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DELTARES, September 2016
B
alance. That’s what it’s all about, according
to Ivo Pothof. He is the person at Deltares
with responsibility for the renewable energy
and energy efficiency portfolio. ‘Supply and
demand for renewable energy are not always matched.
We are used to working with boilers and power plants
that you can turn up or down without any difficulty.
But natural sources are not suitable for peak loads.
And it is still very difficult to store renewable energy
and use it later.’ So renewable energy is sometimes
wasted.
Ivo Pothof is working with Dirk Schwanenberg, an
expert in freshwater systems, to see how renewable
energy capacity can be used better. ‘We have to move
with the source.’ Ivo is looking at consumption and
Dirk is focusing on energy production.
Weather forecast
‘In any energy network, the trick is to produce the
same amount as is being consumed at any given time.
So water is very interesting indeed: it is much more
predictable than wind or other renewable sources,’
explains Dirk Schwanenberg. ‘Hydroelectric plants
are the most important natural resource that you can
regulate to some extent.’
Of course, power plants of this kind are not new. They
are popular in Canada, the US and China. They already
supply 70 percent of Austria's energy. And even 96
percent of Norway's. ‘But we can use this technique
even more efficiently by better planning. To do that,
we need more information about the weather.’
The more accurate the weather forecast, the more
efficiently the plant can be used. ‘For example by
increasing storage capacity when a lot of rain is
expected. That allows you to control and spread
energy production. Because if you deliver too little
energy, it is much more expensive to buy back the
difference.’
Ensemble forecasts
Until now, the main approach when it comes to man-
aging hydroelectric plants has been to use a single
forecast for a maximum of ten days. ‘That's why we
are increasingly using a combination of fifty fore-
casts covering fifteen days. The less variation there
is between the forecasts, the more reliable the final
forecast is.’
Deltares now produces ensemble forecasts of this
kind for a range of power plants around the world. We
are also optimising the operating system. ‘A hydro
electric plant depends on all kinds of factors, such as
an average flow of water per hour, or a maximum per
day. That is because people depend on the water sup-
ply: farmers use it for irrigation and there are industrial
and domestic consumers, as well as recreational water
users. In addition, you preferably want to sell energy
when the price is high. We balance all these different
interests, which are sometimes conflicting.’
The exact benefit of the ensemble forecasts? ‘That is
still difficult to quantify. At the moment, we believe
there is an increase in energy production of between
two and five percent. For a company like Bonneville
Power Administration in America, which produces
22,000 megawatts, an improvement of just one
percent represents a huge difference.’
Smart pumping
Ivo Pothof is looking at how we can consume less
energy and consume it differently. He is using the
same forecasting tools as Dirk Schwanenberg to focus
on one of the largest Dutch energy consumers with
flexible energy consumption: the water authorities.
It takes a lot of energy to manage water levels in the
polders. The Smart Pumping Joint Industry Project
was established early this year to improve efficiency.
This is a joint project involving eight water authori-
ties, four energy companies, a pump manufacturer,
Rijkswaterstaat, the Netherlands Enterprise Agency
(RVO) and the Foundation for Applied Water Manage-
ment Research (STOWA). The study will be conducted
by Deltares, the Technical University of Eindhoven,
Nelen en Schuurmans and the e-Risk Group.
Smart Pumping is not just about more accurate fore-
casting but also about flexibility. How can pumping
be re-scheduled while maintaining the right water
levels? ‘Changing the approach to pumping can, in the
first place, save energy. If you know the weather will
be very sunny, you can delay pumping because a lot
of water is lost to evaporation. You can also keep an
eye on tidal levels. In some places, you don't have to
pump at all when the sea level is low; you just have to
open the sluices.’
Smart Pumping is now being used by the Hollands
Noorderkwartier, Zuiderzeeland, Rivierenland en
Wetterskip Fryslân water authorities. All that is needed
is a central system that can feed forecasts straight
into the pumping stations by turning them on or off
at the same time. ‘Feasibility studies have shown that
we can achieve 20% savings in energy consumption.
That is the energy requirement for 10,000 homes.’
More information:
ivo.pothof@deltares.nl