An energy crisis remedy: Let us use the solar panels on our rooftops

Like several other countries, Bangladesh had placed its bets big time on Liquefied Natural Gas (LNG) as its 'transition' fuel toward cleaner horizons. A transition technology bridges the gap between the old and the new. Once legacy technologies and incumbent business models stop producing the desired results, a transition mode starts. 

However, this time, the sudden recurrence of legacy technologies, triggered by an LNG price hike - which is ten times higher today than it was at the point when the government decided to double down on imported fossil fuel - has caught us all by surprise.  

The fact that Europe is bidding at much higher prices, making it attractive to Qatar to default on fixed delivery contracts of LNG to South Asian countries, including Bangladesh, is only exacerbating the situation, and is broadly underreported in the media.

Unfortunately, LNG prices are likely to remain high and volatile. Further, they need to be financed by a ballooning subsidy burden, which ultimately is borne by the people of Bangladesh as the pressure to raise end-user gas and power tariffs is mounting. 

Continuing to pay precious foreign exchange (Forex) resources for the import of fossil fuels puts immense pressure on Bangladesh's economy.

The Government of Bangladesh knows this, of course. It has already taken several measures to save electricity across the country and notably banned diesel-run power plants from operation in a bid to lessen the burden on forex reserves. 

Now that load shedding has started to expand into urban centres, those few who can afford it, have started burning diesel by using diesel generators – a very noisy, expensive and dirty affair. Once the individual diesel reserves run out, they will also have to succumb to power cuts like everyone else.

If you ever stood on a tall building in Dhaka City, you must have noticed that the roofs are plastered with solar photovoltaic (PV) panels. Are we actually using those?  If not, why? Because they are expensive, small and do not really work? But the truth could not be any further from that.

They are not expensive at all. In fact, they are the cheapest energy source available. At least, as long as we do not require a battery, but instead connect the panel with the electricity grid. 

The country's Ready Made Garment factories have gone on a spree of commissioning solar PV rooftop installations since the solar net metering policy was introduced a few years back. And they do not install those to power their production out of pure good will, let alone because some foreign buyers demand it. 

They do it predominantly because it is good business and it is significantly cheaper than the national grid tariff. Now, in the case of urban residential rooftops, the PV panels are actually already there, already existing – so it is literally for free! 

Yet for some strange reason, a sea of solar PV panels sprinkled all over the rooftops of Dhaka city, goes largely unused.

As for their supposedly small size - sure, they would not be able to power the whole building, let alone the whole time, especially given the height of the buildings covering Dhaka city's bird's eye landscape. But these systems can be as big as you want, all you have to do is to add more panels, as much as your rooftop space allows you to. 

Let us say you have 20kWp (kilowatt peak) on your roof, which will require a space of 150m2 and it will, on a yearly average, produce roughly 80kWh (kilowatt hour) per day, or 2.30MWh (megawatt hour) per month. For comparison, a 1.5 ton AC consumes, depending on its level of energy efficiency, approximately between 2.0 to 2.5kW. Hence, if you run your AC for three hours a day, this comes to 6.0 to 7.5kWh. 

From the example above, your rooftop solar could thus support around 10 to 12 AC's daily energy requirement in the given use case.

But why is it not being done then? Because it sounds too good to be true? It is because solar does not really work, right? Of course, it works, we just have to allow it to work. And herein lies the catch. 

To date, solar PVs are not installed to generate electricity, but to comply with some building code, which compels us to have a marginal percentage of our electricity from renewable sources in order to get a gas connection for any new building constructed. 

This means the rooftop solar PV installations we see all around us have usually been installed by a developer and are only connected to power common utilities (security lights, staircase lighting etc). 

As a consequence, the actual solar PV rooftop installation is grossly underutilised, more often than not tenants are not even aware whether it works at all, plus there is very little incentive to take care of it.

So, here is a suggestion: We are in a crisis, so let us act accordingly. Let us use all those solar PV panels which are right now ornamenting our rooftops in Dhaka. 

Let us connect them either with the grid (policy change needed in current net-metering policy to allow for single phase inverters for residential buildings to feed in - something long overdue) or connect them at least within the building circuit to allow for self-consumption. 

Once done, we will all have a couple of cascading positive effects: we will burn less diesel, leading to lower running cost and less noise and air pollution. We will also have less pressure on the national electricity grid and less outage times.

As a bonus, if connected to the national grid, we will have a cleaner electricity mix. However, please note that any threat of grid imbalance through single phase inverters will only become a real concern once we actually reach a couple percentage points (right now 0.0%), and even then appropriate measures can be taken proactively.

Let us do it now.

Dr Sebastian Groh is the CEO and co-founder of the climate tech startup SOLshare and an associate professor at the Brac Business School, Brac University.

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.