Generation vs demand: why a region can still run short
A region can import electricity and still be fully supplied. It can also face a shortage while another region has spare generation. The connection between them matters.
A local generation gap is not automatically unserved demand. Check imports, export paths, line limits and losses before deciding what to build.
Capacity, generation and demand are different numbers
Installed capacity is a plant’s nameplate rating. Available output is what it could provide under current resource and equipment conditions. Dispatched generation is the output the system actually uses.
Suppose a region has 2 GW of solar installed. At 40% availability, its available output is 0.8 GW. If local consumption and export paths can use only 0.5 GW, dispatch is 0.5 GW and 0.3 GW is curtailed. None of these numbers tells you the region’s demand without another measurement.
Demand is the load people and businesses would consume. Served demand is the part actually supplied. In the game, deliberate emergency reductions count as unserved underlying demand so they cannot create a misleading reliability improvement.
A generation gap can be covered by imports
Consider an illustrative region with 1.0 GW of local generation and 1.4 GW of demand. It needs 0.4 GW of received imports if it has no exports or storage activity. That is an import requirement, not yet a shortage.
= served demand + storage charging − storage discharge
Received imports already exclude transmission losses. If instead you use the amount sent by neighbouring regions, put the incoming losses on the right-hand side. Do not subtract them twice.
For a line with 5% losses, sending 0.4 GW delivers 0.38 GW. To deliver a full 0.4 GW requires about 0.421 GW at the sending end. That extra generation matters for both capacity and operating costs.
Why sufficient national generation is not enough
Now give the importing region a single line whose sending-end limit is 0.3 GW. With the same 5% losses, at most 0.285 GW arrives. Its 0.4 GW gap leaves 0.115 GW unserved even if its neighbour could generate much more.
In this small example, adding another plant to the exporting region does not remove the bottleneck. Increasing transfer capacity, adding usable local generation or supplying the shortfall from a charged local battery could help. Each option has different costs and operating limitations.
EIA describes transmission and distribution as the networks that deliver electricity from generators to consumers. Grid Operator represents those connections with a simplified, loss-aware flow optimization. It is not an AC power-flow or frequency-stability simulator.
Use a full daily profile, not one arrow
A solar-rich region might export at midday and import at night. An average net flow can hide both movements. PowerLab’s regional profiles therefore show transfers in each direction as well as the general net tendency.
Use Current power flows to see the present dispatch. Use Typical flows to view the selected analysis period, and Connections & capacity to inspect the network itself. The next 24-hour forecast assumes current controls and known events; the last 24 observed hours contain only settled results.
Compare average and maximum generation with demand, but remember that two maximums may occur at different hours. A region’s midday generation peak does not necessarily cover its evening demand peak.
Put the idea to work.
Select a region, compare its local supply and demand, then inspect every connected line. Switch between current flows and typical flows. Look for a region whose transfer direction changes during the day.
Inspect the grid →Common questions
Is importing electricity a sign of an unreliable region?
No. Imports can fully cover local demand if supply and transfer capacity are available.
Can national spare capacity coexist with a local shortage?
Yes. In the game, transmission constraints and losses can prevent spare generation from reaching the region that needs it.
Sources & model boundary
Examples and calculations: PowerLab’s illustrative model, checked against the local simulation. Background reading: EIA: electricity delivery to consumers.
This guide is educational. Grid Operator’s network, economics and construction are simplified game assumptions; Market Lab’s uniform-price model is a separate one-hour experiment.