Okay, the the final enabling technology we talked about was hydrogen, which is a slightly kind of confusing one. Hydrogen is just an element, it exists mostly as H2 gas, the most common element in the universe, what's the significance for renewable energy? Well, you can make it, if you take renewable energy, electricity, and water, you can create hydrogen and oxygen and that hydrogen can act as essentially flexible storage. There's a lot of things you can do with hydrogen, one of the most promising is there are a number of sectors that don't lend themselves, it's not clear what the path forward is to decarbonize them, to fuel them with low carbon or zero carbon fuels, hydrogen can be that. So the vision is we have hydrogen, plus solar PV, plus wind, is it could be a zero carbon energy future, not requiring any fossil fuels. There's a lot of ways that could play out, here's one diagram of what that might look like where we have renewable electricity and a device called an electrolyser, which essentially takes water and electricity and creates hydrogen, which is all shown in blue here. That hydrogen can be stored, it could fuel fuel cell cars, it could heat buildings, it could be turned back into electricity, it could be turned into heat, so the idea is renewable electricity plus hydrogen could do everything. Well, that's an appealing vision but there are challenges. It's a compelling zero carbon vision of an energy future, it's gotten a newfound attention in recent few years because the necessary input to make this hydrogen economy work is low cost renewable electricity, but we now have that so that was a big barrier we've gotten over. But there are still remaining technical and cost barriers, the electrolysers that make a hydrogen, the what are called induced conversion devices that turn hydrogen into something useful like fuel cells and engines, they're available, they exist, but they in some cases are rather expensive, they're much too small for basically operating a global system. So there are issues, there's very little what we'll call hydrogen infrastructure, hydrogen pipelines, large hydrogen based power plants, and there's a bit of a chicken and egg where do we start? The hydrogen economy is something that's hard to do in little steps and you need to do it or not, so it's going to take some significant leaps and that means significant investment to make this happen. And it's likely that policy will need to drive that, so for example aggressive and firm zero carbon requirements for an entire area, well that could jumpstart a move to hydrogen economy. So it's a fascinating technological idea, but it's going to be difficult to make the hydrogen economy happen. So we then turn to what I call the emerging issues in renewable energy, we talked about seven, I'll very briefly review them now. The first is electrification, so what does it mean? If we switch an energy using device, a car, heating for a building, from fossil fuels to electricity, examples, classic ones are electric vehicles or electric heat pumps for buildings, why would you do this? Well, if the electricity comes from a renewable source, then those end uses, cars, heating for buildings, is essentially fueled by renewable energy. So the availability of low cost renewable electricity from wind and solar PV make this an appealing path to a renewable fueled future. There is a constraint that not all end-uses are easily fueled by electricity, for example airplanes, it's not clear how to make large airplanes run on electricity. So it's a good solution but not an entire solution or path to a low carbon future, and it can be summarized in this graphic that talked about the two major technologies for electrification, first being electric cars, second being heat pumps. And in this vision of a low carbon future had 49% of final energy coming from electricity from 20% now. And the other metric, this vision had 86% of electricity coming from renewables as opposed to 26% now. So electrification is a promising way to move some end-uses, some energy using devices to renewable energy. We then talked about distributed energy. So the concept here is the old, well, we rephrase that, the past way of thinking about electricity as a centralized system you generate, transmit, and distribute electricity to end users. But the distributed system is a different way to thinking about it where there can be distributed resources, ways to make electricity so the energy can flow in both directions in essence and the money can flow in both directions. And a principal component of distributed energy system, or so called distributed energy resources, which could be distributed generation, rooftop PV being the major one, could be batteries, so called behind the meter batteries, could be electric cars. So it's a concept, let me just summarize distributed energy because it can be a bit conceptual. That new technologies, notably low-cost smaller solar PV, rooftop PV for example, open up the electricity system to new business models, new participants, there's the idea of the prosumer, a producer and a consumer combined. Now the shift towards a more distributed electricity system is in the early stages, most electricity systems are still mostly centralized where most electricity comes from big power plants and is sent down the lines. But things are changing, we talked about early indicators. The debate over net metering, what's the value of electricity from rooftop solar PV system? We talked about community solar systems where a community could get together and build a small, could be 100 kW up to 1 megawatt rooftop, or not rooftop but brown based PV system. We talked about aggregators who combine distributed resources and essentially create a marketable product. Now, the future of distributed energy will be strongly influenced by regulatory and policy decisions, not just market forces. For example if a grid electricity system doesn't allow distributed energy to compete, obviously it's not going to happen, so this is very much a regulatory policy issue. We'll take a brief break here and then come back and talk in more detail about these emerging concepts.
