Gotland - Sweden

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Residential consumers with load management
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Residential consumers with real-time measurements
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PV plants

Introduction

The project, which overall goal is to upgrade an existing rural distribution system to a modern smart grid, is carried out on Gotland because the islands large renewable power production in combination with the limited power transmission capacity is the first region in Sweden, has been forced to limit the installed capacity in order to ensure the power quality.

With the ambition to take advantage of recent advances from the telecom and information technology, with emphasis on cost efficiency, the objectives of the project is to:

  1. Achieve a small but not insignificant increase the hosting capacity for renewable power in the distribution grid by use of load shift from active customers
  2. Improve the power quality for the customers by a decrease of the number and duration of power outages
  3. Attract a large number of household- and business customers to become active on the electricity market

Smart Grid Gotland and its subprojects are conducted as a consortium between GEAB, Vattenfall, ABB, Schneider Electric, SvK, the Royal Institute of Technology and Swedish Energy Authority.

Project description

The project has a total of nine subprojects whereof three subprojects (Smart Customer Gotland, Power Quality and Wind Power Integration) are responsible for the overall objectives of the project.

The largest subproject, from a budget perspective and in terms of involved customers as well as external publicity, is the market test, called Smart Customer Gotland. The initial idea behind the market test was to incite customers to turn off large electricity consuming equipment during periods of high load by use of price signals. Periods of vulnerable operation would thus be shorter and fewer, which would justify an increase of the hosting capacity.

In the project pre-study it was concluded that approximately 8600 electricity customers on Gotland had the potential (large enough consumption, controllable load etc.) to participate in the test. If a rough quarter of these customers were to be able to shift +/- 10% of their consumption, it would correspond to approximately 5MW, i.e. the overall goal of the project.

In addition to the overall project goal, the objectives of Smart Customer Gotland are to:

  • Conduct a market test under market driven conditions
  • Achieve better understanding of customers' behavior, interest and acceptance of active participation
  • Lower electricity costs for active customers

The market test started in September 2013 and was be concluded April/May 2016.

The overall goal to improve the power quality is handled by subproject Power Quality and generally centered on new functionalities in the distribution grid management system. Besides a new Smart Grid Control Center, including a non-operative supervisory control and data acquisition system for research and development purposes, a new substation, a zone concept, based on seven reclosers, and about 3000 smart meters has been installed in the test area. The idea is to use information from equipment in the grid (specifically the reclosers in the medium voltage grid and the smart meters in the low voltage grid) together with the intelligence in the management system to locate faults, isolate the fault to an as small area as possible and restore the rest of the grid as fast as possible. By minimizing the number of affected customers and improving the time for recovery it is believed that the installations will contribute to a cost efficient increase in customer satisfaction as well as apply to regulatory requirements. Calculations and physical tests indicates a cost efficient (compared to replacing overhead lines with cables) improvement of interruption duration with more than 20%.

Subproject Wind Power Integration, which is responsible for the increase in capacity to host renewable power production in Gotland’s distribution grid, is largely theoretical since no means of production or storage is included in the project. The subproject investigates how much the load shift from active customers affect the hosting capacity as well as other techniques to combine large scale intermittent power production with grid stability, such as synthetic inertia and just curtailment of production.

Gotland-Sweden

Location