Water scarcity is a global challenge. A growing population, which is expected to increase from around 7.5 billion today to nearly 10 billion by 2050, according to a forecast by the United Nations (UN), is putting growing pressure on a finite supply of water. Global demand for water is expected to increase by 55% by 2050. Within the next decade, two thirds of the world’s population could be living in “water stressed” countries.

Regions affected won’t be limited to arid regions, such as Sub-Saharan Africa and the Gulf States in the Middle East. The strain on the water supply will be particularly acute in cities. The number of people living in cities is expected to rise from about 55% in 2016 to 66% by 2050, according to the UN. This population increase could cause major disruption to cities if suitable water technologies are not in place to serve demand. In the United Arab Emirates (UAE) − one of the most arid parts of the world with little rainfall − groundwater levels are low and in steady decline. What groundwater there is, is typically very salty (saline). For the UAE and about 150 other countries on or near the coastline, with minimal rainfall and little freshwater, there is currently little choice but to rely on desalination technology. Desalination involves pumping and processing sea water to remove excess salt and other minerals to obtain fresh water suitable for human consumption or irrigation. The technology is already widely used, with more than 300 million people relying on desalinated water for some or all their daily needs, according to the International Desalination Association.

Desalination has been vital for the UAE’s rapid growth and development. The country gets 96% of its domestic water through desalination. Two of the big disadvantages of desalination technology are closely linked to each other – firstly, desalination is energy intensive, and secondly these energy needs have historically been met by fossil fuels. In the UAE, seawater desalination needs about 10 times more energy than surface, freshwater production. In the Gulf region alone, desalination plants account for 0.2% of the entire world’s electricity consumption. However, these challenges are now being addressed and desalination technology is expected to play a key role in serving growing demand for fresh water. Energy accounts for around 70% of the cost of desalination and is typically derived from fossil fuels. By reducing energy intensity and running desalination plants on renewable energy, operators could both reduce their operating costs and minimise their carbon footprint.

In the UAE, Abu Dhabi Future Energy Company (Masdar) has piloted five energy-efficient seawater desalination projects at a testing facility on the Ghantoot coast. The long-term goal is to implement renewable energy-powered desalination plants in the United Arab Emirates, as well as the wider region, and to have a commercial scale facility operating by 2020. Once rolled out, this project is likely to have implications well beyond the Middle East. Elsewhere, island countries including Japan, Taiwan and South Korea have been using variations of desalination technology, which involve sucking up seawater through long pipes running hundreds of metres out to sea so that they gather water from deep under the ocean’s surface. Water from more than 300 metres deep is purer and has more nutrients, making desalination simpler and cheaper because less energy is required to process the seawater.

Desalination technology has played a key role in helping the UAE and other countries in water scarce regions grow their cities and industries. Over the next decades, desalination will also be vital in helping emerging economies develop, although how these countries power their plants will be different. Desalination, when combined with renewable energy and potentially energy storage, will significantly improve the economic viability of processing sea water and make it more environmentally sustainable. This will play a critical role in responding to the growing global challenge of water scarcity.

LCOE has reached its limits  We regularly read about new record lows for the Levelized Cost of Energy (LCOE); such as US$ 1.79 ct/kWh for solar photovoltaic (PV) projects in the Kingdom of Saudi Arabia or US$ 1.97 ct/kWh in India. Those who are more familiar with the subject know that these numbers sometimes represent the levelized cost of energy, and at other times they indicate the anticipated levelized revenues for the energy sold under the terms of an auction. If you dig deeper, you start to understand that this number is based on multiple assumptions: not only about Capex and Opex but also debt and equity levels, the cost and term of financing, the life time of the asset, availability, wind speed and solar irradiation, the period and method of depreciation, residual value, and the exchange rate. Where the number represents levelized revenues, you also need to factor in assumptions about how the offtake agreement is adjusted over time and what the market price for energy will be after this agreement expires. With all these considerations in mind, you may wonder what the value is of an LCOE? Can you rely on the figure; or should you only trust LCOEs when they come from one source, because then at least you can compare one LCOE with another? Or is the LCOE about as insightful as the typical statement in a press release where the new owners proudly announce that their project will supply so and so many households with electricity? Let’s take a step back and ask ourselves if cost per kWh is the right number to look at? Is the underlying assumption that every kWh has the same value correct? Can I use the LCOE index in a world where storage is becoming more and more prevalent? Batteries typically increase the LCOE, but perhaps these higher costs increase the value of the system at the same time? And if so, by how much? We all like a method that allows us to compare different solutions and technologies in a simple way. As long as LCOEs are calculated using the right assumptions, then they provide a straightforward comparison. But we should be cautious. There is an old saying, “what gets measured gets done”. But is a low LCOE what we want to get done, or would we rather demand and supply are matched at the lowest possible cost? Do we want to have security of supply that is sustainable environmentally? If the answers to these three questions are ‘yes’, or even if it is ‘yes’ to just the first question, then we need to go beyond a simple LCOE number. In future, we need to work with a “function” rather than with a single “index”. Our new Cost of Energy Function (COEF) needs to start by capturing the system cost of power generation, and then progressively show how this cost changes, typically increasing, if the generation (supply) profile is adjusted to a demand profile. The resulting curve may well end before full adaptation has been reached as this amount of flexibility may not be possible technically. The demand profile will be a new assumption that is factored into our equations. We may also need to accept that two demand profiles are necessary: one for summer daily demand, another for winter. We will also need to include whether we are considering a base load or a peak load generation source. In addition to generation curves, we can construct demand curves that start with demand today. By creating two curves, we can show the cost of energy efficiency (how much investment would be needed to reduce energy consumption) and the cost of flexibility (how much it would cost to move the point in time when energy is consumed by 30 minutes or one hour, for example). Moving from a LCOE index to a function is not an easy undertaking, and it may well progress in stages. The car industry currently measures gas consumption using different driving profiles, depending on whether it’s in the city, on country roads, or on the highway. Regardless of the question, if we use a function or a group of values that are profile-based, we need to ensure that we all mean the same thing. Here, an independent body or workgroup could play an important role in developing and codifying a workable framework: a framework that captures the complexity of demand and supply, that captures the value of storage, and that helps regulators to set policies because it measures what needs to be done.

Bloomberg’s new European headquarters in London was described as the world’s most sustainable building when it was unveiled last month.

The 3.2 acre site in London’s financial district, designed by architects Foster + Partners, cost an estimated £1bn according to some media reports. The building will use about 70% less water and one third less energy and associated carbon emissions, than an average office building, said Bloomberg, a news and information provider.

The building generates its own power from gas and re-uses “waste heat” to heat the building in the winter and cool it by circulating chilled water in the summer. It captures rainwater on the roof and re-uses it in the building, while its airplane-style “vacuum flush” toilets minimise water use.

“Flaps” on the outside of the building open and close, letting it breathe while reducing noise from outside.

According to Bloomberg, the building scored 98.5% when judged by BREEAM (Building Research Establishment Environmental Assessment Method), a widely-used assessment method for sustainability in buildings.

The new Bloomberg building isn’t an isolated development, of course. It’s the natural progression of an iterative process of learning and incorporating new techniques and materials.

Foster & Partners was also the architect of the first phase of Masdar City – home to one of the world’s largest clusters of high performance buildings. Masdar City has become a “greenprint” for sustainable design, drawing on both passive and active design techniques to minimise water and energy use. While technology has advanced since the project was designed, its capacity to demonstrate the potential of sustainable design remains constant.

10 years later, sustainable urban design is now mainstream and part of business as usual among developed nations. In arid climates such as the Middle East, the impact of sustainability measures can be dramatic. Up to 80% of energy in Middle East countries is consumed by buildings alone – this can be cut by 30% with “quick win”, low cost measures.

It is little wonder that sustainable design is at the heart of ambitious development plans across the region, including Saudi Arabia, which last month announced plans to build a $500 billion city, known as NEOM (short for “new future”), which will get all its power from renewable energy.

Sustainable design can also provide solutions to challenges and natural disasters associated with climate change. In China, for instance, a pilot “sponge cities” project is seeking to minimise the threat of floods through measures such as covering rooftops with plants and permeable pavements that store excess water, as well as the creation of wetland reservoirs. Such ideas could be adopted by flood-prone cities across the world.

Collaboration, partnership and knowledge sharing is vital to ensure that sustainable design (including new technology, approaches to design and engineering) continues to spread. Brick by brick.