In my last two articles about smarter destinations, we focused on energy efficiency and the smart destinations of Boston, Abu Dhabi and India. Back home in Washington, D.C., I recently met a renewable energy guru, Scott Sklar, a George Washington University professor and longtime advisor to industry and governments around the world on maximizing the benefits of renewable energy, especially solar power. He shared some of his wisdom and tips with me for helping to create a smarter hotel, thus helping to create a smarter tourism industry and smarter destinations.
Scott Wayne: For many years, we have heard about the cost savings of renewable energy for commercial buildings and residences. However, you once wrote that renewables have limited value unless building loads are reduced significantly. So, is renewable energy not quite the solution that we think it is?
Scott Sklar: The economic rule-of-thumb is that it is always less expensive to utilize energy efficiency than energy generation, and by saving the maximum energy, makes any on-site generation easier to do and more economical. So LED lighting, efficient appliances, smart energy controls, solar pool heating and water heating are all examples of such options.
SW: With on-site generation, what are some of the renewable energy-generation solutions that you recommend for commercial buildings, including especially hotels and restaurants?
SS: Solar, waste heat, small wind and geothermal and direct exchange heat pumps are actually some of the most efficient and cost-effective renewable energy solutions available. But at the same time a building adopts solar power, for instance, while the energy load is reduced, often from 25 to 35 percent, it is also important to continue adopting other energy-efficiency measures. It is possible and, frankly, highly desirable and achievable to aim for net zero and zero energy buildings.
SW: What are net zero and zero energy buildings?
SS: A net zero building is one that produces most of the energy it needs, although may sometimes need to fall back on the grid when renewable energy is unavailable, such as on a cloudy day. A zero energy building is a self-powered building that is fully self-contained and off the grid.
SW: What are some examples of net zero and zero energy hotels?
SS: One of the most prominent examples is Hilton’s LightStay, an energy-efficiency program that has reduced energy consumption at thousands of Hilton hotels around the world. They have also succeeded in getting more than 4,000 hotels certified for ISO 50001 for energy management. Another example comes from Vienna - the Boutiquehotel Stadthalle, which has used a Siemens building-automation system to make it into the world’s first net zero energy city hotel.
SW: What are the top energy-efficiency measures that you would recommend to hotels and restaurants?
SS: Well, there are many ways that a hotel could reduce its energy costs and more efficiently use and store energy. One obvious way, which is increasingly being optimized in construction today, is through better building insulation and super-insulated windows.
SW: What insulation materials, window types and equipment types do you recommend for hotels and restaurants?
SS: There are lots of insulation materials on the market that could lead to effective R-38 in walls and R-50 in ceilings and roofs. Windows should minimally be double-pane, argon-filled, with low-e coatings. Office equipment and kitchen appliances should be EnergyStar (if U.S.-made), and lighting should be predominantly LEDs.
SW: For those not in tune with construction terminology, by R-38 and R-50, you are referring to the R-values that are used to describe how resistant materials are to heat variations, right?
SS: Exactly. The higher the R number, the greater the insulating effectiveness. R-38 and R-50 are considered standards. With better insulation, less energy is needed to cool or heat a building. Windows are also important in terms of insulation with electrochromic or what we often refer to as smart glass. Without getting too deep into the technicalities, this type of window is multilayered and coated with a thin layer of see-though materials, and electrochromic materials have see-through that darkens the window when a bit of voltage is applied, thus keeping a room cooler.
SW: Couldn’t a building also reflect away some of the heat through the types of paints used?
SS: Yes, absolutely. Actually, by using white roofs, reflective paints and a type of insulation known as a low-emissivity thermal barrier, summer heat gain can be reduced by as much as 30 percent. That’s quite a lot of heat diverted away from the building, for low cost and fast paybacks.
SW: Inside a building, what are some of the measures that a hotel or restaurant could take?
SS: Another obvious, but sometimes overlooked, solution is to increase solar and natural lighting. And when you do need lighting, LEDs are, of course, increasingly the standard for many commercial buildings now. Related to this also are motion-detector light sensors for hotel hallways. Solar daylighting uses lenses and concentrators to bring in full-spectrum light without the heat. This technology zeroes out electricity for lighting, even on on the cloudiest days.
SW: What about air conditioning and heating systems? These are huge sources of energy consumption.
SS: Yes, for commercial buildings, including especially hotels, which are occupied 24 hours a day, the HVAC systems are one of the biggest users of electricity. Achieving efficiencies in these systems can go a long way to helping a hotel or really any commercial building reduce their energy consumption and costs. Advanced HVAC systems that can be integrated into traditional HVAC systems like ductless heat pumps and geo-exchange heat pumps can reduce electricity use greater than 50 percent.
SW: Wouldn’t this require major changes in a building?
SS: Sometimes that is the case, especially if inefficient duct systems are replaced with more efficient and, frankly, healthier ductless or radiant systems that are fed by geothermal or solar thermal or even cogeneration. Though in many cases, installers can just slide the heat transfer tubes within the same ducts.
SW: What about solar water heaters? I’ve seen many hotels around the world using these.
SS: But a simpler change is to use solar water heaters to reduce the high-energy use of heating water for kitchens and bathrooms. Solar water heaters can help reduce costs. Some hotels, especially in hot countries, are using these effectively. And in some cases, higher-temperature solar thermal systems can drive absorption air conditioners.
SW: Hotels and restaurants require substantial energy-consuming equipment such as washing machines and dishwashers. What do you advise in regards to these choices?
SS: From my experience working with hundreds of buildings in the U.S. and around the world, many really fall short in this area when it can be one of the easiest and most cost-effective solutions to apply. Energy Star appliances and other machines really do save energy and operate more efficiently. Either hotels should opt for the most efficient choices from the earliest stage or replace aging inefficient equipment. The paybacks will happen sometimes in as few as three years.
SW: One of the most-heard criticisms of renewable energy is that when it is unavailable, for example solar at night, the building has to go back on the grid and the alternating between solar and grid can actually result in more energy consumption on average. We hear a lot about battery storage options improving. How do you see these applying to buildings?
SS: Increasingly, we are seeing situations where each sub-circuit breaker panel in a building is fitted with its own dedicated smart battery pack. The batteries can store excess energy generated during the day and then used for night time loads. Battery use also obviates the need to use noisy, polluting back-up diesel generators. The result is also a much healthier building and a much more reliable back-up power solution. Battery banks have reduced 50 percent in costs, are standardized, modular and web-enabled, and also provide very high electric power quality (surge, sag and transient protection). And healthy and reliable buildings are a great selling point for hotels, restaurants and really any commercial building.
Note: The interviewer’s tourism development consultancy, SW Associates, and Scott Sklar’s Stella Group have teamed up to assist destinations, their public administrations and businesses with developing and implementing renewable energy strategies. If you wish to obtain further information, please contact us at [email protected] and [email protected].