====== Watt Price Driver (.Net) ======
The Watt Price Driver (.Net) provides access to daily electricity market results published at http://www.ote-cr.cz. Data is retrieved from the official SOAP API available at: https://www.ote-cr.cz/services/PublicDataService.
> **Note:** OTE introduced a new service endpoint in April 2026 (''https://www.ote-cr.cz/pw-data/services/PublicDataService''). As of independent testing on 31 August 2026, both the legacy and new endpoints return identical, working responses. OTE has not announced a firm cutover date, but migrating the Price API URI to the new endpoint when convenient is still recommended for long-term stability.
===== Driver Setup =====
  * Add a PLC with a running .Net Server for Mervis RT to the project, see [[en:mervis-ide:35-help:70-dotnet-server|Installation / update guide for .Net Server for Mervis RT]]
  * Enable .Net drivers in the PLC configuration: ''PLC\Configuration => Common\Enable .NET Drivers: true''
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  * Add a Channel to the PLC, Protocol: Watt Price (.Net)
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  * Add a Library Device to the Channel: ''CzechRepublic\OTE\Watt Price 15-Minute Period (Array)''
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  * The following parameters are preconfigured on the added device:
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^ Parameter ^ Description ^
| Price API Type | The protocol used to query the price source. Preconfigured as ''SOAP'' and should not need to be changed. |
| Price API URI | The service endpoint URL the driver queries for price data. Defaults to OTE's public SOAP endpoint. |
| Price API Time Zone | The time zone used when interpreting and aligning price data. Defaults to ''Europe/Prague''. |
| Date Shift Days | Which day's prices to retrieve, relative to today. ''0'' returns today's prices. ''-1'' returns yesterday's prices, ''-2'' the day before, and so on. Positive values shift forward (e.g. ''1'' returns tomorrow's prices, once published). |

  * Data point mapping is done via ''Variable Identifier'':
    * PriceInQH_0xx (e.g. PriceInQH_001) – price for the specific quarter-hour
    * PriceInQH – array of prices for the quarter-hours of the day
    * QuarterHoursInDay – number of quarter-hours in the day
    * PriceMinimum – minimum price
    * PriceMaximum – maximum price
    * PriceAverage – average price
    * PriceCurrent – current price
  * Variables can be created and linked manually, or by using the Set Autogen function
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===== About Quarter-Hour Pricing =====
OTE publishes day-ahead prices at **hourly** resolution. The Watt Price Driver retrieves this hourly data and derives the four quarter-hour (''PriceInQH'') values for each hour by dividing the hourly price evenly across its four 15-minute periods. This is expected, correct behavior — the driver does not query OTE for a separate, genuinely 15-minute-resolution dataset, since OTE's day-ahead market does not publish prices at that granularity in the first place.
===== ENTSO-E Transparency Platform: API Access Reference =====
The Watt Price Driver uses OTE as its data source. For teams that also want to query electricity market data directly from ENTSO-E's Transparency Platform (for example, for markets outside the Czech Republic, or for independent verification of OTE data), the platform offers a public REST API. Access requires a free registered account and an approved security token.

==== Setting Up API Access ====

  - Register for a free account on the Transparency Platform, then email ''transparency@entsoe.eu'' with "Restful API access" in the subject line, including your registered email in the body.
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  - ENTSO-E support confirms access has been granted, typically within a few business days, along with a link to the REST API user guide.
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  - Once access is granted, log in to the Transparency Platform and open **My Account** from the account menu in the top right.
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  - Under **Web API Access**, click **Generate Token** to create your security token.
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==== Format Reference ====

For teams comparing OTE's SOAP response against ENTSO-E's REST response (for example, when writing custom integrations), the two formats differ as follows:

^ Feature ^ ENTSO-E REST (A44) ^ OTE SOAP ^
| Protocol | REST GET | SOAP POST |
| Price field | ''<price.amount>'' inside ''<Point>'' | ''<PriceCZ>'' |
| Time field | ''<timeInterval><start>'' + ''<position>'' (1–24) | ''<Date>'' + ''<Hour>'' |
| Resolution | PT60M (hourly) only | Hourly |
| Error format | Acknowledgement_MarketDocument XML | SOAP Fault |
| Auth | ''securityToken'' query parameter (requires registration + approval) | None |

Both sources publish day-ahead prices at hourly resolution only, consistent with how the Watt Price Driver derives quarter-hour values from hourly data (see "About Quarter-Hour Pricing" above).