What To Do With Excess Solar Power Off Grid?

The building electrical energy demand does not always match the photovoltaic production in photovoltaic installations. The extent of this mismatch varies depending on the building’s activity and consumption profile, but it applies to the vast majority of structures.

When sun irradiation is low in the morning and evening, residential buildings and hotels need more energy. As a result, load consumption is not coordinated with photovoltaic power output. Under these circumstances, solar self-consumption is only viable if a significant amount of end-user demand is switched to daylight hours.

The majority of power use occurs during the daytime in office buildings, schools, and shopping malls. These buildings, on the other hand, have a very different consumption profile on weekends and other days off, with lower flat usage. Furthermore, most schools and institutions reduce their activity during the summer months, consuming far less energy, or none at all in certain circumstances.

Depending on how their activities are organized, industrial buildings may have typically flat consumption but also have periods of low demand. Another example of a solar production profile that does not match consumption well is this one.

Solar energy does, in fact, have a daily production profile that is dependent on weather conditions, with no output at night. It’s difficult to match building demand with photovoltaic production when these factors are taken into account, as well as the unpredictability of individual buildings’ consumption profilesincluding fluctuations owing to changing seasons and days of the week. As a result, even when the solar system is sized to not exceed the building’s baseload demand, surplus photovoltaic production occurs frequently.

When locally generated power exceeds consumption loads, there are numerous alternatives for dealing with the excess power:

The movie “Four approaches to manage excess photovoltaic production,” the second in a new video series published by Schneider Electric’s technical communication and training branch, explains these technologies.

Solar energy storage systems that store excess solar production and make it available for use later in the day can be quite effective. However, this option is currently expensive and has a significant payback period. Storage can be combined with various use cases to improve return on investment, such as providing a backup power supply, enhancing demand responsiveness, and minimizing peak power usage to enable low-power contracts. Another video in this series delves deeper into this strategy.

Load management is a very appealing solution that entails simply turning on some loads during the photovoltaic production time, if that is possible. Through the control system, these loads must be flexible and manageable. Electric vehicle charging, water heating, and, to a degree, HVAC (heating, ventilation, and air conditioning) are examples.

The load management technique has obvious benefits: it is cost-effective, simple to deploy, and ensures a quick return on investment. It is more profitable than a storage integration solution because it does not involve the installation of new equipment.

When a load shifting strategy is insufficient to absorb the complete excess of PV production, a storage system can be utilized in conjunction with it. In that situation, load shifting has the added benefit of shrinking the storage system’s size while increasing its efficiency.

As shown in the video below, a combination of the four optionsgrid injection, power limiting, storage, and the extremely appealing option of load shiftingoften proves to be the most effective approach to handle excess PV production.

Is it possible to sell the excess energy generated by solar panels?

Selling solar energy in the form of renewable energy credits can also benefit mall businesses. One MW of solar electricity is represented by a single renewable energy credit. As part of the Renewable Portfolio Standard, which is in place in many states, utilities are now required to purchase a specific fixed quantity of renewable energy credits. Small enterprises can benefit immediately by selling solar energy credits at the market value of electricity. Businesses can sell SRECs to utility companies directly or through an agency.

When the off-grid solar batteries are depleted, what happens?

When the battery bank is full, the solar system’s power is no longer absorbed. The solar panels will continue to create voltage, but it will not be used or stored until there is a demand for energy or sufficient battery capacity.

What happens to solar energy that isn’t used?

Solar panels generate the majority of their energy during the day, when most of us are at work and unable to use it at home. When your system generates more energy than it consumes, the excess energy is either fed back into the grid or utilized to charge your battery, if one is present.

Negotiate a good Feed-in-Tariff (FiT)

The value of your solar electricity exported is equal to or near to the wholesale electricity market price. Many shops will provide feed-in rates, with the majority relying on IPART’s annual recommendations on suitable FiT rates and ranges. Some retailers will provide a fixed rate, while others will provide a credit based on the same Time-of-Use (ToU) retail rate as when the electricity is exported.

Review your current agreements for surplus solar energy generation treatment and try to agree on a reasonable cost or include this demand in your future retail energy negotiation.

Find a retailer who is willing to net off your supply and demand

If no FiT can be achieved, crediting export to another site could result in savings at the full retail electricity rate for the recipient building. Although we are not aware of any small-scale arrangements like this, you might be able to work something out with your retailer.

It is feasible to transfer generation from one location to another, but the following prerequisites must be met:

  • The retailer must have a billing system that allows for generation assignment according on time of use a difficult problem for tier-1 retailers with antiquated billing systems.

The University of Technology Sydney provides an example of this scenario in the form of a Power Purchase Agreement (UTS). The University of Technology Sydney and its electricity reseller have agreed to ‘pass through’ generation from a 200 kW Singleton solar PV farm to the university’s Broadway campus. However, the electricity generated by the Singleton solar farm accounts for only 2% of UTS’ overall load.

Ask your network provider for local network sharing tariffs

Historically, network pricing has not taken into account a consumer’s proximity to a prosumer. This, however, must evolve to reflect the grid’s transition to two-way energy flows. Change is possible if a growing number of customers request it.

Network providers have agreed to a new local sharing network tariff in experiments that are currently underway. For example, the town of Newstead in Victoria was able to work with Powercor to design a local sharing tariff (for a two-year experiment).

Similar procedures have not yet been established in NSW, though discussions are ongoing. In the Byron Bay Arts and Industrial Estate, for example, Enova Energy and Essential Energy are attempting to develop a local generation tariff.

Consider an embedded network

A private network in which just one parent meter is connected to the grid is known as an embedded network. Several consumers are provided with energy behind that parent meter, with the Embedded Network Operator supervising the private network’s operation.

The operator purchases electricity for the embedded network from a retailer and resells it, usually at a lower price than market. You must obtain a retailer exemption from the Australian Energy Regulator in order to set up an embedded network (AER).

Caravan parks, business parks, shopping malls, apartment buildings, office buildings, airports, and university campuses all have embedded networks. They are simple to set up from the ground up, but they are costly to retrofit.

If you want to share your excess solar electricity with renters in the same building that your company owns, an embedded network might be the way to go.

Use battery storage to increase self-consumption from solar

Rather than transmitting extra solar energy to the grid, you might store it in an onsite energy battery system. You can then use this stored energy to generate electricity when the sun isn’t shining or to assist you minimize peak consumption.

Unfortunately, the costs of battery storage remain high at this time. This is especially true if you export the majority of your energy on weekends. To deliver cost reductions during working weekdays, you’d need a huge battery.

If the battery is utilized solely to reduce peak demand, the business case will be slightly better because a smaller battery will be required.

Solar with battery storage in a virtual power plant (VPP)

The NSW government recently announced plans to build a 200 megawatt (MW) virtual power plant (VPP) that will utilise the capacity and stored energy in household and business batteries to produce dispatchable energy during peak network demand periods, such as hot summer days. This is part of the Smart Energy for Homes and Businesses program, which is set to debut in early 2019.

Stored energy can also be valuable if it can be combined with additional batteries to compete in the wholesale market. This is a crucial component of certain pre-existing VPPs, such as Powershop-Grid Reposit’s Impact product, and comparable VPPs in other jurisdictions, including as the Australian Capital Territory, with a large-scale VPP in the works in South Australia.

Consider a microgrid

A microgrid is an option if you want to share electricity with others in order to increase your resilience in the case of a grid breakdown. Microgrids and embedded networks at the customer level are similar in that they seek to exchange energy in a private distribution network. The microgrid, on the other hand, has the ability to disconnect from the main grid.

A microgrid works best when combined with enough battery storage to keep you powered up even during a blackout.

Peer-to-peer solutions like PowerLedger or Greensync

At current time, a number of P2P trials are underway, with the majority of commercial ventures taking place in strata or similar areas where energy can be shared behind the main meter. This is due to the fact that P2P solutions are now the easiest to set up in embedded networks.

If you want to use a P2P solution outside of an embedded network, where energy is transferred between locations via the grid, you’ll need the help of a retailer who can sell you a product that stacks up against credits from the distribution network provider.

Consider a portfolio approach

Last but not least, when it comes to maximizing the financial benefits of solar, you should always consider a portfolio approach. Every time you go to market for a new retail contract, you must weigh the possibilities that will provide you with the best overall financial return for your asset portfolio. You may choose to combine solar export with demand flexibility methods in addition to analyzing solar export.

Is it possible for me to sell my solar energy to the grid?

Solar energy may be a terrific financial investment, without a doubt. It’s not because of the money you earn, but rather because of the money you save.

Unfortunately, selling your solar energy to earn revenue does not work that way. You won’t be able to resell the electricity generated by your solar system to the utility. However, one of the most significant advantages of solar energy is its financial impact. Your solar system will save you money on your monthly electricity bill that you would otherwise pay to the utility company.

While it is true that certain large solar development businesses can profit by building a solar system on leased property and selling the electricity to the property owner, this is not the case for the common solar investor.

There are, however, laws in place that govern how utilities compensate you for the energy generated by your solar system. If you have a grid-tied solar system, you can transfer the solar energy to the grid and get a credit from the utility or they will buy it at a wholesale price. These compensation plans, on the other hand, will earn you very little money; they’re more like a free method to store your electricity.

Is it possible for me to return my solar panels to the company?

So you’ve decided to take the plunge: You’ve put solar panels on your roof or in your office. You’re feeling pretty good about this decision you’re bringing in environmentally beneficial, renewable energy; the panels were affordable and easy to install; and you’re convinced that you’ll save money on energy expenditures year after year. However, there is an additional benefit to the solar tax credit that you may not be aware of: you can sell your solar power back to a utility company. That’s right: solar energy may help people save money while also earning money. That’s what I call multitasking.

Many electric companies will credit your monthly account if you generate more power from your solar panels than you use in your home or company. The amount the electric company pays for solar power varies depending on the month. For example, the true up rate in November 2018 is $.03988 ($.40 cents) per kilowatt. SDGE will credit your account for every kilowatt you sell back to them. A kilowatt costs 40 cents. The electric company would credit your incoming account $40 if you sold 100 kilowatts of solar electricity back to them!

Of course, obtaining a large payout from your utility company every month for the solar electricity you don’t use isn’t nearly as simple. There are a few different rules to follow and things to keep in mind, depending on where you live. However, net metering can be an added benefit to an already worthwhile investment, so let’s look at how to make your solar panels work even harder for you.

What happens if a solar panel isn’t connected to anything?

The quantity of electricity utilized by devices powered by the panel is referred to as a “load.” The term “no load” refers to a solar panel that is not connected to any electronics.

A solar panel will absorb sunlight even if it is not linked to anything, but it will have nowhere to send the energy. It has voltage, but there is no current flowing.

The voltage will become heat in the solar cells and radiate out from the panel until it dissipates because it has nowhere to go.

The battery will remain full until the load is restored, but leaving the panels in the sun for long periods of time could cause damage to your system.

Is it possible to leave a solar trickle charger running all the time?

A solar trickle charger is a device that charges various electronics using solar power. These low-power chargers are ideal for recharging cellphones, laptops, and tablets. They can be left plugged in all the time, giving a home outlet for these devices without using power from the grid.

What happens if you produce more energy than you consume?

When your renewable energy system generates more electricity than you can consume at the time, the excess electricity is sent to the electric grid, where it is used by your utility. The Public Utility Regulatory Policy Act of 1978 (PURPA) mandates that electricity providers purchase excess power from grid-connected small renewable energy systems at a rate equivalent to the cost of producing the power. This obligation is usually implemented by power companies through various metering setups. The following are the types of metering arrangements you’re likely to come across:

  • Net purchase and sale Two unidirectional meters are installed under this arrangement: one records electricity drawn from the grid, while the other records excess electricity created and supplied back into the grid. You pay the retail rate for the electricity you use, and the power company buys your excess generation at a discounted rate (wholesale rate). The difference between the retail rate you pay and the saved cost of the power provider could be significant.
  • Net metering is a term that refers to how much electricity is used You, as a consumer, will profit the most from net metering. A single bi-directional meter is used to track both the electricity you take from the grid and the extra electricity your system feeds back into the grid under this arrangement. When you use electricity, the meter spins ahead, and when you use less, it spins backward. If you use more electricity than your system produces at the end of the month, you must pay the retail price for the surplus electricity. If you produce more energy than you consume, your electricity provider will usually reimburse you at the avoided cost. The actual benefit of net metering is that the electricity you give back into the grid is essentially paid at retail price by the power company.

Some electricity suppliers now allow you to carry over the balance of any net additional electricity your system creates from month to month, which might be beneficial if the resource you use to generate electricity is seasonal. If you produce more energy than you consume at the end of the year, you must provide the excess to the power provider.

Cost

The cost of purchasing a solar system is relatively expensive at first. Solar panels, inverters, batteries, wiring, and installation are all included in this cost. Nonetheless, because solar technology is continually improving, it’s realistic to predict that prices will continue to fall in the future.

Weather-Dependent

Although solar energy can be collected during overcast and rainy days, the solar system’s efficiency is reduced. Solar panels must be exposed to sunlight in order to collect solar energy. As a result, a couple of overcast, rainy days can have a significant impact on the energy system. It’s also important to remember that solar energy cannot be collected at night.

Thermodynamic panels, on the other hand, are an option to consider if you need your water heating solution to work at night or during the winter.

Check out our video for a breakdown of how effective solar panels are in the winter: