I'm guessing: fewer people buying from the power companies/grid => the fixed costs of these companies are pushed onto the poorer customers, who already couldn't afford much.

The following isn't a grid problem (more of a demand issue), but maybe they're referring to this:

> But 45 percent of Pakistanis live below the poverty line, according to the World Bank, putting solar panel systems well beyond their reach. The pool of customers for the national grid has gotten smaller and poorer, and the costs of financing old coal-powered plants have increasingly been passed on to those who can least afford it. [1]

1. https://www.msn.com/en-us/news/world/how-pakistan-s-solar-en...

Previously, pretty much everyone (not just 'rich people', although, well, 'rich' is relative here, of course...) had diesel generators, which were not connected to the grid, since that would be seriously expensive, plus syncing would be pretty much impossible anyway.

With solar, you can feed back into the grid much more easily, to the point that this is the default. This sort-of doubles the load on the grid (not exactly, but you get the idea), since both 'consumption' and 'production' need to cross the same wires.

This is a problem even in, like, Germany, where the grid operator can send a "kill signal" to local solar inverters to shut down. In Pakistan, I can't even imagine...

Because storage is incredibly expensive and thus, for every GW of installed solar capacity you need and an exact another GW reserve capacity from other sources for the rare times when the sun doesn't shine (like, for example, during the night or during large spells of bad weather).

Besides being intermittent, solar and wind are not really dispatchable, that is, the grid operator doesn't have many levers to control the power output of a plan, and thus this imposes more stress on the other dispatchable power sources.

Some of those backup sources are not very flexible and take a long time to turn on and off, like coal based, and a lot of nuclear plants. Others, can be brought up online, ramped up and down faster, like gas turbines and hydro.

But other than gas turbine, most other firm sources economics are based on a predictable demand and a minimum duty cycle. A nuclear plant is very capital expensive, have an excellent capacity factor, but, it can't pay itself and its investor if it is not going to be run most of the time.

Base load is cheaper, because you dilute fixed costs, peak load is more expensive, because you sell less units to dilute your fixed costs.

Despite whatever the renewable lobby says, experience has shown over and over, that after a certain proportion of intermittent generation in a grid, large frequency excursions, deteriorated economics and frequent load shedding events are rather the norm than the exception.

AC grids are stupidly complex beasts. Most politicians, journalists and investors that drive our current discourse on the grid don't have even the most basic pre-requirements to understand it.