15.09.2019 | How peak shaving balances the grid and generates income

Curtailing power peaks

As the President of Swissolar, Roger Nordmann is calling for massive expansion of solar capacities in Switzerland by the year 2050. However, such an expansion of volatile energy production would be a strong burden on the existing power grid. As a result, he proposes the reduction of solar energy surplus production during the summer by means of peak shaving. What is peaking shaving and how is it used? Find the answers here.

Roger Nordmann is a solar lobbyist and faction leader of the SP party in the National Council. He has developed a "Solar plan for Switzerland". He is currently promoting his book throughout Switzerland and in it he estimates that in the future Switzerland will need an additional 40 to 45 TWh of electricity after the nuclear phase-out and owing to the new climate goals based on the de-carbonisation of transport and households (replacement of fossil fuels through renewable energies). He claims that this demand can be covered primarily by increasing Swiss solar capacities from 2 GW today to 50 GW in the future.

However, energy experts criticise that an expansion on this scale would result in a power surplus in the summer, and power shortages during the winter months would remain unsolved. Furthermore, a massive photovoltaic expansion would overload the grids and contribute to power price cannibalisation during the summer (over-production results in lower prices). In order to prevent this, Nordmann proposes limiting the nominal output of solar plants to 35 per cent in critical phases through peak shaving. Experts, for example the Association of Swiss Electricity Companies (VSE), think Nordmann is underestimating the technical challenges for the grid even if peak shaving were introduced here. In order to connect the growing solar capacities to the grid, extensive grid upgrades would be necessary.

Peak shaving?

Peak shaving refers to reducing and balancing out peaks in the power grid. The power supply system must be designed to accommodate high demand in the short term as well as production peaks. Nordmann and experts agree that with peak shaving the distribution grid can be balanced and used more efficiently, whilst reducing costs for grid expansion.

Peak shaving can be achieved in two ways: Individual consumer load is reduced and delayed (load management or demand side management) or consumers cover demand by switching on or ramping up their own additional production facilities, for example generators or battery storage systems.

Axpo, CKW, SN Energie and EW Rapperswil-Jona: Battery storage system to level out laod peaks
Axpo and CKW services

When a consumer or an electricity utility procures electricity from the upstream grid they incur costs for peak power supply. These costs are often very high and do not change much over the years. By reducing peaks (peak shaving) consumers can save costs.

Peak shaving will also be an important application area for battery storage systems. Batteries can level out load peaks by discharging power when demand is high and recharging when demand is low. They can also balance out production peaks from decentralised production, for example photovoltaic plants.

Axpo and CKW are active in this area. Together they offer comprehensive large-scale battery solutions from planning and installation to energy market integration. The first such battery storage system with an output of 2 MW was realised for Elektrizitätswerken Jona-Rapperswil in a joint project.  

Twice the know-how

Axpo has concluded a 10-year contract for regular maintenance and on-call service. The subsidiary CKW has taken over management of the battery storage system in collaboration with SN Energie AG and ensures connection to the energy and control energy market.

The customer benefits financially from the profitable integration in energy trading and connection to the CKW control pool that comprises production facilities, consumers and other decentralised storage systems. Thanks to an optimisation algorithm developed by CKW, the battery is maintained at an optimal charge level and can be simultaneously used as needed to balance load peaks. The combined know-how reduces costs and optimises security of supply, which is advantageous for the end customer.

More information on:

Axpo grid services

CKW battery management

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