Environmental Engineering Reference
In-Depth Information
and from this compute a new price profile of the trading interval. This would in some cases
encourage to reschedule generation to achieve the highest possible price. Thus, instead of
predicting the price for the bid, the “price taker” predicts the intervals with highest prices
and schedules the generation, so that most hours are delivered during the high price time
interval. This strategy secures that the ”price taker” will get rid of the energy at the highest
possible price. However, it also means that the “price taker” needs a rather flexible pool of
generating units.
4.4.
The Combi-Pool Optimisation Scheme
The lower the predictability of the energy pool the better. Pumped hydro energy is one
of the key storage units along with combined heat and power (CHP) and in smaller portions
with biogas (e.g. [7], [8], [9]). In a CHP plant the energy can be stored as heat, if the
energy regulations allow to do this on market terms. It is however useful to introduce the
concept of scheduled demand, which is a better description of what such a “combi-pool”
needs to include. Some markets do not allow direct coupling of generation and demand. It is
nevertheless the most efficient way to level out differences between demand and generation.
Generally, the system operators often export imbalances and there seems to be a trend
that larger markets work with increased import and export. This is on the one hand levelling
prices out and helping non-scheduled generation and it may in many cases even be a better
alternative to use scheduled demand. This would mean that heavy industry could benefit
from low prices. Using both would allow for more intermittent energy on the grid.
What is going to increase the efficiency of a BRP is therefore a number of inventive
solutions. The difficulty in predicting the price and output from a BRP increases with the
amount of negative scheduled MWh and MW in the pool. However, information of the pool
needs to be kept highly confidential for maximum competitiveness, which is under strong
debate in Europe at present [10], if the BRP are TSO's.
Last but not least, the question has to be raised whether it is scientifically correct to
optimise a system with a mechanism, where the primary target is to generate confusion
for the market participants? The answer is yes, because this is the primary principle of
the free market to maintain fair competition. Wind power does not operate under such
fair competition, because it is exposed to the world via weather forecasts, which is strictly
speaking against market principles.
5.
Wind Power Forecasting Methods
Now that various optimisation strategies have been discussed, it is important to get
an understanding of the forecasting methodologies and possibilities to set up optimisation
functions for the trading of wind energy. Therefore, the following sections will provide
various approaches of wind power forecasting and discuss the error that the forecasting
process is subject to. An error decomposition is used to give insight into the forecasting
problem, but also into the limitations of forecasting. These limitations are the prerequisite
to build up an optimisation system that benefits from this information to predict the required
reserve to balance the intermittent energy source.
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