Mar 19, 2015

Why Better Energy Storage Matters

Green Tech
Energy Digital Staff
6 min
This article originally appeared in the January 2015 issue of Energy Digital.

This article originally appeared in the January 2015 issue of Energy Digital.

Renewable energy, by nature, is unreliable.

Solar panels require sunlight, wind turbines require wind, hydroelectric requires flowing water and so on. Unfortunately, not all of these are always readily available. In somewhere like Scotland, which is a generally cloudy country, solar power isn’t a preferable choice of renewable energy. California’s drought is wreaking havoc on the hydroelectric industry.

On the other hand, sometimes there can be abundance of sunlight or wind, which results in the production of more energy than needed. Currently, this excess energy is often times not being used and is essentially wasted. This is often a major criticism of renewable energy and one the industry has been working to address for some time.

As it turns out, the solution is a concept we’re all familiar with: storage.

Saving it for Later

While the science and engineering behind energy storage is quite complex, the idea is simple. For example, a solar farm with a storage system–say, a large battery–can save up that extra energy generated during sunnier days and use it on the days on which less energy is generated. This solves much of the problem with the intermittency of renewable energy.

The applications are also extremely broad, with storage serving a purpose in both the commercial and residential sectors. In the residential solar sector, storage is expected to see a tenfold growth by 2018. In part, this is because the incentives to have a home solar storage system are so great. Not only does it allow for energy independence during times of crisis, but even using stored energy daily rather than buying energy from the grid can lead to major cost savings.

“Another thing that can help make the solar plus storage combo attractive sooner is time of use (TOU) pricing,” Zachary Shahan wrote for CleanTechnica. “Electricity demand is greater in the afternoon and early evening. Some utilities have switched to charging more at high-demand times and less at low-demand times, like in the middle of the night. This makes a lot of sense, but it also makes storing electricity generated at lower-demand times, like the morning, and using it at peak demand times more sensible.”

Not all countries will see this major growth, however. There are several major regions that will be the largest drivers of this transition. In particular, Germany, Australia, Italy, and the UK, are expected to account for 40 percent of the growth by 2018, with California and Hawaii expected to be important markets.

Also driving this growth is the falling cost of the batteries themselves, with lithium ion expected to see a major drop in the coming year.

“My personal view is that we underestimate the impact of storage,” John Ryan, an associate secretary of the federal Department of Industry in Australia, said. “We are starting to see it with hybrid vehicles and I think we’ll see bigger changes.”

Imergy Power Systems

One company making strides in the storage of energy is California-based Imergy Power Systems.

Imergy Power specializes in a proprietary, vanadium based flow battery system, which is the most cost-effective energy storage technology available today. The flow batteries store energy in a liquid electrolyte that circulates between tanks, allowing for a simple design that creates a robust and efficient system that can be cycled thousands of times in a year, and charged and discharged completely without impact on its lifespan. This also allows for customizable sizing for the batteries, allowing each storage project to be tailored to its specific needs. Its latest project is the long-term storage battery called the ESP 30, which can store up to 200 kWh of energy. 

Also unique about Imergy’s battery is its utilization of a single element: vanadium. Other batteries, such as a car batter or lithium ion battery, utilize multiple elements. The vanadium can act in four different phases, essentially allowing it to act as two different elements.

“Why that is important is very simple,” Imergy President Tim Hennessy explained. “All batteries die after time. The natural reaction that occurs in the charging and the discharging causes damage to the elements or the structure within the battery. If you leave your car lights on all night, you come back in the morning and you just can’t get that battery to ever recover. The same thing happens if you discharge your cell phone rapidly by taking the battery from 100 to 0 percent very rapidly. You’ll find you don’t get a recovery in the cell battery life.”

Imergy’s Vanadium Advantage

According to Hennessy, the vanadium batter doesn’t have this type of impact because it’s vanadium on both sides.

“In 100 years time,” he said, “whatever you put in there is what you’ll get back. All the bad things that can be thrown at it that we see in the real world can be thrown at it and it will continue to function.”
Vanadium can also be obtained sustainably from waste sources, making it a greener option.

“That’s the Imergy difference,” Hennessy said. “They all require incredibly pure vanadium, around 99.6 percent pure. What we have done is created the same vanadium benefits, but we’ve gone three steps further.”

The first step of that is the reclamation of less pure vanadium from waste such as fly ash or mining slag that can be used in the batteries. This leads to a major decrease in cost without sacrificing of quality. This is also preferable because of its sustainable nature. Also important is the ability of the batteries to operate at high temperatures–up to around 130̊ Fahrenheit–without needing to cool it. Finally, and perhaps most importantly, with Imergy’s battery, there is no degradation, allowing for long-term deployment in more extreme regions.

Hennessy said for storage to be truly successful, it needs to allow for the proper distribution of power during peak times of day, which are generally from 4 to 7 pm. This is demonstrated in what’s called the “Duck Curve,” or the chart showing the peak hours of energy generation and its potential overgeneration. By storing the extra power generated during the day and using it then, it’s possible to reduce demand from the grid and ensure power is distributed evenly, rather than in the shape of a duck.

“You look at distribution by going down to the end users and addressing the issues there,” Hennessy explained, “which cumulatively add up at the top to help the overall grid by reducing the peak demands that the grid faces. That has a massive impact on what we do and what we need as a society.” 

Storing the Anticipation

Imergy’s systems are going in several places around the world, including California and Hawaii. Oncor, another company working on storage solutions in Texas, are also deploying a large-scale project, though it’s up to the public utilities commission in Texas whether it moves forward.

“Is an unprecedented energy storage deployment on the horizon for Texas?” asks Scientific American’s Robert Fares. “That depends on the Public Utility Commission. Regardless, I think it is clear Oncor’s proposal has the potential to fundamentally change how we make and distribute electricity in the future.”

But Forbes contributor Peter Kelly-Detwiler believes that stories such as these storage project deployments won’t be noteworthy for much longer.

“Whether for small systems or large ones, the announcements for projects will accelerate until they are soon no longer newsworthy,” he wrote. “The storage market appears poised to take off with very real and cost-effective solutions.”

In the world of renewable energy, storage very much matters and it’s time to take note.

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May 13, 2021

All but two UK regions failing on school energy efficiency

Dominic Ellis
2 min
Yorkshire & the Humber and the North East are the only UK regions where schools have collectively reduced how much they spend on energy per pupil

Most schools are still "treading water" on implementing energy efficient technology, according to new analysis of Government data from eLight.

Yorkshire & the Humber and the North East are the only regions where schools have collectively reduced how much they spend on energy per pupil, cutting expenditure by 4.4% and 0.9% respectively. Every other region of England increased its average energy expenditure per pupil, with schools in Inner London doing so by as much as 23.5%.

According to The Carbon Trust, energy bills in UK schools amount to £543 million per year, with 50% of a school’s total electricity cost being lighting. If every school in the UK implemented any type of energy efficient technology, over £100 million could be saved each year.

Harvey Sinclair, CEO of eEnergy, eLight’s parent company, said the figures demonstrate an uncomfortable truth for the education sector – namely that most schools are still treading water on the implementation of energy efficient technology. Energy efficiency could make a huge difference to meeting net zero ambitions, but most schools are still lagging behind.

“The solutions exist, but they are not being deployed fast enough," he said. "For example, we’ve made great progress in upgrading schools to energy-efficient LED lighting, but with 80% of schools yet to make the switch, there’s an enormous opportunity to make a collective reduction in carbon footprint and save a lot of money on energy bills. Our model means the entire project is financed, doesn’t require any upfront expenditure, and repayments are more than covered by the energy savings made."

He said while it has worked with over 300 schools, most are still far too slow to commit. "We are urging them to act with greater urgency because climate change won’t wait, and the need for action gets more pressing every year. The education sector has an important part to play in that and pupils around the country expect their schools to do so – there is still a huge job to be done."

North Yorkshire County Council is benefiting from the Public Sector Decarbonisation Scheme, which has so far awarded nearly £1bn for energy efficiency and heat decarbonisation projects around the country, and Craven schools has reportedly made a successful £2m bid (click here).

The Department for Education has issued 13 tips for reducing energy and water use in schools.

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