Your bill, translated: what you pay and which part you can attack
Every electricity bill has four blocks: the power term, the energy term, taxes and other items. Regulated grid charges and levies account for around 40% of a household bill, so a good part of what you pay does not depend on how much you use but on what you have contracted.
Captia Energy Team · Chartered, qualified engineers · Published · Reviewed
What blocks make up an electricity bill?
Strip away your supplier's design and every household bill says the same: an energy term, paying for the kilowatt hours you use; a power term, paying for the right to a maximum contracted power whether you use it or not; regulated grid fees and charges, which fund the networks and system costs; and taxes, the electricity tax and VAT, applied on top of nearly all the above.
The order matters because each block is attacked with a different tool, and some blocks cannot be attacked at all.
What share of the bill are grid charges?
For a typical household, the regulated fees and charges hover around 40 percent of the bill. That explains two things that puzzle many people: why the bill never reaches zero even when the roof produces plenty, and why comparing suppliers on the kilowatt-hour price alone falls short. Part of the bill is fixed by regulation and follows you to any company.
Where each decision acts
With the blocks clear, every tool finds its place:
- Solar attacks the energy term: every kilowatt hour you produce and use directly is one you do not buy, taxes included.
- Surplus credits also act inside the energy term, up to the compensation ceiling: they can bring it to zero, never below.
- Contracted power is reviewed separately: many homes pay for inherited power they do not need, and adjusting it trims the monthly fixed cost. With solar and a battery, it can sometimes be tuned further.
- Switching tariff or supplier acts on the energy and surplus prices: it is the final tweak, not the first move.
The fifteen-minute exercise
Take your last bill and find three numbers: how many kilowatt hours you used, what you paid for the power term, and the price charged per kilowatt hour. With those three you can answer what matters: whether your problem is consumption, oversized power or an expensive price. And if you want the diagnosis done for you, bring us the bill: it is literally the first thing we ask for in any study, because your real case is written on it.
How do you read the export credit on the bill?
Once your installation is legalised, the bill changes shape and a new line appears: the surplus energy you have exported to the grid. That line reduces what you pay, but it helps to understand how. Under the simplified compensation scheme, the discount applies only to the energy portion of each bill. If you export a lot and use little in a given month, the credit brings that portion down to zero and stops there: it does not create a balance in your favour or carry over to the next month, unless your supplier offers its own accumulation scheme, which is a commercial arrangement rather than anything to do with the grid.
The price you are paid for each exported kWh is set by your contract with your supplier, not by any official body. That is why two neighbours with identical installations can see different credits. Your bill should show the total kWh exported and the unit price applied; if all you see is a single overall figure with no breakdown, ask for one.
The most common mistake we come across is assuming the credit switches itself on. Some time can pass between legalisation and the first bill showing surplus, and there are cases where the line simply never appears because the contract was never updated. It is worth going through the first two or three bills after commissioning calmly. That is part of what staying means to us: the job is not finished until the bill reflects it.
Reading mistakes we see every week around the comarca
La Costera has plenty of village houses used at weekends or in summer. Their owners are surprised to pay almost the same for an empty month as for a lived-in one. It is not an error: it is the weight of the fixed charges. On a meter that barely registers any use, the contracted power and fixed charges dominate the bill, and neither panels nor a cheaper energy rate will move it much. What you can review is whether the contracted power matches what the house genuinely needs.
The other classic is services smuggled into the contract: maintenance plans, insurance or payment protection added over the phone years ago, showing up as small lines that add up all year round. After switching supplier, it is also worth checking the closing bills, where unexpected charges tend to appear.
- Always separate the fixed part from the variable part before comparing two months
- Look for service lines you do not remember signing up for
- Check whether the reading is actual or estimated
- In second homes, review the contracted power before anything else
Frequently asked questions
I barely set foot in the house this month, so why has the bill hardly dropped?
Because a large part of what you pay does not depend on consumption. Grid charges and levies come to roughly 40% of the bill, and the contracted power charge applies even with the house empty. That is why second homes have a floor the bill never drops below.
How do I know whether I am on the regulated or the open market?
Check the first page of your bill. The regulated tariff (PVPC) is only offered by the reference suppliers and is usually identified by those initials. If your bill mentions a plan with a brand name, a fixed price or discounts, you are on the open market. Your contract confirms it too.
My bill says the reading is estimated. What should I do?
It means the distributor did not have the actual figure and calculated your consumption from your history. With digital meters it is rare, but it happens with communication faults. Photograph the meter with the date visible and ask for a corrected bill. If it repeats, complain to the distributor.