La industria y su localización en la ciudad de Barcelona

This theme is W3, why should the transition take place. In general, four discussions emerged from the interviews. The first was about centralised generation and distribution verses distributed generation. Secondly, even if distributed generation has advantages over a centralised topology, why should the electricity system within the built environment be DC voltage, why can it not be AC? Thirdly, what is the role of the utility company in the

154 proliferation of distributed DC systems? Fourthly what was the meaning and importance to the interviewees of ‘energy security’ and ‘energy independence’? These discussions were deliberately part of the questions asked to the interviewees, as they had emerged from the literature review in chapter 2. This theme seeks to explore these discussions surrounding this research through the eyes of the interviewees.

Centralised or distributed generation

The components and topology of both the centralised and distributed, (islanded or off-grid) electricity systems are shown above in Section 2.2 above. There are two distributed topologies, one where the building is not connected to any other building and has the capacity to provide its own electricity. The second is where the building is connected to other buildings and is perhaps reliant on electricity generated at a different location. Small or localised grids are still classified as distributed as they are not connected to a large national grid. However, this research still classifies grids with a single generation system even if they are not connected to a national grid as centralised systems as there is only one point of connectivity to many points of consumption.

Some of the interviewees were uncomfortable with a completely off grid electrical system, i.e. one that was completely independent from their neighbours. They wanted a distributed generation system, as it provides system resilience and security of supply against centralised power cuts, yet at the same time they wanted their houses to be interconnected to their neighbours so that they could trade energy and that their neighbour could act as a backup system if their own system failed. As interviewee 18 put it;

“...so if there is any point of failure in your own house, if you are not connected to anyone else’s house, then you’re off grid for electricity. As a consumer I might feel that I’m not quite sure why I would go to that system.”

Interviewees 10, 12, 17 and 18 were worried that if many distributed intermittent generators are connected to a grid system it would be harder to balance the centralised system. There is a common theme within the renewables discussion (Lamont, 2008; Parliamentary Office of Science and Technology, 2014b; Skea et al., 2008), that system security becomes harder to maintain when too many intermittent renewables are connected to the centralised system. Interviewee 18 provided a solution whereby local generation will be connected to a local grid

155 thus forming microgrids. Each microgrid can themselves be as far as possible self-balancing, thus reducing the interconnecting points between the centralised grid and the renewable generation thus reducing the present pressure on the grid from intermittent generation.

Interviewee 19 pointed out that while there is a trend towards a decentralised system using PVs, he still sees the future need for a national transmission grid for “bulk power” and for the

imports of electricity from the continent. The prevailing energy policy is about smart grids, smart meters, the ‘internet of things’ and demand side management (Ofgem, 2010; Parliamentary Office of Science and Technology, 2014a; Strbac, 2008), which all provide inbuilt lock-in mechanisms for the prevailing centralised system.

The policy in 2015 favours centralised midscale PVs in solar parks and wind turbines in offshore wind farms, over local rooftop generation (Department of Energy and Climate Change, 2014b). This means that renewable generation is seen within the context of the centralised system, which itself requires capital investments to modernise, thus reinforcing the centralised topology of the electricity system. Therefore, proposing a completely distributed electricity system is counterintuitive to the prevailing policy. However, some of the interviewees still see the advantages provided by DC voltage systems as being a strong argument for distributed generation. As interviewee 18 stated “If you are auto consuming and not connected to the grid, then you would not be paying any grid charges, which obviously

take up about 20% of the bill so there are advantages to doing this.” Counter to this is, if the

homeowner was able to claim a feed-in tariff (FIT) this will now be lost, however given that cutbacks in the FITs by the Government (in 2015) this loss may not be as significant as in previous years.

‘If it isn’t broken don’t fix it’ is a maxim that encapsulates people’s locked-in attitude. In interview 12 the concept of the vulnerability of the national grid to cyber or terrorist attack came up. The incident in the 1970s where alleged IRA terrorists planned to destroy the grid supplying London (Nye, 2013), was used as a reason to show the vulnerability of the centralised system. Interviewee 12 stated that ‘I don’t think that you can say the national grid

type system is actually that vulnerable, actually historically it has worked very well that is

why there is not the kind of big political drive’. The question for 21st _{century energy policy}

156

should energy policy only react to external landscape pressures once they are in

existence, i.e. should energy policy be proactive or reactive?

For those interviewees who saw the office as being the more appropriate place for DC voltage, there was still concern that there would not be enough energy generated to meet all the needs of a modern large office environment. As interviewee 10 put it “...but there are substantial holes in this argument related to power supply. How do you generate enough energy for the office for example, how do you supply it? How do you balance supply and

demand each second, so that productivity is not lost?” Therefore, they stated that there would

always be a need for a centralised system. Similarly, given that the UK has one of the most inefficient housing stocks in Europe (Guertler et al., 2015) there were concerns about how such houses would meet peak winter loads, (particularly for heating) if they were off grid (interviewees 12 and 18)

The idea to use DC voltage was new to most of the interviewees. Therefore, even those in favour of rooftop solar, saw PV systems in the context of an AC consumption system. In fact, none of the trade associations and business promoting the use of solar generation, including Tesla and Moixa, while promoting DC generation with storage still don’t see DC voltage replacing AC in the home.

Therefore,about decentralising the UK electrical system, “I think it is good to champion

it, we need more narrative, more conversation and more evidence about how that would work” (Interviewee 11).

AC verses DC systems

Note: this part of the discussion is the opinion of the engineers and therefore focuses mostly on technical issues. As stated, the most fundamental question about this research is if there exists a fully functioning AC electrical system why would one want to have DC systems? A prerequisite to this discussion is to understand that DC technology, for a fully functioning DC voltage house, does not yet exist. Therefore, all the interviewees who discussed their opinions about AC verses DC were from the viewpoint of the centralised AC system. In their discussions they were trying to highlight either barriers or enablers to DC from within their

157 AC mind frame, therefore many of their opinions have to be taken as a snapshot as is in 2015. In the future as the AC and DC technology changes, so will opinions.

The first question to answer when deciding on AC or DC is: what are the efficiencies of the components within the electricity system and therefore the losses? All engineers know that AC technology loses electrical energy through heat. The question is, is this inherent to AC and can, or are there, new technological steps being taken to reduce these losses. From Calwell (2002) a cheaply made AC transformer could lose more energy in transformation than is absorbed into the battery on charge, i.e. for every 100 Watts of energy inputted into the transformer it was delivering 45 Watts to the battery. However, interviewee 10 stated that using the latest ‘Switch Mode’ power supplies it is possible to have a 96-97% efficient transformation and that “definitely in 2015 a good quality switch mode power supply is as

efficient as an AC to DC transformer”. Interviewee 20 stated that with technological advances

in AC design, the marginal difference between AC and DC is small enough to negate any thoughts of a DC ring main in the home. Interviewee 19 maintained that: one, many of these AC transformers are still manufactured with a minimum specification and two, these efficiency values like 99% are only valid at full load. However, the inverter, for example, in rooftop PV systems will rarely be operating at full capacity, as solar is an intermittent energy source therefore the actual operating efficiency will be much lower than the quoted 99%. As interviewee 19 said:

“What I do know is that inverters and switch mode power supplies are being used on solar panels, the cheapest ones passed the standards at full output in terms of waveform quality, but at part load where most of them operate at most of the time, they have horrible wave forms and the better design, which keeps its waveform quality across the range is more expensive and isn’t adopted.”

Rooftop PV systems always need a ‘maximum point power tracker’ regardless of whether the system is AC or DC. Interviewee 5, who is an engineer, pointed out that since some sort of DC to DC conversion and battery management systems will be needed, there is only a marginal cost difference between the DC and AC technology that in his opinion makes staying with AC for transmission within the home more sensible. This same point was brought out by other interviewees who saw the need for DC to DC transformation and therefore introducing a new set of losses similar to the AC to DC transformation: as

158 interviewee 6 stated “...if you’re not careful you are swapping one set of inefficiencies with

another which doesn’t move the game further forward.”. Interviewee 5 said: “AC to DC

power supplies are becoming increasingly efficient. The cost benefit analysis just makes it not worthwhile that is much more likely to kill DC, than a lack of research”. However, DC is

being used in the IT environment, that includes the usage of 380 V DC systems by the Met Office, 24 V DC systems at The University of Bath library, the Bristol SoLa project (interviewee 8) and data centres across the world use 48V and 380V DC (EMerge Alliance, 2013). Therefore, further research is needed to settle this efficiency and energy

consumption discussion.

Interviewees 8 and 9 had installed, in a library and 30 houses, a DC system for IT and lighting and low powered loads. Both these systems were powered off the AC mains and the AC system in the houses was still in use for the higher-powered loads. However, they were able to measure significant advantages with the use of DC voltage even though only part of the overall electricity supply was DC. Computers are electronic and therefore require DC voltage to operate. Each has a universal power supply (UPS) that internally converts the AC voltage to the different DC voltages required by different parts of the computer. The characteristics of AC electricity are that its voltage output is sinusoidal in form and is at a frequency of 50 Hertz. There is a phenomenon called ‘harmonic distortion’. This is similar to water waves that hit the wall and bounce back, some cancel each other out while some combine to create larger waves. Similarly, in AC systems the electric ‘waves’ create harmonic distortion that is injected back into the electricity supply and reduce the power factor of the circuit: “…total

harmonic distortion is excessive on the AC network” (Interviewee 9). To stop these distorted

‘waves’ destroying the electricity circuits, large filters are used to block them. As well as this, sometimes to lessen the problem, the size of the input AC system (wiring etc.) is made bigger to counter the harmonic distortion. Both these problems add costs to the customer. However, what they found when they converted the library computers to operate with the DC voltage supply was, that the 3rd, 5th and 7th harmonics were much reduced. This therefore saved both energy and money on a large input filter.

As stated, AC power supplies generate heat. Therefore, when they were removed from the library computers, they found that there was less usage of the air-conditioning system

159 throughout the year. Even though on cold winter days they had to turn the heating up, both interviewees reported that overall energy consumption went down. Another advantage of the DC system was that the noise generated by the fans within the UPSs was eliminated, this made the IT environment quieter and therefore more attractive to the students. The IT environment was on a time-of-day tariff, which means that the charge per unit of electricity is higher at peak times of the day and lower in off-peak times. This system used battery backup to provide security of supply in times of power cuts and to offset its use of electricity from peak to off peak times. By charging the battery bank in off-peak times and using the stored electricity at peak times they were able to save the difference in the on and off peak tariff. This is known as load shifting (Caves et al., 1989). In both the IT project and the houses, it was reported that the overall electricity bill went down. The cost benefit analysis, including the payback period for the DC system is not known. Interviewee 15 discussed the advantages and disadvantages to using AC or DC motors. In his final analysis he stated it would depend on the design and size of motor used, sometimes it is better to use AC and sometimes DC.

Therefore, there is a need to undertake more research in comparing AC and DC systems.

Given that the interviewees see things through the eyes of the present AC system, none of the interviewees could envision a UK without the national grid system and AC voltage. Where they saw DC was as local generation with all its advantages and for only powering very low powered appliances and LED lights. They saw a house with both AC and DC ring mains, each with a different type of plug, as existed within the UK and France up to the 1980s. The AC would be for devices that required more than 1KW. Interviewee 6 compared this to the USA system that supplies each property with a 2 or 3-phase supply and appliances have either a two pronged or three-pronged plug depending on the voltage required. These were part of the scenario analysis for the DC house highlighted in previous research (Kinn, 2011a, Chapter 5). Therefore,there is the need to do innovative research that will form the foundation

160

The role of the utility company

One of the discussions around the usage of distributed DC is how will this affect the utilities and what will be their role in the future? The UK electrical system is broken up into different regional and market sectors each one feeding into the other. However, there are some of the large companies that are vertically integrated, “so they are both the generation owners and the

retailers, now those are separate arms and have Chinese wall ring fenced organisations”

(interviewee 19). Nevertheless, as a company they control the whole vertical process from generation to selling to customers. Within this discussion PV or wind were looked at from the point of their intermittence and how that affects the national grid, i.e. how will it fit into the incumbent centralised system. There were those who saw the large national utilities becoming defunct or changing their whole business model, while others who could only envision a centralised system saw the status quo remaining.

Many of the interviewees saw the utilities as being a strong barrier to DC proliferation. It was explained that through their ‘marketing’ and lobbying efforts they convince the policy makers to not only keep the status quo, but also to introduce mechanisms into the market that help them keep their hold on the market. As interviewee 6 put it “Basically energy companies are rewarded for selling people more electricity, therefore it is not in their interests to reduce consumption”. Others saw the utilities shrinking as centralised generators of electricity and

moving to the ‘energy service company’ model as rooftop PV proliferates. The new types of services utilities could provide include: data management, selling a level of ‘thermal comfort’, owning the hardware, as in ‘rent-a-roof’ schemes and providing health care and elderly care services and consultative advice. It was pointed out that one must look to Germany to see how the national utility companies are transitioning their business models.

According to interviewee 18, the European and American utilities have had their credit ratings reduced in recent years (2015) as they are seen to be vulnerable to a trend towards distributed generation.

“I think the existing utility business model is going to become defunct quite quickly, you can already see that the credit rating of the European-based utilities companies have already been massively slashed, the entire US utility sector credit rating has been slashed quite recently...”

161 Richter (2013) has warned that if the German utilities do not invest in customer-side renewables they will continue to lose market share. Furthermore, he found that: “A surprising result is that most utility managers do not see renewable energy as a threat to their current business model, although utilities have already lost significant market share to investors from

outside the industry.” This mind frame is definitely a barrier to be overcome, if the utilities

are going to play any part in DC proliferation.