Anyone with a photovoltaic system on their roof knows the problem: during the day the system produces plenty of electricity, yet a large proportion flows into the grid — often at a feed-in tariff far below the current electricity price. The solution is obvious: the more solar power you consume yourself, the more economically efficient your PV system becomes. But how can self-consumption be increased in practice?
Without targeted measures, the self-consumption rate of a typical household PV system is only 20 to 30 percent. That means up to 80 percent of the electricity generated feeds unused into the public grid. With the right strategies, however, you can raise your self-consumption to 60 to 80 percent — and dramatically cut your electricity costs as a result.
In this article we present seven tried-and-tested tips for optimising your PV self-consumption and meaningfully increasing your independence from the grid. Use our PV Planner to calculate in advance how much potential there is in your individual situation.
1. Load Shifting: Move Consumption into the Sunny Hours
The simplest and most cost-effective method of optimising your PV self-consumption is so-called load shifting. The principle is straightforward: consume electricity when your system is producing it — primarily between 10 a.m. and 4 p.m.
Practical examples of load shifting:
- Washing machine and tumble dryer — run them at midday rather than in the evening. A single wash cycle consumes around 1 to 2 kWh. Over a year, five loads per week adds up to 260 to 520 kWh that you can draw directly from your PV system.
- Dishwasher — programme it to start in the early afternoon. Most modern appliances have a delayed-start function you can use for exactly this purpose.
- Robot vacuum cleaner — schedule its cleaning cycle to run around midday.
- Pool pump or garden irrigation — set these to run during the sun-rich hours.
Consistent load shifting alone can increase the self-consumption rate by 5 to 10 percentage points. The great advantage: this measure costs nothing at all — it requires only a change of habits.
Tip: Draw up a weekly plan noting which appliances you run at which times. Load shifting will quickly become routine.
2. Battery Storage: Securing Solar Power for the Evening Hours
A battery storage system is the single most effective measure for increasing self-consumption. It stores surplus solar power during the day and makes it available in the evening and at night — precisely when your household consumption is typically at its highest.
What does a storage system actually deliver?
- A properly sized battery raises the self-consumption rate from 30 to 60–70 percent.
- An average household of four people generally needs a battery with 5 to 10 kWh of usable capacity.
- A useful rule of thumb: plan for approximately 1 kWh of storage capacity per 1,000 kWh of annual electricity consumption.
Economic viability:
Battery storage costs have fallen significantly in recent years. Current prices are around €500 to €800 per kWh of storage capacity, including installation. With a price differential of 25 cents (grid purchase price minus feed-in tariff) and 250 full cycles of storage use per year, a battery system typically pays for itself within 8 to 12 years.
Important selection criteria:
- Pay attention to the usable capacity, not just the nominal capacity.
- The discharge power should match evening consumption — at least 2.5 kW, ideally 5 kW.
- Lithium iron phosphate (LFP) batteries offer the best combination of service life and safety.
3. Operating a Heat Pump with PV Power
A heat pump combined with a PV system is a genuine dream team for self-consumption optimisation. Because heat pumps draw around 75 percent of their energy from the environment and need only 25 percent as electrical drive energy, you effectively quadruple your solar power output.
How to maximise the PV share of your heat pump:
- Use the SG-Ready interface: Modern heat pumps feature an SG-Ready interface. Through this, the inverter can signal to the heat pump that surplus PV power is currently available. The heat pump then raises the flow temperature and charges the buffer tank — effectively using the house as a thermal storage medium.
- Size the buffer tank generously: A buffer tank of 500 to 1,000 litres can store enough heat to bridge the evening and overnight hours.
- Heat domestic hot water at midday: Programme the hot water preparation to run at noon, when your PV system is delivering peak output.
Savings potential: A typical heat pump consumes 3,000 to 5,000 kWh of electricity per year. If you cover 50 to 60 percent of that from your PV system, you save €450 to €900 in electricity costs annually.
4. Electric Car as a Mobile Energy Storage Unit
An electric vehicle offers enormous potential for increasing PV self-consumption. The batteries of modern EVs have capacities of 40 to 100 kWh — many times that of a typical home storage system.
Strategies for optimal PV charging:
- Surplus charging: Many wallboxes offer the option of charging the vehicle exclusively from PV surplus. The charging power adapts dynamically to the available solar output.
- Single-phase charging at 1.4 kW: From a PV surplus of around 1.4 kW, single-phase charging is possible. This allows meaningful surplus charging even on days with moderate solar irradiance.
- Plan charging times: If you are at home during the day or your vehicle is parked there, schedule charging between 9 a.m. and 4 p.m.
Worked example: With an average annual mileage of 15,000 km and a consumption of 18 kWh per 100 km, you need around 2,700 kWh. If you cover 70 percent of that with PV power, you save approximately €567 per year at 30 cents per kWh — on top of the already lower running costs compared to a combustion-engine vehicle.
Future perspective — bidirectional charging: Some vehicle manufacturers already offer bidirectional charging. This allows the EV not only to draw electricity but also to feed it back into the home grid — turning the car into a mobile home battery.
5. Smart Home: Intelligent Control of Energy Flows
A smart home system takes self-consumption optimisation to the next level by automatically matching consumers to the current PV output. Instead of manually checking the inverter, the intelligent control system takes care of everything.
Useful smart home components for PV optimisation:
- Energy management system (EMS): The centrepiece of intelligent control. An EMS knows the current PV output, the battery state of charge, the household consumption and the weather forecast. Based on this data, it controls all connected consumers.
- Smart plugs: Via Wi-Fi plugs, appliances such as the washing machine, tumble dryer or dishwasher can be started automatically as soon as sufficient PV surplus is available.
- Smart immersion heaters: An immersion heater in the hot water tank can convert surplus PV electricity into heat. This is a particularly efficient solution in summer, when the PV system produces more electricity than is needed.
- Timers and smart thermostats: Even simple solutions such as programmable timers can make a contribution.
Practical example: A well-configured smart home system detects, for instance, that the PV system is currently producing 6 kW while the household is consuming only 1 kW. It then automatically starts the washing machine (2 kW), activates the immersion heater in the hot water tank (2 kW), and signals the EV to charge with the remaining surplus.
Use our PV Planner to calculate how much surplus your system typically produces, so you can choose the right smart home strategy.
6. Consumption Analysis: Tracking Down the Energy Guzzlers
Before investing in expensive technology, it is worth taking a close look at your consumption profile. Only when you know when and how you use electricity can you optimise your self-consumption in a targeted way.
How to approach a consumption analysis:
- Install a monitoring system: Many inverters already provide an app that visualises generation and consumption. Advanced solutions such as a home energy manager or similar systems show the energy flow in real time.
- Use electricity meters: With plug-in energy monitors at individual sockets you can identify appliances with high standby consumption or unfavourable usage patterns. Common surprises: old chest freezers, heating circulation pumps or servers running around the clock.
- Create a typical daily and weekly profile: Record for at least two weeks when and how much electricity you consume. Compare this profile against your PV generation curve.
- Identify and replace energy guzzlers: An old refrigerator with energy efficiency class B can consume up to three times as much as a modern class A appliance. Replacing it not only reduces total consumption but also improves the ratio of self-consumption to grid export.
Typical findings from a consumption analysis:
- The standby consumption of an average household amounts to 200 to 400 kWh per year — equivalent to costs of €60 to €120.
- Electric hot water heating in the evening wastes enormous PV potential.
- Chest freezers can be set to run their compressor cycle at midday and then use the cold as a form of thermal storage.
Our PV Planner helps you analyse your current situation and quantify the optimisation potential.
7. The Right System Size: Not Too Small and Not Too Large
Optimal sizing of your PV system is the foundation for a high self-consumption rate. If the system is too small, roof space goes to waste. If it is too large, the percentage self-consumption falls and a growing proportion feeds into the grid.
Guidelines for optimal system size:
- Basic rule: Orient yourself around your annual electricity consumption. A good benchmark is 1 to 1.5 kWp of system output per 1,000 kWh of annual consumption.
- Plan for future consumption: If you are planning to purchase a heat pump or an electric car, factor in the additional electricity demand at the planning stage. A heat pump increases demand by 3,000 to 5,000 kWh; an electric car by 2,000 to 3,500 kWh per year.
- Consider roof orientation: An east-west orientation produces slightly less total electricity than a south-facing roof, but it distributes generation more evenly throughout the day. This often matches the consumption profile better and increases self-consumption.
- Account for shading: Partial shading from trees, chimneys or neighbouring buildings not only reduces yield but also shifts the generation curve. Module-level optimisers or micro-inverters can help in such situations.
Worked example:
| Scenario | Annual consumption | Recommended PV output | Self-consumption rate (without storage) |
|---|---|---|---|
| Household without EV/heat pump | 4,000 kWh | 5–6 kWp | 25–35 % |
| Household with heat pump | 7,000 kWh | 8–10 kWp | 30–40 % |
| Household with heat pump and EV | 10,000 kWh | 12–15 kWp | 35–45 % |
Bear in mind: a larger system generates more absolute self-consumption, but the percentage share falls. A battery storage system can partially compensate for this effect.
Frequently Asked Questions
What is a good self-consumption rate for a PV system?
A self-consumption rate of 30 percent is typical without any special measures. With a battery storage system you generally reach 60 to 70 percent. By combining all the measures presented here — load shifting, storage, heat pump, electric car and smart home — 70 to 80 percent is even realistic. Reaching 100 percent self-consumption is not economically sensible in most cases, as the final percentage points become disproportionately expensive to achieve.
Is a battery storage system economically worthwhile?
A battery storage system is particularly worthwhile when the gap between your electricity price and the feed-in tariff is large. At current electricity prices of around 30 cents per kWh and a feed-in tariff of approximately 8 cents, the differential is 22 cents per kilowatt-hour stored. With 200 to 250 full cycles per year and a service life of 15 years, the investment can pay off. The key is correct sizing: an oversized battery will not be used sufficiently and will lengthen the payback period.
How much energy self-sufficiency is realistic?
Self-sufficiency and self-consumption are two different metrics. The self-sufficiency rate indicates what proportion of your total consumption you generate yourself. With a PV system and storage, typical single-family homes achieve self-sufficiency of 50 to 70 percent. One hundred percent self-sufficiency is barely economically feasible in the German climate without very large storage systems and additional generation sources, since solar yields drop significantly in winter.
Can I significantly increase self-consumption without a battery?
Yes, self-consumption can be noticeably increased even without a battery storage system. Through consistent load shifting, the use of a heat pump connected to the PV system, and charging an electric car with solar power, you can raise your self-consumption to 40 to 50 percent. Smart immersion heaters in the hot water tank are a particularly cost-effective alternative to battery storage for making good use of surplus electricity — though only for domestic hot water heating.
What subsidies are available for self-consumption optimisation?
The subsidy landscape changes regularly, so you should always check for the latest information. At the federal level, the KfW programme offers funding for battery storage in conjunction with PV systems. Many German states and municipalities offer additional support programmes for storage systems, wallboxes and energy management systems. The feed-in tariff under the Renewable Energy Sources Act (EEG) is not a direct self-consumption subsidy, but it forms the economic framework. Also check whether your energy supplier offers special tariffs or bonuses for PV system operators.
Optimise Your PV Self-Consumption Now
Would you like to know how much potential there is in your specific situation? Our free PV Planner calculates, based on your location, roof area and consumption profile, what your current self-consumption level is and which measures you can take to increase it.
Start your individual calculation now and take the first step towards greater energy independence. Use of the planner is free of charge and non-binding.