Line graph on energy production in district heating of the Helsinki capital area

energy.R

library(tidyverse)
library(readxl)
library(httr)

#-------------------------------------------------------------
# hri.fi
#
# Pääkaupunkiseudun kaukolämmön tuotannon energialähteet (GWh)
#-------------------------------------------------------------

url <- "https://www.hsy.fi/sites/AvoinData/AvoinData/Kaukolammon_paastot_kulutus_polttoaineet_PKS_1990_2000-2013.xlsx"

GET(url, write_disk(tf <- tempfile(fileext = ".xlsx")))
df <- read_xlsx(tf, sheet = "Energialähteet", skip = 3)
unlink(tf)

df <- df %>% 
  rename(Source = `POLTTOAINEET (GWh)`)

df_t <- as.data.frame(t(df), stringsAsFactors = FALSE)
names(df_t) <- df_t[1,]
df_t$Year <- row.names(df_t)

data <- df_t[2:nrow(df_t),]
data2 <- data %>% 
  select(Year, Coal = Kivihiili, Gas = Maakaasu, 
         Oil = Öljy, Bio, `Heat pump`= Lämpöpumput)
data3 <- data.frame(data2, row.names = NULL)

data3$Coal <- as.numeric(data3$Coal)
data3$Gas <- as.numeric(data3$Gas)
data3$Oil <- as.numeric(data3$Oil)
data3$Bio <- as.numeric(data3$Bio)
data3$Heat.pump <- as.numeric(data3$Heat.pump)
data3$Year <- as.integer(data3$Year)

energy <- data3 %>% 
  gather(Source, Production, Coal:Heat.pump)

before2000 <- energy[energy$Year <= 2000,]
after2000 <- energy[energy$Year >= 2000,]

e <- ggplot() +
  geom_line(data = before2000, 
            aes( x = Year, y = Production, colour = Source), linetype = "dashed", size = 1.5) +
  geom_line(data = after2000, 
            aes( x = Year, y = Production, colour = Source), size = 1.5) +
  scale_x_continuous(breaks=seq(1990, 2013, 2)) +
  scale_colour_brewer(palette="Spectral") +
  labs(title="District heating in Finnish capital region 1990-2013",
       subtitle = "Energy sources used in production",
       caption="Data: hri.fi",
       y = "Production (GWh)") +
  theme_dark()

ggsave("energy.png", e, height = 8, width = 10)