diff --git a/openelectricity/client.py b/openelectricity/client.py
index 86c671c..192c03e 100644
--- a/openelectricity/client.py
+++ b/openelectricity/client.py
@@ -5,8 +5,10 @@
 """
 
 import asyncio
+import concurrent.futures
 import os
 import ssl
+from collections.abc import Coroutine
 from datetime import datetime
 from typing import Any, TypeVar, cast
 
@@ -32,6 +34,22 @@
 logger = get_logger("client")
 
 
+def _run_sync(coro: Coroutine[Any, Any, T]) -> T:
+    """Run a coroutine to completion from synchronous code.
+
+    Uses ``asyncio.run`` when no event loop is running. When a loop is already
+    running — as in a Jupyter/IPython notebook — the coroutine is run on its
+    own loop in a worker thread, so the synchronous client works there too.
+    """
+    try:
+        asyncio.get_running_loop()
+    except RuntimeError:
+        return asyncio.run(coro)
+
+    with concurrent.futures.ThreadPoolExecutor(max_workers=1) as pool:
+        return pool.submit(asyncio.run, coro).result()
+
+
 class OpenElectricityError(Exception):
     """Base exception for OpenElectricity API errors."""
 
@@ -162,8 +180,9 @@ class OEClient(BaseOEClient):
     """
     Synchronous client for the OpenElectricity API.
 
-    Note: This client uses aiohttp with asyncio.run() internally to maintain
-    API consistency while using the same underlying HTTP client as the async version.
+    It runs aiohttp under the hood and is safe to call from inside an existing
+    event loop (e.g. a Jupyter/IPython notebook) — when a loop is already
+    running, requests are dispatched to a worker thread.
     """
 
     def __init__(
@@ -387,7 +406,7 @@ async def _run():
                 self._session = session
                 return await self._async_get_facilities(facility_code, status_id, fueltech_id, network_id, network_region)
 
-        return asyncio.run(_run())
+        return _run_sync(_run())
 
     def get_network_data(
         self,
@@ -437,7 +456,7 @@ async def _run():
                     secondary_grouping,
                 )
 
-        return asyncio.run(_run())
+        return _run_sync(_run())
 
     def get_facility_data(
         self,
@@ -458,7 +477,7 @@ async def _run():
                     network_code, facility_code, metrics, interval, date_start, date_end, unit_code
                 )
 
-        return asyncio.run(_run())
+        return _run_sync(_run())
 
     def get_market(
         self,
@@ -479,7 +498,7 @@ async def _run():
                     network_code, metrics, interval, date_start, date_end, primary_grouping, network_region
                 )
 
-        return asyncio.run(_run())
+        return _run_sync(_run())
 
     def get_current_user(self) -> OpennemUserResponse:
         """Get current user information."""
@@ -489,7 +508,7 @@ async def _run():
                 self._session = session
                 return await self._async_get_current_user()
 
-        return asyncio.run(_run())
+        return _run_sync(_run())
 
     def close(self) -> None:
         """Close the underlying HTTP client."""
@@ -498,7 +517,7 @@ def close(self) -> None:
             async def _close():
                 await cast(ClientSession, self._session).close()
 
-            asyncio.run(_close())
+            _run_sync(_close())
 
     def __enter__(self) -> "OEClient":
         return self
diff --git a/tests/test_run_sync.py b/tests/test_run_sync.py
new file mode 100644
index 0000000..44d4326
--- /dev/null
+++ b/tests/test_run_sync.py
@@ -0,0 +1,28 @@
+"""
+Tests for _run_sync, the helper that lets the synchronous client work both
+standalone and inside an already-running event loop (e.g. a notebook).
+"""
+
+import asyncio
+
+from openelectricity.client import _run_sync
+
+
+async def _echo(value: str) -> str:
+    await asyncio.sleep(0)
+    return value
+
+
+def test_run_sync_without_running_loop() -> None:
+    """With no event loop running, the coroutine runs via asyncio.run."""
+    assert _run_sync(_echo("standalone")) == "standalone"
+
+
+def test_run_sync_inside_running_loop() -> None:
+    """With a loop already running (the notebook case), it still completes."""
+
+    async def _notebook_like() -> str:
+        # A loop is running here; a naive asyncio.run() would raise RuntimeError.
+        return _run_sync(_echo("notebook"))
+
+    assert asyncio.run(_notebook_like()) == "notebook"