Energy efficiency: greening the bottom line

The economics of global energy demand can be counterintuitive. For example, a 2016 McKinsey report points out that although global population will probably increase to around 9.7 billion by 2050 and GDP per capita will likely double, the energy efficiency of this economic growth is expected to double as well. And that’s good news for the planet.

Continuing innovations in product, tool and process design that improve energy efficiency can translate into significant financial gains, with the added bonus of reducing environmental impact. In the retail sector, for example, a 20% cut in energy costs could represent the same bottom-line benefit as a 5% increase in sales. A few industries have been slow to grasp this new reality, but there is now a general consensus: energy efficiency is good for business. European efforts in this new innovation frontier range from expensive shoot-the-moon concepts to seat-of-the-pants solutions that leverage little more than elegant machine learning algorithms.


3D chip technology heats up

Cloud computing traffic continues to grow, gobbling up huge amounts of energy. EPFL’s EcoCloud is developing a range of solutions to control the environmental cost.

In 2014 Amazon Web Services, one of the leading providers of cloud computing, grew their server capacity per day by the same amount that they had amassed over the course of the entire preceding decade. Data centres are notorious energy hogs, currently consuming about 3% of the global electricity supply. In 2015, worldwide data centre electricity consumption was more than 400 terawatt hours, significantly more than the UK’s total electric consumption for the year.

The École Polytechnique Fédérale de Lausanne’s (EPFL) Centre for Sustainable Cloud Computing, EcoCloud, is looking into ways of dealing with this energy challenge, including exploring new generations of processors that can be combined with novel cooling, energy management and storage approaches to improve energy efficiency.

Much of a data centre’s efficiency depends on the efficiency of its processors. Although processing power has followed Moore’s law and doubled every two years since 1965, we’re now bumping up against fundamental physical limits – chips just can’t be made much smaller. One novel aspect of EcoCloud’s R&D is their integration of a very large three-dimensional “System on a Chip” (SoC). Chips are normally distributed two dimensionally across a system board. Stacking chips vertically as well as horizontally reduces the average distance between system components, making them up to 10 times faster and lowering power demand by a factor of four.

Unfortunately, this also generates more heat. Even for single chips, removing heat is a significant challenge. Up to 30% of older data centres’ total energy consumption is directed just to cooling. A 3D processor architecture would multiply this heat-removal headache by the number of layers in the system.

“The temperature of 3D stacked memory chips can be easily maintained with air cooling”, explains IBM Research expert Thomas Brunschwiler. “In contrast, processor cores have up to 10 times higher power density, so they get much hotter, especially if stacked in a 3D SoC. Dissipating this additional heat requires more advanced technologies.” EcoCloud researchers have responded by using cutting-edge micro-fabrication techniques to create microchannels that measure just 50-100 microns – about the width of a human hair. Liquid coolant circulating in these capillary-like microchannels between the layers would draw heat away from the processors.

“Eradicating the old large-scale refrigeration units from data centres could reduce energy consumption from 30% to around 5%, but liquid cooling would be even better, since it would allow centres to re-use the heat for residential heating in colder climates”, says Brunschwiler. EcoCloud’s two-phase cooling system, which uses refrigerants as a coolant instead of water, would enhance this even further, because the refrigerant forms bubbles that are super-efficient heat removers. “This system allows us to dissipate heat at an order of magnitude higher than previous capabilities”, explains EcoCloud founding director Babak Falsafi. Two-phase cooling also represents a safer approach than water cooling because the refrigerant is not electrically conductive.


Sky-high savings

OptiClimb is a novel tool that uses flight data and machine learning to allow pilots to chart the most fuel-efficient climb.

It’s not surprising that aircraft and engine manufacturers are constantly striving to improve the fuel efficiency of their products; after all, fuel represents 30% of an airline’s operational costs. What’s more unexpected is how a relatively simple but as yet untapped operational change could result in added savings.

During the part of the flight directly after take-off – known as the climb phase – aeroplanes simply maintain constant speed until they reach a set cruising altitude. When former pilot and aerospace engineer Pierre Jouniaux, now CEO of aviation solutions experts Safety Line, noticed that fuel performance during this flight phase varied by as much as 10% from plane to plane within the same aircraft model, he recognised an opportunity to optimise the process.

Safety Line joined forces with the French Institute for Research in Computer Science and Automation to produce OptiClimb, an optimisation tool that applies machine learning algorithms to real-time and historic data on the model, weight and age of each aircraft. Combined with weather data, OptiClimb creates an optimal climb profile for each flight, giving a very precise curve to the aircraft’s ascent. And because it doesn’t require any additional equipment, it would be easy to implement in existing aircraft.

OptiClimb is significant because flights produce more than 780 million tonnes of CO2 worldwide – that’s 2% of all human made carbon emissions – and the climb phase, in which engines are running at full power, is particularly fuel-intensive. In initial trials with Transavia France, a subsidiary of Air France, fuel consumption in the climb phase fell by an average of 5%. This would translate into a cost savings of €60–70,000 per year for a Boeing 747. “I’m surprised climb phase optimisation hasn’t been done before”, says Tim Coombs, an energy expert from the University of Cambridge. “If you’re an aircraft or engine manufacturer, you will want to design your product for maximum efficiency during highest loading points. Exploiting in-flight data is certainly a logical step.”


Vindskip’s novel hull design allows the merchant ship to travel at high speed propelled by a combination of wind power and liquefied natural gas.

Sustainable shipping

Terje Lade’s merchant-ship design works like an aeroplane’s wing, allowing wind power to drive it forward and cutting fuel consumption by a massive 60%.

Air travel is a popular target for environmental ire, but in reality, 90% of all goods are transported by sea. According to the International Maritime Organization, maritime transport is responsible for about 2.5% of global greenhouse gas emissions. In addition, sulphur dioxide emissions from oceangoing vessels are a huge contributor to ocean acidification. Although the shipping industry is very resistant to change, the multinational brands that use them to ship cargo are not, and in fact, for many of them sustainability is a priority. If cargo owners set emissions targets, then the shipping industry will have to adapt. That’s the logic behind Terje Lade’s effort to design a merchant ship that doesn’t rely on heavy fuel oil.

Inspired by the aerospace industry, Vindskip is designed to use the wind for propulsion. The vessel’s above-water hull is shaped like a symmetrical air foil that creates aerodynamic lift and pulls the ship forward. The below-water hull generates an equal and counterbalancing force that keeps the ship on course. This works in tandem with the “sail wind” (the combined force created when wind comes into contact with a moving boat) to create forward motion in the same way an airplane wing creates lift during take-off. The sail-like hull provides pull for more than 50% of the journey time, even when sailing across the wind.

Because the contribution of wind power to the ship’s propulsion will vary over time, cruise control will be used to balance liquefied natural gas propulsion, creating a dynamic dual propulsion system. “The basic problem with planes and ships is that you usually only have one propulsion system, meaning it can’t be optimised for all situations”, Cambridge University’s Tim Coombs observes.

Lade estimates their design would reduce fuel consumption by about 60%, which would result in around $2.4 million in cost savings per year compared with an average carrier. Emissions would drop by around 80%. In virtual tests travelling straight into a headwind, the vessel creates very little drag. The Tesla Model S has a drag coefficient of 0.24, the lowest in the automotive market. Vindskip’s drag coefficient, by comparison, is an astonishing 0.19.

The final piece of the puzzle, a weather routing module, would use computerised weighting of meteorological data to calculate the sailing route that would best exploit the available wind energy potential. Although many challenges lie ahead for the project, particularly around performance in real-life storm conditions, “real-time weather data systems have certainly been improving constantly and meteorological models are getting better all the time”, says Coombs.


Building concrete solutions

A new concrete additive speeds up the curing process and strengthens the final product. In some cases, it could even halve construction costs.

Approximately 17% of the energy used to produce building materials is used to make concrete, a production process that itself is responsible for at least 5% of global CO2 emissions. Yet in the two centuries that humans have been using this building material, its production has changed very little.

Making high quality concrete is more of an art than one might think. Because the raw materials used don’t necessarily perform the same way from batch to batch, a range of additives is usually blended in to ensure quality. Nanogence, a start-up launched at EPFL has developed an additive that works as a one-stop shop for high quality concrete production.

The ratio of water to cement is a key factor in concrete strength. Too much water can cause an excess of nanoscale pores, weakening the concrete. The Nanogence additive reduces porosity, lowering the likelihood that iron in the concrete will come into contact with moisture: “That contact is like a cancer in concrete and will eventually leadto failure of the structure”, says nanomaterials expert and Nanogence founder Abhishek Kumar.

The start-up has already generated interest in the market and is looking to start production in September. In projects in which concrete is the primary construction material, the additive allows constructors to build thinner walls that harden rapidly and last longer, which could reduce a project’s lifecycle energy demand (including site labour and repairs) by an estimated 20%–50%, according to Kumar. Improving efficiency by just a couple of percentage points could have a huge environmental impact, given the 30 billion tonnes of the material produced per year. However, as Maarten De Groote, head of research at the Buildings Performance Institute Europe explains, construction materials are only part of the equation: “If we’re talking about buildings that aren’t energy efficient, lowering the energy demand during the production process may be rather insignificant. Production energy becomes more relevant when we talk about modern, zero-energy buildings.”

“The trend in construction is starting to move towards prefabrication, which is dominated by lightweight materials”, adds De Groote. “It will be interesting to see how the concrete industry responds – will it develop assembled products, or will this trend start to fundamentally threaten the sector?”