not been released, but it is safe to assume that it will be high considering electric motors produce 100% torque from 0 rpm unlike petrol and diesel engines – where it is almost linearly produced. The power to weight ratio is not high, but it would be better to wait for the 0-60 figures to get an idea of its performance. 

Is it worth buying? 

This is difficult to answer as the prices have not been revealed yet. If Maruti were to price this slightly or in the range of the diesel variant, it could be well justified. Though there is the FAME incentive of Rs.1.38 lakhs, a few key components like the motor, battery, etc are going to be imported, and so it could be priced higher. The DZire can be a safer bet considering Maruti has a bigger margin there – around Rs.80k more for 10 kg of metal and a little bit of engineering. Plus the ‘sedan class’ image is a huge draw in India. The Swift Hybrid has the potential to become the 1^st mass market hybrid car in India as the only options currently are the Rs.30 lakhs plus Toyotas, the Prius and the Camry, or the Rs.2.2 crores BMW i8. 

Apart from that, if your everyday driving is around 25 km or there is a provision to charge the car at your office (just a 15A plug point), this could be very ideal for you. Public charging points are getting popular. In some European and American cities, there are more charging points for electric cars than petrol pumps. Mahindra has taken the initiative to introduce charging points in Bangalore at popular parking places like Malls, Coffee Shops, Offices, etc. Battery pack warranty is also a concern. Mahindra gives 5 years while California mandates 8 years on all battery driven vehicles. Hybrids offer the best of both worlds; they are greener than petroleum driven cars, while having no range-anxiety unlike pure electric cars. They weigh a lot more due to both powertrains and this is inefficient, strictly speaking in an engineering point of view. They are not so green if your daily drive is a lot more than their electric range. The future is bigger batteries, offering higher pure electric range (like the Chevy Volt – 60km and BMW i3 – 150 km) and smaller petrol engines just for ‘range extending’. This is until pure electric cars like the Tesla Model S become more affordable or the Nissan Leaf and Mahindra Reva e2o get more range.      

Indian Railways experiments Solar Powered Train - but is it green enough?

Indian Railways is the single biggest consumer of diesel fuel in the country. In order to save of heavy oil imports, the railways have recently affixed a few solar panels on a non-ac coach of the Rewari-Sitapur passenger train. This ‘solar powered’ coach produces 17 units of electricity in a day. Though it is very less compared to the total energy requirement of a train, the Indian Railways claim that such a train is going to save them up to 90000 litres of diesel and 200 tonnes of CO2 every year. This is impressive. It is very important to note that powering an entire train with solar panels on top is currently not possible.

(stat courtesy: http://www.dailymail.co.uk/indiahome...pollution.html)

The electrical power (17 kWh) produced by these solar panels can only be used for lighting and may be mobile charging points in the coaches. A ‘Solar Powered’ Train is still a distant dream. It is important to note here that 17 units of electricity are minuscule considering a 3000 HP train. We are assuming that such train would be consuming 20 kWh per km, which is 20000 kWh for a 24 hour trip. Even if all the coaches are fitted with solar panels, it would still be a mere 1-2 % of the total energy needs for the train. The entire surface area (40 m2) of the roof is not covered yet. If covered, an extra few panels can be accommodated. The Railways say that in a 40 hours trip, 15 hours will be exposed to the Sun as the train keeps moving. This is inefficient compared to stationary installations. Further there are shades from trees, tunnels, platforms and more importantly angle of inclination which will reduce the power generated. In comparison, the Indian Railways could install massive solar panels on top of stations and feed it into the grid. This would offset the carbon produced. But the Indian Railways’ biggest problem is that only around 34% of the routes are electrified. There are practical problems like theft of copper, lack of adequate power supply, security, etc. Hence putting up solar panels on top of the trains is a safer choice and this will help in direct reduction of expensive diesel fuel imports. It costs the Railways Rs.20 per unit for power generated from diesel. Plus PR wise, a train with solar panels on top makes more impact than others.

Even if all the coaches are fitted with solar panels, it would still be a mere 1-2 % of the total energy needs for the train...It is very important to note that powering an entire train with solar panels on top is currently not possible.

It will cost Rs.3.96 lakhs per coach and the payback period is 3-4 years. Maintenance wise, though this will be exposed to harsher climatic conditions compared to stand alone units - they will undergo a wash at the sheds which is debatable for stations or other rooftops. The Indian Railways going green is a welcome move considering the resources they have and need. On the environment day, the East Coast Railways has installed a 50 kW solar power plant on one of their buildings in Bhubaneswar. There is news that the Indian Railways is chalking out a 1000 MW solar power plan for their network. We hope they becomes greener by installing LED lights, harvesting rain water from stations, utilize toilet waste, making bio diesel by planting near tracks, and other ways.  

Paint the town white!

Summers are getting hotter. Air Conditioners are expensive. So are energy bills - which makes ACs un-affordable for many. Painting the roof white is a low cost solution to beat the heat relatively. This is for rooms and spaces where the roof is exposed to direct Sun light. A little bit of tech gyan first. Heat and light from the Sun travel together. A body is black in color because it absorbs all light falling on it. Hence it absorbs all heat too. A white body on the other hand reflects all light (and so heat) falling on it. In simple words, white is coolest, black is hottest. A dark concrete roof absorbs and transmits a lot of heat during daytime and also radiates during the evening. On the other hand a reflective surface like white painted roof reflects away the light and heat and is often several degrees cooler. Indoors can become 10-15 degrees (Celsius) cooler after being coated with white paint. The hot oven-like feeling on entering rooms during afternoon and evening can be eliminated using this technique. For buildings having air conditioning, energy bills will reduce as it takes lesser energy(also less power plants, less CO2) to cool a cooler room than a hot one. 

White roofs can also help reduce global warming too. According to a research by Department of Energy, USA, white roofs not only reduce air conditioning loads of a building but also help reflect back the solar irradiation back to space. Darker surfaces on the other hand absorb the heat during Sun shine, and radiate it afterwards making cities and the surroundings hot. This is urban heat island effect. These radiations being in different wavelength than the ones incident are not rejected back to space. Studies suggest that if roofs of all buildings in the whole world are painted white, global warming can be reverted. Yes, lower energy bills, a comfortable interior & also saves the environment.

The options:

White paints come in different forms. Traditionally limestone(choona) mixed with adhesive is available commercially in India. Lime is cheap and easy to apply. Other alternative is white cement paint, which is affordable and also is slightly better in resisting rains than lime. Do note that these two paints have to re-coated every year. Another alternative is elastomeric paints. Some Indian brands like ICI Dulux and Berger Paints sell it. These paints form a rubber like stretchable membrane on the surface and are highly resistive to rains. It can last 3-5 years. The downside is that it costs a lot, generally 20 rupees per square feet area. In contrast, lime and cement paint come at around just 1-2 rupees per sqft including labor charges.  

A permanent but expensive alternative is white ceramic tiles. They come at 50-60 rupees per sqft at the least. They can last a lifetime and are much easier to clean, and your terrace looks beautiful too. The roof can be water proof too if grouted properly. It provides an all year cooling as paints are usually washed after rains, and in our tropical climate, we often need air conditioning for more than 6 months in the year. Any white surface (both paints and tiles) provide a longer life to the roof, as expansion and contraction due to heat is greatly reduced. Crack formations are minimized too. Solar Reflectance Index (SRI) values on commercial products are a good way to compare - higher the better. For tiles, vitrified variety is better suited to outdoors due to lower water absorption capacity. 

White is the new green. Cars too in white color save fuel as compared to black ones. Yes your walls and everything exposed to Sun is better off in white. We do white cement paint every year and it is a big relief in this sultry Odisha heat. We have temperatures touching 45 degrees Celsius every summer. White paint works beautifully here. Let us know if you have done it, your experience or any questions if you have - we will be happy to answer them. So cool interiors, climate change arrest, longer roof life – when are you going white?

Electric buses - ideal for our cities

BYD K9 electric bus in London

The Bangalore Metropolitan Transport Corporation has recently started trial runs of Electric Buses for its vast public transportation network. Electric Buses are slowly gaining acceptance and have been adopted in few cities around the world. The most popular of these buses is the E9 – manufactured by BYD – a popular Hong Kong based battery and automobile company. Electric buses are commercially in use at various places in China. They are in trial at Utah, Chile, London, South Korea.

The batteries that BYD uses are Lithium Iron Phosphate, developed in-house. These give a range of 250km per charge, which is quite respectable for a day’s intra-city route. They can be charged in 6 hours at normal rate and 3 hours for a quick charge. Ideally electric city buses can be fully charged overnight or given short bursts of high speed charging during terminal stops. Another possibility is wireless induction charging. Read more about that here. It consumes 100 kWh in an hour and that translates to just Rs.4 per km, as compared to Rs.20 per km in diesel buses. The battery is expected to last 6000 recharging cycles or 1.5 million kms, thereby capable of saving nearly a crore of rupees before a battery swap. This is considering the fact that there are hardly any maintenance costs in electric vehicles. Unlike petroleum operated vehicles, they do not have filters, oil changes, turbochargers, etc. These expenses are a lot in heavy vehicles like buses, and the time taken to service also accounts for revenue loss. In fact there is only one moving part in the electric motor.   

Electric buses are an ideal choice for cities with dense traffic and otherwise too. They are very silent. A V8 roar may be appreciable in a sports car, but an old bus noisily accelerating and blowing soot on your face is never charming.  Apart from that, electric buses have regenerative braking. This is a technology that helps vehicles recover the kinetic energy of motion that is otherwise lost during braking. What happens is when the foot is left off the accelerator, the motor acts in reverse as a generator using the motion to top up the excess energy into the batteries. This also reduces the need of brakes in predictable situations (Bus routes = more predictable), thereby elongating the life of brake pads and shoes by a huge margin. This technique is very useful in stop-start situations which are very high in dense city traffic. Going downhill, a Mahindra Reva e2o (an electric car from India) has been able to recover 20% more range on the return journey on a particular trip to hilly region.  

Then there is the usual electric advantage of not wasting fuel at traffic stops – they use energy when the accelerator is pressed. Hence there is no wastage of energy like internal combustion engines which have to kept on during idling and consume fuel in that process. This is particularly beneficial in dense cities and typically for buses as they stop for loading and unloading of people. This frequent dis-acceleration also helps in regenerative braking. Also electric motors produce 100% torque at 0 rpm. This high torque nature is more suited to heavy vehicles like buses and trucks.

With rising costs of polluting petroleum, the operating cost difference will widen further for sure. Electric buses at present scenario are able to recover the initial investment fast too. A proper charging infrastructure is highly necessary. The grid needs to get greener. Dirty coal needs to be replaced with renewable sources like hydro, solar and wind energies. Karnataka produces a fair share of green electricity. These low floored, air conditioned electric buses will go head-on with the red Volvo city buses and are expected to be even more comfortable than them. They will also make the Bangalore air more breathable. We hope this model is a success and it is replicated in more cities throughout the country.

Why India needs economical and green two seater cars

Office hour traffic in India

How often is this nazara real – office hour, four doors and one person? This and innumerable motorcycles make up the city roads traffic scene in our country, apart from buses. This division between the two is primarily because of fuel economy – 15:60. This predominates the upfront cost difference too. The need of the hour is something in between a car and a two wheeler; in terms of fuel economy, cost and size. Two seater cars have never worked in India, but there seems to be a case for this now; more so because the population of both human beings and automobiles is rapidly increasing. Infrastructure issues are plaguing the country. Urban Indian life demands the need of a single person vehicle that protects one from the pollution, harsh weather conditions or simply from overcrowded uncomfortable public transportation.

Toyota iQ - a two seater compact car

A compact two seater the size of the Toyota iQ or the Smart Fortwo would be ideal for India. Parking woes have become a daily routine in urban places and are ever increasing. Worldwide, compact two seater cars in the affordable segment have worked in select places like a few European nations. But these cars are not really cheap there. Why are they expensive? Simply because they were never made for the Indian market. What needs to be done here is frugal Indian engineering. Something around 3 metre length, a fuel efficiency of at least 30 kmpl, 2 seats with a little shopping bag storage area, and basic modern amenities like air conditioning and power steering cannot be missed. In short, it has to be a proper car because ours is a country that sees cars as status symbols.  Such cars can be electric as this will be the everyday office car and so range wouldn’t be much of an issue. The Mahindra Reva e2o did make a good case but it still is expensive. It makes sense for it to be an hybrid at least as most of the commute in this would be done in stop and go traffic. Hybrids and electrics with regenerate braking capture the lost power during braking and slowing down. An automatic transmission is a highly necessary option for our busy roads, and it is very much preferred by women – a big potential market for a car like this. 

Renault Twizy - an urban electric vehicle

An interesting alternative to self transportation is the Renault Twizy. It is a two seater electric vehicle, has 4 wheels and a steering, but is neither a car nor a motorcycle. It has an average range of 100km per charge. There are a few models, base model starting at GB£6,990 and top speed of 45 – 80 kmph depending on model. This right now is an expensive proposition for India, but this green transportation concept is interesting for our roads. 

In Japan, such vehicles are categorized as ‘Kei car’ and in Europe and other places as ‘Quadricycles’. The Indian Govt. has recently announced that Quadricycles will be categorized here. The Bajaj RE 60, an improved 4 wheeled auto rickshaw could be the first to enter this space. The petroleum powered four door car has been in the world for more than a century now, it is definitely time for a change.

Wireless Charging

Wireless charging is the next big thing. Not only is it going to replace clumsy wired cables but it is going to unveil a whole new world of possibilities. Before we get into that, a little bit of tech gyan on how it works. Wireless charging or technically inductive charging is similar in principle to a transformer. The primary coil is in the base unit that creates an alternating electromagnetic field and the secondary winding in the portable device receives the flux and converts it back to alternating current to recharge the battery.

Continuous in-road wireless charging

One of the biggest possibilities of inductive charging is in-road wireless charging. This is similar to the power supply to trains and trams minus the overhead cables and clumsy pantographs. Primary cables are laid inside the road surface to which electricity is supplied and receivers are placed underneath electric vehicles which acts as secondary coil. This non-contact method can be used for charging as well as providing a continuous electrical power supply to vehicles where plugging-in is not convenient or possible. This is weather proof and safer also as no electrical points are exposed.

Wireless Mobile Charger

Charging an electric car takes a long time and requires expensive and bulky batteries for long ranges. A very practical application of in-road induction charging would be to lay cables throughout the lengths of highways where electric/hybrid vehicles can ply over the entire length without the need of big and expensive batteries. This is particularly very suitable for electric/hybrid buses and trucks which travel long distances on a fixed route. When used by electric cars, it can help eliminate range anxiety – one of the biggest hindrances in the popularity of electric cars. If this is coupled with green electricity, then zero carbon transportation is possible.Static chargers can be helpful at homes, parking lots or under bus stops for quick top-up.

There are a couple of challenges to be met before this technology can be put to use. First, the efficiency is lower than conductive chargers though 90% efficient wireless chargers have been developed at Utah State University. Secondly, electromagnetic interference with patients wearing pacemakers is a concern. Qualcomm Halo, a leading wireless charging developer believes there needs to be an universal set of regulations and limits to address this. Also the modes of payment by user needs to be figured out. So far, the pros of this technology does sound very tempting. The fact that stationary wireless chargers for mobile phones and electric cars are available commercially is promising enough that the day of in-road wireless chargers is not far away.