IEEE Power & Energy Magazine - November/December 2017 - 49

In energy systems with a high share of wind and solar power,
it is crucial that RES production can be curtailed or redispatched
by different stakeholders of the energy system.

forecast type that best suits the purpose. The evaluation can
then look at the costs impacted by a forecast. The forecast
evaluation, in itself, is accomplished with a decision-support
tool that holistically examines whether the forecast fulfills
certain criteria and supports the business processes. Figure 7 shows a possible decision-support matrix that could
be applied by a system operator evaluating forecasts for
reserve allocation.

Conclusions
Complex dynamic systems such as the electrical power system
require continuous scheduling of nearly all components. Without wind and solar forecasts, secure operation of a power system with high shares of RES and economically driven markets
would not be possible. RES forecast models have been developed, improved, and specially adapted to end users' needs for
more than 20 years. The forecast quality in terms of average
errors has already leveled off.
New ground must be broken to enable even larger shares
of RES. Probabilistic forecasting constitutes such a ground
by fostering a paradigm shift in the way forecasts are used
and evaluated, as well as finding new ways of handling uncertainties inherent in the generation of power from renewable
sources. We are moving down a path from state-of-the-art
deterministic approaches to the application of uncertainty
forecasts in major parts of the power industry. New terminology and processes are being used to integrate uncertainty
forecasts into forecasting systems and enhance TSO and
DSO operations under high-RES conditions (which increasingly depend on knowledge of the uncertainty of a forecast
for better decision making).
The value of forecasts can no longer be reduced to simple
statistical measures. Instead, a more holistic view of forecasting skill and quality is required that looks at the best fit for
the purpose and the level of support of crucial business processes. In this way, future challenges toward more flexible
yet secure and economic power systems can be tackled and
further developed. Uncertainty forecasting can, therefore, be
considered as a key element in developing the next-generation
power system. It is here to stay.

For Further Reading
P. Du, R. Baldick, and A. Tuohy, Integration of Large-Scale
Renewable Energy into Bulk Power Systems. From Planning to Operation. New York: Springer, 2017.

november/december 2017

J. Dobschinski, M. Siefert, Y-.M. Saint-Drenan, A. Braun, S.
Vogt, and A. Röpnack, "Development of innovative weather
and power forecast models for the grid integration of weather dependent energy sources," in Proc. Wind AC Conf., Cape
Town, South Africa, Nov. 2016.
K. D. Orwig, M. L. Ahlstrom, V. Banunarayanan, J.
Sharp, J. M. Wilczak, J. Freedman, S. E. Haupt, J. Cline,
O. Bartholomy, H. F. Hamann, B.-M. Hodge, C. Finley
D. Nakafuji, J. L. Peterson, D. Maggio, and M. Marquis,
"Recent trends in variable generation forecasting and its value to the power system," IEEE Trans. Sustain. Energy, vol. 6,
no. 3, pp. 924-933, July 2015.
P. Pinson, "Wind energy: Forecasting challenges for its
operational management," Stat. Sci., vol. 28, no. 4, pp. 564-
585, 2013.
J. LeClerc and S. Joslyn, "The cry wolf effect and weather-related decision making," Risk Anal., vol. 35, no. 3, pp.
385-395, Mar. 2015. doi: 10.1111/risa.12336.
V. S. Pappala, I. Erlich, K. Rohrig, and J. Dobschinski, "A
stochastic model for the optimal operation of a wind-thermal
power system," IEEE Trans. Power Syst., vol. 24, no. 2, pp.
940-950, May 2009.
G. Giebel, J. Cline, H. Frank, W. Shaw, P. Pinson,
B-M. Hodge, G. Kariniotakis, J. Madsen, and C. Möhrlen,
"Wind power forecasting: IEA Wind Task 36 and future
research issues," in Proc. TORQUE 2016: The Science of
Making Torque from Wind Conf., 2016. doi: 10.1088/17426596/753/3/032042.

Biographies
Jan Dobschinski is with Fraunhofer IWES, Germany.
Ricardo Bessa is with INESC TEC, Portugal.
Pengwei Du is with Electric Reliability Council of Texas
ERCOT, Austin, Texas.
Kenneth Geisler is with Siemens, Minnetonka, Minnesota.
Sue Ellen Haupt is with the National Center for Atmospheric Research, Boulder, Colorado.
Matthias Lange is with Energy and Meteo Systems
GmbH, Germany.
Corinna Möhrlen is with WEPROG, Denmark and Germany.
Dora Nakafuji is with Hawaiian Electric Company, Honolulu, Hawaii.
Miguel de la Torre Rodriguez is with RED Eléctricia De
España, Spain.
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