Across the Atlantic Ocean, governments and businesses are taking big steps toward renewable energy. Their transition could provide lessons for Kentucky.This is the last in a five-part series. Read the others here.In Germany, the three hotel rooms I stay in all have one thing in common. I open the door with a key card and walk into a dark room. To turn the lights on, I have to insert the key card into a slot on the wall.This means it’s impossible to leave the lights on when I leave the room — unless I want to get locked out. And it illustrates another pillar of the German Energiewende, or energy transition: efficiency.Energy efficiency is often referred to as low-hanging fruit. Using less energy — either by changing a behavior or installing things like insulation to cut waste — saves money and reduces pollution. In Kentucky, decades of increased energy use started trending down recently; in 2014, the average Kentuckian used 3.6 percent less electricity than he did in 2005.Using more renewables and reducing the amount of coal it’s burning aside, for Germany to meet its ambitious energy goals, it will also have to use a lot less energy. By 2050, the Energiewende sets out a goal of the country using half the energy it did in 2008. That will help meet the steep reductions in carbon dioxide emissions also required under the plan.Germans are already doing this. While the country’s per capita energy use is in no way the smallest in Europe, on average, Germans use about half the energy Americans do.Take the newest area of Hamburg: HafenCity.HafenCity is a not-yet-finished inner city development in Hamburg. The city took industrial land on the waterfront and is slowly reclaiming it. A public-private partnership is turning the land into several mixed-use residential and commercial neighborhoods just a 10-minute walk from Hamburg’s center. There are terraced public spaces overlooking the River Elbe, architecturally interesting buildings, including a brand-new concert hall, and shopping areas.[aesop_quote type="pull" align="right" quote="“It’s also the choice one can take at home. The choice one can take when switching off the light in a room that you are not in. When choosing a car which is not a gas guzzler. When deciding how hot you want to have it in your room in the winter.”" cite="Camilla Bausch"] Showing off one of the area’s newest green spaces, which is complete with a gaggle of German preschoolers getting excited about the nature that surrounds, HafenCity spokeswoman Susanne Bühler said the development is the definition of sustainable. It’s next to the city’s core, not sprawling into farmland on the outskirts. There’s a lot of green space, energy-efficient buildings and a sustainable recycled heating system.“I think if you have the chance to create quite a new area of a city which is so centralized, it is a chance to be innovative and to create sustainable buildings or sustainable constructions, or to think about possibilities of sustainable mobility, for example,” Bühler said. “And I would say we have a certain responsibility to be ambitious in this way.”And, of course, there’s the public transportation. Bühler leads me into one of HafenCity’s two brand-new U-Bahn, or subway, stations.“And the underground system, for sure, it is crucial for a development like HafenCity,” she said.Even the subway station is aesthetically pleasing, with large glowing green cubes hanging from the ceiling. There isn’t much traffic here yet, because the area is still under construction.HafenCity is innovative, but on the whole, Germany may have difficulty meeting the efficiency goals laid out in the Energiewende.In 2014, the country was using 8.7 percent less energy than it did in 2008. The short-term goal — for 2020 — is a 20 percent reduction.This is a problem; if the Germans can’t cut energy usage, it will be even harder to reach other goals like steep reductions in carbon dioxide emissions.Camilla Bausch of the German think tank Ecologic Institute said cutting individual energy usage is a more personal part of the Energiewende and will require widespread public buy-in.“It’s also the choice one can take at home,” she said. “The choice one can take when switching off the light in a room that you are not in. When choosing a car which is not a gas guzzler. When deciding how hot you want to have it in your room in the winter.”Some are skeptical. Guido Steffen is a spokesman for energy company RWE. He said he thinks Germans agree with the Energiewende in theory, but actually changing their behavior will be more difficult.[aesop_quote type="pull" align="right" quote="From Bundestag to Bluegrass is a five-part web and radio series examining Germany’s energy transition—and its potential lessons for Kentucky."]“So the Germans, they love recycling. In my home I have four garbage containers,” he said. “And Germans love that. And it works perfectly. But on the other hand, Germans love to consume. And they also say yes, we have to protect the climate. But no German will then sell his big Beamer to buy a small Toyota that produces half of the carbon dioxide.”Still, Bausch is hopeful.“Can Germany meet the targets?” she said. “I would say yes, but it has to implement the right instruments and take the right choices to do so.”This story was originally published on December 11, 2015.Photo credit: Erica PetersonThis series was supported in part by a grant from the Heinrich Böll Foundation