Project Examples

Project Examples

• Molten Salt Storage in energyPRO
• Danish cogeneration plant and solar collectors in separate sites
• Power plant and wind farm with electricity storage in island operation
• Cogeneration plant and electric heat pump on fixed tariffs
• Tri-generation plant on a Day-Ahead market
• Photovoltaic and battery on fixed tariffs

If you cannot find an example that is relevant for the system you wish to model, feel free to contact us at energyPRO@emd.dk

From installing energyPRO, a part of the installation contains a library of different examples and country specific datasets such as weather data and electricity prices. The default directory for this library is C:\energyPRO Data\.

From energyPRO these data and examples can be loaded and used for inspiration when setting up your own project.

Please have a look at this video where we visit a district heating plant in Denmark using energyPRO on a daily basis.

Molten Salt Storage

It is a method of storing energy generated from renewable energy sources such as solar power plants or wind farms. In a molten salt storage system, a mixture of molten salts is used as the medium to store and release thermal energy.

Here’s how it typically works:

Heat Collection: The molten salt mixture can be heated using renewable electricity through an electric heater, or by concentrated sunlight that is directly converted into heat in a specially designed receiver.

Energy Storage: The heated molten salt is then stored in insulated tanks, where it retains its heat energy for later use. The salts used in these systems are chosen for their ability to retain heat over long periods without significant loss.

Energy Release: When electricity is needed, the stored hot molten salt is pumped through a heat exchanger. Heat from the molten salt is transferred to a working fluid (such as water or steam), which then drives a turbine to generate electricity.

How did we benefit from using energyPRO?

To make sure that the Molten Salt Storage, which is part of the solution in the SOLARX project, is effective and optimized, we have created a model of this process in energyPRO.

The model allowed us to see the operation income, amount of electricity generated by specific units, storage capacity as well as CSP consumption.

Where did we use the above model?

In SolarX, we use energyPRO for modelling and sizing the heliostat field and the three types of receivers for concentrating solar power: PV-production, hydrogen production and thermal heat production (for heating molten salt). However, in this energyPRO model, the hydrogen production is not included.

Danish cogeneration plant and solar collectors in separate sites

Model of the Danish district heating plant

This project example is a model of the Danish district heating plant in the city of Ringkøbing. For further information about Ringkøbing District Heating, see our online presentation where you can monitor the daily operation.

Goal of the project

The energyPRO model of the mentioned plant includes a natural gas fired CHP, an electric boiler, solar collectors, gas fired boilers and a thermal storage. These units must at all times cover the city’s heat demand. Produced and consumed electricity is traded on the Day-Ahead spot market in West Denmark.

Solution

The district heating grid is divided into three different sites: “The Rindum central”, “Ringkøbing district heating grid” and “Solar collector field”. The arrows between each site indicate heat flow directions and limitations.

energyPRO calculates the optimal operation of the units in the project, which in this case is by covering the heat demand at the lowest possible price. Since the solar collectors have a low marginal production cost, their production is prioritized before the other units in the system.

The solar collectors should therefore produce as much heat as possible supported by the flexibility the heat storage provides. The CHP should be operated in hours with high electricity prices and the electric boiler in hours with low electricity prices.

Data generated with energyPRO

You can access a graphical representation of the operation (figure 2), which allows to see the following data:

• Solar radiation in every hour for the given location (to calculate the heat production from the solar collectors)
• Electricity price in West Denmark every hour
• Heat production of the different units and the total heat demand
• Electricity production and consumption
• Storage capacity and content

You can also see that the CHP (green color) is operated in hours with high electricity prices and the electric boiler (orange color) in hours with low electricity prices. The solar collectors (red color) produce as much as possible and the boilers (blue color) cover the rest of the heat demand.

Reports

It is also possible to generate a number of technical and economic reports with data such as operational payments, i.e. revenues and expenditures from one year’s operation.

Power plant and wind farm with electricity storage in island operation

About

This example includes a 6 MW wind farm, a pumped hydro storage and an oil fired backup generator. There is no connection to an electricity market, which means that export or import of electricity is not possible. Therefore, the model is said to be running in “island operation”.

Goal of the project

energyPRO calculates the optimal operation of the units in the project. In this case, the wind farm should cover as much of the electricity demand as possible by utilizing the hydro storage in the best possible way.

Gathered information

• Wind speed in every hour for the given location. This is used to calculate the electricity productionfrom the wind farm.
• Electricity production from the wind farm (red color), the backup generator (blue color) and the total electricity demand (orange curve).
• Charging (orange color) and discharging (blue curve) of the battery.
• Electric storage’s capacity and its content.

Solution

The excess wind power production is used to charge the storage by pumping water up in the reservoir. This energy is saved until the wind power production cannot cover the electricity demand and the storage is discharged. The backup unit is used to cover the rest of the demand when the store is empty.

Cogeneration plant and electric heat pump on fixed tariffs

About

This project includes two gas fired CHPs, an electric heat pump, gas fired boilers and a thermal storage. These different production units must at all times cover the total heat demand which is divided into “Total sale of heat” and “Network loss”. Produced and consumed electricity is traded on a fixed tariffs market with a high day-time tariff and a low night-time tariff. The weekend is also a low tariff period.

Solution

The optimal operation is calculated in energyPRO, which in this case is achieved by minimizing the net heat production cost. In order to do so, the two CHPs must be operated in hours with high electricity prices (Day tariff) and the heat pump in hours with low electricity prices (Night tariff and weekends). The storage tank will be used to support this strategy by storing excess heat from the CHPs and the heat pump to be used at a later time.

energyPRO allows us to see:

• The heat production of the different units and the total heat demand
• The electricity production and consumption
• The storage capacity and content

From the figure it can be seen that the two CHPs (red and green colors) are producing in the day-time in the weekdays, while the heat pump (blue color) is operated during night-time and in weekends. The gas boilers are operated when the heat pump cannot cover the heat demand and storage tank is empty.

Tri-generation plant on a Day-Ahead market

This project includes two gas fired CHPs, an electric chiller, an absorption chiller, gas fired boilers and a thermal storage. These production units must at all times cover both the cooling demand and the total heat demand which is divided into “Total sale of heat” and “Network loss”. Produced and consumed electricity is traded on a the EPEX Day-ahead market.

energyPRO calculates the optimal operation of the units in the project, which in this model is achieved by minimizing the net heat and cooling production cost. The two CHPs should therefore be operated in hours with high electricity prices and the electric chiller in hours with low electricity prices. The absorption chiller must be supplied with heat in order to run, but this heat must be produced at the lowest possible price. For this reason, the absorption chiller should produce cooling when cheap excess heat is available from the CHPs in hours of high electricity prices. The storage tank will be used to support this strategy by storing excess heat from the CHPs to be used at a later time.

In the figure, a graphical representation of the operation can be seen. The figure is composed of five graph windows: The top graph shows the EPEX electricity price in every hour. The second graph shows the heat production of the different units and the total heat demand including the heat consumed by the absorption chiller. In the third graph, the electricity production and consumption can be seen. The fourth graph shows the cooling demand and the cooling production from the two chillers. The fifth and last graph shows the storage capacity and its content.

From the figure it can be seen that the two CHPs (red and green colors) are producing in hours with high electricity prices. When excess heat is available and at the same time there is a demand for cooling, the absorption chiller (dark blue color) will consume heat and produce cooling. Since there is no cold storage in the model, cooling must be produced as it is needed and the electric chiller (light blue color) will cover the rest of the cooling demand. The gas boilers are operated only when the heat demand cannot be covered by the CHPs and the storage tank is empty.

Photovoltaic and battery on fixed tariffs

This project includes 500 kW photovoltaics, a battery (5 MWh), an electricity demand and a fixed tariff market.

In this model, the optimal operation is simply to cover as much of the electricity demand by the PVs. If the demand cannot be covered by the PVs and the battery, electricity is imported from the fixed tariff market. Conversely, if more electricity is produced than can be consumed or stored in the battery, electricity is exported.

In the next figure, a graphical representation of the operation can be seen. The figure is composed of four graphs: The top graph shows the solar radiation in every hour for the given location. This is used to calculate the electricity production from the PVs. The second graph shows the electricity production from the PVs (red color) and the total electricity demand (orange curve). The third graph, shows the charging (orange color) and discharging (blue curve) of the battery. The last graph shows the electric storage capacity and its content.

As it can be seen in the figure, the battery is charged when electricity production from the PVs exceed the demand. In hours with no or little electricity production from the PVs, the battery is discharged, supplying the demand.