Pakistan’s solar surge: a new era of affordable, scalable energy

Photovoltaics (PV), the ability to directly convert sunlight anywhere on the planet into electric power, has changed human life for good. Only 12 years ago, there was no PV system installed in Pakistan. The first solar power plant near Bahawalpur was bravely commissioned amid some public scepticism. Now PV systems can be found across the country, delivering daytime electric power for agriculture, households, factories, and the common grid. It is only the beginning of how this renewable energy source can change the economic fortunes of the country.

What is a PV system?

A PV system consists of three essential components: the solar panel, aka a PV module, an inverter, and mounting. The solar panel contains a semiconductor (typically silicon the second most abundant element in the Earth) that absorbs solar energy to transform it into electric power for external use. The physics of how a solar panel works is fundamentally similar to photosynthesis. The inverter, acting as the brain of the system, controls a collection of solar panels to deliver the electric power for its intended use. Inverters can ramp the electric power up and down, fine-tune the power quality, and adapt it for the grid or off-grid application. The mounting holds the solar panel so that it is optimally angled towards the Sun, for the available space, and is thermo-mechanically stable to changing conditions. A well designed, built, and maintained PV system can deliver a guaranteed power schedule for at least three decades, with a fixed reduction of less than half a percent per year from its initial output. Other electrical parts such as cables, transformers, and switchgear, are also important as for any electric power delivery system connected to the grid.

The beauty of a PV system is in its modularity and scalability. The systems can be deployed on rooftops, backyards, in between agricultural crops, vast barren fields, hills, or on top of water reservoirs, the open sea as well (the mounting design and material has be adapted). No other electric power source known to humanity offers such democratic empowerment.

Economy and quality

PV is the cheapest source of daytime electricity worldwide, even in less sunny locations at higher latitudes. There is no fuel required for the power generation, so once successfully commissioned, the solar electricity cost is fixed for the long run. The turnkey capital cost of a basic PV system kit can start from as low as USD30o/- per kilowatt, these days, depending on the location space, grid connection requirements, and tariffs on imported components. The electricity output cost will depend on the location sunshine and any financing repayments. It is almost always cheaper than other power sources on the grid. The variability of sunshine at the location is predictable for the long run, estimated in an energy output simulation, and priced into the solar power purchasing. Hence, it is the most economical and price stable form of electric power available.

This unbeatable economics of PV power cannot be taken for granted. It depends on the quality of the system design and installation. The key components of panels, inverters, mounting, have to be carefully selected for the system deployment. Hidden or latent defects, especially in the panels, might result in chronic underperformance after a few years or more disastrous outcomes of electrical fires and premature system breakdown.

To mitigate these risks, the solar power buyer needs due diligence of quality control measures from the factory production oor to post-installation tests including imaging of the panels for defects that the human eye cannot see. Mounting tests for various thermal, mechanical, and chemical stresses have to be verified. The warranties, and liability exclusions, for each component have to be understood. Such due diligence is di cult for ordinary public buyers of small to medium PV systems. A public service bureau for free advice on buying and using PV systems is recommended. In addition, this solar service bureau could advise buyers on overall system design considerations for their use-cases, the latest technologies, best practices, versus what has become obsolete, and fair legal terms for the purchasing transaction. The service would be of mutual benefit to private solar buyers and the public electricity regulatory authorities.

Grid support and virtual power plants

Solar PV is a disruptive technology. Legacy power suppliers, their market positions and business relationships, are disturbed by the industrial emergence of this new power source. Therefore, it’s unsurprising a lot of misinformation is publicly spread to try and slow its growth, self- empowerment of prosumers. One frequent argument is that PV weakens the grid, could cause it to collapse, and may drive distribution grid companies into bankruptcy. It’s opposite to the truth of the matter.

The strength of the grid depends on maintaining its prescribed frequency and voltage at all points – the former has to do with active or useful power, and the latter with what is called reactive power. Although active power can be delivered over long distances of transmission and distribution lines, that is not the case for reactive power. More distributed electric power from PV systems enables local delivery points, greater control of reactive power over the grid network. The inverters can both inject and absorb reactive power, thereby enhancing the voltage stability of the grid.

The physical mechanism of power losses in electrical grid lines is ohmic resistance that increases in proportion to the distance of the power transmission. Distributed PV systems can reduce these distances. Voltage drops in the grid also increase power losses -- reduced by the reactive power capability of the inverters. These benefits strengthen the grid rather than weaken it, providing intelligent distribution grid companies with greater means to control their power losses and quality of supply.

The potential of solar power has been extended into the evening hours, by the possibility of economically storing it in electrochemical batteries. These batteries are also a modular and scalable technology. The prices of batteries have plummeted in the last year to less than $50 per kWh for a lithium- ion battery unit cell (complete battery system prices start from three to four times the unit cell cost, depending on energy transfer speed).

So far, private PV systems are being installed in Pakistan without any exible coordination. Distribution grid operators allow for net metering, but there is no aggregated control of how the individual PV systems can be made to operate in unison. With the latest technology, the solo PV systems can be operated as one gigantic power plant spread over different locations but serving the grid as if it were one consolidated virtual power plant of several gigawatts power capacity. Virtual power plants are being successfully deployed across the globe. This prospect would take the country’s solar power capacity and its grid support to the next level. It requires more advanced collaboration between the electricity regulatory authorities, grid operators, consumers, and the international solar plus storage industry expanding into the Pakistan market.

The writer is director of Vivantive Ltd, London, international advisory services for renewable energy ventures and market development. He can be reached at: omar@vivantive.com