Hybrid vigor is a pretty simple genetic concept. Diverse gene pools do better. The same might soon be said of power plants. The world is filling up with examples of groundbreaking hybrid power systems that marry wind, solar, natural gas, hydrogen, and even coal to provide the right mix of performance (high), cost (low), and environmental impact (minimum).
One of the first is Germany’s new Enertag power plant, which harnesses wind turbines, hydrogen, and a dose of biogas, to create zero-carbon heat and energy. The arrangement draws on three 2MW wind turbines that feed power directly to the grid. When demand drops (and the wind is blowing), excess electricity is used to power hydrolysis, splitting water molecules into oxygen and hydrogen atoms. Hydrogen gas is stored to fill up vehicles or mixed with biogas to burn for heat and electricity.
“This plant, unique in the world, makes it possible to transform the fluctuating wind energy into a reliable factor that can then be deployed in the long-term as a predictable source of energy for electricity, heat and mobility,” said Prime Minister Matthias Platzeck during the plant’s opening ceremony, according to Renewable Energy Magazine. We are assisting a quantum leap in modern storage technology today.”
Although the €21M joint project between energy supplier Enertrag, oil company Total, and others, is a radical departure from the standard coal plant, it is not a panacea for fossil fuels: there’s an energy penalty to produce hydrogen by hydrolysis, and the scale of the energy output (at least at this stage) remains small. But it’s likely to be first of many hybrid plants to take shape in the coming decade.
A host of other similar plants have already started construction around the world, as fossil fuel prices climb alongside government incentives for renewable energy. The most familiar hybrids burn biomass–the sector is already a $1 billion industry with 80 facilities across the country, according to the Biomass Power Association–and have steadily converted former coal boilers into renewable biomass-fired ones.
Solar is now taking hold as an ingredient in hybrid plants. Innovative projects are using solar energy to boost the efficiency of coal or natural gas plants by heating steam, and more than doubling the efficiency rating while slashing the cost of the solar power itself. “The thing that’s attractive about this is you only have to buy the solar field portion of the plant, which is 50 to 60 percent of the cost of the plant,” Hank Price, director of technology at Abengoa Solar, said in Technology Review. The rest of the costs are shared by the infrastructure needed for the complementary (or existing) fossil fuel plant. If successful, the approach could slash the price of solar-thermal power by 30 to 50 percent, allowing it to compete with conventional sources of electricity.
GE is already pushing ahead with its own hybrid plant in Turkey. The facility will yoke together 450 megawatts of natural gas capacity with 50 megawatts of solar power and 22 megawatts of wind power. Led by GE, eSolar, and Turkish project developer MetCap Energy Investments, the plant will burn natural gas in a jet engine that spins a generator, while exhaust gases will be used to boil water, subsequently superheated by solar collectors, turning a steam turbine and another generator. GE says the plant’s efficiency will surge to 69 percent relative to the 30 to 50 percent achieved by conventional plants.
Turkey’s only the first. GE and eSolar have already signed an MOU to start exploring generation in other countries. Their next stop? China.