Solar cells & batterier · KUNSKAPSGUIDE
Solar cells and self-use - when does your solar power do the most good?
See the difference between producing, using and selling solar energy. Calculate the timing and the value before choosing a facility.
THE MOST IMPORTANT THING IN ONE MINUTE
- Annual production and direct self-use are different measures.
- Egenanvänd solel kan ersätta ett köp från nätet; såld solel följer andra villkor.
- Start from the conditions of the roof and the real use of the home, not just a big annual figure.
The important thing happens when the sun and the home meet
A solar cell plant can produce a lot over the year without the entire production being used directly in the home. Production and needs need to coincide in time. A household can therefore both sell solar electricity in the middle of the day and buy electricity later.
The Swedish Energy Agency emphasizes self-use when assessing plant size. View usage over the day and year along with expected production. Two roofs of the same size can fit different solutions if the households use electricity at different times.
Source material: The Swedish Energy Agency: the right size of solar cells ↗
Self-use and self-sufficiency
Self-use rate describes how much of the production is used in the own facility. Degree of self-sufficiency describes how much of the home's needs are covered by own production. They have different denominators.
As your own example: if you produce 8,000 kWh and use 3,200 kWh directly, the self-use is 40 percent. If the home's total need is 16,000 kWh, the same 3,200 kWh covers 20 percent of the need. Both percentages can thus be correct at the same time.
Source material: The Swedish Energy Agency: the right size of solar cells ↗
A bought and a sold kWh have different values
Solar electricity used at home can replace variable costs of purchased electricity. When you sell surplus, you will instead receive compensation according to the terms of sale. It is not automatically equal to the entire purchase cost.
Keep flat charges outside the value you assume for each kWh avoided, if the charge still exists. Also check the current tax and compensation conditions when you calculate. A general calculation with a single electricity price may otherwise overestimate the value.
Source material: The Swedish Energy Agency: the right size of solar cells ↗ · Energy Market Agency: the electricity bill ↗
Use flexibility where appropriate
If the car can be charged while the sun is producing, it can increase its own use, provided the car's needs and the charging equipment allow it. A battery can move some solar power to later, but storage has limitations and losses.
Don't increase usage just to get a higher percentage. The goal is a home that functions with reasonable total energy use. Creating an unnecessary need does not automatically lead to a better economy.
Source material: The Swedish Energy Agency: batteries for solar cells ↗ · Ei: control the charging of your electric car ↗
Evaluate the offer across multiple scenarios
Request production, direct own use and export as separate values. Ask what assumptions were made about weather, roof, shading, lifespan, maintenance and price.
Prova sedan ett lägre värde för både köpt och såld el i kalkylen. Se hur mycket slutsatsen ändras om egenanvändningen är mindre än väntat. Bruttovärdet i vårt räkneexempel är bara en start; det behöver jämföras med investering, finansiering och löpande kostnader.
- Which values are measured and which are calculated?
- What purchase costs are actually lost per kWh?
- How sensitive is the outcome to lower price or less self-use?
Source material: The Swedish Energy Agency: the right size of solar cells ↗
Try the value of various self-uses.
Change production, direct self-use and values for purchased and sold electricity.
Immerse Yourself
FAQ.
Will I be self-sufficient if the annual production corresponds to the annual consumption?
Not automatically. Summer production and winter needs do not coincide. A year's net says nothing about each individual delivery interval.
Is highest self-use always best?
Assess the entire system. Unnecessary consumption or an expensive storage solution can cost more than the value of additional self-use.
FROM KNOWLEDGE TO EVERYDAY
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The material was checked on 26 October 2026. Follow the links for current terms and conditions.