Demand for energy is increasing, but what’s driving it?
Can we mitigate the environmental effects by focusing on the positive contribution that developments in power electronics are making?
According to the International Energy Agency (IEA), global electricity demand will rise by an average of 3.4% annually over the next three years.1 This is mostly due to an improved economic outlook, with roughly 85% of this growth coming from developing countries — China, in particular.
One of the big drivers of this growth is data centres, following exponentially increased demand for computing performance from artificial intelligence (AI) and cryptocurrency. Electricity consumption from data centres is estimated to possibly double by 2026, reaching a global figure of 1,000 TWh.
Alongside this sector, the move from petrol and diesel internal combustion engines to electric vehicles (EVs), both encouraged and enforced by government legislation globally, is also boosting electricity usage and increasing strain on the power distribution grid.
This rapid increase in electricity usage will cause major issues if greenhouse gas (GHG) emissions grow at a similar rate, because power generation is currently the largest source of carbon dioxide emissions globally.2 The shift from fossil fuels to renewables is a significant step towards reducing GHG emissions — but this will inevitably take many years.
It’s crucial that we improve the efficiency of power systems to keep emissions under control. The IEA’s latest report — Electricity 2024 — states: “Updated regulations and technological improvements, including on efficiency, will be crucial to moderate the surge in energy consumption from data centres.”3
Balance, then, is what’s needed. To enable economic growth while reducing GHG emissions, we need to shift our energy mix from fossil fuels towards electricity that has been generated by renewables. The IEA says that electricity accounts for about 20% of final energy consumption worldwide, but this figure must jump to 30% by 2030 if we hope to keep global heating to 1.5ºC.
At the same time, we’ll only succeed in the task of keeping GHG emissions down if we can improve power efficiency throughout our economy, thus reducing how much electricity we need overall.
Introducing WBG semiconductors
The great news is that much of this demand for electricity will be met by the roll-out of renewable energy production, including solar and wind, but what can we do to ensure that the continuous improvement of power system technology plays its part?
The answer, to an extent, lies in the choice of semiconductors used in power conversion systems. Silicon has always been the dominant material used in semiconductors — this will continue to be the case — but wide bandgap (WBG) semiconductors are transforming many applications, including power consumption.
WBG materials are also known as ‘compound semiconductors’, because they are chemical compounds of two or more different elements. For power systems, the two most important examples are silicon carbide (SiC) and gallium nitride (GaN), while other compounds such as gallium arsenide (GaAs) are finding uses in other types of applications.
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With the ongoing shift to renewable energy and the electrification of transport and industry, the demand for higher power and greater energy efficiency in electronics is increasing. Wide bandgap technologies including SiC and GaN bring many advantages.
WBG OVERVIEWThe most important advantage of WBG semiconductors for power conversion is that they enable more energy efficient systems than silicon alternatives. This is because the WBG devices enable higher switching frequencies, reducing power loss.
As well as their high efficiency, WBG semiconductors are physically smaller than silicon alternatives, helping to improve power density and the design of more compact power supplies. In addition, the faster switching of WBG devices means external passive components can be smaller, further reducing power system size. Also, SiC can operate at higher temperatures (175–200ºC) than silicon, potentially reducing the need for a heatsink or other cooling mechanisms.
For data centres, there’s a win-win, both in terms of emissions and financial costs: improving power conversion efficiency reduces the amount of heat generated, which reduces how much cooling is needed, which further reduces the electricity needed to run that cooling.
The main disadvantage of WBG materials is still their cost. WBG-based components can cost around twice as much as silicon-based alternatives. This means WBG materials are unlikely to find applications into all low-cost end products, particularly where high efficiency is not seen as essential. This mostly relates to cost-sensitive consumer product, power supplies and chargers.
How much electricity can compound semiconductors save?
We’ve discussed how WBG devices are more efficient than silicon, but can we quantify the improvements, and what does this mean in practical terms?
The efficiency improvements that can be realised in practice depend heavily on the specific application. In general terms, however, conventional silicon-based power electronics typically achieve an efficiency of between 85–95%, meaning on average around 10% of electrical energy is lost as heat during each power conversion stage.
In contrast, WBG semiconductors can achieve efficiencies of 96% or more, meaning they can eliminate a considerable amount of energy loss during power conversion compared to silicon options.
When considering overall power consumption, we need to remember that there will be multiple conversion stages in many applications. For example, in a data centre, there’s first a need to convert the grid’s higher AC voltage (such as 240 V in the UK) into an intermediate DC voltage, such as 48 V. Then, further power systems will convert this to multiple lower voltages for the different devices within the data centre — for example, there may be two or more supply rails at different voltages within one server.
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Grid efficiencies
While we’ve looked mostly at power conversion, the improved efficiency of WBG semiconductors also drives major savings in power transmission and storage and can enable more effective power infrastructure overall.
Capacity issues in the electricity supply grid are most important when we look at peak demand — the times of day when power is most needed by consumers — for example, in the evening when many people are home.
Instead of having to activate short-term extra power sources on the grid, such as a gas power station, we can instead manage peaks in future with energy storage in batteries — but this requires efficient power conversion to avoid unduly large losses, as energy is repeatedly stored in the batteries and then retrieved.
By moving to ‘smart grids’, which can handle bidirectional power transfer and provide control features to enable consumers to time-shift their demands, this efficiency becomes ever more important. WBG semiconductors are the technology that will make it all possible.
WBG: a fast-growing technology
The next few years will be an exciting time for compound semiconductors, with fast-growing adoption across multiple sectors.
According to Yole Group, the SiC device market will grow by an average rate of 24% over the next six years, to reach nearly $10 billion by the year 2029.4 The main driver of this growth is likely to be EVs and their chargers, while photovoltaic inverters and other renewables applications will also contribute.
The reason for this growth in demand is clear: the efficiency benefits of WBG semiconductors can pay back their extra cost many times over. Even just a fraction of a percentage increase in efficiency in data centre power systems can significantly reduce power use, saving millions of dollars in energy costs for operators of large, hyperscale data centres.
As well as purely financial reasons, the efficiency of WBG semiconductors also reduces GHG emissions by cutting the demand for electricity, thus enabling companies and governments to comply with their legal obligations on the pathway to net zero.
We started this article with facts and a quote from the IEA, and we’ll give them the last word, too — as the IEA website states: “Efficiency is the single most important measure to avoid energy demand.”5
Reference
[1] https://www.iea.org/reports/electricity-2024/executive-summary
[2] https://iea.blob.core.windows.net/assets/18f3ed24-4b26-4c83-a3d2-8a1be51c8cc8/Electricity2024-Analysisandforecastto2026.pdf
[3] https://www.iea.org/reports/electricity-2024/executive-summary
[4] https://compoundsemiconductor.net/article/120114/SiC_market_will_be_worth_10B_by_2029
[5] https://www.iea.org/energy-system/energy-efficiency-and-demand
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