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Tips on improving Solar Self-Consumption
Solar Self-consumption is typically given as a percentage and refers to the total amount of PV energy consumed in relation to the total amount of energy generated. For example, if your solar PV system generates 4000kWh/year and you consume 2000kWh and export 2000kWh, your self-consumption value is 50%. Typically, the generational pattern of solar does not match the consumption pattern of a household, with out altering your energy usage. However, there are numerous ways to shift your demand and increase your self-consumption, some of the main ways are detailed in this blog.
Understanding your current energy usage
The first step to improving solar self-consumption is understanding the energy you use at home, when you use it and how much you use. If you have a smart meter installed in your home, you will have access to daily or half-hourly consumption data for your premises. As a default daily data is recorded, although you can request your electrical company to change this to 30-minute data This information is an efficient and easy way to view your current energy trends. Using this information, you can identify high energy usage periods outside of solar generation and look to shift the demand. you may not be able to shift all of the demand but identifying this is a step in the right direction.
Changing your usage
Once you have identified areas of high usage you can start changing your energy habits to better suit your solar generation curve. Typically, as a rough guide, solar generation is highest during the middle of the day, which is a good time frame to start shifting your energy usage. While a change in habit is possible with just consumption data, the addition of solar generation data is beneficial. Several smart meters including the SMA Home Manager 2.0, SolarEdge’s Smart meter and Solis data logging stick will monitor production and provide usual visual graphics to aid understanding.
SolarEdge monitoring portal
The image above is a capture of the monitoring portal offered by SolarEdge, displaying the users consumption from the grid, solar production and self-consumption. An area for this user to focus on would be between 18:00-20:00 where consumption far outweighs solar production.
The lowest cost solution to achieve an increase in self-consumption is to change the time that energy is used in the home. This best suits those who are home for large parts of the day particularly during the hours of 9 a.m. – 3 p.m. Switching on appliances such as, dishwashers, tumble dryers, hoovers and any other large intermittently used appliance will get results. Another technology worth thinking about are tablets, laptops and phones, if you are able to charge these items during the day instead of overnight this will help increase solar consumption.
While, physically managing your load throughout the day is a solution for some, for many it is not possible. There are numerous technologies available that will partially and fully automate the process, technologies that are discussed below include, time dependant plugs, smart appliances, immersion heater controllers, smart EV chargers and home managers.
Time Dependant Plugs
A time dependant plug is a mechanism for electrical appliances plugged in to a mains socket that limits the access to the electrical supply on a time basis. The plug allows the user to specifically set when the socket is switched on and this can be set for times when there is excess PV generation. Appliances that would benefit from this timer would include, Laptop and tablet chargers, pool pumps, air conditioning units and electric heaters. Typically, any appliances that can function upon start-up could be connected with a time dependant plug.
Smart appliances are appliances that are connected to the wi-fi and can be controlled remotely, common examples of appliances include, dishwashers, washing machines, dryers, fridges, freezers and ovens. There are numerous manufactures that are developing smart appliances, including Bosh, Samsung and LG. The ability to control various functions allow the users to have greater flexibility in selecting what program they run and at what time of the day they run it. This greater control makes it easier for the user to plan certain appliances at times when the solar generation is at its peak. It is recognised that not all activities can be shifted to during the day, but the ability to shift appliances when convenient will boost solar consumption.
Immersion Heater Controller
An immersion heater control is a device that can be retrofitted to the majority of immersion heaters. The device diverts excess generation from the PV system to the heater rather than exporting this to the grid, allowing your self-consumption to increase. The controller will automatically switch off when there is a drop in solar production, prioritising other loads in the home. SolarEdge have a smart immersion heater controller that communicates directly with the inverter and monitoring platform. While SolarEdge offers a fully integrated solution, many manufactures offer similar products that work with other inverter brands, including myEnergi and SolarIboost+.
Battery storage technology in recent years has become increasingly popular as it becomes a mature technology, dropping in cost, increasing in efficiency and storage density. The addition of a battery within your PV system will allow a proportion of the excess solar generation to be stored on site within the battery rather than being sent to the gird. The stored energy is then discharged, when required. The amount of energy that can be stored by the system depends on the capacity and the amount of excess generation. A higher battery capacity combined with high levels excess generation means more energy can be stored and later utilised. Any energy stored in the battery and later used will increase your self-consumption figures. Not sure if a battery is right for you? Click here to read our 2021 battery review!
Smart EV Chargers
The ownership of an electric vehicle (EV) or hybrid electric vehicle (HEV) offer the opportunity to directly consume much of the PV generation. Battery sizes of the base Nissan Leaf and Tesla Model 3 are 40 and 50kWh respectively, as such represent a large amount of electricity usage and a potential sink for PV generation. Simply plugging in your EV during the day will help consume the PV, however, there is also a smarter solution. Zappi offer a 7kW domestic EV charger that allows the user to charge solely using PV generation in its ECO or ECO+ mode. The ECO mode has a minimum charge rate of 1.4kW, and will fluctuate as solar PV increases and decreases, while ECO+ requires a minimum input of 700W from solar.
Home Managers offer a complete solution that monitors a households generation, consumption, self-consumption and battery usage. There are numerous manufacturers that offer such systems including is the SMA Home Manager 2.0 and the SolarEdge Smart Meter.
The SMA Home Manager 2.0 can be connected to various appliances through smart radio-controlled plugs enabling the system to monitor the energy properties in your home. Once connected to the various appliances the home manager will intelligently manage your energy to ensure the maximum amount of PV is consumed. The home manager can perform numerous takes, including storing energy intelligently, switching appliances on and off, and efficiently charging your EV with PV.
If you are interested in any of the hardware solutions considered in this article, feel free to contact us for a no obligation discussion on how we can help you improve your PV self-consumption.