By Gerhard Hope
The ambitious US$22 billion, carbon-neutral Masdar City development is to be scaled back dramatically. But it remains at the forefront of innovation, particularly in energy management.
Afshin Afshari is in charge of Masdar City’s
strategy for energy efficiency, demand side management (DSM) and the smart grid,
during the design and operational stages. This encompasses the optimisation of available
resources and the reduction of demand, which are equally important. Afshari gave
a presentation at the World Architecture Conference at Cityscape Global 2010 at
the Dubai International Conference and Exhibition Centre.
“I have not been involved too much with what Masdar is most known
for, namely PV and active generation systems. We are working on the more low-key
stuff, which is actually becoming more important as the project evolves.” Afshari
says DSM refers specifically to the efficiency of buildings, and “how we can save
energy at the source rather than produce expensive renewable electricity.”
Energy efficiency, of course, is a major pillar of sustainability.
“It is one of the most important issues, with direct implications for water use
and carbon reduction, for example,” says Afshari. Energy efficiency is critical
in terms of Masdar
City overall, which has a
built footprint of 2.8 km². “The sustainability targets of Masdar City
have not changed really since its origins, although the timeline has been extended.
We will now be approaching those targets in a more progressive fashion.”
The first building of Masdar City
to be up and running is the initial phase of the Masdar Institute campus, while
the Masdar Headquarters, which will also house Irena, is ongoing. Afshari highlights
some of the passive design features: “The streets are relatively narrow to enhance
shading; we use natural ventilation such as wind cones; we use an undercroft for
all the utilities and public transportation.”
Masdar City, and the Middle East
region in general, has specific climatic conditions that impact on the design. In
summer, the dry bulb temperature typically peaks at 45˚C. “The humidity, on the
other hand, is typically low during the day, but gets higher in the evening.” In
terms of solar radiation, “we rarely have any cloud in the summer. However, we do
have an effect which has become quite important in our designs, namely that, because
of the dust and haze, the direct normal radiation is actually quite low compared
to places like California, Nevada
and the south of Spain,
for example. What I am stating here was not always so obvious to Masdar City,
but now everyone is more or less convinced that trying to achieve a low-carbon city
without first optimising the demand side can be very expensive.
“You can build ‘business as usual’ buildings and then put in
as much PV as it takes to cover that demand, but then it is not a very sustainable
approach. So right now we are really focusing on demand-side reduction, which is
the buildings, the air-con systems and the infrastructure generally speaking, before
even starting to look at active renewable energy resources,” says Afshari.
“Typically, energy efficiency can be seen in different lights.
Of course, through efficient design of buildings and systems we can conserve energy,
which means basically that the profile of the load or demand for energy will come
down across the board. On the other hand, we can also do things after the commissioning
of the buildings and systems to further save energy, but also to do things that
are generally covered under the term of ‘demand side management’, namely load shifting
or peak shaving, which are not strictly speaking energy conservation, but are very
significant for the grid and for the utilities. If you can shave your peak demand,
it is usually welcomed by the grid,” says Afshari.
This implies “a lot of emphasis on design-stage efficiency, as
we want to conserve energy and reduce water use through standardisation and building
codes and appliance labels, for example. We will also try to reduce energy and water
consumption through optimal integration of utilities. When the buildings are operational,
what then? Then we rely on what is now known as smart grids or smart buildings to
continuously commission a building – you keep monitoring a building and its HVAC
systems, and intervene as soon as you detect a discrepancy or a loss of efficiency.
Continuous commissioning means you can make a building even more
efficient than it was originally due to new technology coming in. For us we will
be happy if we can keep the building as efficient as it was during the original
“We can also go further and actually connect the building management
system to the city-level operations centre, and then send tariff signals to the
buildings, and have intelligent devices or systems in the buildings that can react
to these tariff signals. This then achieves peak shaving and load shifting. As far
as buildings and systems are concerned, we have our own energy design guideline,
loosely based on ASHRAE 90.1, but which is about 50% more efficient than that. We
are now actually at version three of that guideline, and it is mandatory throughout
the city. It is a typical building energy code, but it has some atypical features
such as allowing for energy-recovery systems.
“We have also emphasised efficient lighting, appliances and fixtures
such as programmable thermostats; we enforce advanced daylighting controls, lux
sensors and dimmers; demand-controlled ventilation is mandatory in our buildings,
with some exceptions; chilled beam is really the preferred method of cooling in
Masdar City,” says Afshari. “We are also testing some new advanced systems, which
are pilots basically.” This includes ‘geothermal exchange’, which basically means
using the structural piles to ‘exchange’ energy with the soil, together with radiant
cooling. “We are not yet sure how they will work and be received by the occupants,
so these are not yet prescribed in any way.”
Afshari says the smart grid “is still a notion only at Masdar City
because we have only one building, so obviously we cannot really boast of having
any kind of smart grid yet, but we are seriously thinking about it. If you look
at design-stage energy efficiency, there is a point where you do not want to go
any further from a cost-effectiveness point of view. If you look at the lifecycle
of your building, it is not worth having 35 cm of insulation in your walls as the
money could be better spent elsewhere.
“We have become more sensitive to these issues of lifecycle cost
analysis, and where to put the money. We do not want to go too much into demand
side matters, as at some point we want to stop working on the efficiency of the
building systems and start looking at how we can increase the efficiency during
the operational stage,” says Afshari.
Dynamic peak load management, or demand response, “means we have
established a connection between the demand and supply side. If the supply side
hits a peak, for instance, we issue a tariff signal, and the demand system is intelligent
enough to interpret that signal and then shed some load.” ‘Smart’ appliances will
be able to go to reduced load or maybe even actually stop until the peak has passed.
“The other thing we are thinking of is overriding thermostats
for a short period without really affecting the comfort level, which will have a
huge impact on the actual load, or even changing the lux level slightly. We can
do this with sophisticated IT or a smart grid.”
A smart grid is “basically a bi-directional grid, meaning you
can have distributed generation throughout the city, PV and other types of generation,
and these can all inject power back into the grid. Not any grid can accept this
type of behaviour. Right now the Abu Dhabi
grid is not really right, but the Masdar grid will be ‘smart grid ready’ in that
it can work in a bi-directional fashion,” says Afshari.
“The other characteristic of a smart grid is you are going to
superimpose an information network, so again you will again have bi-directional
information exchange with all your points of demand and supply. Why we have this
insistence on demand response is that, as our buildings and cooling systems become
more efficient, what we have realised is that the relative share of plug load suddenly
becomes much higher than in a conventional building.
“In a conventional building in Abu Dhabi, cooling will be at least 50% to 60%
of your electricity consumption. In Masdar
City, cooling will be 30%,
which means that, on a proportional basis, other electricity consumption like lighting
suddenly becomes important, as your peak will mostly comprise these things rather
than cooling. That is why we want to have devices, appliances, thermostats that
are reactive to tariff signals, so we can control this. The plug load is notoriously
difficult to control. It is usually under the direct control of the end user; you
cannot tell people to turn their appliances off. We want to have some kind of intelligence
inserted in-between the grid and the end user, or inside the appliance itself, to
give us the ability to control it. In conjunction with GE, we are testing some prototype
appliances that have wireless communication built in and automatically adjust their
operational mode according to the signal they receive from the grid.”
Afshari says Masdar
City is also looking at solar
and geothermal cooling. “This is basically the idea of using solar heat to run some
absorption chillers. The same chillers can be run with geothermal thermal heat.
Two geothermal wells have been drilled to 2.5 km, and we have access now to an aquifer
which is at 100˚C. Using this aquifer, we could produce several thousand refrigeration
tons of cooling day and night, as this is a 24/7 resource. Whereas solar energy
is only available during the day, geothermal energy is almost unlimited. Even if
you draw energy from it for years and years, it will not lose its temperature. So
the idea is for one of the wells to be a production well. We will pump the water
up, extract the heat with a heat exchanger and then pump it back so there will be
no environmental impact,” says Afshari.
“We want to optimise the system so basically nothing is lost
in the process. Even the TSE may have some energy; the sewerage water that comes
from the buildings is at 28˚C to 30˚C throughout the year. This can be a huge heat
sink for rejecting the heat of the chillers, so instead of using cooling towers,
we can reject the heat of the chillers to this stream and heat it up, which actually
helps the treatment process that comes later.”
Afshari says it is the cost of efficiency “that has now become
more and more important at Masdar
City.” A critical concept
in this regard is levelised avoided electricity cost (LAC). “This is when you are
using demand side features like insulation and improved efficiencies for the smart
grid to save energy. You quantify that cost through LAC, which means how much these
measures cost us to avoid 1 kWh of electricity, and then we can compare these and
see which is more cost-effective.”
Afshari says “the most cost-effective thing you can do is sustainable
design, and maybe working a bit on the cooling systems to make them more efficient.
This will cost you, in the lifecycle definition of the term, about 10 to 15 US cents
per kWh electricity saved. It is still higher than the grid price of electricity,
but of course that is a different debate.
“The next best thing to do is to have smart buildings – IT systems,
smart grid – to further reduce energy consumption. That will be a little bit more
expensive than working on the design or the cooling system of the buildings, and
will cost you 15 to 20 cents per kWh saved. Only then do we come to active renewable
energy. Once we have done all these demand side features, then the next best thing
is geothermal. The next best thing is solar cooling, and then the most expensive
feature of this whole energy efficiency scheme is PV. From a cost-effectiveness
point of view, you work on your PV capacity last.
“Our ultimate goal is that the people who come to Masdar pay
per square metre the same for their utilites as they would in Abu Dhabi. Of course, our cost of generation is
much higher, but then on the demand side we are much more efficient, as our buildings
use much less energy. So we are still not competitive in that regard, but it will
happen within a few years according to our projections.
What is the payback on the initial investment in building efficiency
as a function of the price of electricity? “Right now the payback is quite high,
but in the future the electricity price in Masdar City
will drop. So initially the cost will be high, and the payback will be high, but
when the contractor learns how to build an airtight building, there is really no
cost associated with quality. It is really just the tricks of the trade. So that
is why the learning curve is so important in the construction industry. Also the
supply chain needs to adjust itself to the new requirements of these energy-efficient
buildings. So whatever Abu Dhabi
is going to face in the coming years, Masdar is going to face the same things, maybe
with a higher level of intensity,” concludes Afshari.
In the quest for hi-tech and smart buildings, something very often ignored in modern day design and construction is the wisdom of the ancients. It would do no harm for designers to attempt to understand how people managed 50/100/200 years ago, not only in the immediate region of UAE, Oman and Saudi Arabia but also in extended regions, particularly the more ancient cultures like Persia, Egypt and India. Agreed, they would not contribute any precedents to electrical load management but there are definitely a lot of simple techniques (ventilation and extraction of air, distribution of water, etc., among others) that can be integrated or adapted to modern building design, which in turn can contribute to significant gains from the perspective of demand management.
NASA spent millions of Dollars to develop a pen that works in space, while the Russians simply used a pencil.
The same applies today in our quest for Renewable energy and energy efficient buildings, we simply overlook the obvious that is staring us in the face.
Are you referring to improved building operation & equipment setup (i.e. Building Optimization or Recommissioning)?