Solar Integration: Inverters and Grid Services Basics
An inverter is one of the most important pieces of equipment in a solar energy system. It’s a device that converts direct current (DC) electricity, which is what a solar panel generates, to alternating current (AC) electricity, which the electrical grid uses. In DC, electricity is maintained at constant voltage in one direction. In AC, electricity flows in both directions in the circuit as the voltage changes from positive to negative. Inverters are just one example of a class of devices called power electronics that regulate the flow of electrical power.
Fundamentally, an inverter accomplishes the DC-to-AC conversion by switching the direction of a DC input back and forth very rapidly. As a result, a DC input becomes an AC output. In addition, filters and other electronics can be used to produce a voltage that varies as a clean, repeating sine wave that can be injected into the power grid. The sine wave is a shape or pattern the voltage makes over time, and it’s the pattern of power that the grid can use without damaging electrical equipment, which is built to operate at certain frequencies and voltages.
The first inverters were created in the 19th century and were mechanical. A spinning motor, for example, would be used to continually change whether the DC source was connected forward or backward. Today we make electrical switches out of transistors, solid-state devices with no moving parts. Transistors are made of semiconductor materials like silicon or gallium arsenide. They control the flow of electricity in response to outside electrical signals.
A 1909 500-kilowatt Westinghouse “rotary converter,” an early type of inverter. Illustration courtesy of Wikimedia.
If you have a household solar system, your inverter probably performs several functions. In addition to converting your solar energy into AC power, it can monitor the system and provide a portal for communication with computer networks. Solar-plus–battery storage systems rely on advanced inverters to operate without any support from the grid in case of outages, if they are designed to do so.
Toward an Inverter-Based Grid
Historically, electrical power has been predominantly generated by burning a fuel and creating steam, which then spins a turbine generator, which creates electricity. The motion of these generators produces AC power as the device rotates, which also sets the frequency, or the number of times the sine wave repeats. Power frequency is an important indicator for monitoring the health of the electrical grid. For instance, if there is too much load—too many devices consuming energy—then energy is removed from the grid faster than it can be supplied. As a result, the turbines will slow down and the AC frequency will decrease. Because the turbines are massive spinning objects, they resist changes in the frequency just as all objects resist changes in their motion, a property known as inertia.
As more solar systems are added to the grid, more inverters are being connected to the grid than ever before. Inverter-based generation can produce energy at any frequency and does not have the same inertial properties as steam-based generation, because there is no turbine involved. As a result, transitioning to an electrical grid with more inverters requires building smarter inverters that can respond to changes in frequency and other disruptions that occur during grid operations, and help stabilize the grid against those disruptions.
Grid Services and Inverters
Grid operators manage electricity supply and demand on the electric system by providing a range of grid services. Grid services are activities grid operators perform to maintain system-wide balance and manage electricity transmission better.
When the grid stops behaving as expected, like when there are deviations in voltage or frequency, Smart inverters can respond in various ways. In general, the standard for small inverters, such as those attached to a household solar system, is to remain on during or “ride through” small disruptions in voltage or frequency, and if the disruption lasts for a long time or is larger than normal, they will disconnect themselves from the grid and shut down. Frequency response is especially important because a drop in frequency is associated with generation being knocked offline unexpectedly. In response to a change in frequency, inverters are configured to change their power output to restore the standard frequency. Inverter-based resources might also respond to signals from an operator to change their power output as other supply and demand on the electrical system fluctuates, a grid service known as automatic generation control. In order to provide grid services, inverters need to have sources of power that they can control. This could be either generation, such as a solar panel that is currently producing electricity, or storage, like a battery system that can be used to provide power that was previously stored.
Another grid service that some advanced inverters can supply is grid-forming. Grid-forming inverters can start up a grid if it goes down—a process known as black start. Traditional “grid-following” inverters require an outside signal from the electrical grid to determine when the switching will occur in order to produce a sine wave that can be injected into the power grid. In these systems, the power from the grid provides a signal that the inverter tries to match. advanced grid-forming inverters can generate the signal themselves. For instance, a network of small solar panels might designate one of its inverters to operate in grid-forming mode while the rest follow its lead, like dance partners, forming a stable grid without any turbine-based generation.
Reactive power is one of the most important grid services inverters can provide. On the grid, voltage— the force that pushes electric charge—is always switching back and forth, and so is the current—the movement of the electric charge. Electrical power is maximized when voltage and current are synchronized. However, there may be times when the voltage and current have delays between their two alternating patterns like when a motor is running. If they are out of sync, some of the power flowing through the circuit cannot be absorbed by connected devices, resulting in a loss of efficiency. total power will be needed to create the same amount of “real” power—the power the loads can absorb. To counteract this, utilities supply reactive power, which brings the voltage and current back in sync and makes the electricity easier to consume. This reactive power is not used itself, but rather makes other power useful. Modern inverters can both provide and absorb reactive power to help grids balance this important resource. In addition, because reactive power is difficult to transport long distances, distributed energy resources like rooftop solar are especially useful sources of reactive power.
A worker checks an inverter at the 2MW CoServ Solar Station in Krugerville, Texas. Photo by Ken Oltmann/CoServ.
COVID– 19 Impact
The COVID- 19 disrupted global supply chains and caused a significant decline in the manufacturing and installation processes. Travel restrictions and workforce limitations also led to various delayed or cancelled solar projects. Further, economic hardships faced by individuals and businesses during the pandemic may have impacted consumer spending and investments in solar energy systems, including microinverters. However, governments’ continued support for renewable energy initiatives along with growing awareness of solar energy’s benefits.
Micro Inverter industry will witness an appreciable momentum owing to factors including improved energy harvesting efficiency in comparison to traditional string inverters coupled with real-time monitoring and data collection at the individual panel level. Technological advancements in the semiconductor technology and power electronics will lead to improved efficiency and reduced costs for microinverters. Ongoing proliferation of renewable energy sources including solar, has posed challenges to grid stability owing to their intermittent nature. However, microinverters with their ability to operate independently, contribute to grid stability by reducing voltage fluctuations and reactive power issues. In addition, they can be integrated into Smart grid systems, thereby enabling advanced demand-response capabilities and grid management.
Micro Inverter Phase Segmentation
Based on phase, the micro inverter market is segmented into single phase and three phase. The single phase market holds a market share of over 91% in 2022. The microinverters allow each solar panel to operate independently. Thus shading, soiling, or performance issues do not affect the overall output of the entire solar array and maximize the system’s efficiency. It allows homeowners and installers to access detailed data on each panel’s performance, allowing easier maintenance and early detection of any potential issues with specific panels. over, Single-phase microinverters operate at a lower DC voltage improves safety during installation, maintenance, and in case of emergencies.
Micro Inverter Connectivity Segmentation
On Grid micro inverter market is set to grow over 9% CAGR by 2032 on account of various advantages comprising higher energy yield, simplified design and installations and enhanced safety of the solar systems during installation, maintenance, and emergencies. On-grid microinverter systems seamlessly interact with the utility grid. Excess electricity generated by the system can be fed back into the grid, allowing homeowners to receive credits for the surplus energy through net metering programs. This feature can lead to cost savings and even financial incentives for solar system owners. In addition, improved grid stability by providing reactive power support and voltage regulation will support offset voltage fluctuations making them beneficial for grid operators.
Residential micro inverter market is set to grow more than USD 6 Billion by the year 2032. Greater flexibility in system design makes the systems easier to accommodate across the varying orientations and sizes of rooftops, allowing the homeowners for custom solar installation. The units also lead to a more aesthetically pleasing installation compared to large, centralized arrays. Further, In a microinverter-based system, if one apartment’s microinverter fails, the rest of the apartments’ solar panels can continue to function independently. This inherent system redundancy ensures a more reliable and resilient solar energy system for the entire apartment complex. Additionally, Apartments with microinverter systems can benefit from grid interaction and net metering programs.
Global solar micro inverter market was valued at US 977.5 Million in 2018 and is anticipated to reach US 5,604.6 Million by 2025 displaying explosive CAGR of 28.4% over the forecast period 2019-2025. Energy supply from renewable sources forms an essential part of energy distribution, particularly when there are issues pertaining to sustainable environment. In this regard, microinverters are of great help. Traditional solar systems comprise a single inverter and in case of any failure of inverter, there remains no backup of energy transfer. Therefore, microinverters are an alternative energy source. A solar micro-inverter, or simply microinverter, is a plug-and-play device used in photovoltaics, that converts direct current generated by a single solar module to alternating current. Unlike conventional string/central inverters, a microinverter works on Module Level Power Electronics i.e. power conversion takes place at individual module level. This mitigates the negative effect of module mismatch and improves the overall efficiency of the system. Microinverters also enable module-level monitoring, easier installation, enhanced design flexibility and better safety than conventional inverters. The solar microinverter market is driven by constant RD activities and significant reduction in the costs of microinverters. The solar micro inverter market also receives a great boost due to its compact size and versatility. Further, increasing requirement of consumers, based on modularity, safety, and maximum energy harvest will continue to drive the market at a considerable pace in coming years.
Working Model of Integrated Micro Inverter
Owing to increasing demand, a lot of innovation is taking place in the solar micro-inverter industry. For example, Tesla has launched a solar roof. This solar roof consists of the power wall battery, turning sunlight into electricity. The solar roof is made of tempered glass tiles and these tiles are stronger than non-solar tiles and regular plate glass. The micro inverter addresses many of the shortcomings of central inverters. Microinverters minimize the issue of one module in shade affecting the entire array. A homeowner whose roof may get some shade throughout the day has a good reason to consider micro inverters. Due to the varying use of micro inverters across the world, global players are concentrating on regions where awareness about using renewable energy resources is higher. Robust adoption of PV storage systems in the U.S. will continue to fuel demand for solar micro inverters in North America.
Photovoltaic Micro Inverter Shipments and Year on Year Growth, Global 2013-2017, (MW, %)
“Single Phase solar micro inverter is expected to dominate the market during the forecast period.”
Based on the inverter type, the solar microinverter market is segmented into single-phase and three-phase micro inverters. Single-phase micro inverters have showcased surging demand among residential households as they require single-phase power supply to run household appliances such as lighting heating devices and few electric motors. The segment accounted for 68.1% share in 2018.
“Integrated solar microinverter would be the most preferred microinverter in major markets”
Based on connectivity, the solar microinverter market is divided into standalone and integrated. Integrated occupied the lead share in solar micro inverter market specifically due to their cost-effectiveness and ease of installation
“Direct sales channel occupied the major market in the solar microinverter market”
Based on the distribution channel, the market is bifurcated into a direct and indirect sales channel. Direct sales channels dominated the market in 2018, with 82.2% share and are expected to maintain its dominance throughout the forecast period, on account of surging number of organized retailers such as supermarkets, hypermarkets, convenience stores, and discount stores in different countries proving to be extremely beneficial for the vendors.
“Residential End Users were the major adopter of solar microinverter technology”
In terms of end-users, global solar micro inverters market has been categorized into residential and commercial end-users. The residential sector accounted for majority share in 2018 and is expected to witness a healthy growth rate during the forecast period. The expected market dominance of the residential sector can be majorly attributed to increasing adoption of energy conservation measures for controlling the increased energy expenditure in residential applications. Over the coming years, commercial sector is also anticipated to account for a significant portion of the global solar inverters market.
Research Methodology for Solar Micro Inverter Market
Analyzing historical market, estimation of the current market and forecasting the future market for solar microinverter technology were the three major steps undertaken to create and analyze the adoption trend of solar microinverter in major regions/countries worldwide. Exhaustive secondary research was conducted to collect the historical market numbers and estimate the current market size. Secondly, to validate these insights, numerous findings and assumptions were taken into consideration. over, exhaustive primary interviews were conducted with industry experts across value chain of the solar micro inverter market. Post all the assumptions, market sizing and validation of market numbers through primary interviews, bottom-up approach was employed to forecast the complete market size of solar microinverter at regional/country level. Thereafter, market breakdown and data triangulation methods were adopted to estimate and analyze the market size of segments and sub-segments the industry pertains. Detailed methodology is explained below:
Analysis of Historical Market Size
Step 1: In-Depth Study of Secondary Sources:
Detail secondary research was conducted to obtain the historical market size of the solar micro inverter through company internal sources such as annual report financial statements, performance presentations, press releases, inventory records, sales figures etc., and external sources including trade journals, news articles, government publications, economic data, competitor publications, sector reports, regulatory bodies publications, safety standard organizations, third-party database and other credible publications. For economic data collection, sources such as Trading Economics and Trade Map, World Bank, IMF among others were used.
Step 2: Market Segmentation:
After obtaining the historical market size of the solar microinverter technology, detailed secondary analysis was conducted to gather historical market size and share of different segments sub-segments of the sector. Major segments included in the report are inverter type, connectivity, distribution channel and end-users. Further analysis was also done for different regions/countries to analyze the overall adoption of the technology.
Step 3: Factor Analysis:
After acquiring the historical market size of different segments and sub-segments, detailed factor analysis was conducted to estimate the current market size of the solar micro inverter market. Factor analysis was conducted using dependent and independent variables such as purchasing power, consumer behavior, adoption level of solar panels, cost of solar microinverters etc. The demand and supply-side scenario were also thoroughly studied through analyzing top partnerships, top merger and acquisition, top business expansion, top product launches and emergence of start-ups in the solar microinverter industry.
Current Market Size Estimate Forecast
Current Market Sizing: Based on actionable insights from the above 3 steps, we arrived at current market size, key players in the solar microinverter market and their market shares. All the required percentage shares split, and market breakdowns were determined using the above-mentioned secondary approach and were validated through primary interviews through key opinion leaders in the market.
Estimation Forecasting: For market estimation and forecast, weight was assigned to different factors including drivers trends, restraints, and opportunities the industry witnesses. After analyzing these factors, relevant forecasting techniques i.e. Bottom-up approach was applied to arrive at the market forecast pertaining to 2025 for different segments and sub-segments in major regions/countries globally. The research methodology adopted to estimate the market size encompasses:
- The industry’s market size, in terms of value (US) and penetration rate of solar microinverter technology in major region/country
- All percentage shares, splits, and breakdowns of market segments and sub-segments
- Key players in the solar microinverter industry with key FOCUS on product portfolio, technologies offered as well as their market share. Also, the growth strategies adopted by these players to compete in the ever-growing market
Market Size and Share Validation
Primary Research: In-depth interviews were conducted with the Key Opinion Leaders (KOLs) including Top Level Executives (CXO/VPs, Sales Head, Marketing Head, Operational Head, and Regional Head, Country Head, etc.) in major regions/countries. Primary research findings were summarized, and statistical analysis was performed to prove the stated hypothesis. Inputs from primary research were consolidated with secondary findings, hence turning information into actionable insights.
This one is a little technical as well, as you can add a Tesla Powerwall to pretty much any system… however the battery works a lot better with certain inverters, and Enphase is one of them. The others are SolarEdge, SMA and Fronius.
The other thing to consider is that Enphase is bringing their popular new battery to Australia soon. It’s been a big hit in the USA, and we are expecting it to be really popular here too. One of the main benefits is that it is smaller than the Tesla Powerwall, so you can choose to start with a smaller battery if you’d like, and then add to it over time if you want more storage capacity.
Request An Enphase Microinverter Quote Today From The Experts:
If you’d like more information or personalised pricing, we’d love to help. On a 15-minute call (without the annoying sales pressure), we can help you get a better understanding of the right system for your home. We like to give you all the information so that you can make an informed decision. The 3 key numbers we can help you with are:
- The right size system
- How much it will cost compared to a standard system
- How much you can expect to save
You can get the ball rolling here:
Choose The Company Enphase Recommends For Your Installation
We know it’s not all about us, but we know just how good our service is compared to the industry average, and we want you to know that if you choose Solaray for your Enphase installation, you are getting a whole lot more included with the system.
Here are the main reasons we keep getting recognised as Australia’s #1 Enphase installed (by Enphase!):
- No high-pressure sales, just great advice. Our experts will provide you with all the information you need to find the perfect system for your home or business.
- Talk with real people on your terms. Whether you prefer a phone call, a home visit or an email, we are here to help.
- High-quality products. Solaray only works with the best products available to maximise output, reliability and longevity.
- Solar that looks as good as it performs. Scroll down to see some of our install pics – from neat cabling to perfect rows of panels, we want your solar system to look amazing
- Industry-leading install standards. In over 10 years we have never had to remove or replace a system because it wasn’t working.
- Fast friendly customer support. Our support team is local (no call centres) and the best in the business. All Solaray installations come with full technical support and warranty service. In the unlikely event that there is a problem – we always fix it. This level of service is something almost no other solar installer offers and it is why we are awarded by the world’s leading solar companies as the best installer in Australia, year after year.
- All of this at the most competitive pricing available in the industry!