R/metal_emissions.R

In carbonr: Calculate Carbon-Equivalent Emissions

#' Metal Emissions
#' 
#' @description This function calculates the emissions produced from different metal sources based on the specified inputs. It considers emissions from primary material production and waste disposal of various metal types.
#'
#' @param aluminuim_cans Numeric value indicating the weight of aluminum cans. Default is `0`.
#' @param aluminuim_foil Numeric value indicating the weight of aluminum foil. Default is `0`.
#' @param mixed_cans Numeric value indicating the weight of mixed metal cans. Default is `0`.
#' @param scrap Numeric value indicating the weight of metal scrap. Default is `0`.
#' @param steel_cans Numeric value indicating the weight of steel cans. Default is `0`.
#' @param aluminuim_cans_WD Numeric value indicating the weight of aluminum cans disposed of using waste disposal methods. Default is `0`.
#' @param aluminuim_foil_WD Numeric value indicating the weight of aluminum foil disposed of using waste disposal methods. Default is `0`.
#' @param mixed_cans_WD Numeric value indicating the weight of mixed metal cans disposed of using waste disposal methods. Default is `0`.
#' @param scrap_WD Numeric value indicating the weight of metal scrap disposed of using waste disposal methods. Default is `0`.
#' @param steel_cans_WD Numeric value indicating the weight of steel cans disposed of using waste disposal methods. Default is `0`.
#' @param waste_disposal Character vector specifying the waste disposal method to use for calculating emissions. Possible values: "Closed-loop", "Combustion", "Landfill", "Open-loop". Default is "Closed-loop".
#' `"Open-loop"` is the process of recycling material into other products.
#' `"Closed-loop"` is the process of recycling material back into the same product.
#' `"Combustion"` energy is recovered from the waste through incineration and subsequent generation of electricity.
#' `"Landfill"` the product goes to landfill after use.
#' @param units  Character vector specifying the units of the emissions output. Possible values: "kg", "tonnes". Default is "kg".
#'
#' @return The function returns the calculated CO2-equivalent emissions as a numeric value in tonnes.
#' @export
#'
#' @examples
#' metal_emissions(aluminuim_cans = 1.4, units = "tonnes")
metal_emissions <- function(aluminuim_cans = 0, aluminuim_foil = 0, mixed_cans = 0, scrap = 0, steel_cans = 0,
                            aluminuim_cans_WD = 0, aluminuim_foil_WD = 0,
                            mixed_cans_WD = 0, scrap_WD = 0, steel_cans_WD = 0,
                            waste_disposal = c("Closed-loop", "Combustion", "Landfill", "Open-loop"),
                            units = c("kg", "tonnes")){
  
  waste_disposal <- match.arg(waste_disposal)
  units <- match.arg(units)
  checkmate::assert_numeric(aluminuim_cans, lower = 0)
  checkmate::assert_numeric(aluminuim_foil, lower = 0)
  checkmate::assert_numeric(mixed_cans, lower = 0)
  checkmate::assert_numeric(scrap, lower = 0)
  checkmate::assert_numeric(steel_cans, lower = 0)
  checkmate::assert_numeric(aluminuim_cans_WD, lower = 0)
  checkmate::assert_numeric(aluminuim_foil_WD, lower = 0)
  checkmate::assert_numeric(mixed_cans_WD, lower = 0)
  checkmate::assert_numeric(scrap_WD, lower = 0)
  checkmate::assert_numeric(steel_cans_WD, lower = 0)
  
  MU <- uk_gov_data %>%
    dplyr::filter(`Level 2` == "Metal") %>%
    dplyr::filter(`Column Text` == "Primary material production") %>%
    dplyr::mutate(`Level 3` = ifelse(`Level 2` == "Metal",
                              gsub(".*: ", "", `Level 3`),
                              `Level 3`))
  WD <- uk_gov_data %>%
    dplyr::filter(`Level 1` == "Waste disposal") %>%
    dplyr::filter(`Level 2` == "Metal") %>%
    dplyr::filter(`Column Text` == waste_disposal) %>%
    dplyr::mutate(`Level 3` = ifelse(`Level 2` == "Metal",
                              gsub(".*: ", "", `Level 3`),
                              `Level 3`))
  emission_values <- MU$value
  WD_values <- WD$value
  metal_emissions <- aluminuim_cans*emission_values[1] + aluminuim_foil*emission_values[1] + mixed_cans*emission_values[2] +
    scrap*emission_values[3] + steel_cans*emission_values[4] +
    aluminuim_cans_WD*WD_values[1] + aluminuim_foil_WD*WD_values[1] + mixed_cans_WD*WD_values[2] +
    scrap_WD*WD_values[3] + steel_cans_WD*WD_values[4]
  if (units == "kg") metal_emissions <- metal_emissions * 0.001
  return(metal_emissions)
}