test.lua

name = "solar"

modem = peripheral.find("modem")
modem.closeAll()
modem.open(3)

meter = peripheral.find("energy_meter")

while true do
  print("wait modem event...")
  local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
  print("message incoming")
  print(textutils.serialise(message))
  if message == name then
    print("reading meter...")
    energy = meter.getTransferRate()
    print("sending data...")
    modem.transmit(replyChannel, 3, energy)
  else
    print("ignoring")
  end

end