App: Simplex Nodal
Developer: Simplex Nodal Limited
Genres: Education, Business

In conjunction with the tutorial document, available at www.simplexnodal.com, use the app to learn about electricity markets by graphically building and solving your own electricity market models. The tutorial also describes the simplex algorithm that solves the model and the app lets you see the internal workings of the algorithm. 

Demonstrates nodal electricity markets features such as: locational marginal pricing, line losses, parallel flows, binding constraints, price separation, the spring washer effect, negative prices, risk and reserves, ramp-rates, congestion charges, transmission rentals, multiple electrical islands, HVDC branches, HVDC risk, HVDC risk subtractor, HVDC reserve sharing, and more. 

See www.simplexnodal.com for more screenshots and the tutorial document.

Highlights:
• The tutorial explains nodal electricity markets and the simplex algorithm via worked examples using the app
• Start with small models to learn the basic concepts of the electricity market model the simplex algorithm
• Learn how to explain prices by relaxing constraints to determine shadow prices
• Enable/disable electricity market features to focus on individual effects, e.g., risk and reserve is easier to explain with line losses disabled
• View full details of the simplex modelling including basic and non-basic variables, constraints, shadow prices, and details of the simplex iterations
• Learn how the simplex algorithm works by viewing the step by step simplex operations that solve the electricity market model. View iteration details in the app and/or export the simplex tableaux as a csv file
• The app implements its own simplex algorithm but you can also export the model in GAMS format to solve externally if you have access to the GAMS solver 
• Includes sample models that represent sections of an actual electricity market

iPhone and iPad functionality is the same. Zoom and scroll allow the iPhone to access iPad sized models.

Release notes:
Tidied up the displays so they look good on iPhone 11 and iPad (and prepared for macOS... yes, there is now a Mac version).