The proposed off-grid built-in system might be very helpful when there’s a sudden grid failure. It is going to proceed to supply charging for two- and four-wheelers. Apart from it’ll allow bio-CNG shelling out, sale of milk, sale of natural manure, sale of cow urine for medical utilization that may even be exported, and allow you to declare carbon credit as nicely.
Many new applied sciences are getting launched throughout the size and breadth of our nation, similar to:
- EV charging stations
- Compressed biogas vegetation
- Agri-voltaic farms (coming quickly)
- Battery based mostly vitality storage programs (coming quickly)
- Hydrogen era programs (coming quickly)
As of right this moment, all these programs are being deliberate in silos and are being constructed as unbiased programs. However that is the fitting time to plan built-in programs, which might provide further advantages, aside from their supposed use. It is going to permit us to derive a number of advantages. A quick introduction to every of the above listed applied sciences is given beneath.
EV charging stations
The variety of electrical autos is rising daily, which can be rising the necessity for EV charging stations. Each authorities and personal corporations have began constructing charging stations. These stations are of two principal classes: throughout the metropolis and alongside the highways. Right here we will concentrate on the charging stations being put in alongside the highways and main roads between cities.
Virtually all of those charging stations are grid-based. Grid-connected programs are straightforward to put in, want much less funding, and take up much less area. Nonetheless, they’ll put an enormous load on the already overloaded grid. Additionally, think about what is going to occur if there’s a grid failure?
Subsequently, to sort out such a scenario, we must always have some off-grid charging stations as nicely. Such charging stations will cut back load on the grid and might be very helpful in case of a protracted grid failure.
There are two- and three-wheeler chargers in addition to four-wheeler chargers. The four-wheeler chargers themselves are of three sorts.
Degree 1 (L1) chargers
These are sluggish chargers that take eight to 10 hours to cost a depleted battery. Therefore these are utilized in residences for in a single day charging.
Degree 2 (L2) chargers
These take about 4 hours to cost. Such chargers are put in in housing complexes, workplaces, eating places, malls, and many others.
Degree 3 (L3) chargers
These are DC superfast chargers. An L3 charger can cost a depleted battery to 80% inside an hour or two. These are particular chargers which might be put in by the automotive producers or authorities businesses alongside the freeway.
Compressed biogas vegetation
Biogas vegetation are fairly widespread. These vegetation use bio waste materials, cow dung, and many others, and produce methane fuel. This fuel is often used for cooking. Nonetheless, if we’ve to make use of it for CNG autos or for turbines, the uncooked biogas must be handled; it incorporates carbon-dioxide, water vapour, and hydrogen sulphide fuel. When these undesirable gases are eliminated, we get 90% focus of methane, which is then compressed. Compressed biogas is an effective substitute for CNG.
If biogas is used to generate electrical energy utilizing commonplace out there bio-gas turbines:
- One cow gives 1000kWh (items) {of electrical} vitality per yr
- One cow gives 2.75kWh vitality per day
- Hundred cows present 275kWh vitality per day
If biogas is used for making bio-CNG:
- One cow gives 1.5 cubic metres of uncooked biogas per day
- Hundred cows present 1500 cubic metres of uncooked biogas per day
- If purified, 100 cows present 900 cubic metres of pure methane per day
Agri-voltaic farms
Agri-voltaics is a mix of agriculture and photo voltaic photovoltaic (PV) vitality era. PV energy vegetation want massive stretches of land. Often, the land chosen for PV installations is barren land. In lots of locations fertile land can be getting used. If agriculture land must be used, then agri-voltaics ought to be most well-liked.
In agri-voltaics, the PV panels are put in at a top of greater than 244cm (8 ft). And solely 50% space is roofed by the panels, as proven in Fig. 1. Fig. 2 reveals shut up view of an meeting of three panels every.
The gaps between the panels permit the daylight to fall on the land beneath, allowing cultivation. Within the shade of photo voltaic panels, varied forms of vegetable and flowers may be simply grown. Because the land is partially shaded, the vegetation want much less water. Despite much less water utilization the yield is identical or typically higher.
The presence of vegetation gives cool air to the photo voltaic panels. Cooler PV panels produce elevated energy output. The water used for cleansing the panels irrigates the vegetation and doesn’t go waste. The farmer is assured of normal revenue by promoting electrical energy generated by the PV panels. Additionally, he can do the farming and double his revenue.
Allow us to take a look at a PV system design:
- One acre space=43560sq ft
- Space of every 300Wp PV panel =6.5×3.25=21.125sq ft
- Variety of 300Wp panels potential=43560/21.125=2062
- Variety of panels if solely 50% space is roofed=1031
- Panels after leaving 13% space for development=900
- With 3 panels in every PV meeting, variety of assemblies=300
- Slots with 20×30 association =600 (adjoining slots left vacant)
- Energy output=300Wp×900= 270,000Wp or 270kWp
- Charging energy (assuming 90% effectivity of chargers)=270× 0.9=243kWp
- Common charging energy out there for 8 hrs on a sunny day =200kW
- Most variety of 25kW prices which could possibly be run=8
- Whole vitality generated in 8 hours=200kW×8hrs=1600kWh or 1600 items
Battery-based vitality storage programs
Electrical grid will get energy from varied sources, similar to coal energy vegetation, hydel turbines, nuclear, photo voltaic, and wind. As a larger variety of photo voltaic and wind energy vegetation are getting put in, the renewable vitality content material within the combine is rising.
Sadly, the renewable vitality sources are extremely variable and unpredictable. This poses downside for the grid stability. Generally there may be extra energy era and different occasions there may be sudden discount in generated energy.
In an effort to stabilise the grid, there may be want for short-term vitality storage. A battery financial institution can be utilized in such a scenario. When there may be extra vitality, the batteries can retailer the vitality. When there may be demand for vitality from the grid, saved vitality from the batteries can be utilized.
Although use of batteries seems to be a easy answer, the price of these batteries may be very excessive. Fortunately, this being a land based mostly utility, measurement and weight of batteries is just not very vital. Therefore, even the cheaper lead-acid batteries can be utilized.
Another choice for decreasing the fee is to make use of discarded lithium-ion batteries from electrical autos. Such batteries nonetheless have about 75% storage capability. These batteries can be utilized for just a few years, as their second life.
Gravity batteries
Because the demand for lithium-ion batteries is rising, the costs of metals like lithium, cobalt, and nickel are taking pictures up, leading to elevated value of lithium-ion batteries. To beat this downside, options similar to gravity batteries are being examined.
A heavy block of cement is raised utilizing a crane or elevator mechanism. The block acquires potential vitality proportional to the peak to which it’s raised. When energy is required, the block is slowly lowered, which drives the generator. Such batteries are cost-effective and have life span of greater than 25 years.
Right here is an instance of the gravity battery’s capability:
- Potential vitality=[(mass× acceleration due to gravity×height)/ 3600]Wh
- Mass in kg, g=9.81m/sec2, top in metres
- For 100-ton slab, raised to 100m top, vitality saved=27.25kWh
Hydrogen era programs
Hydrogen is rising as an alternative choice to fossil fuels. To make inexperienced hydrogen, renewable vitality is used. When present is handed by an electrolyser, it splits the water molecules into hydrogen and oxygen.
Hydrogen has many makes use of
We are able to combine hydrogen with CNG as much as 20%. This combination of gases can be utilized in the identical tools as the unique CNG generator or automobile, with none modification to the engine. Additionally, the security precautions stay the identical as for pure CNG dealing with. Thus, every time renewable vitality is obtainable in extra amount, it may be saved as hydrogen fuel.
The above calculations assume common values of the parameters and are for common steerage solely. Whereas designing an precise system extra correct information must be thought of. For instance, sort of PV panel, the typical daylight circumstances for the chosen area, breed of the cows, and many others may have massive affect on the accuracy of calculations.
A phrase of warning. Inexperienced hydrogen is an rising area, and the fuel is very explosive in nature. There are security issues whereas dealing with hydrogen. Authorities has introduced Nationwide Hydrogen Mission. We have to arrange secure working procedures and will have educated manpower to deal with the fuel. Until then, it isn’t advisable to go for hydrogen based mostly programs. It might take just a few years to achieve maturity stage.
System design
The format of proposed EV charging advanced is proven in Fig. 3. The agri-voltaics farm is central to this technique, round which the entire advanced is designed. This farm generates DC energy in daytime from the daylight. The PV energy is equipped to DC superfast chargers, L2 chargers, and 2- and 3-wheeler chargers.
Customary L2 chargers want AC enter. Subsequently, an inverter is used to transform DC provide to AC earlier than connecting to L2 chargers. The DC and L2 chargers want just a few tens of kW, therefore these will work solely when daylight is powerful. The two- and 3-wheeler chargers want a lot much less energy, so these will begin working as quickly because the solar rises.
EV charging as a service gives good return on funding as in comparison with promoting vitality to the grid.
At any time when there may be extra PV energy, it may be saved within the batteries. If the DC voltage drops as a result of clouds, energy from the battery can be utilized to help the availability.
When the batteries get totally charged, extra PV energy can be utilized for hydrogen era. The electrolyser splits water into hydrogen and oxygen. The hydrogen may be saved in a storage tank. The only method to make use of this hydrogen is to combine it with CNG. As much as 20% hydrogen may be combined with no need any modification to the CNG system.
As talked about earlier, inexperienced hydrogen know-how is in preliminary levels of growth. Dealing with hydrogen, as a result of its explosive nature, may be very difficult. We’ve to attend until this know-how matures earlier than utilizing it. Therefore, within the preliminary implementation of proposed EV charging system, we have to discover out an alternative choice to hydrogen electrolyser.
One easy different is to have second set of batteries. This generally is a chemical battery or a gravity battery. Gravity batteries may have very lengthy life as in comparison with chemical batteries.
A cow-shed may be established close to the farm. As talked about earlier, the land beneath the PV panels can be utilized for farming. Within the proposed scheme, the land is used to provide fodder (contemporary grass) for the cattle. After assembly fodder requirement, if nonetheless there may be spare land out there, greens and fruits may be grown for extra revenue.
Common revenue may be earned by promoting cow’s milk. There may be additionally an enormous demand for cow urine for medical functions. The cow dung can be utilized for the biogas plant. The uncooked biogas generated incorporates carbon-dioxide and water vapour. As soon as these two are eliminated, we get 90% methane, which may be compressed to get bio-CNG.
This compressed bio-CNG can be utilized for electrical energy era throughout evening. The output of this generator is AC, which may be immediately fed to the L2 chargers. A rectifier is used to transform AC to DC for the DC superfast charger.
In summer season, the PV energy generated is greater than in winter. Therefore, in summer season we might have extra bio-CNG within the tanks. Extra bio-CNG may be crammed within the autos by the CNG dispenser, as proven in
Fig. 3.
The PV panels may be put in on roof-top of the cow shed. It will additional enhance the PV energy era, offering further revenue.
Automation
The proposed system is pretty advanced. Subsequently, full automation must be executed for correct operation of the system and to maximise return on funding. Additional, all security programs ought to be put in for avoiding any untoward incidents.
The photo voltaic radiation and climate adjustments are extremely fluctuating. Therefore, climate forecasts for subsequent few days ought to be offered as enter to the automation system. Equally, the sample of demand for EV charging may be studied and fed as enter to the system.
Throughout extended spell of rains, the PV energy will not be ample for assembly the ability calls for. In that case, for few days, the conventional CNG could possibly be used as a backup gas. Use of synthetic intelligence and machine studying program might be very helpful for optimum working of the system.
Implementation
The proposed scheme may be applied in two steps. Step one is to verify technical feasibility. A pilot plant may be established and run for 2-3 years to realize perception into the operation of the system. It is going to generate very helpful information.
Within the second step, full-scale plant may be constructed, based mostly on the learnings from the pilot plant. Optimisation may be executed based mostly on the information out there, as a way to cut back the price of the system.
The price of implementation will he on the upper facet as a result of advanced nature, however this built-in system will provide a number of advantages. The return on funding might be a lot larger, which can cut back the payback interval.
Some benefits of the system are:
- Off-grid operation reduces burden on grid on day by day foundation
- Off-grid operation is extraordinarily helpful throughout emergency grid outages
- Shorter cables and fewer transmission losses
- Carbon-neutral system
- Self-sufficient with minimal motion of fabric
Some sources of income era are:
- EV charging service
- Bio-CNG shelling out
- Sale of milk
- Sale of natural manure
- Sale of cow urine for medical utilization (may even be exported)
- Can declare carbon credit
And a few avenues of the financial savings from the mission are:
- Autos used for promoting milk and manure get free charging or free CNG
- Free electrical energy for the advanced
- Conservation of water due to agri-voltaics
- Further energy era due to decrease working temperature of panels
- Water used for cleansing the panels goes for irrigation
- Fodder for cattle grown inhouse; much less value and no transportation
- Car house owners ready for EV to cost can go to cow shed and feed the cows
Conclusion
Alongside the highways there may be sufficient land out there for implementing the proposed scheme. An built-in system presents many extra benefits. The return on funding is excessive. Many of the inputs for working the system can be found inhouse. Therefore there may be minimal motion of fabric.
Besides inexperienced hydrogen, all different applied sciences may be simply applied. The tools required for the system is obtainable throughout the nation. Thus, a pilot plant may be began with many of the tools procured regionally.
In future, extra superior applied sciences, similar to gas cells, could possibly be used for extra environment friendly and silent operation. This off-grid system might be very helpful when there’s a sudden grid failure. It is going to proceed to supply charging for two- and four-wheelers.
Dr Vijay Deshpande presently works for photo voltaic vitality initiatives. He has additionally labored as electronics {hardware} engineer in a number of corporations
