Grid Scale Energy Storage Solutions For Future Virtualization

Examines grid scale energy storage solutions ranging from pumped hydro, compressed air, thermal storage, advanced batteries, fuel cells and purely electric storage systems.


Renewable energy sources often have a common problem of matching supply with demand, hence the need for energy storage to bridge the gap.  One major component of future VPP (Virtual Power Plants) is energy storage, in the form of battery storage, fuel cells, pumped hydro, flywheels, compressed air or other forms of existing and new technologies.

One promising form of energy storage combines gravity with water where energy is stored in raising heavy weights.  Electrical energy is converted to potential energy during periods of over-supply and then converted back to electricity when demand is greater than supply.

>”A Cutting Edge Variation of Pumped Hydro

Gravity Power, LLC, a privately-held company, based in Southern California (in Goleta, CA just north of Santa Barbara) is developing a novel grid-scale energy storage system for global commercialization called the Gravity Power Module (GPM). Like pumped hydro the working energy carrier is water that is pumped between a high pressure and a low pressure reservoir running a reversible generator/pump assembly to either produce power by drawing down the high pressure reservoir or store it up by pumping water from the low pressure store back into the high pressure store. In this sense it operates on the very same principles – and thus can also benefit from existing capital equipment, such as the reversible hydro generator/pump assemblies for example – as traditional pumped hydro.

Gravity Powers technology circumvents traditional pumped hydro difficulties related to siting, negative environmental impact, huge land demands, permitting, long-lead times and the very large investment required, by burying it all underground…. literally.

The GPM system uses a very large and very dense high mass piston that is suspended in a deep, water-filled shaft. The piston is equipped with sliding seals to prevent leakage around the piston/shaft interface and its immense mass pressurizes the supporting water column beneath it. A high pressure pipe from the bottom of this shaft enables water to be run or pumped through a generator/pump assembly of the same types now used in pumped hydro systems. The low pressure low energy potential water is returned above the piston adding somewhat to its weight and further pressuring the remaining high energy potential water column.

The massive piston moves up and down the shaft, storing and releasing power in a closed sealed cycle. It is compact with a small land footprint and the units can be clustered together into larger groups. It also is environmentally benign, no toxic chemicals or explosive dangers.

I like the scalable nature of this store that makes it suited to incremental growth of capacity. I also like how this energy storage system could be placed very near the big urban areas of greatest need for this kind of electric capacity. The fact that this energy storage system can take advantage of a lot of already existing infrastructure and technical knowhow from the existing pumped hydro sector is a definite advantage.

I would like to see more details on the costs of the boring of the immense vertical shafts; the long term performance metrics of the shaft seals (that would be an expensive repair job I would think. All in all I think this or something like it is a strong contender in the energy storage sector.”<

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Kitimat community prefers LNG projects over the Enbridge pipeline

“We’re not trying to hold out for a better deal,” said Chief Ellis Ross from the Haisla First Nation. “We know the potential for wealth here. We’ve been doing it for 10 years, we know how to negotiate but there’s no real price we can put on an oil spill happening in these waters.”

VPP – New Models for the Distributed Grid Network

National Instruments, LocalGrid, and Toronto Hydro pilot the software-defined, peer-to-peer distributed grid architecture.


>” […] Because each CompactRIO endpoint is inherently flexible, LocalGrid can provide “protocol conversion which we can update dynamically over the air, analytics that we can update to the system, and run multiple applications on the same device,” he said. This is similar in intent to the kind of field-distributed computing capability that Silver Spring Network’s new SilverLink Sensor Network platform and Cisco’s new IOx platform are opening up to partners, but it’s pretty far ahead of the capabilities of the vast majority of today’s grid edge devices.

In fact, in terms of technology that allows interoperability without a lot of expensive and complex pre-integration work, “The existing players do not have solutions that will do this job,” Leigh said. “They’re not fast enough, they’re not open enough, or they don’t have solutions that are cost-effective enough in the distribution space.”

So far, LocalGrid has connected four sites with a combination of solar PV and wind turbine inverters and metering hardware, and is now in the midst of its second phase of developing custom algorithms for tasks such as detecting faults and forecasting solar and wind generation and loads on distribution circuits, Leigh said. These aren’t necessarily huge challenges for Toronto Hydro’s existing IT infrastructure at pilot scale, “But if we were to multiply that across the network, it’s just not feasible to get all that data to be analyzed into a back-end system,” he said.

As for how to expand LocalGrid’s software capabilities to a broader set of grid endpoints, Leigh cited Cisco’s IOx-enabled grid routers as potential future partners. Other big grid vendors like General Electric, ABB and Siemens “are at different stages starting to open up their systems,” he said. “The question that still has to be worked out is how much third-party development can take place on their new systems.”

That’s the same question that Duke has been asking the grid vendor community, via its plans to open its source code and hardware adapter reference designs to the public. The past half-decade has seen open-source grid systems emerge from simulation software and data management tools to a few real-world grid applications, albeit still in the experimental stage. Perhaps the next half-decade will see the open grid edge platform attain real-world status.”<

Virtual Power Plants (VPP): A New Tech Based Utility Model for Renewable Power Integration

Today’s global energy market is in the midst of a paradigm shift, from a model dominated by large centralized power plants owned by big utilities to a mixed bag of so-called distributed energy generation facilities — smaller residential, commercial and industrial power generation systems &mdas


>”Virtual Power Plants

One distributed generation technology with significant growth potential is the virtual power plant (VPP). In the VPP model an energy aggregator gathers a portfolio of smaller generators and operates them as a unified and flexible resource on the energy market or sells their power as system reserve.

VPPs are designed to maximize asset owners’ profits while also balancing the grid. They can match load fluctuations through forecasting, advance metering and computerized control, and can perform real-time optimization of energy resources.

“Virtual power plants essentially represent an ‘Internet of Energy,’ tapping existing grid networks to tailor electricity supply and demand services for a customer,” said Navigant senior analyst Peter Asmus in a market report. The VPP market will grow from less than US $1 billion per year in 2013 to $3.6 billion per year by 2020, according to Navigant’s research — and one reason is that with more variable renewables on the grid flexibility and demand response are becoming more crucial.

Asmus called VPPs “an ideal optimization platform for the coming transformation of the power grid,” adding that both supply and demand flexibility will be increasingly necessary to accommodate fast ramping periods and address corresponding supply forecast errors.

German utility RWE began a VPP in 2012 that now has around 80 MW of capacity. According to Jon-Erik Mantz, commercial director of RWE Energy Services in Germany, in the near future flexibility will become a commodity. Virtual power plants generate additional value from the flexibility they can offer the grid, he said-so, for RWE, “this is why we concentrate on building VPPs.” As large utilities’ market share falls in response to growing self-consumption, he said, utilities can still “be part of a VPP and profit.”

Dr. Thomas Werner, senior key expert in product lifecycle management at Siemens, said that in order to integrate diverse smaller energy sources, “You need an energy management system with good data models which represents energy resources on the one hand and, on the other, the energy market environment.” Werner believes VPPs fulfill these conditions and are the best way to integrate a growing number of power sources into the grid and the market.

“VPPs can be handled like other conventional generation,” he said. “They can target different energy markets and regulatory environments. They can play as important a role as conventional concentrated generation.”

“No Real Competition”

“From my point of view, there is no real competition for the VPP concept,” Werner said, pointing to VPPs’ use of cheap and ubiquitous information and communication technologies, while other technology trends like building energy storage systems incur comparatively heavy costs. VPPs can also avoid expensive installation costs in, for example, a home system, he notes. Self-consumption for home or industrial use is hampered by having to produce “the right amount of power at the right time.”

VPPs can deliver needed energy at peak usage times, and can store any surplus power, giving the energy aggregator more options than would exist in a single power plant. Other advantages include improved power network efficiency and security, cost and risk savings in transmission systems, increased value from existing infrastructure assets and reduced emissions from peaking power plants. And, importantly, VPPs can also enable more efficient integration of renewable energy sources into the grid by balancing their variability.

For example, explains Werner, if one wind power source generates a bit more energy than predicted and another generates a bit less, they will compensate for each other, resulting in a more accurate forecast and making it easier to sell the capacity in the market or to use it in power systems operation.

A VPP can also combine variable renewable power sources with stable, controllable sources such as biomass plants, using the flexibility of the biomass source to smooth out any discrepancy between planned and actual production.”<

Australian Waste to Energy Gasification Plants Secure $50m Financing

See on Scoop.itGreen & Sustainable News

“Australian renewable energy investment firm, Clean Energy Finance Corporation (CEFC) has agreed provide up to AU$50 million ($47 million) in senior debt finance for the development of two waste to energy facilities that will use low temperature gasification in Western Australia.”

Duane Tilden‘s insight:

>”According to CEFC CEO, Oliver Yates waste management has been a growing issue in Australia for all levels of government and with recycling rates remaining fairly constant, the country will need to seek solutions to its increasing dependence on landfill.


The company added that the facilities will generate cost competitive, base load energy and a lower emissions outcome than current grid electricity sources.

The investor also noted that while both projects will be eligible for Australian Renewable Energy Certificates (RECs) for the majority of the energy produced, their financial viability is not reliant on RECs.

The investment is also expected to help to encourage further waste to energy facilities across the country and facilitate access to private sector funding for similar projects in the future which divert waste from landfills, increase recycling rates, recover energy and reduce greenhouse gas emissions.

CEFC said that its finance for the New Energy facilities takes its total investment in waste-to-energy projects to over $150 million, and that it has another $280 million of waste to energy proposals in its project pipeline that would unlock a further $1.0 billion in additional finance.


According to New Energy, its low temperature gasification process ‘cooks’ waste over a 16 to 24 hour period at temperatures of between 600°C and 875°C during which small amounts of air and steam are introduced.

This is said to break the molecules in the waste which are converted into a syngas that contains molecules such as methane with a high energy content.

The syngas is combusted to heat water and produce steam, either for use as either heat or for electrical generation. This secondary oxidation stage is said convert the syngas into water vapour and carbon dioxide.

The exhaust gases are cleaned and filtered, which the company said to neutralises acidic gases such as sulphur dioxide, as well as particulates and heavy metals. It is then released to the atmosphere.”<


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