Solar for university and college campuses in Bangladesh: several roofs, several meters
How campus metering, the long summer break and UGC development funding change a rooftop solar project, and what to fix in the specification before the tender goes out.
The first question on a campus solar project is not how much roof there is. It is how many electricity meters the campus has, and whose name each one is in. A university that looks like a single customer to its own vice chancellor can look like nine customers to the distribution utility, and net metering in Bangladesh is settled per connection. Get that wrong at survey stage and the plant that was approved on paper cannot be built the way it was drawn.
Count the connections before you count the roof area
Campuses grow building by building, and the electrical supply grows with them. It is normal to find an older academic block on one low tension connection, a newer block on its own, halls of residence on a third, a workshop or auditorium on a fourth, and a pump house connection nobody in the estate office remembers sanctioning. Some campuses instead take a single high tension supply at 11 kV into their own substation and distribute internally. That is the easier case by a distance.
It matters because the net metering guidelines cap the plant at a share of the consumer's sanctioned load, and that ceiling attaches to the connection, not to the institution. Six small connections do not add up to one large allowance. Each also needs its own application, its own agreement and its own bi-directional meter, which multiplies the paperwork and multiplies the number of desks at which the file can stop moving.
One high tension connection. If the campus already has an 11 kV supply and its own substation, the plant ties in on the low tension side of the transformer or at the busbar, one agreement covers it, and the whole campus load is available to absorb generation.
Several low tension connections. Each array has to be tied to the connection feeding that building, sized against that building's sanctioned load, and approved separately. You cannot generate on the library roof and net it against the hall of residence meter.
Consolidating first. On a campus already planning a new substation, ask the utility whether connections can be merged before the solar application goes in. It is a slow conversation and it should start long before the tender.
There is no group or virtual netting provision to fall back on. If the buildings are metered separately, the design has to live with it.
The academic year moves the load, and the long break moves it most
An office building draws roughly the same load every working day of the year. A campus does not. Teaching weeks, examination weeks, the long summer break, Ramadan and Eid closures and the gap between sessions all produce different curves, and the distance between a full teaching week and a vacation week is wide enough to change the sizing decision.
Three things usually keep running through a break, and they are what stops export from becoming the whole story: halls of residence, where a proportion of students stay on, research laboratories with incubators, freezers and animal houses that cannot be switched off, and the campus network room. Everything else, lecture theatre air conditioning above all, goes quiet.
Size against the vacation baseline first and the teaching load second. A plant sized to a full teaching week spends the longest holiday of the year exporting, and exported units are settled on the terms written into the net metering agreement rather than at the retail rate you avoid paying when you consume your own generation. That is not an argument for building small. It is an argument for knowing which months are paying for the plant, so that nobody is surprised by the September bill.
Choosing which roofs to use
The instinct is to start with the tallest building. The better starting point is the building whose meter carries the largest daytime load, because a unit consumed behind that meter is worth more than a unit exported from it.
Academic blocks. Reinforced concrete roofs, usually the soundest structural case, and the load underneath is the daytime one you want.
Libraries and auditoria. Long spans, sometimes a shell roof or a plant room on top. Check both the structure and what the architect intended the roof to look like from the approach road.
Halls of residence. Evening load, water tanks and drying lines already on the roof, and resident students who treat the roof as their own space. Usable, but not the first choice.
Workshops and sheds. Corrugated sheet on light purlins. The purlin spacing and the sheet gauge decide whether the mounting structure is straightforward or unbuildable, and both are measured on site, not read off a drawing.
Campuses are spread out, and the temptation to run one long cable from a distant roof back to a central inverter room is expensive in copper and in losses. Keep inverters close to their arrays, aggregate on the alternating current side, and check the voltage drop calculation on the longest run before the cable schedule is priced.
What UGC funding does to the process
A public university buying solar with development funds is not buying the way a private company buys. The project has to appear in a development project proposal, be approved, sit in the annual development programme and then be tendered under the Public Procurement Rules through e-GP. That sequence has technical consequences, and they are worth understanding before the specification is written rather than after the bids are opened.
The specification is the only lever you have. Under open tendering the contract goes to the lowest evaluated responsive bid. Everything you care about, module certification, inverter protection functions, structure galvanising, cable type, monitoring access, spares and the maintenance period, has to appear as a requirement rather than a preference. What is not specified will not be supplied.
Do not split supply from installation. Two packages produce two contractors who blame each other for every defect, and a performance guarantee neither of them will sign.
Ask for the structural check as a deliverable. A signed structural assessment of the roof and of the mounting structure, for the basic wind speed at that site, is a document the university should hold in its own file, not something the contractor keeps.
Put the maintenance period in the same contract and tie retention release to it. A defect liability period that ends before the first monsoon has tested the waterproofing has tested nothing.
Create the running cost line before you need it. Development funds buy the plant. Cleaning, monitoring and repairs come out of the revenue budget, and if nobody opens that line the array runs unwashed from year two.
Private universities have a shorter route, usually a board approval and a negotiated award, but they meet the same trap in another form: a quotation that looks cheap because the structure, the earthing or the maintenance has been left out of it. Ask any bidder to price the same scope, in the same order, on one page.
Specify for the teaching value or you will not get it
Almost every campus proposal says the plant will double as a teaching resource. Few of them end up being one, because the monitoring turns out to be a vendor portal with a single login, the data cannot be exported, and the electrical engineering department has no route onto the roof.
String level monitoring, not plant level. One production figure teaches nothing. String currents show shading, soiling, a failed connector and a degrading module, and those are the lessons worth having.
Open data access. Require Modbus TCP or a documented interface from the data logger, and require that the university is handed the credentials and the register map at commissioning. A portal you cannot query is not a dataset.
A weather station with a pyranometer in the plane of the array. Without irradiance you cannot calculate performance ratio, and performance ratio is the number a student should be taught to compute.
A display in a public space, driven from the same logger. It is the only part of the plant most of the campus will ever see.
A written roof access rule. Students standing on a live direct current array need supervision, an isolation procedure and footwear that will not damage the module glass or the backsheet. Agree it with the department before the first site visit.
What goes wrong on campuses
One connection stalls and the whole project waits. Submit the applications in parallel and appoint a single person to chase all of them, with a copy of every submitted file.
A new building shades the array. Read the campus master plan, not the current skyline. A block that is approved but not yet built will take a row out of service for half of every winter afternoon.
The roof leaks and the array is blamed. Photograph the roof before work starts, record every penetration, and make the waterproofing detail part of the handover file.
The project engineer leaves. Monitoring passwords, warranty certificates and as built drawings live on one laptop. Require three sets of handover documents and lodge one with the registrar.
Cleaning stops. The first year is inside the contract, the second year needs a purchase order, and by the third year the modules are grey. Dhaka dust and construction dust on a growing campus are not a small effect.
A sequence that works
Collect twelve months of bills for every connection, with the sanctioned load and tariff category written on each one.
Log the largest connections for a week in teaching term and again during a vacation, so the two load curves are measured rather than assumed.
Survey the roofs for structure, shading, access and cable route, and get the original structural drawings out of the estate office while you are there.
Fix the connection strategy: which array feeds which meter, and whether any connections can be merged first.
Write the specification, including monitoring, structure, maintenance period and documentation, then tender it.
Apply for net metering connection by connection, with the single line diagram, datasheets and test certificates the utility asks for, and track each file separately.
Commission with the university's own engineer present, and record string level readings on the day, because that set of numbers is the baseline every future year is judged against.