The microwave oven has now become a common piece of equipment in many kitchens worldwide. The core of this technology is a cavity magnetron, which was invented a century ago. Significant development of magnetrons for microwave radar applications emerged during World War II. Over the years, the growth of the market has been exponential and today the microwave oven has become a basic, clean, and affordable electric appliance for many households worldwide.
Its uptake is often accompanied by the replacement of old, polluting forms of cooking with new, cleaner ways of heating food. Despite the large installed capacity today, the energy consumption of microwave ovens is low as a result of their limited usage time. The paper Surfing the Microwave Oven Learning Curve published in Journal of Cleaner Production, authored by Remko J Detz and van der Zwaan, raises three main questions. First, can additional growth and further cost reductions for microwave ovens be expected? Second, could the idle time of today’s capacity somehow be usefully employed? Third, could their contribution to the implementation of cleaner processes be expanded beyond the residential sector?
India. Revenue in the microwave ovens segment in India is expected to amount to USD 287 million in 2020. The segment is expected to show a revenue growth of 4.3 percent in 2021. The average revenue per person in the market for microwave ovens is projected to USD 0.2 in 2020. The volume is expected to amount to 3.22 million pieces by 2025. There will be a volume growth of 3.6 percent in 2021. The average price per unit in the market will amount to USD 99.24 in 2020. With a market volume of USD 1369 million in 2020, most revenue is generated in the United States.
Global. Amid the COVID-19 crisis, the global market for microwave ovens estimated at USD 11.2 billion in the year 2020, is projected to reach a revised size of USD 12.5 billion by 2027, growing at a CAGR of 1.6 percent, according to ReportLinker. Convection is projected to record a 1.8 percent CAGR and reach USD 6.2 billion. After an early analysis of the business implications of the pandemic and its induced economic crisis, growth in the grill segment is readjusted to a revised 1.3 percent CAGR for the next 7-year period. In the global solo segment, USA, Canada, Japan, China, and Europe will drive the 0.9 percent CAGR estimated for this segment. These regional markets accounting for a combined market size of USD 1.8 billion in the year 2020 will reach a projected size of USD 2 billion. China will remain among the fastest growing in this cluster of regional markets. Led by countries such as Australia, India, and South Korea, the market in Asia-Pacific is forecast to reach USD 1.7 billion by the year 2027, while Latin America will expand at a 1.8 percent CAGR.
Innovations so far
A huge range of models expands, but also complicates the choice of microwave. Functionally, today companies offer basic budget solo models, microwave ovens with grill, convection, steam generator, or combinations thereof, and innovative inverter microwave with smooth power control.
Additional accessories are significantly expanding the functionality. For example, companies often equip their models with a multi-level grill for simultaneous preparation of 2-3 dishes, a pan for frying, which can replace a traditional frying pan, skewer, or double boiler, among others.
The price of a microwave also significantly depends on the chamber coverage. Today, companies use stainless and enameled steel, and bioceramics. In addition, many companies additionally use an antibacterial coating.
Technologically, the microwave waves generated by the magnetron are directed along the waveguide into the working chamber, and fall on the foods surface after several chaotic reflections from the walls. Accordingly, each of its points receives microwave energy simultaneously from several waves. As a result, the waves overlap each other, creating an interference effect.
Unfortunately, the phases of the waves may not coincide, partially compensating for each other’s power. But in addition to reducing energy efficiency, chaotic distribution reduces the cooking quality due to uneven heat treatment. Therefore, companies are constantly improving the technology of microwave field forming inside the chamber, achieving its maximum uniformity. Today, its evolution contains several stages.
Turntable, this simple, but very effective solution appeared in the first models. Typically, an electric motor rotates it on three small wheels. Of course, companies are constantly improving this design. For example, some companies use hexagonal-shaped Turn-Stable with six wheels for increasing stability. This innovation eliminates tipping over while heating, even when dishes are not in the center. Companies often use stirrer (rotating antenna) in the upper part of the microwave chamber. Usually it is a slowly rotating metal blade. Some companies use this technology instead of rotating turntable. According to research, this mode provides maximum efficiency. But some companies offer Duplomatic models with the simultaneous use of turntable and stirrer. Some companies have developed 3D cyclonic wave technology and circularly polarized waves instead of plane-polarized.
The rapid development of inverter control technology has opened up new possibilities for developers of microwave ovens. Functionally, any inverter technology is an analog of the gas pedal in a car, providing smooth adjustment of power. In recent years, companies have been actively offering inverter air conditioners, washers, and refrigerators, among others. Microwave ovens are no exception. Companies have recently begun to offer inverter models with smooth adjustment of magnetron power.
Formally, this technology reduces temperature fluctuations. But, probably, only a very experienced chef will be able to use this pros. A 20 percent reduction in energy consumption due to the lack of a transformer is a more powerful argument. Unfortunately, an additional inverter control circuit increases their price. But lower power consumption and longer magnetron life compensate for this factor.
The triple distribution of microwave waves with two additional antennas has become the next evolution stage. Of course, the idea of a design without turntable has long attracted developers. But this design does not provide uniform heating due to the lateral arrangement of the magnetron, which can heat food only on one side. But FlatBed technology with a rotating magnetron in the bottom panel under the food has solved this problem.
As known, all modern models use a magnetron as a source of microwave waves. But science does not stand still. In 2017, the RF Energy Alliance (RFEA) and MACOM (GaN-on-Si) announced a solid-state RF energy source, which could become its alternative. According to the company, the technology provides an unprecedented control range, even energy distribution, and fast adaption to changing load conditions.
In particular, the MACOM’s GaN-on-Si 300W amplifier increases energy efficiency by no less than 80 percrnt at 2.45 GHz. In addition, unlike the magnetron, the service life of solid-state RF energy amplifiers can be up to 10 years. Of course, today this technology is far from real implementation. But it may well become one of the possible directions for the further improvement of microwave ovens.
Steam ovens have been on the market for a while; they continue to gain in popularity and are making a push in 2020. By retaining more nutrients as it cooks, steam remains the go-to method for anyone looking to make healthier menu choices. Nevertheless, the future may look bright for microwave oven manufacturers, as long as they note the health and climate considerations reiterated by both the international organizations and public opinion.
On the one hand, albeit fears for the microwaves’ potentially harmful effects have existed ever since the product’s inception, research into these issues has grown in recent years. However, the rumors have yet to be empirically demonstrated, with the World Health Organization praising the microwave oven’s advantages, if utilized correctly. Despite inconclusive findings on the microwave’s negative implications for health, consumers are not reticent – they have made it part and parcel of their daily lives on account of its convenience.
There are other concerns. A 2017 Greenpeace International report ranks the renowned consumer electronics companies by their contribution to the fight against climate change, with Fairphone and Apple being the most environmentally aware, neither of which produce microwaves. It is uncertain, however, the extent to which environmental awareness ranks in consumer choice, especially over convenience and price, beyond the premium sector.
Surfing the learning curve
The development of novel microwave heating technology, e.g., for use in the energy sector, might be significantly stimulated if one can use existing experience from the residential microwave oven industry. Rapid and economically attractive deployment of a technology often involves a steep learning curve.
The microwave oven market has reached a mature scale, for which we find that the global annual production capacity today amounts to almost 100 million units per year. The cumulative amount of microwave ovens produced over the period from 1947 to 2016 surpasses 1.7 billion units. Today, more than 50 percent of households worldwide possess a microwave oven. Plotting unit price data versus cumulative global production on a double logarithmic scale results in a learning curve for microwave ovens.
More than 80 percent of all microwave ovens have been installed during the last decade. This number may still grow substantially when market uptake in, for instance, Africa and India increases. In these regions, the microwave oven introduces a new cleaner form of cooking and is likely to continue to contribute to sustainable development.
Consumers often replace or discard their microwave oven because of outdated product design, and much less due to poor product quality or costs of spare electrical parts.
Minor changes in the design of used microwave ovens may improve their re-usability and lifespan. Currently, the average product lifetime is 12 years and replacement rates impact considerably future cumulative production figures. These expectations project at least two additional doublings in cumulative capacity during the coming decades and, thus, a price reduction of close to 40 percent. Such a price reduction estimate seems justified in view of likely novel microwave developments, such as semiconductor generators and fifth generation (5G) mobile telecommunication technology.
Although enormous microwave oven capacity is available worldwide, the overall energy consumption of residential microwave ovens is fairly limited, since the average usage time amounts to typically only a few minutes per day. The average electricity use of a microwave oven is around 72 kWh per year. Total electricity use of today’s installed capacity adds up to some 77 TWh per year or 0.3 percent of global electricity generation (which was 24,919 TWh in 2016).
If other or new types of use of these electric appliances are developed in the future, their energy demand may substantially increase. Might it be possible to use kitchen microwave ovens to heat tap water for storage in tanks? Such an (ideally plug-in) application could, thus, store excess electricity, produced for example by residential solar panels, and thereby promote sustainable development.
Microwave ovens have played a large role in the substitution of old polluting forms of cooking with new cleaner ones. This substitution process is expected to continue into the foreseeable future, for example in Africa and Asia, so that the spread of microwave ovens can continue to contribute to sustainable development. Microwave ovens could expand their contribution to the implementation of cleaner processes beyond the residential sector, if microwave technology can be applied in other sectors such as energy supply and industry. TVJ Bureau