Excess Solar Energy Storage As Compressed Air

sohaibnaqvi3 Registered Users Posts: 1

Dear All,

Please suggest me some tips for Excess Solar Energy Storage:

I have installed Solar Power system at my home which has the following details:

PV Modules Installed capacity= 2.160KW (08modules with 270Watt/panel)

Off/On grid Inverter (Has multiple functions including Net-metering option) = 3.5KW

Deep Cycle Batteries= 04 (120Amp each)

Average Energy consumption (Load) = 15KWH (60% of this is used at night-from Grid)

Net-metering option is not available in our area. What I am asking here, Can I store excess Solar Energy as compressed air during the day time and use it at night?

What will be the compressor specifications/type for providing 9KWH during night hours?

How it can be coupled with an A.C. generator?

Is there any system already in market that meets my set-up demand?


  • 706jim
    706jim Solar Expert Posts: 516 ✭✭✭✭

    I have an air compressor with a 60 gallon storage tank. From empty, the 3hp motor runs maybe 5 minutes to bring the tank to 140psi.

    My thoughts are that if I were to release this compressed air to power a generator or other device, I would only get part of the energy used to compress this air to 140psi.

    In other words, not much unless you had a tank the size of a swimming pool which most people do not.

    I'm too lazy to calculate the power going in but I think you get the idea.

    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 30th year.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,493 admin

    In general, the best you can do to store energy in smaller (home) power situations... Things like pumping water while you have sun to a cistern/pond/irrigation.

    Another is to use an electric water heater (several tanks, larger tank) to store hot water--Pump excess daytime solar energy into the electric element--Draw water at night.

    Another for your hot summers.... Run a freezer to create ice during the day and use the ice to make cool air and/or to cool your A/C condenser (lower operating costs).

    If you get an electric vehicle--Charge the batteries during the day when the car is parked.

    Otherwise, look at your energy usage. Get a Kill-a-Watt type meter to measure the power of your major appliances. Or get a whole house monitor to measure hardwired loads (like A/C, electric water heater/stove/dryer, etc.).



    In general, it is almost always cheaper to conserve energy than to generate/store energy. Insulation, shade on windows (hot climates), looking at energy usage for each appliance, LED lighting, energy efficient refrigerator/freezer, mini-split A/C and/or Heat Pump (use "reverse A/C" to heat your home in winter).

    Look at alternate fuels... I guess you are somewhere around Lahore Pakistan. Do you have natural gas or propane available (typically, cooking, hot water, dryer, home heating) is cheaper than using electricity (although, Heat Pump for heating with electricity can be very cost effective).

    Using solar thermal panels + Water Storage Tank for hot water--Can be very nice in sunny climates (you have a monsoon season during "summer"--Lots of rain and clouds?)--Cloudy weather is terrible for any sort of solar harvest (as is shading of your solar electric panels).

    Look at all of your loads... People feel that a microwave at 1,200 Watts is a major load, but forget about the desktop computer system:

    • 1,200 Watts * 1/3rd of an hour (20 minutes a day) = 400 WH = 0.4 kWH per day
    • 300 Watt desktop computer * 24 hours per day = 7,200 WH = 7.2 kWH per day

    The loads that run 12 to 24 hours per day can be much worse than a Microwave or Water Pump that runs less than an hour per day.


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset