Photovoltaics and Net-billing - redirect surpluses... but not to the grid! Energy storage or...

Auto-consumption of energy - i.e. consume when you produce

  • Self-consumption of energy is becoming more and more important.
  • Thanks to it, the prosumer saves more on electricity bills (he does not have to bear distribution costs).
  • Additionally, it relieves the network without introducing energy into it.
  • Consuming energy on an ongoing basis will be even more important for owners of net-billing photovoltaic installations when hourly prices become applicable in July 2024 instead of monthly prices.

    How to increase autoconsumption from a photovoltaic installation?

    • Energy consumption can be increased on an ongoing basis by implementing simple habits such as turning on devices such as washing machines, dishwashers, etc. during hours of overproduction of energy from the photovoltaic installation. This can be automated. All you have to do is remember to put in the laundry or load the dishwasher :-)
    • Energy storage . This is a more advanced and naturally more expensive way to increase auto consumption. It should work every day, or in fact every evening, and be sufficient to meet the demand from about 5 p.m. until the next start of panel production. (east-west option and, of course, the hours vary throughout the year) It also has a voltage stabilization function, which has a positive effect on all electrical devices in the house, extending their life.

      Typically, an energy storage with a capacity of approximately 10 kWh is optimal for a standard single-family house. However, it all depends on the individual characteristics of each building.

    • Buffer. Another solution is to store this energy in a large-capacity water buffer for central heating and hot water and use it to heat the building and domestic water. Many washing machines and dishwashers with this function can be connected directly to hot water. However, remember to use a thermostatic valve at the outlet from the buffer so as not to overdo the temperature.
    • Hybrid installation . For example, if we have a gas furnace, we can support its operation with photovoltaics both during the heating season and outside of it, heating only hot water electrically.
    • Storage heating . This is a solution for the heating season for those who heat with electricity. Heating cables , heating mats or heating foils and storage furnaces embedded in the screed. A larger domestic water tank and the connection of, for example, a dishwasher and a washing machine with this function will also work well here. Remembering about the thermostatic valve
    • Sauna ...It is quite a popular but expensive pleasure on cold evenings. How about heating your sauna for free? Of course, here too you can redirect surpluses from production to heating using a sauna heater .
    • Anti-icing heating mats . They are designed to heat sidewalks and driveways to protect against snow and ice. Well-fitting heating mats put an end to winter snow shoveling and keep you safe with a dry surface. You can find more about them in our article Outdoor heating mats. Safe and comfortable space heating

    anti-icing mats

    All solutions have pros and cons, and so far no perfect solution has been found. You should optimize everything to suit your preferences and budget.

    Principles of selecting energy storage

    • The energy storage should be selected according to the customer's daily energy consumption.
    • In order to properly select an energy storage system, we should also pay attention to the daily energy generation in the RES micro-installation.
    • Typically, an energy storage with a capacity of approximately 10 kWh is optimal for a standard single-family house.
    • Equally important is the appropriate control of energy surpluses.
    • An optimally selected warehouse guarantees not only greater efficiency of use of the photovoltaic micro-installation, but also lower costs.

      Cost of a photovoltaic installation with energy storage

      • The cost of a 10 kW photovoltaic micro-installation with an energy storage capacity of 7.1 kWh is approximately PLN 65,000.
      • For comparison, a photovoltaic installation on roof tiles without energy storage and with a traditional (non-hybrid) inverter costs approximately PLN 40,000.
      • Adding an energy storage facility and a hybrid inverter to the installation increases the investment costs by approximately PLN 25,000.
      • The Moje Prąd subsidy program is an opportunity for prosumers to reduce investment costs in a photovoltaic installation.
      • The program provides for up to PLN 7,000 for a PV installation with a capacity of 2-10 kW with additional components. PLN (PLN 6,000 without accompanying elements), and for electricity storage – up to PLN 16,000. zloty.
      • The difference in costs between an installation with a hybrid inverter and an energy storage system is approximately PLN 25,000. zloty.
      • If we assumed that these 25 thousand PLN is the cost of the warehouse with assembly, then the subsidy to which the prosumer is entitled would amount to 50% of the value of the warehouse, i.e. PLN 12.5 thousand. PLN + 7 thousand PLN for photovoltaics - total - 19.5 thousand. zloty.

      net-billing

      Summary
      • Energy storage is a solution that can significantly increase the autoconsumption of energy from a photovoltaic installation.
      • When choosing an energy storage facility, you should take into account your daily energy consumption, daily energy generation in a renewable energy micro-installation and the control of energy surpluses.
      • The cost of a photovoltaic installation with energy storage is higher than that of an installation without storage, but it can be reduced thanks to funding from the Moje Prąd program.
      • Self-consumption of energy is becoming more and more important, so it is worth considering installing an energy storage facility.
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