In general, the agents involved in the electricity sector (producers, system operators, regulatory bodies, governments, etc.) are facing an important challenge in the short-term in order to guarantee a sustainable, economic and reliable system. Daily, weekly and seasonal fluctuations in electricity demand are increasingly noticeable, particularly in economies that have greater dependency on the services sector and less on industry. The other significant factor that causes fluctuations is the impact that intermittent renewable energy has on the system. Due to concern for climate change, many countries have embarked on ambitious plans to reduce CO2 emissions (for example, the EU’s 20-20-20 programme). However, the integration of significant amounts of electricity generation from renewable sources is not easy from the electrical system standpoint.
The very nature of wind and solar power means that they are intermittent energy sources. At most sites, wind turbines only operate at their rated output 20% of the time, and even at optimal sites, such as offshore, operation occupies just 30% of the time. Similarly, due to the variation in solar radiation and the effect of clouds, the capacity of a solar PV collector is at maximum levels for only around 20% of the year.
In addition, renewable energy has to be quickly dispatched whenever possible, both due to the incentives that attract investments in these assets and because it makes sense to use renewables as much as possible thanks to their low marginal cost. As such, so as to marry supply with demand, in large electrical systems the thermal plants will have to compensate in real time for the tens of gigawatts of power from renewable sources that fluctuate up and down. This will increase the need for more secure and flexible generation solutions to balance the system, which in turn will lead to the development of new types of electrical markets. Read more…
Wärtsilä Power Plants Division
Article published in: FuturENERGY May 2015