Circularity MILP

benches/assets.rs

@@ -95,13 +95,15 @@ fn calculate_seed_prices(
     candidates: &[AssetRef],
     writer: &mut DataWriter,
 ) -> Prices {
-    let solution_existing = DispatchRun::new(model, base_year_assets, BASE_YEAR)
+    let market_demands = collect_preset_demands_for_year(&model.commodities, BASE_YEAR);
+    let solution_existing = DispatchRun::new(model, base_year_assets, BASE_YEAR, &market_demands)
         .run("bench setup: without candidates", writer)
         .expect("Dispatch without candidates failed");
-    let solution_with_candidates = DispatchRun::new(model, base_year_assets, BASE_YEAR)
-        .with_candidates(candidates)
-        .run("bench setup: with candidates", writer)
-        .expect("Dispatch with candidates failed");
+    let solution_with_candidates =
+        DispatchRun::new(model, base_year_assets, BASE_YEAR, &market_demands)
+            .with_candidates(candidates)
+            .run("bench setup: with candidates", writer)
+            .expect("Dispatch with candidates failed");
 
     calculate_prices(
         model,

schemas/input/model.yaml

@@ -95,10 +95,6 @@ properties:
     type: integer
     description: Number of iterations to perform when calculating prices for cyclically-dependent markets
     default: 1
-  capacity_margin:
-    type: number
-    description: Slack proportion for assets selected during cycle balancing to absorb small demand shifts
-    default: 0.2
   mothball_years:
     type: integer
     default: 0

src/input.rs

@@ -296,7 +296,8 @@ pub fn load_model<P: AsRef<Path>>(model_dir: P) -> Result<Model> {
     )?;
 
     // Solve investment order for each region/year
-    let investment_order = solve_investment_order_for_model(&commodity_graphs, &commodities, years);
+    let investment_order =
+        solve_investment_order_for_model(&commodity_graphs, &commodities, years)?;
 
     let model_path = model_dir
         .as_ref()

src/model/parameters.rs

@@ -115,13 +115,6 @@ pub struct ModelParameters {
     pub price_tolerance: Dimensionless,
     /// Number of iterations to perform when calculating prices for cyclically-dependent markets.
     pub price_cycle_iterations: u32,
-    /// Slack applied during cycle balancing, allowing newly selected assets to flex their capacity
-    /// by this proportion.
-    ///
-    /// Existing assets remain fixed; this gives newly selected assets the wiggle-room to absorb
-    /// small demand changes before we would otherwise need to break for re-investment.
-    #[serde(deserialize_with = "deserialise_finite_non_negative")]
-    pub capacity_margin: Dimensionless,
     /// Number of years an asset can remain unused before being decommissioned
     pub mothball_years: u32,
     /// Absolute tolerance when checking if remaining demand is close enough to zero
@@ -155,7 +148,6 @@ impl Default for ModelParameters {
             max_ironing_out_iterations: 1,
             price_tolerance: Dimensionless(1e-6),
             price_cycle_iterations: 1,
-            capacity_margin: Dimensionless(0.2),
             mothball_years: 0,
             remaining_demand_absolute_tolerance: DEFAULT_REMAINING_DEMAND_ABSOLUTE_TOLERANCE,
             highs: HighsOptions::default(),
@@ -368,8 +360,6 @@ impl ModelParameters {
         // price_cycle_iterations
         check_price_cycle_iterations(self.price_cycle_iterations)?;
 
-        // capacity_margin already validated with deserialise_finite_non_negative
-
         // remaining_demand_absolute_tolerance already validated with
         // deserialise_finite_non_negative; check remaining constraints here
         check_remaining_demand_absolute_tolerance(

src/simulation.rs

@@ -15,7 +15,7 @@ use std::sync::Arc;
 pub mod optimisation;
 use optimisation::{DispatchRun, FlowMap};
 pub mod investment;
-use investment::perform_agent_investment;
+use investment::{collect_preset_demands_for_year, perform_agent_investment};
 pub mod market;
 pub mod prices;
 pub use prices::PriceMap;
@@ -178,13 +178,15 @@ fn run_dispatch_for_year(
     debug_assert!(assets.iter().all(|asset| !asset.is_candidate()));
     debug_assert!(candidates.iter().all(|asset| asset.is_candidate()));
 
+    let market_demands = collect_preset_demands_for_year(&model.commodities, year);
+
     // Run dispatch optimisation with existing assets only, if there are any. If not, then assume no
     // flows (i.e. all are zero)
     let (solution_existing, flow_map) = if assets.is_empty() {
         (None, FlowMap::default())
     } else {
-        let solution =
-            DispatchRun::new(model, assets, year).run("final without candidates", writer)?;
+        let solution = DispatchRun::new(model, assets, year, &market_demands)
+            .run("final without candidates", writer)?;
         let flow_map = solution.create_flow_map();
         (Some(solution), flow_map)
     };
@@ -195,7 +197,7 @@ fn run_dispatch_for_year(
         None
     } else {
         Some(
-            DispatchRun::new(model, assets, year)
+            DispatchRun::new(model, assets, year, &market_demands)
                 .with_candidates(candidates)
                 .run("final with candidates", writer)?,
         )

src/simulation/investment.rs

@@ -56,7 +56,8 @@ pub fn perform_agent_investment(
     writer: &mut DataWriter,
 ) -> Result<Vec<AssetRef>> {
     // Initialise net demand map
-    let mut net_demand = collect_preset_demands_for_year(&model.commodities, year);
+    let preset_demands = collect_preset_demands_for_year(&model.commodities, year);
+    let mut net_demand = preset_demands.clone();
 
     // Keep a list of all the assets selected
     // This includes Commissioned assets that are selected for retention, and new Ready assets
@@ -110,7 +111,7 @@ pub fn perform_agent_investment(
 
         // As upstream markets by definition will not yet have producers, we explicitly set
         // their prices using external values so that they don't appear free
-        let solution = DispatchRun::new(model, &all_selected_assets, year)
+        let solution = DispatchRun::new(model, &all_selected_assets, year, &preset_demands)
             .without_commodity_constraints()
             .with_market_balance_subset(&seen_markets)
             .with_input_prices(&prices.shadow)
@@ -179,10 +180,14 @@ pub fn update_net_demand_map(demand: &mut AllDemandMap, flows: &FlowMap, assets:
                 let selection = level.containing_selection(time_slice);
                 let key = (commodity_id.clone(), asset.region_id().clone(), selection);
                 // Note: we use the negative of the flow as input flows are negative in the flow map.
-                demand
+                let value = demand
                     .entry(key)
                     .and_modify(|value| *value -= *flow)
                     .or_insert(-*flow);
+
+                if *value < Flow(0.0) {
+                    *value = Flow(0.0);
+                }
             }
         }
     }