Distributed energy generation from renewables may well become one of the greatest enablers of a sustainable future. But are the technologies available that allow the combination of ecological value with economic viability? That was the central theme of a panel discussion held at the 2016 Imec Technology Forum in Brussels. Triggered by questions from the audience, five energy experts from different angles gave their view on the technological innovations, on the price of sustainable energy generation and storage, and on the energy markets evolution.
Members of the panel, from left to right - panel moderator: Wim Sinke, Manager Program Development, ECN Solar Energy; Fanny Bardé, Project Manager Battery Team, Toyota Motor Europe; Raphael Schoentgen, Director Research and Technologies (CTO) and Member of the Executive Committee, ENGIE; Jef Poortmans, Scientific Director Photovoltaics, imec; and Ronnie Belmans, VP KU Leuven Energy Institute and Cofounder & CEO, EnergyVille.
A changing energy landscape
As we move toward a smart electricity grid, we see important shifts happening in the energy landscape. Jef Poortmans: “A major trend is the transition towards a decentralized generation of energy by renewables such as sun and wind. And this shift may well become one of the greatest enablers of a sustainable future.” In this landscape, “stakeholders are interested in having the largest possible panel of primary (green) energy sources, and look for the right balance between energy price and environment”, says Raphael Schoentgen. The panel of renewable energy sources is no longer limited to sun and wind, but is expanding with newer sources. “In recent years, also batteries have entered the field of renewables to deal with the intermittency of energy generation,” adds Wim Sinke.
In future smart energy systems, we will witness the integration of energy carriers other than electricity, such as heat. Ronny Belmans: “We will see different networks operating together: a heat network, an electricity network, a network based on green gas, and, potentially, hydrogen. All these energy vectors will bring services to people. And these services will become much more important than the price per kWh.” To clarify his vision, Ronny Belmans divides the energy consumers in large and small consumers. “For the large energy consumers (the large industrial sites), the price of energy will still remain key. They look at energy as a commodity and merely rely on gas and electricity. But for the small consumers (SMEs, residentials, office buildings...), besides price, services, comfort and well-being become increasingly important, regardless of where the energy comes from. And this calls for a different way of billing.”
Today, with energy sources such as sun and wind, the energy supply has become fatal and generation will drive the demand.
In this landscape of distributed renewable energy generation, we will need more flexibility at the consumer side. Ronny Belmans: “In the good old days, demand has driven energy generation. Today, with energy sources such as sun and wind, the energy supply has become fatal and generation will drive the demand. This calls for more flexibility at the consumer side. What we need is a time-flexible and shiftable demand, enabled by demand-side energy management schemes.” These schemes would allow, for example, to delay the operation start time of our dishwasher or drying cabinet in function of the available energy.
PV: An economically viable technology?
To come to a massive deployment of renewable energy, the technologies have to be economically viable. What about photovoltaics? Can we make it the cheapest form of energy generation? Jef Poortmans: “For the PV system, prices have come down according to a learning curve that has made PV electricity one of the cheapest forms of electricity generation – after wind and coal. PV model prices have reduced by a factor of 10 since 2005, and are expected to stabilize for the next two or three years.”
The combination of scaled production and rapid injection of innovation into production has led to massive price reductions. “All this was stimulated by the support mechanisms, especially in Europe”, adds Ronnie Belmans. Jef Poortmans: “If the same learning rate can be kept during the next 10-15 years, the further cost reduction of PV will make it eventually the cheapest electricity generation technology.”
Also the balance-of-system costs (which includes e.g., the inverter and the mounting structure) adds to the PV system price. Jef Poortmans: “This puts much more pressure than before on maximizing the performance (in terms of efficiency and energy yield) and the lifetime of the system, activities that are ongoing at imec. For example, we try to achieve a performance increase by combining the best of c-Si and thin-film PV technology.”
The cost of (electrochemical) storage
Battery storage will be an essential part of the future smart grid to balance supply and demand. Electrochemical storage by batteries is, however, still expensive and the levelized cost of the battery is at least three times higher than that of the PV system. Jef Poortmans is optimistic: “Recent updates on lithium-ion (Li-ion) battery cost – the mainstream battery technology for PV applications – tell us that the learning curve for these batteries is not so different from the solar learning curve.”
Both imec and Toyota see an all-solid state Li-ion battery as an alternative to the current liquid-electrolyte based Li-ion battery.
Storage is not only essential for realizing a sustainable energy system, it is a key enabler for sustainable mobility as well. The transformation of the transport system toward electrification of cars is also seen an enabler of a more sustainable society. Fanny Bardé: “The introduction of new electric vehicles will undoubtedly increase the demand for batteries. Today, we mainly use nickel-metal-hydride (Ni-MH) and Li-ion batteries in our eco cars. But they all have their issues. The Li-ion battery, for example, has a good power performance, but has a low energy density and suffers from performance degradation. Moreover, it contains liquid flammable electrolytes which endanger the safety of our vehicles.” Both imec and Toyota see an all-solid state Li-ion battery as an alternative to the current liquid-electrolyte based Li-ion battery.
Moderator Wim Sinke points towards the sustainability of the batteries as one of the major concerns of the ITF audience: “Sustainability may be inherent to PV, but how sustainable are batteries?” “It is possible to recycle parts of the battery. Several companies, such as Umicore in Belgium, have activities in battery recycling. Of course, depending on the materials used in the batteries, the business cases can differ,” says Fanny Bardé. “We can also think of giving batteries a second life in the world of energy”, adds Raphael Schoentgen. Jef Poortmans: “To do so, you have to be able to measure the state of health of the battery. In the context of EnergyVille, we are setting up activities in his field.”
Ronny Belmans: “In the future energy system, we will probably make use of alternative storage devices as well, such as power-to-gas which converts electrical power into a gaseous energy carrier. There will be a group of storage devices that each will serve different purposes. There will be not something as one silver bullet for storage.”
The Internet of Power and the Internet of Things
Jef Poortmans: “We often look at renewable energy as something which we will never have enough of. But given the evolution of solar and wind energy generation, I’m convinced that at certain moments, we will have more than enough energy. The main question is then to store the excess energy in the right storage device or form as to have it available at the right moment. Combined with the possibilities offered by the Internet of Things, we will be able to dispatch at every moment the right amount of energy to the right application or storage device.” Ronny Belmans agrees: “Enabling flexibility in demand has been a real challenge in the past. The reason why it will work now is that the Internet of Things will allow us to control the components in the grid to the lowest level.”
Written by Dr. Mieke Van Bavel, Scientific Editor at imec