The intermittent (at times, not all times) sources of energy by nature are supplementary sources to power supply industry, that is to say, renewable energies are grid-dependent for continuous supply of power to consumers. This reason of intermittency alone had locked the true potential of RE and it could never be expected of RE to become a bankable or sole input to the dependable power supply sector. The intermittency drawback of RE is unfixable in itself, while on the other hand its advantages are tremendous and not-ignorable, more than that the environmental damages caused by conventional carbon-producing methods of producing the electricity further adds to the case of RE. Logically, there is a situation – if the intermittency problem is tackled, then RE wins a clear position of bankable and independent source for electricity production.
Howdy, that looks like a change; there we may expect a paradigm shift in the approach of traditional power policymakers who find it difficult to think beyond centralized generation options and where they have no solution for poor distant people; if we see those 3.5 million households in the country who are not likely to see the grid even in next decade – the idea sounds like a ray of hope denoting far reaching significance for the people. Hitherto, the RE power has been a grid-ally in one way or the other assuming the role of supplementary source to the centralized generation system for its rigid and fixed electricity-cycle,
where the consumption or demand of electricity has a pattern or forecast that has to be managed; the generation of electricity is under control; distribution of electricity is also under control; so when electricity can be generated and distributed as the demand-side requires – this makes one case of electricity management.
Now, think of the situation when you have no control on the generation side (since power is produced only by RE sources), means you will also lose control on distribution side – this makes a different case of electricity management (vis-à-vis intermittency issue).
A simple logical resolve of the problem is – generate as much kWh as the consumption-cycle demands, store it and use it – that’s it. Rationally it is that straightforward but of course, technical considerations might be challenging enough and depending on RE type used for the generation of electricity, baseload size, storage medium/technology, consumer type etc. It is imperative to note that the technology & economics of storing electricity we are talking about here is different in nature from what we understand previously i.e., interim or backup storage when the mains fail. We are talking about storage of electricity as a fundamental building block of the system for baseload applications where there is no main i.e., the autonomous RE power supply setups. The current unprecedented wave of undertakings on energy storage systems (ESS) is witnessing this resolve; the solution of RE intermittency is in “the storage of energy/electricity techniques” which will eventually prove a “game changer” within power supply industry.
The national power policy makers and professionals shall keep eye on the developments and potentials of energy storage systems for RE implementations since RE + ESS is going to change a lot positively; it can eliminate Transmission (on macro level) whereas it can eliminate Transmission & Distribution both on micro level.
Presently, RE power is connected to grid mostly along with its intermittent weakness. In the mainstream centralized generation and management system, when RE power is sent to the grid, the available control mechanism in place is able to accommodate this intermittent power and manage the demand by other controllable points in generation and distribution. From micro level (domestic systems employing reversible meters) to the national grid, RE power has a workable place in conventional grid system, like:
Although, a direct feed from RE power plant to grid is managed by existing control mechanism of the grid but even then sudden fluctuations in RE power can cause problems for the grid, the safest method of RE power interaction with grid is to bring a shock-absorber kind of mechanism in between – here we have no better choice than energy/electricity storage apparatus. This RE+ESS combination will also provide exceptional operational and technical flexibility in grid management, for instance, in managing peak and off-peak hours, issues related to transmission line capacity and load variations, expansion and up-gradation programs of the grid points etc. there is so much convincing economics in this arrangement with monetary benefits to operators and consumers that the time is not away when no direct RE feed to grid would be seen probably.
On-grid or off-grid, any type of RE generated power in unison with an appropriate kind of energy/electricity storage mechanism is desirable option in every respect relevant at any level – micro (domestic) to national (grid) use. Well expressly, we are not looking at any particular technology vis-à-vis RE or ESS rather the focus here is to emphasize the applicability of this combination in any way where RE can be generated by any means; potentially, it is the future of distributed generation since the input is free and plentiful; and given that it reduces the dependency on foreign sources (i.e., the import of fossil fuels) inherently thus, is a security pillar too. The economic feasibility of RE power is definite in our national context, whereas its financial workability which is mostly misquoted is also viable. Let us see, for instance, the potential and economics of one renewable source which is considered more expansive than wind i.e., solar, even this so-called and misquoted expansive method of electricity generation is feasible both economically and financially that is too with selected bulk storage if added.
The potential and economic glimpses of solar energy in Pakistan
- The annual insolation (solar radiation) level throughout the country ranges from 5 to 7.5 with few exceptions.
- An area of less than 70 square miles can generate electricity sufficient for the needs of whole nation that it consume maximum in a day time today.
- The levelized cost of energy per unit (kWh) from MW scale on-grid solar plants can be as low as Rs.7 to Rs.8 with purposefully designed financial plan without any subsidy offered; rather the unit cost can be further less than this provided the government is proactive and aggressive.
- With the addition of some appropriately selected storage technology to interact with the grid that will though add to the cost of energy, but still the levelized cost of energy per unit (kWh) with buffer storage can be as low as Rs.9 to Rs.10.
- The deployments are fast, for instance multiple 100MW of solar facilities to be built in tandem can start producing electricity within 6 to 8 months.
- One unit of electricity generated from RE would reduce the import of diesel oil by at least Rs.18 or even more which will minimize the import bill considerably.