diff --git a/README.md b/README.md
index 5ec01dc..9849cd1 100644
--- a/README.md
+++ b/README.md
@@ -63,3 +63,4 @@ Please read [SUPPORT](SUPPORT.md) for how to connect and get into contact with t
 [github:create-from-template]: https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/creating-a-repository-on-github/creating-a-repository-from-a-template
 [kotlin]: https://kotlinlang.org/
 [gradle]: https://gradle.org/
+
diff --git a/measure/build.gradle.kts b/measure/build.gradle.kts
index e09062f..e1c7bd4 100644
--- a/measure/build.gradle.kts
+++ b/measure/build.gradle.kts
@@ -10,7 +10,7 @@ plugins {
     `java-library`
 
     // Apply dokka plugin to allow extraction of ducumentation from KDoc comments
-    id("org.jetbrains.dokka") version "1.4.20"
+    id("org.jetbrains.dokka") version "1.9.20"
 
     // Make sure we can publish to maven
     `maven-publish`
diff --git a/measure/src/main/kotlin/com/alliander/open/measure/Measure.kt b/measure/src/main/kotlin/com/alliander/open/measure/Measure.kt
index c25a09e..b955861 100644
--- a/measure/src/main/kotlin/com/alliander/open/measure/Measure.kt
+++ b/measure/src/main/kotlin/com/alliander/open/measure/Measure.kt
@@ -117,8 +117,16 @@ data class Measure<U : Units>(val amount: BigDecimal, val units: U) : Comparable
         val absoluteFactor = (factor `in` base).abs()
         return dividend.roundToMultiple(absoluteFactor, roundingMode) * base
     }
-
 }
 
 private fun BigDecimal.roundToMultiple(factor: BigDecimal, roundingMode: RoundingMode): BigDecimal =
-        this.divide(factor, 0, roundingMode) * factor
+    this.divide(factor, 0, roundingMode) * factor
+
+operator fun <U : Units> BigDecimal.times(m: Measure<U>): Measure<U> =
+    Measure(amount = m.amount.times(this), units = m.units)
+
+operator fun <U : Units> Int.times(m: Measure<U>): Measure<U> =
+    BigDecimal.valueOf(this.toLong()) * m
+
+operator fun <U : Units> Long.times(m: Measure<U>): Measure<U> =
+    BigDecimal.valueOf(this) * m
diff --git a/measure/src/main/kotlin/com/alliander/open/measure/SpecificUnits.kt b/measure/src/main/kotlin/com/alliander/open/measure/SpecificUnits.kt
index 421b942..7435504 100644
--- a/measure/src/main/kotlin/com/alliander/open/measure/SpecificUnits.kt
+++ b/measure/src/main/kotlin/com/alliander/open/measure/SpecificUnits.kt
@@ -4,16 +4,60 @@
 
 package com.alliander.open.measure
 
+import com.alliander.open.measure.Current.Companion.ampere
 import com.alliander.open.measure.Energy.Companion.joule
 import com.alliander.open.measure.Power.Companion.watt
 import com.alliander.open.measure.Time.Companion.seconds
+import com.alliander.open.measure.Voltage.Companion.volt
 import java.math.BigDecimal
 
+@JvmName("powerTimesTime")
 operator fun Measure<Power>.times(duration: Measure<Time>): Measure<Energy> {
-    val p = this `as` watt
-    val dt = duration `as` seconds
+    val p = this `in` watt
+    val dt = duration `in` seconds
+    return Measure(p * dt, joule)
+}
+
+@JvmName("currentTimesVoltage")
+operator fun Measure<Current>.times(voltage: Measure<Voltage>): Measure<Power> {
+    val i = this `in` ampere
+    val v = voltage `in` volt
+    return Measure(i * v, watt)
+}
+
+@JvmName("voltageTimesCurrent")
+operator fun Measure<Voltage>.times(current: Measure<Current>): Measure<Power> {
+    val v = this `in` volt
+    val i = current `in` ampere
+    return Measure(i * v, watt)
+}
+
+@JvmName("powerDivVoltage")
+operator fun Measure<Power>.div(voltage: Measure<Voltage>): Measure<Current> {
+    val p = this `in` watt
+    val v = voltage `in` volt
+    return Measure(p / v, ampere)
+}
+
+@JvmName("powerDivCurrent")
+operator fun Measure<Power>.div(current: Measure<Current>): Measure<Voltage> {
+    val p = this `in` watt
+    val i = current `in` ampere
+    return Measure(p / i, volt)
+}
+
+class Voltage(suffix: String, ratio: BigDecimal = BigDecimal.ONE) : Units(suffix, ratio) {
+    companion object {
+        val volt = Voltage("V")
+        val kiloVolt = Voltage("kV", 1_000.toBigDecimal())
+    }
+}
 
-    return Measure(p.amount * dt.amount, joule)
+class Current(suffix: String, ratio: BigDecimal = BigDecimal.ONE) : Units(suffix, ratio) {
+    companion object {
+        val ampere = Current("A")
+        val kiloAmpere = Current("kA", 1_000.toBigDecimal())
+    }
 }
 
 class Power(suffix: String, ratio: BigDecimal = BigDecimal.ONE) : Units(suffix, ratio) {
@@ -30,7 +74,7 @@ class Energy(suffix: String, ratio: BigDecimal = BigDecimal.ONE) : Units(suffix,
         val kiloJoule = Energy("kJ", 1_000.toBigDecimal())
         val megaJoule = Energy("MJ", 1_000_000.toBigDecimal())
         val kiloWattHour = Energy("kWh", 3_600_000.toBigDecimal())
-        val megaWattHour = Energy("mWh", 3_600_000_000.toBigDecimal())
+        val megaWattHour = Energy("MWh", 3_600_000_000.toBigDecimal())
     }
 }
 
@@ -41,4 +85,3 @@ class Time(suffix: String, ratio: BigDecimal = BigDecimal.ONE) : Units(suffix, r
         val hours = Time("h", 3_600.toBigDecimal())
     }
 }
-
diff --git a/measure/src/test/kotlin/com/alliander/open/measure/MeasureTest.kt b/measure/src/test/kotlin/com/alliander/open/measure/MeasureTest.kt
index 28866db..1aca4b6 100644
--- a/measure/src/test/kotlin/com/alliander/open/measure/MeasureTest.kt
+++ b/measure/src/test/kotlin/com/alliander/open/measure/MeasureTest.kt
@@ -8,36 +8,21 @@ import com.alliander.open.measure.Energy.Companion.joule
 import com.alliander.open.measure.Energy.Companion.kiloJoule
 import com.alliander.open.measure.Energy.Companion.kiloWattHour
 import com.alliander.open.measure.Energy.Companion.megaJoule
-import com.alliander.open.measure.Energy.Companion.megaWattHour
 import com.alliander.open.measure.Power.Companion.kiloWatt
 import com.alliander.open.measure.Power.Companion.megaWatt
-import com.alliander.open.measure.Power.Companion.watt
 import com.alliander.open.measure.Time.Companion.hours
 import com.alliander.open.measure.Time.Companion.minutes
 import com.alliander.open.measure.Time.Companion.seconds
-import com.alliander.open.measure.extension.sum
 import io.kotest.core.spec.style.StringSpec
 import io.kotest.data.headers
 import io.kotest.data.row
 import io.kotest.data.table
 import io.kotest.matchers.shouldBe
-import io.kotest.matchers.shouldNotBe
 import io.kotest.property.checkAll
 import java.math.BigDecimal
 import java.math.RoundingMode.UP
 
 class MeasureTest : StringSpec({
-    "Joule, Watt and seconds are different units" {
-        joule shouldNotBe watt
-        joule shouldNotBe seconds
-
-        watt shouldNotBe joule
-        watt shouldNotBe seconds
-
-        seconds shouldNotBe joule
-        seconds shouldNotBe watt
-    }
-
     "joules and kiloJoules can be added" {
         val left = 1000 * joule
         val right = 1 * kiloJoule
@@ -47,15 +32,6 @@ class MeasureTest : StringSpec({
         sum shouldBe 2000 * joule
     }
 
-    "power times time is energy" {
-        val power = 10 * kiloWatt
-        val duration = 15 * minutes
-
-        val energy = power * duration
-
-        energy `as` megaJoule shouldBe 9 * megaJoule
-    }
-
     "joules can be added" {
         checkAll { leftQuantity: Int, rightQuantity: Int ->
             val left = leftQuantity * joule
@@ -123,14 +99,6 @@ class MeasureTest : StringSpec({
         }
     }
 
-    "energySum returns correct amount of energy when given a list of measures of energy" {
-        val list = listOf(100 * joule, 1 * megaWattHour, 1 * megaJoule)
-        val result = list.sum()
-
-        val expectedResult = 3601000100 * joule
-        result shouldBe expectedResult
-    }
-
     "roundUpToNextMultiple processes different units correctly" {
         io.kotest.data.forAll(
                 table(
diff --git a/measure/src/test/kotlin/com/alliander/open/measure/SpecificUnitsTest.kt b/measure/src/test/kotlin/com/alliander/open/measure/SpecificUnitsTest.kt
new file mode 100644
index 0000000..5a9927d
--- /dev/null
+++ b/measure/src/test/kotlin/com/alliander/open/measure/SpecificUnitsTest.kt
@@ -0,0 +1,94 @@
+// SPDX-FileCopyrightText: 2021-2022 Alliander N.V.
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package com.alliander.open.measure
+
+import com.alliander.open.measure.Current.Companion.ampere
+import com.alliander.open.measure.Current.Companion.kiloAmpere
+import com.alliander.open.measure.Energy.Companion.joule
+import com.alliander.open.measure.Energy.Companion.kiloJoule
+import com.alliander.open.measure.Energy.Companion.kiloWattHour
+import com.alliander.open.measure.Energy.Companion.megaJoule
+import com.alliander.open.measure.Energy.Companion.megaWattHour
+import com.alliander.open.measure.Power.Companion.kiloWatt
+import com.alliander.open.measure.Power.Companion.megaWatt
+import com.alliander.open.measure.Power.Companion.watt
+import com.alliander.open.measure.Time.Companion.hours
+import com.alliander.open.measure.Time.Companion.minutes
+import com.alliander.open.measure.Time.Companion.seconds
+import com.alliander.open.measure.Voltage.Companion.kiloVolt
+import com.alliander.open.measure.Voltage.Companion.volt
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.should
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.types.beInstanceOf
+
+class SpecificUnitsTest : StringSpec({
+    "The units have the correct measure" {
+        joule should beInstanceOf<Energy>()
+        kiloJoule should beInstanceOf<Energy>()
+        megaJoule should beInstanceOf<Energy>()
+        kiloWattHour should beInstanceOf<Energy>()
+        megaWattHour should beInstanceOf<Energy>()
+
+        watt should beInstanceOf<Power>()
+        kiloWatt should beInstanceOf<Power>()
+        megaWatt should beInstanceOf<Power>()
+
+        seconds should beInstanceOf<Time>()
+        minutes should beInstanceOf<Time>()
+        hours should beInstanceOf<Time>()
+
+        volt should beInstanceOf<Voltage>()
+        kiloVolt should beInstanceOf<Voltage>()
+
+        ampere should beInstanceOf<Current>()
+        kiloAmpere should beInstanceOf<Current>()
+    }
+
+    "power times time is energy" {
+        val power = 10 * kiloWatt
+        val duration = 15 * minutes
+
+        val energy = power * duration
+
+        energy `as` megaJoule shouldBe 9 * megaJoule
+    }
+
+    "current times voltage is power" {
+        val current = 10 * ampere
+        val voltage = 15 * volt
+
+        val power = current * voltage
+
+        power `as` watt shouldBe 150 * watt
+    }
+
+    "voltage times current is power" {
+        val current = 10 * ampere
+        val voltage = 15 * volt
+
+        val power = voltage * current
+
+        power `as` watt shouldBe 150 * watt
+    }
+
+    "power divided by voltage is current" {
+        val power = 150 * watt
+        val voltage = 15 * volt
+
+        val current = power / voltage
+
+        current `as` ampere shouldBe 10 * ampere
+    }
+
+    "power divided by current is voltage" {
+        val power = 150 * watt
+        val current = 10 * ampere
+
+        val voltage = power / current
+
+        voltage `as` volt shouldBe 15 * volt
+    }
+})