DISPATCH & REDISPATCH

ELECTRICITY POWER PLANT OPERATIONS AND SOURCING

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For a power network to remain stable, the amount of electricity fed into the grid must equal that being drawn out of it, at any point in time. Imagine then, a means to store electricity as green hydrogen for the load levelling of national grids, while also supplying energy for commercial vans and heavy duty trucks. Fuel cells provide a way to convert hydrogen gas into electricity, but on their own they do not represent a solution.  The way forward is with hydrogen batteries, as the beating heart of the Smartnet™ dual-fuel infrastructure.

Smartnet™ service stations could be developed to automatically detect voltage and frequency deviation, and soak up or supply energy to networks to keep them running efficiently.

Electricity doesn't have a fixed price. It is (short-term) traded, like a commodity. You need to buy and sell at the right price. Hence, efficient operation of power plants becomes important, to stay in business, and this is where resource planning is important.

The term ‘dispatch’ refers to resource planning at an electricity generating power plant, by the plant’s operator. The term ’Redispatch’ refers to a short-term change in how a power plant is utilized. Requests come at the behest of a Transmission System Operator (TSO) to prevent bottlenecks in the grid.

DISPATCH

Dispatch exists to achieve the most economically profitable operation schedule at a power plant - whose sole objective is to make money from generating electricity - from converting a fuel source (coal, oil, gas) into electricity, this includes hydro and renewable electricity.

This calculation includes the variable costs of each plant (such as the cost of fuel at a coal-fired plant) along with anticipated prices on the energy markets. A power plant will only operate if its variable costs come in lower than the sales prices that can be secured - or it loses money.

Dispatch creates a schedule that determines the allocation of available capacity for the plant or plants. Factors include:

1. Location (which plant will be used?)

2. Time (how long will the plant be used, and from when?), and 

3. Graduation (should the plant run at a partial or full load?)

Power plant operators are usually required to register their schedule with the respective transmission grid operator to enable forecasting of the grid’s available power.

Dispatch is also used in the field of renewable energies. Operators of fluctuating renewable energies, such as solar power and wind power, evaluate weather forecasts and plant availability to determine the following day’s schedule.

Controllable renewable energy operators create multiple-day schedules for their assets, which might include biomass and hydropower plants. This allows an operator to base resource allocation on prices from the energy exchange.

REDISPATCH

Redispatch is mainly used in regions with a high proportion of renewable power production, such as California or Germany. It is less common in other regions, but will of course extend to all regions as we wean off coal and nuclear power. At that stage smart load-levelling becomes much more important, with automation seen as being essential with vehicles using electricity. At this stage Smartnet™ service station come into their own.

To further understand redispatch, consider how power plants submit their schedules to transmission system operators as outlined above. As soon as the schedules have been received, the grid operators conduct what is known as a load-flow or grid-load calculation to prepare an overview of the grid’s expected feed-in and consumption for the next day.

They analyze the dispatch to determine if any parts of the electricity grid might be negatively impacted, and to what degree.

To keep the number of the next day’s short-term, grid-stabilizing interventions at a minimum, the transmission system operator can instruct plant operators to postpone schedule power production based on the next day’s load-flow calculation to prevent grid bottlenecks.

The request to shift electricity production is called a redispatch.

GERMANY AS A REDISPATCH EXAMPLE

Germany’s power system is increasingly based on fluctuating renewable energy sources, and that’s creating challenges for the country’s grid operators. In days gone by, conventional power was supplied to meet demand by a few large power stations.

Now, with renewables, a change of weather can result in a sudden influx of electricity. Meaning that TSO and DSO operators have to work hard to keep the grid stable, through “re-dispatch” measures that ensure a balance between supply and demand.

Rising re-dispatch costs for grid stabilization have become a new point of concern in Germany's Energiewende, the transition from fossil and nuclear to renewable energy sources.

The easiest way to illustrate this is with what happens on very stormy days in north Germany.

Germany’s energy transition is taking wind power production to new record highs. In 2015, the share of wind in total Germany’s total energy consumption rose by 50 percent. Onshore wind capacity expanded by 3.3 GW, and offshore capacity by 2.2 GW during that time.

In February 2016, wind farms generated an unprecedented 33 gigawatts (GW) of electricity on a single day. All that additional power has to go somewhere – and often its needed most in Germany's industrial south.

On particularly windy days when demand in the north is low, this means renewable electricity fed into the grid exceeds the capacity of the power lines that are supposed to transport electricity to the south of the country. A kind of congestion (or block) occurs, forcing grid operators to take re-dispatch measures in order to stabilise the network.

If on a stormy day the north-south power lines are too congested to deliver wind power that has been bought in the south, grid operators can resort to three different types of re-dispatch measure:

A. They can order conventional power stations in north Germany to reduce generation, in order to “make space” in the grid for the high influx of wind power

B. They can temporarily shut down wind turbines (only as a last resort, because renewables have grid priority)

C. They can order conventional power stations in south Germany to produce more electricity to meet demand from consumers in the south whose suppliers bought north German wind power that can’t get through.

All of these re-dispatch measures result in extra costs for consumers:

D. When grid operators tell power stations to limit production, they must compensate them for the power they would have been paid for supplying (minus expenses the power plants save on fuel).

E. When grid operators order renewable power producers to disconnect from the network, they too must be compensated for some of their lost profit

F. Conventional power stations in south Germany that grid operators call on to produce extra power, do so at costs higher than the market price.

In 2014, re-dispatch interventions were necessary on 330 days (232 in 2013), concerning 5,197 gigawatt-hours (GWh) of power, and costing €186.7 million euros (132.6 million in 2013), the Federal Network Agency reported @ p.100 monitoring report 2015.

In 2015, re-dispatch measures in Germany cost an estimated €402.5 million euros, according to transmission grid operators' estimates. Jochen Homann, president of the Federal Network Agency, warned the annual figure could rise to €1 billion euros by 2020. Though Covid19 saw a reduction in electricity use in 2020 and rather upset such predictions.

Re-dispatch costs are passed on to consumers as part of the grid fee households pay via their electricity bills.

Compensation payments for the curtailed renewables increased by more than seven times from €43 million euros in 2013 to nearly €315 million euros in 2015. Clearly, TSOs could benefit from Smartnet™ installations at strategic locations, where the €millions of euros wasted in compensation payments could have gone to developing an asset to reduce forward operational costs.

One company that specializes in electricity use prediction and trading is:

Next Kraftwerke GmbH
Headquarters
Lichtstraße 43 g
50825 Cologne
Germany

General inquiries:
info@next-kraftwerke.com
Tel +49 (0) 221/ 82 00 85-0

Energy transition means decentralization. The age of a few huge power plants providing for all of the energy supply in  grid is passé. Distributed energy resources are already and will continue to be the trade mark for an energy system based on renewable energy resources.

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