diff --git a/li/cil/oc/api/network/Producer.scala b/li/cil/oc/api/network/Producer.scala
deleted file mode 100644
index 857f57149..000000000
--- a/li/cil/oc/api/network/Producer.scala
+++ /dev/null
@@ -1,30 +0,0 @@
-package li.cil.oc.api.network
-
-trait Producer extends Receiver {
-  demand = 0
-
-  def powerDemand:Double= {
-    if (main != null) {
-      main.getDemand
-    }
-    else {
-      0.0
-    }
-  }
-
-  def maxEnergy:Double= {
-    if (main != null) {
-      main.MAXENERGY
-    }
-    else {
-      0.0
-    }
-
-  }
-
-  def addEnergy(amount: Double) {
-    if (main != null) {
-      main.addEnergy(amount)
-    }
-  }
-}
diff --git a/li/cil/oc/api/network/Receiver.scala b/li/cil/oc/api/network/Receiver.scala
deleted file mode 100644
index 79240b2c7..000000000
--- a/li/cil/oc/api/network/Receiver.scala
+++ /dev/null
@@ -1,141 +0,0 @@
-package li.cil.oc.api.network
-
-import li.cil.oc.common.tileentity.PowerDistributor
-import scala.collection.mutable
-import net.minecraft.nbt.NBTTagCompound
-
-
-trait Receiver extends Node {
-  var powerDistributors = mutable.Set[PowerDistributor]()
-
-  private var _demand = 2.0
-
-  def demand = _demand
-
-  def demand_=(value: Double) = {
-
-    powerDistributors.foreach(e => e.updateDemand(this, value))
-    _demand = value
-  }
-
-  override def receive(message: Message): Option[Array[Any]] = {
-    message.name match {
-      case "system.connect" => {
-        message.source match {
-          case distributor: PowerDistributor => {
-            println("connect")
-            if (!powerDistributors.contains(distributor)) {
-              powerDistributors += distributor
-              distributor.connectNode(this, _demand)
-            }
-          }
-          case _ =>
-        }
-      }
-      case "system.disconnect" => {
-        message.source match {
-          case distributor: PowerDistributor => {
-            println("connect")
-            if (powerDistributors.contains(distributor)) {
-              powerDistributors -= distributor
-              distributor.disconnectNode(this)
-            }
-          }
-          case _ =>
-        }
-      }
-      case _ =>
-    }
-    super.receive(message)
-  }
-
-
-  override protected def onDisconnect() {
-    super.onDisconnect()
-    powerDistributors.foreach(e => {
-      e.disconnectNode(this)
-    })
-
-  }
-
-
-
-  def main: PowerDistributor = {
-    powerDistributors.find(p => p.isActive) match {
-      case Some(p: PowerDistributor) => p
-      case _ => null
-    }
-
-
-  }
-  override def load(nbt: NBTTagCompound) = {
-    super.load(nbt)
-    buffer = nbt.getDouble("buffer")
-  }
-
-  override def save(nbt: NBTTagCompound) = {
-    super.save(nbt)
-    nbt.setDouble("buffer",buffer)
-  }
-
-  private var buffer = 0.0
-  private val maxBuffer = 100.0
-  private var hasEnergy = false
-  private var isConnected = false
-
-  override def update() {
-    super.update()
-    //if has enough energy to operate
-    if (isConnected) {
-      //increase buffer
-      if (maxBuffer > buffer + 1)
-        buffer += 1
-      //notify if energy wasn't available before
-      if (!hasEnergy) {
-        hasEnergy = true
-        onPowerAvailable()
-      }
-    }
-    else {
-      //continue running until we are out of energy
-      if (buffer - demand < 0) {
-        if (hasEnergy) {
-          hasEnergy = false
-          onPowerLoss()
-        }
-      } else {
-        buffer -= demand
-      }
-    }
-  }
-
-  /**
-   * called from the producer when he has enough energy to operate
-   */
-  final def connect() {
-    isConnected = true
-  }
-
-  /**
-   * Called from the producer when there is not enough energy to operate
-   */
-  final def unConnect() {
-    isConnected = false
-  }
-
-  /**
-   * Called when the receiver has enough power to operate.
-   */
-  def onPowerAvailable() {
-    println("received energy")
-  }
-
-  /**
-   * Called when the receiver has no power to operate. This can happen at a later time
-   * then unConnect was called, because of the internal capacity
-   */
-  def onPowerLoss() {
-    println("no more energy")
-  }
-}
-
diff --git a/li/cil/oc/api/power/Producer.scala b/li/cil/oc/api/power/Producer.scala
new file mode 100644
index 000000000..74f6401e0
--- /dev/null
+++ b/li/cil/oc/api/power/Producer.scala
@@ -0,0 +1,20 @@
+package li.cil.oc.api.power
+
+trait Producer extends Receiver {
+  demand = 0
+
+  def powerDemand: Double = provider match {
+    case Some(p) => p.getDemand
+    case _ => 0
+  }
+
+  def maxEnergy: Double = provider match {
+    case Some(p) => p.MAXENERGY
+    case _ => 0
+  }
+
+  def addEnergy(amount: Double) = provider match {
+    case Some(p) => p.addEnergy(amount)
+    case _ =>
+  }
+}
diff --git a/li/cil/oc/api/network/Provider.scala b/li/cil/oc/api/power/Provider.scala
similarity index 76%
rename from li/cil/oc/api/network/Provider.scala
rename to li/cil/oc/api/power/Provider.scala
index 93745dcd6..15b28e907 100644
--- a/li/cil/oc/api/network/Provider.scala
+++ b/li/cil/oc/api/power/Provider.scala
@@ -1,34 +1,20 @@
-package li.cil.oc.api.network
+package li.cil.oc.api.power
 
-import scala.collection.mutable
+import li.cil.oc.api.network.{Message, Node}
 import net.minecraft.nbt.NBTTagCompound
+import scala.collection.mutable
 
-
-trait Provider extends  Node{
+trait Provider extends Node {
 
   var isActive = false
   var updateNodes = false
-  var energyDemand =0.0
-  var storedEnergy =0.0
-  var MAXENERGY :Double =2000.0
-
+  var energyDemand = 0.0
+  var storedEnergy = 0.0
+  var MAXENERGY: Double = 2000.0
 
   var energyStorageList = mutable.Set[EnergyStorage]()
 
-  override def load(nbt: NBTTagCompound) = {
-    super.load(nbt)
-    storedEnergy = nbt.getDouble("storedEnergy")
-
-  }
-
-  override def save(nbt: NBTTagCompound) = {
-    super.save(nbt)
-    nbt.setDouble("storedEnergy",storedEnergy)
-
-
-  }
-
-  override def receive(message: Message): Option[Array[Any]] = {
+  override def receive(message: Message): Option[Array[Any]] = super.receive(message) orElse {
     if (message.source != this) {
       message.name match {
         case "system.connect" => {
@@ -61,13 +47,27 @@ trait Provider extends  Node{
               }
             case _ =>
           }
-
         }
         case _ => // Ignore.
       }
     }
-    super.receive(message)
+    None
+  }
 
+  override protected def onConnect() {
+    //check if other distributors already are in the network
+    searchMain()
+    super.onConnect()
+  }
+
+  override def load(nbt: NBTTagCompound) = {
+    super.load(nbt)
+    storedEnergy = nbt.getDouble("storedEnergy")
+  }
+
+  override def save(nbt: NBTTagCompound) = {
+    super.save(nbt)
+    nbt.setDouble("storedEnergy", storedEnergy)
   }
 
   /**
@@ -76,7 +76,7 @@ trait Provider extends  Node{
    * @param amount
    */
   def connectNode(receiver: Receiver, amount: Double) {
-    if (energyStorageList.filter(x => x.node == receiver).isEmpty) {
+    if (!energyStorageList.exists(_.node == receiver)) {
       energyStorageList += new EnergyStorage(receiver, amount)
       energyDemand += amount
       updateNodes = true
@@ -110,9 +110,8 @@ trait Provider extends  Node{
       else if (e.node == receiver) {
         energyStorageList -= e
         energyDemand -= e.amount
-        if(isActive)
-        {
-          receiver.unConnect()
+        if (isActive) {
+          receiver.isReceivingPower = false
           updateNodes = true
         }
       }
@@ -122,36 +121,31 @@ trait Provider extends  Node{
       println("demand now (disc) " + energyDemand)
   }
 
-  override protected def onConnect() {
-    //check if other distributors already are in the network
-    searchMain()
-    super.onConnect()
-  }
+  private var hasEnergy = false
 
-   private var hasEnergy = false
-   override def update() {
+  override def update() {
     super.update()
-     //check if is main
+    //check if is main
     if (isActive) {
-      //if enough energy is available to supply all recievers
-      if(storedEnergy>energyDemand){
-        storedEnergy-=energyDemand
-        if(!hasEnergy)
+      //if enough energy is available to supply all receivers
+      if (storedEnergy > energyDemand) {
+        storedEnergy -= energyDemand
+        if (!hasEnergy)
           updateNodes = true
         hasEnergy = true
-        println("energy level now "+storedEnergy)
+        println("energy level now " + storedEnergy)
       }
-      else{
-        if(hasEnergy)
+      else {
+        if (hasEnergy)
           updateNodes = true
         hasEnergy = false
       }
       //if nodes must be updated send message to them
-      if(updateNodes){
-         if(hasEnergy)
-           energyStorageList.foreach(storage=>storage.node.connect())
-         else
-           energyStorageList.foreach(storage=>storage.node.unConnect())
+      if (updateNodes) {
+        if (hasEnergy)
+          energyStorageList.foreach(storage => storage.node.isReceivingPower = true)
+        else
+          energyStorageList.foreach(storage => storage.node.isReceivingPower = false)
         updateNodes = false
       }
     }
@@ -163,8 +157,6 @@ trait Provider extends  Node{
 
   def addEnergy(amount: Double) {
     storedEnergy += amount
-
-
   }
 
   def searchMain() {
@@ -182,7 +174,6 @@ trait Provider extends  Node{
     })
   }
 
-  class EnergyStorage(var node: Receiver, var amount: Double) {
+  class EnergyStorage(var node: Receiver, var amount: Double)
 
-  }
 }
diff --git a/li/cil/oc/api/power/Receiver.scala b/li/cil/oc/api/power/Receiver.scala
new file mode 100644
index 000000000..ebee47ca1
--- /dev/null
+++ b/li/cil/oc/api/power/Receiver.scala
@@ -0,0 +1,114 @@
+package li.cil.oc.api.power
+
+import li.cil.oc.api.network.{Message, Node}
+import net.minecraft.nbt.NBTTagCompound
+import scala.collection.mutable
+
+trait Receiver extends Node {
+  def demand = _demand
+
+  def demand_=(value: Double) = if (value != _demand) {
+    providers.foreach(_.updateDemand(this, value))
+    _demand = value
+  }
+
+  def provider: Option[Provider] = providers.find(_.isActive)
+
+  /**
+   * Called when the receiver has enough power to operate.
+   */
+  def onPowerAvailable() {
+    println("received energy")
+  }
+
+  /**
+   * Called when the receiver has no power to operate. This can happen at a later time
+   * then unConnect was called, because of the internal capacity
+   */
+  def onPowerUnavailable() {
+    println("no more energy")
+  }
+
+  // ----------------------------------------------------------------------- //
+
+  override def receive(message: Message) = super.receive(message) orElse {
+    message.name match {
+      case "system.connect" => {
+        message.source match {
+          case p: Provider => {
+            if (providers.add(p)) {
+              p.connectNode(this, _demand)
+            }
+          }
+          case _ =>
+        }
+      }
+      case "system.disconnect" => {
+        message.source match {
+          case p: Provider => {
+            if (providers.remove(p)) {
+              p.disconnectNode(this)
+            }
+          }
+          case _ =>
+        }
+      }
+      case _ =>
+    }
+    None
+  }
+
+  override protected def onDisconnect() {
+    super.onDisconnect()
+    providers.foreach(_.disconnectNode(this))
+  }
+
+  // ----------------------------------------------------------------------- //
+
+  override def load(nbt: NBTTagCompound) {
+    super.load(nbt)
+    buffer = nbt.getDouble("buffer")
+  }
+
+  override def save(nbt: NBTTagCompound) {
+    super.save(nbt)
+    nbt.setDouble("buffer", buffer)
+  }
+
+  // ----------------------------------------------------------------------- //
+
+  private var _demand = 2.0
+  private val providers = mutable.Set.empty[Provider]
+  private var buffer = 0.0
+  private val maxBuffer = 100.0
+  private var isPowerAvailable = false
+
+  /** Set from the provider whenever its power state changes. */
+  private[power] var isReceivingPower = false
+
+  override def update() {
+    super.update()
+    //if has enough energy to operate
+    if (isReceivingPower) {
+      //increase buffer
+      // TODO maybe make the speed of the "cooldown" dependent on the demand?
+      // TODO another possibility: increase the demand dynamically while charging?
+      if (maxBuffer > buffer + 1)
+        buffer += 1
+      //notify if energy wasn't available before
+      if (!isPowerAvailable) {
+        isPowerAvailable = true
+        onPowerAvailable()
+      }
+    }
+    //continue running until we are out of energy
+    else if (buffer >= demand) {
+      buffer -= demand
+    }
+    else if (isPowerAvailable) {
+      isPowerAvailable = false
+      onPowerUnavailable()
+    }
+  }
+}
+
diff --git a/li/cil/oc/client/gui/Screen.scala b/li/cil/oc/client/gui/Screen.scala
index 7656b3188..6172a5577 100644
--- a/li/cil/oc/client/gui/Screen.scala
+++ b/li/cil/oc/client/gui/Screen.scala
@@ -31,7 +31,7 @@ class Screen(val tileEntity: tileentity.Screen) extends MCGuiScreen {
   private val pressedKeys = mutable.Map.empty[Int, Char]
 
   /** Must be called when the size of the underlying screen changes */
-  def setSize(w: Double, h: Double) = {
+  def changeSize(w: Double, h: Double) = {
     // Re-compute sizes and positions.
     val totalMargin = Screen.margin + Screen.innerMargin
     val bufferWidth = w * MonospaceFontRenderer.fontWidth
@@ -83,7 +83,7 @@ class Screen(val tileEntity: tileentity.Screen) extends MCGuiScreen {
     MonospaceFontRenderer.init(mc.renderEngine)
     Screen.init(mc.renderEngine)
     val (w, h) = tileEntity.screen.resolution
-    setSize(w, h)
+    changeSize(w, h)
   }
 
   override def onGuiClosed() = {
diff --git a/li/cil/oc/common/tileentity/Computer.scala b/li/cil/oc/common/tileentity/Computer.scala
index edd026284..61a1b592f 100644
--- a/li/cil/oc/common/tileentity/Computer.scala
+++ b/li/cil/oc/common/tileentity/Computer.scala
@@ -2,7 +2,7 @@ package li.cil.oc.common.tileentity
 
 import java.util.concurrent.atomic.AtomicBoolean
 import li.cil.oc.api.driver.Slot
-import li.cil.oc.api.network.Receiver
+import li.cil.oc.api.power.Receiver
 import li.cil.oc.client.{PacketSender => ClientPacketSender}
 import li.cil.oc.server.component
 import li.cil.oc.server.component.Redstone
diff --git a/li/cil/oc/common/tileentity/PowerDistributor.scala b/li/cil/oc/common/tileentity/PowerDistributor.scala
index 54b2eafdb..6b6fc3b78 100644
--- a/li/cil/oc/common/tileentity/PowerDistributor.scala
+++ b/li/cil/oc/common/tileentity/PowerDistributor.scala
@@ -3,6 +3,7 @@ package li.cil.oc.common.tileentity
 import li.cil.oc.api.network._
 import scala.collection.mutable
 import net.minecraft.nbt.NBTTagCompound
+import li.cil.oc.api.power.Provider
 
 class PowerDistributor  extends Rotatable with Provider {
 
diff --git a/li/cil/oc/common/tileentity/PowerSupply.scala b/li/cil/oc/common/tileentity/PowerSupply.scala
index 01339829e..d83049e06 100644
--- a/li/cil/oc/common/tileentity/PowerSupply.scala
+++ b/li/cil/oc/common/tileentity/PowerSupply.scala
@@ -12,6 +12,7 @@ import net.minecraft.world.World
 import net.minecraft.nbt.NBTTagCompound
 import universalelectricity.core.block.IElectrical
 import universalelectricity.core.electricity.ElectricityPack
+import li.cil.oc.api.power.Producer
 
 /**
  * Created with IntelliJ IDEA.
diff --git a/li/cil/oc/common/tileentity/Screen.scala b/li/cil/oc/common/tileentity/Screen.scala
index f9bfefb30..71ea93e3c 100644
--- a/li/cil/oc/common/tileentity/Screen.scala
+++ b/li/cil/oc/common/tileentity/Screen.scala
@@ -1,6 +1,6 @@
 package li.cil.oc.common.tileentity
 
-import li.cil.oc.api.network.Receiver
+import li.cil.oc.api.power.Receiver
 import li.cil.oc.client.gui
 import li.cil.oc.client.{PacketSender => ClientPacketSender}
 import li.cil.oc.common.component
@@ -44,7 +44,7 @@ class Screen extends Rotatable with component.Screen.Environment with Receiver {
   override def onScreenResolutionChange(w: Int, h: Int) = {
     super.onScreenResolutionChange(w, h)
     if (worldObj.isRemote) {
-      guiScreen.foreach(_.setSize(w, h))
+      guiScreen.foreach(_.changeSize(w, h))
       hasChanged = true
     }
     else {