Navigant Research Blog

Do Water and Electricity Mix?

— July 21, 2016

Plant - WaterThe water-energy nexus is the interaction between energy, water, and all the aspects of generation and distribution that are involved with each. Many times, this nexus is used to describe the amount of energy used to distribute water and wastewater between water treatment facilities and end uses. This energy use is by no means small. In the United States, energy generated for water ranges from around 4% to 19%; California alone consumes 19% of its electricity for water and wastewater. Variations in energy generation are caused by geographic differences; hilly regions need to expend more energy to pump water across variations in altitude, and arid areas pump source water from aquifers deep underground.

Another aspect of the water-energy nexus is the amount of water it takes to produce electricity. Certain generation types (such as hydroelectric) have an obvious liquid component, but others are less apparent. New innovations in renewable energy, while still consuming water, help to preserve the resource by utilizing more region-specific energies.

A Flood of Electricity Generation

In Hawaii, an ocean thermal energy conversion (OTEC) plant recently began operations. This OTEC plant draws in warm surface water from the ocean, vaporizing ammonia and spinning a turbine, which generates electricity. The ammonia is condensed by water extracted from deep in the ocean. Other types of OTEC plants do not use ammonia at all, but utilize vaporized ocean water to power the turbine. This is the first plant of its kind in the world, though it is worth noting that the United States has been researching OTEC technologies since 1974. Makai Ocean Engineering and the Hawaii Natural Energy Institute developed this 100 kW facility as a way to test the OTEC process, and the plant produces enough energy to power 120 Hawaiian homes for a year.

For cities farther from the water, solar power might seem like the way to go. However, to get the most out of solar, many plant operators are turning to auxiliary steam components. For example, the Ivanpah Solar Power Facility in the Mojave Desert of California utilizes heliostat mirrors to focus sunlight on solar power towers. These towers are heated by the solar energy, and steam is created to drive a steam turbine. The combination of steam power and photovoltaics makes this plant one of the largest solar installations at 377 MW capacity. In addition, its air cooling system means that other than the water used to generate energy, the plant uses 90% less water than other solar thermal technologies with wet cooling systems. However, there are drawbacks to solar power at this concentration. On May 19, 2016, one of the solar generating towers at Ivanpah caught fire due to improperly tracking mirrors that focused sunlight on the wrong part of the tower. There have also been reports of effects on wildlife, such as birds and tortoises. The issues in the development of high intensity renewable energy must be ironed out before these types of plants become widespread.

Renewable energy is important, and not just for the conservation of fossil fuels. Well-integrated renewable energy will utilize the natural resources of the region to produce sufficient electricity without wasting scarce ones. Traditional electricity production uses large quantities of water, but renewables (even those designed specifically to utilize water) can help conserve this. Producing energy may be a very water-intensive process, but many innovations in electricity production hold the promise that this market is becoming less thirsty.


Solar in the Sahara

— December 7, 2015

Set to become the largest concentrated solar power (CSP) plant in the world, Morocco commissioned the first phase of its Noor-Ouarzazate project in November 2015. This 160 MW installation is just the first of four projects that will constitute the larger 580 MW plant. Located on the edges of the Sahara Desert in Ouarzazate, this project aims to ultimately provide power to up to one million people. Large-scale solar projects such as this can provide an array of benefits to nations across the Middle East & Africa. Along with providing reliable electricity access to developing countries, these types of clean technology projects may help mitigate some of the tension and conflict that persists throughout the region.

Rather than utilizing traditional PV technology, the first three projects will use CSP through parabolic mirrors and a trough system to track the sun across the sky during the day. CSP also comes with the benefit of thermal storage, allowing for the prospect of 24/7 solar energy. This will be supported further by the second phase of the project, Noor 2 (200 MW) and Noor 3 (150 MW), set to come online in 2017. The third phase will consist of a PV power station. This complex will be largest CSP plant in the world upon completion, marking a significant milestone as countries in the region begin to adopt solar into their energy portfolios.

Morocco is taking advantage of any opportunities where the Sahara is concerned. The world’s deserts receive enough solar energy in 6 hours to meet the power demands of humanity for an entire year. How to harness and distribute this energy in a cost-effective manner is a significant challenge. Morocco has been able to pursue this project through a mix of political will and falling solar costs. The Moroccan government is choosing to view climate change as an opportunity and ultimately hopes to use the Noor complex as a means to export electricity across the Middle East and Europe. This path toward energy independence is critical in a region where climate security is expected to pose a major problem in the future. Should this project prove successful, it can provide a template for surrounding nations as they begin their forays into solar. According to the University of Oxford Middle East energy expert Justin Dargin, large-scale integration of renewable energy could significantly reduce the budgetary outlays of countries in the Middle East & Africa, allowing increased funding for social services, infrastructure, and more. This reallocation of funds could be used to address some of the socioeconomic demands highlighted during the Arab Spring.

Morocco has set an ambitious target of generating 42% of its electricity using clean energy sources by 2020. Whether fellow countries in the region will follow suit with similar environmental initiatives is yet to be seen, but the Noor complex is a significant step in advancing large-scale solar integration across the region.


Solar Lessons from the North of Chile

— October 30, 2015

Northern Chile is dominated by the Atacama Desert, and other than its large mining industry, the location is otherwise isolated. To supply this area with electricity, Chile established a local grid called Sistema Interconectado del Norte Grande (SING) that is segregated from the main grid, known as Sistema Interconectado Central (SIC).

Traditionally, electricity generation in the SING network relied on relatively expensive imports of coal, natural gas (NG), and diesel. Of the 4.97 GW of installed capacity in 2014, coal represented 42.2% and NG 47.5%. As solar energy prices dropped, the region became a hot spot for solar developers because it offered a perfect combination of high electricity prices in an area with the world’s leading insulation levels. A significant number of developers pulled the trigger and began the construction of their plants, planning to sign power purchase agreements once the project was commissioned.

The problem is that every company had the same idea at the same time. Solar projects have mushroomed in the past year. By October 2015, SING had 157 MW of installed solar capacity, 80% of which was commissioned in 2015. Solar now makes up 3% of the total generation capacity, and that was before the commissioning of First Solar’s 141 MW Luz del Norte plant, which will be the largest in Latin America. This plant is in the late stages of the construction process and it is expected to begin operations before the end of 2015.

Impact on Electricity Prices

The impact of new solar capacity on daytime wholesale electricity prices has been staggering. The average hourly wholesale electricity price in October 2015 dropped 42% between 8 a.m. and 9 a.m., whereas it fell only 10% in 2014 and 16% in 2013. In October 2014, prices averaged $54/MWh between 9 a.m. and 7 p.m. versus $67/MWh throughout the rest of the day. By October 2015, the average day-to-night differential widened to $48/MWh between 9 a.m. and 7 p.m. versus $78/MWh in the rest of the day.

Solar developers now find themselves in a predicament. Daytime electricity prices are expected to fall even further as the projects currently under construction come online, creating a death spiral that would threaten the economics of all plants and the sustainability of the whole industry. But no company wants to throw in the towel and write off all of its investment to date. The question is, who will move first?


Nefarious Solar Applications

— October 14, 2015

Beyond generating clean power, solar PV’s unique attributes as a distributed technology result in a variety of applications outside of the major markets of residential, commercial, and utility-scale power plants. Applications include solar lanterns for remote communities in Sub-Saharan Africa and remote microgrids in India; additional applications include powering satellites, the International Space Station, and Mars rovers. Solar can even be applied to fashionable widgets—fans, cellphone chargers, backpacks, and the like.

But what about the nefarious or even sinister opportunities enabled by solar PV? The following are a list of applications that could fall under that list:

  • Solar Bitcoin harvesting: With rough estimates at 1 GWh per day, several articles and videos have been posted recently about using solar PV for powering the mining of the Bitcoin. A so-called cryptocurrency created in 2009, Bitcoin allows users to pay for goods and services anonymously. This can range from pizza (not so nefarious) to drugs—and increasingly, weapons and ransom. For now, at least, bitharvesters have a strong incentive to utilize renewables, albeit on a micro scale, for the same reason that data centers do: power consumption is one of the main costs, and reliability is particularly important.
  • Solar cannabis: With Colorado, Oregon, and Washington legalizing (and heavily taxing) marijuana for recreational use, entrepreneurs—ranging from DIYers to large-scale agribusinesses—are looking to reduce the large amount of electricity consumed by grow rooms. Breakthroughs in LED pricing have made a major impact on the bottom line—not only for lighting common areas, but also for grow rooms. Grow rooms require lights, heaters, fans, and other appliances that consume large amounts of electricity. A 2012 peer-reviewed study found wide variations in marijuana plant production, and estimated that the large energy requirements of these facilities had lighting levels similar to those of hospital operating rooms (which use electricity at 60 times the rate of a modern home). With many U.S. states moving toward legalization in the future, grow operations will be able to transfer to outdoor facilities and reduce indoor energy demand.
  • Solar drones: Since the solar-powered plane Solar Impulse completed its crossing of the Pacific, more attention has been paid toward how solar powers unmanned aerial vehicles (UAVs). For example, in 2010, Boeing won an $89 million contract to build the SolarEagle unmanned reconnaissance aircraft, designed to fly continuously for 5 years at 65,000 feet. (Boeing had previously built Phantom Eye, a hydrogen powered aircraft that could stay aloft at 65,000 feet for four days.) Airbus has built a competing solar drone, Zephyr, which can carry a 1,000 pound payload. (Facebook and Google have recently launched solar drones themselves, designed for beaming the Internet to remote regions of the world, but fall into the not-so-nefarious category.)

The continued cost reductions of solar make once cost-prohibitive applications more realistic—regardless of their potentially illicit uses.


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