Avoid power instability (blackouts) caused by the increase in photovoltaic and wind power generation! Output control technology for power generation through renewable energy
Did you know that photovoltaic and wind power generation is on the rise? Since a scheme(*) whereby power companies purchase power generated with renewable energies such as photovoltaic and wind power was introduced in 2012, more and more companies and individuals have been investing in equipment for photovoltaic power generation, etc.
An increase in power generation using renewable energy is in itself a wonderful thing. However, it seems the excess generation of power has created a new problem. Apparently NEC has developed new technology aimed at resolving these problems. What kind of problems could be happening? And what is this technology that was developed? I went to ask the staff responsible these and other questions!
* The "Feed-in Tariff Scheme for Renewable Energy" enacted in 2012
Interviewee: Mr. Kosuke Honma
Mr. Honma is a promising young employee who joined the company in 2013. As a specialist in the forecasting of photovoltaic power generation, he is involved in the development of technology for controlling the output of power generated through renewable energy.
Interviewee: Mr. Ryo Hashimoto
Mr. Hashimoto is a specialist in distributed power supply system control who researches the operation of storage batteries, etc. He is involved in the development of technology for controlling the output of power generated through renewable energy.
So the field of renewable energy is currently facing major issues?
- MitaHello Mr. Honma and Mr. Hashimoto. I'd like to get straight to the point and ask about the technology you've developed, but before that, can you briefly tell us about the sorts of things that are currently taking place in the field of renewable energies such as photovoltaic power generation?
- HonmaSince the Feed-in Tariff Scheme for Renewable Energy was put into effect in 2012, there has been a steady increase in equipment for photovoltaic and wind power generation.
- MitaI've heard a little about that.
- HonmaBut because photovoltaic and wind power involve natural energy, their output is influenced by factors such as the weather. That means they are unable to meet people's requirement when they do or do not want power generated. For example, the amount of photovoltaic power generated spikes sharply during the daytime when the weather is clear, and on days with strong wind an extremely large amount of wind power is generated. As a result, when combined with power generated at conventional thermal power stations, there's a chance that more power than we need will be generated.
- MitaI thought the more power generated the better! What happens when we generate more power than we need?
- HonmaThe principle of "same time, same amount" applies to electricity, so demand and supply must constantly match. When this balance is upset, it can cause instability in power supply systems, or even blackouts in a worst case scenario.
- HashimotoBlackouts can be caused by a variety of factors. For example, in the Tokyo Electric Power Company service area, voltage is maintained at 100 V and frequency at 50 Hz, and a range of electrical devices that meet these specifications are plugged in to outlets. However, when a large amount of power is generated, it is necessary to shut down generators due to the difficulty of maintaining the voltage and frequency under these circumstances.
- HonmaBecause of this, power companies regulate their supply capability as needed to maintain balance between supply and demand. But the increase in electricity generated through photovoltaic and wind power, which can't be adjusted, has made it harder to maintain this balance.
- MitaHow is this dealt with?
- HashimotoThe excess electricity is discarded.
- MitaIt's discarded?
- HonmaThat's right. A technique called "output regulation" is one of the measures conceived by power companies. This involves controlling output so that power producers generate only the amount of electricity needed via photovoltaic or wind power, with any excess discarded.
- MitaThat seems a bit wasteful, doesn't it?
- HonmaI agree. There is likely a strong feeling among companies and individuals that benefit from the sale and consumption of generated power that they'd like to generate as much as they can, since they have the infrastructure in place. That's why we have to reduce the amount of regulation as much as possible, and avoid biased regulation that disadvantages certain power producers.
- HonmaThe technology for output control that we developed to regulate power generated through renewable energy makes this possible.
- MitaI think I'm starting to get a better picture of things.