The Renewable Revolution
Solar and wind are growing faster than anyone predicted. But the grid wasn't built for energy that comes and goes with the weather.
Solar and Wind Growth
In the year 2000, renewable sources provided just 6% of Germany's electricity. By 2025, that figure exceeded 55%. This is one of the fastest energy transitions in history, and it happened in a country of 84 million people with one of the world's largest industrial economies.
Solar capacity alone grew from around 5 GW in 2010 to over 100 GW by 2024 — roughly 18x in under fifteen years. Wind now provides more electricity than coal. The renewable revolution is no longer a future ambition. It is the present reality.
The Duck Curve
When the sun shines, solar panels flood the grid with cheap electricity. So much, in fact, that demand for conventional generation — coal, gas, nuclear — collapses during the middle of the day. Then, as the sun sets and solar output drops to zero, demand for conventional generation surges back up within a few hours.
Plot this demand on a chart and the shape looks unmistakably like a duck: a belly sagging in the afternoon, a neck rising sharply at sunset. California's grid operator (CAISO) coined the term in 2013, and the duck has since waddled its way across every grid with significant solar penetration.
The duck curve is not just a curiosity. It is a serious operational problem. Gas plants cannot ramp from idle to full output instantly — they need time to spin up, and each start-stop cycle costs money and causes wear. The steeper the duck's neck, the faster conventional plants must ramp, and the more expensive and precarious the evening transition becomes.
Curtailment: Throwing Away Clean Energy
When solar and wind generate more electricity than the grid can physically absorb, operators have no choice: they tell renewable generators to shut down. This is called curtailment. The turbines stop spinning. The panels are disconnected. Clean, free energy is thrown away.
In Germany, approximately 10 TWh of renewable energy is curtailed every year. Solar curtailment nearly doubled in 2024, rising 97% year-over-year as record solar capacity additions outpaced grid expansion. The operators who curtail these plants still have to pay compensation to the generators — in 2024, that bill came to EUR 554 million.
The irony is hard to overstate. We are spending billions to build solar panels and wind turbines, then paying hundreds of millions more to switch them off — because the grid cannot handle the energy they produce.
Negative Prices
In 2024, Germany experienced 457 hours where the price of electricity went negative — meaning generators had to pay to put their electricity on the grid. In 2025, that number rose to 575 hours.
Negative prices happen when renewable generation so overwhelms demand that there is literally no one willing to buy the electricity at any positive price. Inflexible plants (nuclear, some coal, biomass with feed-in tariffs) keep running because shutting down and restarting is even more expensive than paying to offload their output. The result: a market where energy is so abundant that its price goes below zero.
This might sound like a good problem to have. It is not. When prices go negative, renewable generators lose money on every kilowatt-hour they produce. Sustained negative pricing discourages investment in new solar and wind capacity — the exact opposite of what the energy transition needs.
The trend is accelerating. Germany went from 15 negative-price hours in 2008, to 298 in 2020, to 575 in 2025. As solar capacity continues to grow — Germany's target is 215 GW by 2030, more than double today's installed base — negative pricing events will only become more frequent without a fundamental change in how the grid absorbs surplus energy.
The grid needs a way to absorb this energy — to soak up the surplus when the sun shines and release it when it doesn't. That is exactly what a Virtual Power Plant does.