Since the energy generation of a PV system does not match the typical homeowner’s energy usage, the industry relies on rate structures to deal with energy produced, but not consumed. But with the decline of subsidies for PV in the UK market, system owners need to find a way to evolve past incentive structures and towards self-consumption. System owners can put the control of their energy usage into their own hands with behind-the-meter technology, such as smart inverters and storage.
There are a number of ways that behind-the-meter functionality allows system owners to increase self-consumption and gain energy independence. Adding a battery to a PV system is one of the best ways to increase the amount of self-consumption. This allows system owners to store energy generated during the day for consumption during the evening, when energy usage is high.
While of course the quality of the actual battery is important, it is the inverter that is responsible for its functionality. For instance, you can buy a top-of-the-line guitar, but if you don’t have a talented musician to play it, then it simply becomes decoration.
In a PV plus storage system, the smart inverter controls when the PV is utilised, stored in a battery or transferred to the grid; and controls when the battery is charged, idle, or discharged to generate the maximum economic return.
Depending upon the rate structure, the inverter will decide whether to feed energy to the grid or to store it for later use. For example, SolarEdge’s StorEdge solution is programmed to discharge the battery in an optimal manner to meet its programmed goal, such as electric bill reduction, TOU [Time of Use] gain, or maximising self-consumption. Newer, more complex rate structures reward system owners who can intelligently store PV energy for daily on-grid applications.
A key component needed in a behind-the-meter system is the meter itself. The meter is responsible for monitoring import and export of energy to the grid and load consumption. Based on these readings, the inverter manages PV production and the battery charge/discharge. Without the meter, the inverter does not know if it is pushing energy to the grid or just to the home.
Installing a meter also gives the homeowner insight into self-consumption patterns, as the information can be displayed in the SolarEdge monitoring platform.
Even without a battery, system owners can offset the impact of rate design and increase their self-consumption. One of the simplest ways for system owners to self-consume more is through load management - shifting consumption patterns to match peak PV production to loads, such as with immersion heaters.
System owners can take control of their energy usage via load control solutions that direct PV energy to appliances when home demand is low or rates are low. Smart inverters now offer load management control that can be coordinated with a homeowner’s PV production.
As much as system owners benefit from behind-the-meter functionality, if the utility is open to working with the PV industry, there are additional value streams that can be created. The first and most apparent benefit is grid stabilisation. Voltage regulation, frequency control, and power supply/reservoirs are all possible value streams.
For example, by creating distributed PV “power stations” coupled with storage, load can be reduced from the grid at peak times. This lessens the need for utility investments in generation, transmission, and distribution.
While traditional power generation is built on large single sources for energy production and storage, future power generation may look much different. This is where behind-the-meter functionality plays a role and distributed generation can become a reality. New technologies enable a decentralized model with mini-power stations and offer more value by placing energy production and storage at the same location as the load.
Coupled with advances in communication infrastructure, inverter controls, computing power, and smart inverter technology, there are many additional opportunities for behind-the-meter generation and storage. These technologies could finally be the missing link of technology that unlocks solar energy’s grid parity potential.