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Few questions; few answers (3) – FAQs on Roof Top Solar PV Plants

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Capacity of the power plant Solar PV power plants are specified in KWp, not KW.  KWp means Kilowatt Peak.  Please read this link for more information. So a quote for 100KWp does not guarantee that you will get 100 units of electricity per hour. Typically a 100 KWp plant will produce 1,50,000 to 1,80,000 Units of electricity per year. The actual generation every month, week, day and hour will depend on various factors and location. 2. What are the parameters that affect actual generation? Actual delivery of energy will depend on the following parameters: Sunshine intensity:  The variation of sun\’s intensity in your location. The history of this data is available for your specific location (latitude and longitude). You can look for it in MNRE\’s database. Angle of the sun to the installed base.  We normally propose fixed tilt installation – which means modules are fixed at an angle and sunshine incident angle on the module will vary by the day. Ambient Temperature : Change in Ambient temperature affects the solar cell temperature and in turn that it will affect the power generated. You can look at the solar module specification to know the power de-rating for various cell temperatures. 3. What happens when the solar energy generated is more than what we need or if it is less than what we need? Solar energy is infirm power, and that is why, we either sync it to the Electricity Grid or have a battery back up or Sync it to a DG set. For Industrial applications, we sync with grid or DG. When the solar power generated from the plant is less than what is required by your load, the additional required energy will be drawn from either grid or DG for supplying the load. If it is more than what is required, it can be fed back to the Grid, provided you have a net meter connection. 4. Can Sunshades and porticos be used for mounting solar panels in addition to roof tops? In theory, Yes. But feasibility needs to be studied by an engineer during preliminary assessment. 5. Can the Solar plant be synchronised with Grid Power and DG Power? Yes , it can be synchronised. Check the specifications of the invertor – it should mention that it is sync-able to both DG and Grid. 6. Can AEPL do a turnkey project from design, engineering and supply to mounting on roof top, installation and commissioning, including the electrical circuit for power evacuation? Yes. The detailed scope of work will be detailed in the commercial contract. Drawings will be submitted for customer’s approval. 7. Can AEPL take care of the CEIG approval and also organize Net Metering facility? Yes. There will be a liaising fee for the same. 8. Do we need Lightning arresters in addition to what we already have in the building? If the condition of the existing arresters are OK, then additional arresters may not be required. This will be ascertained during execution. 9. Who will do the Earth pit for the Solar Plant? Separate chemical earthing up to 5ft as per standard design norms will be constructed by us as part of our execution scope. 10. Will the mounting of Solar Panels, damage the roof / weathering course? Will it load the roof? No damage will be caused because of mounting Solar panels. The additional weight of Solar panels will be within the load bearing capability of concrete and metal roofs. If customer uses Asbestos roofing or if the roof is damaged in some places, the same needs to be replaced / repaired by customer. The structural details of the mounting arrangement will be submitted for customer’s approval before commencement of the project. In case of concrete roofs, there are 2 basic approaches: Penetrative fixing of modules: In this case, sufficient care is taken in finishing the rooftop back after competing the foundation to ensure that the resultant surface is equal or better than the original surface. Dead weight:  If you are very strict that there should be no perforations, then we need to go for concrete legs which will function as weights to hold the module and structure.  We can design optimally, based on your requirements. 11. Are there are any Safety Standards for Solar Power Plant? Yes there are published safety standards for roof top solar power plants. AEPL will ensure that the supply and installation follows all the safety standards applicable. 12. Will you guarantee the no. of units produced or the efficiency of Solar Plant? Yes we can guarantee the no. of units produced per year per KWp installed. This guaranteed generation will vary from location to location. The exact guarantee figure will be incorporated in the commercial contract. In any case since the contract is based on price per KWH, if the plant produces less, the revenue is less.  Which means, there is an in-built guarantee and incentive for us to produce the most. 13. Can the Solar Panel withstand wind, rain and seismic conditions? Yes, the design takes care of all these conditions, as relevant to the city / location of installation. The structural engineering and drawings on roof top installation will be submitted for customer’s approval. This can be further validated by the customer with the help of a suitable architect  / expert. 14. What are the warranty terms? Solar PV Modules are covered under a 20 year manufacturer warranty with performance warranty with the following terms: 90% minimum rated performance in 10 years 80% minimum rated performance in next 15 years. Inverters are covered with a 5 years warranty with the following terms: As per the Manufacturer All other structures, electrical wiring and other components are covered by 1 year warranty. 15. Do you offer AMC? Yes. Please refer to our Warranty and AMC terms below: Quarterly inspection of Solar Panels,Inverters,protection circuit, cabling junction boxes,means of isolation and earthing for 5 years, 4 Visits for the entire system Staff will be trained for cleaning as to

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CSP vs CST

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In other words:  Solar Power vs Solar Heat Solar PV for generating electricity using Solar modules has been gaining immense attention worldwide. Small CSP? I do not believe there is an opportunity for small scale CSP.  However, a lot of micro-grids and mini-grids are coming up at rural areas in India with Bio-mass and Solar PV.  Companies like Desi Power, Gram Power, mera gaon power, OMC power,  are all doing good work in this area.  If and when small scale CSP plants become economical, they can play a role.  I am not seeing it any time soon. On the other hand, CST (Concentrated Solar Thermal) is certainly a good opportunity for Indian industry.  Some early installations are doing well.  In the mid-term I expect that to pick up. However, we are betting more on ETC based technologies without tracking in the lower temperatures of 60-150 Deg C.  Here are our reasons: CST is a relatively newer technology, and there are still technology kinks that needs to be worked out.  On the other hand, what we are doing in terms of system level and slight technology modifications of ETC collectors is just incremental innovation, and hence more reliable.  Just to give a perspective – SHIP database, as is referred by IEA (link), has identified many industrial applications across the world. Another statistic:  Against the installed base of solar PV in the world of 175+ GW.  Solar heating is more than 300 GW .  Significant share of this is ETC based technology, and hence the technology kinks of the underlying technology of evacuated tubes are fully solved, and it is proven for decades. All said and done, CST costs are higher than basic ETC based collectors KW to KW or KWH to KWH.  That is another constraint. CST collects only DNI whereas ETC at lower temperatures collect GHI, which makes ETC energy plants\’s PLF much more than that of CST.  Economics rule the roost here. ETC based plants can be implemented on factory rooftops whereas CST needs ground space or RCC roofs. These factors make us bet more on ETC based lower temperature solutions.  Coupled with the recent drop in fossil fuel prices, and the above factors, I feel CST will take longer for adoption in India compared to ETC based solar heaters for the industry.

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Green "Power" Market Development Group at Hotel-Hilton

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When they named it as Green \”Power\” Market Development Group, I was skeptical.  Solar Energy vs Solar Power – the long standing debate,  came to my mind.  But, they invited me to talk about Solar Heat, and actively listened. Overall, the audience was appreciative of the different direction that we are taking in terms of solar heaters for the industry. Some myths of solar thermal, mistaken with Solar Thermal Plants was raised, and I am happy to dispel them.  My take on  \”Solar Thermal Power vs Solar Thermal Energy\”. ~Bhoo, Aspiration Energy

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Better late than never – October 2014 events

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It has been a month since I wrote a blog post.  I noticed that there were few interesting programs I attended during the month of October and November but missed out writing about them. Thought of sharing it now,  it is better to be late than never 🙂 I attended 2 events within a span of 3 days – both focused on our field: The first was a stakeholder Workshop – II on “Vision and Action Plan for development of decentralized solar thermal in India ” on October 14, 2014 in New Delhi.  This was conducted by Shakti Foundation and Greentech knowledge solutions. Sameer Maithel, spoke about the Chasm in Industrial Process Heat. How real! How insightful! Yes, we have such huge number of leads – we are talking with who-is-who of the industry – TVS, Tata, Godrej, ITC, Mahindra, and so on. But, even in our sales cycle – it is a chasm – the technical evaluation gets over, the commercial evaluation gets over – but before it translates to Purchase Order, there is a Chasm. The chasm is one of getting all the stakeholders together and making them fully motivated to transact. I am happy to see that the industry is seeing this Chasm and making efforts to close it. We can all read this book: Crossing the chasm The second was a Workshop on monitoring, design and certification of solar process heat on 16 October 2014 in New Delhi.  This was conducted by So-Pro India. Tarun Kapoor, Joint Secreatry of MNRE attended both the sessions. This shows the growing interest in our chosen area. I am very happy that this often neglected area is grabbing attention. Both sessions talked about how we can get policy / market awareness and credibility changes to grow the market for Solar Heating. There was a significant focus on Solar Heat for Industrial Process (SHIP) So-Pro event was 100% focused on Industrial process heat. One thing of great note here – like in any business, the quality of entrepreneurs and eco-system during the initial period determines the growth of the industry. In that sense, it is great to be part of this community – the people who were present were tachnically, commercially and behaviorally so competent to understand issues, their solutions and way to take this industry forward. Great to be part of this community.

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Raise up and bring down!

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The Step-up, Step-down trap… This is the way the most energy systems in the world are built today – Electricity grids take the voltage all the way up to 11 KV (11000V), 33 KV (33000V) and 66 KV (66000V). Your home consumption may be at 230V (India) or 110 V (USA) and so on. But, we use a transformer next to the consumption point and step it down. Same way, many companies run long steam lines or thermic fluid lines that are generated in a central boiler plant – at 150 Deg C to 250 Deg C. This high temperature steam/thermic fluid pipe is very similar to the high voltage grid. But, the end use is usually at lower temperature levels. Much like our electricity – where our usage voltage is low. Say, metal pre-treatment is at 60-70 Deg C. Washing is at 50 Deg C and so on. If we can interrupt it at lower temperature level and produce energy, why should we not do it? That is what we have done in our Wheels India Padi installation. We stop the high temperature thermic fluid lines, and instead run the low temperature process using solar heaters that produce the requisite lower temperatures.

Aspiration Energy, Blog

Comprehensive tariff order on solar power – TNERC

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Comprehensive tariff order on solar power – TNERC This is good in more than one way for the solar developers. How will Tangedco fund it without massive tariff rationalization is the usual question that lingers in my mind. If not funded well, the payments will stutter and hence development may not happen. I am not seeing escalation specified clearly or may be I am missing something. As always, the reverse – higher the volume or capacity better pricing offer, unique to India and some developing countries is intriguing. Conventional wisdom says otherwise. Main comment is on the opposite view – Tangedco is ready to procure at 6.48. Alright. At generation end! Alright! So, tangedco absorbs transmission losses here. So, why can\’t we waive transmission losses for solar developers or make it concessional – some direct PPAs with end customers with group captive will immediately happen if that is done without much loss to the Government compared to this. Either way transmission loss is absorbed by tangedco, but higher tariff will be paid by the end user. Better, right? ~Bhoo

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I pretend for a living. But, you do not – Leonardo DiCaprio

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Actor and environmental activist Leonardo DiCaprio addresses the UN summit meeting on climate change. DiCaprio was recently named a United Nations Messenger of Peace. ‘This disaster has grown beyond the choices that individuals make. This is now about our industries, and governments…’ he tells the summit. DiCaprio – “Thank you, Mr Secretary General, your excellencies, ladies and gentleman, and distinguished guests. I’m honored to be here today, I stand before you not as an expert but as a concerned citizen, one of the 400,000 people who marched in the streets of New York on Sunday, and the billions of others around the world who want to solve our climate crisis. As an actor I pretend for a living. I play fictitious characters often solving fictitious problems. I believe that mankind has looked at climate change in that same way: as if it were a fiction; as if pretending that climate change wasn’t real, would somehow make it go away. But I think we all know better than that. Every week, we’re seeing new and undeniable climate events, evidence that accelerated climate change is here right now. Droughts are intensifying, our oceans are acidifying with methane plumes rising up from the ocean floor. We are seeing extreme weather events and the West Antarctic and Greenland ice-sheets melting at unprecedented rates, decades ahead of scientific projections. None of this is rhetoric, and none of it is hysteria. It is fact. The scientific community knows it, Industry knows it, governments know it, even the United States military knows it. The chief of the US navy’s Pacific command, admiral Samuel Locklear, recently said that climate change is our single greatest security threat. My Friends, this body – perhaps more than any other gathering in human history – now faces this difficult but achievable task. You can make history … or you will be vilified by it. To be clear, this is not about just telling people to change their light bulbs or to buy a hybrid car. This disaster has grown BEYOND the choices that individuals make. This is now about our industries, and governments around the world taking decisive, large-scale action. Now must be our moment for action. We need to put a pricetag on carbon emissions, and eliminate government subsidies for oil, coal, and gas companies. We need end the free ride that industrial polluters have been given in the name of a free-market economy, they do not deserve our tax dollars, they deserve our scrutiny. For the economy itself will die if our ecosystems collapse. The good news is that renewable energy is not only achievable but good economic policy. This is not a partisan debate; it is a human one. Clean air and a livable climate are inalienable human rights. And solving this crisis is not a question of politics. It is question about own survival. This is the most urgent of times, and the most urgent of messages. Honoured delegates, leaders of the world, I pretend for a living. But you do not. The people made their voices heard on Sunday around the world and the momentum will not stop. And now it’s YOUR turn, the time to answer humankind’s greatest challenge is now. We beg you to face it with courage. And honesty. Thank you.”

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Comprehensive tariff order on solar power – TNERC

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Comprehensive tariff order on solar power – TNERC This is good in more than one way for the solar developers. How will Tangedco fund it without massive tariff rationalization is the usual question that lingers in my mind. If not funded well, the payments will stutter and hence development may not happen. I am not seeing escalation specified clearly or may be I am missing something. As always, the reverse – higher the volume or capacity better pricing offer, unique to India and some developing countries is intriguing. Conventional wisdom says otherwise. Main comment is on the opposite view – Tangedco is ready to procure at 6.48.  Alright. At generation end! Alright! So, tangedco absorbs transmission losses here. So, why can’t we waive transmission losses for solar developers or make it concessional – some direct PPAs with end customers with group captive will immediately happen if that is done without much loss to the Government compared to this. Either way transmission loss is absorbed by tangedco, but higher tariff will be paid by the end user. Better, right?

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Solar Energy Vs Solar Power – 3

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Credit: Ron Tandberg My earlier blog post talks about Solar Power and Solar Energy and recommends to add Solar Energy to our vocabulary. But, the revolutionary change that we pride ourselves with – is to specify solar heaters in terms of power KWth instead of in terms of energy – Litres Per Day – LPD.  Oxymoron! LPD – Litres Per Day vs KWth Solar heaters have been traditionally specified as LPD meaning – Litres Per Day.  Why? The traditional solar heaters have been worldwide used in domestic water heaters.  When do we need hot water at home?  Mornings.  Does the sun shine in the mornings?  No.  So, essentially, we are collecting sunlight and solar energy that shone yesterday and using it today.  In that scenario, it is good to express the capacity as LPD – How many useful Litres of hot water can be generated per day. LPD essentially represents the energy collected throughout the day. LPD vs KWth – how to represent the size of solar heaters? But, when it comes to Solar Process Heating systems, we need to work on generating the high temperature required consistently during the day.  That means, we need to have the “power” to heat requisite quantity of water instantly using solar generation. That is why we specify our collectors in terms of KWth! Here are other articles that talks about KWth rating of solar heater collectors. Methodology to present the installed capacity of solar collectors in GWth Simple method for Converting Installed Solar Collector Area to Annual Collector Output ~ Bhoo, CEO, Aspiration Energy

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SolarMax – 2

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A follow up article on our earlier post SolarMax principle One example to make a difference between LoadMax and SolarMax amply clear is to take an example of Street Lights. Let’s take a standard model – Sharp Street Light. Lets take the model: SSLL 1018 The basic light there is a 18W light. Load per day:  Let’s say the 18W light runs for 12 hours – Dusk to Dawn 18W x 12 Hours = 216 WHr is what is needed per day. Let us look at what thay have designed it with: Solar capacity:  80 W. 216 WHr / 80 W = Less than 3 hours. So, the solar street light is designed to produce enough energy within 3 hours of sunshine. Sounds great and logical – when you evaluate from a general LoadMax principle.  But, imagine this – more than 300 days a year, sunshine will be for more than 5 hours.  So, Every single day on 300 days a year, 80W x 2 = 160 Whr is wasted.  And, we pay for that generation upfront. Lets take batteries:  12 V, 75 AH.  Not to be a purist in battery design for ease of calculations – I will consider VxAH as a proxy for WHr. 12 V x 75 AH = 900 VAH or approximately 900 WHr. We observed above that the requisite WHr per day is only 216 Whr.  So, this is designed with 4 times the requisite capacity. I am not taking accurate figures.  For an application like solar street light where Hybridization with existing conventional sources of power is difficult, and where the focus is on automated reliable operations, I have no arguments against this design philosophy.  And, battery design is more to do with Depth of Discharge and life-time of batteries. But, I am taking this as an illustration of LoadMax principle. If there were backup conventional sources available – I would build this with a 50W module and 50 Ah battery – which is far more economical.  That will be “SolarMax”. One word of caution though: SolarMax immediately means that it needs to be hybrid – to take care of low generation periods of solar energy.  Wherever hybrids are not possible or feasible or desirable – we need to go back to LoadMax.

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